ash
ash v2.7.1

View Source Ash.Resource.Dsl (ash v2.7.1)

The built in resource DSL.

dsl-documentation

 DSL Documentation

index

 Index

docs

 Docs

attributes

 attributes

A section for declaring attributes on the resource.

Examples:

attributes do
  uuid_primary_key :id

  attribute :first_name, :string do
    allow_nil? false
  end

  attribute :last_name, :string do
    allow_nil? false
  end

  attribute :email, :string do
    allow_nil? false

    constraints [
      match: ~r/^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+.[a-zA-Z0-9-.]+$/
    ]
  end

  attribute :type, :atom do
    constraints [
      one_of: [:admin, :teacher, :student]
    ]
  end

  create_timestamp :inserted_at
  update_timestamp :updated_at
end

Imports:

attribute

 attribute

Declares an attribute on the resource.

Examples:

attribute :name, :string do
  allow_nil? false
end

  • :name (atom/0) - The name of the attribute.

  • :type (term/0) - The type of the attribute. See Ash.Type for more.

  • :constraints (keyword/0) - Constraints to provide to the type when casting the value. For more information see the specific type's documentation, for general type information see Ash.Type and for practical example see the constraints topic.

  • :description (String.t/0) - An optional description for the attribute.

  • :sensitive? (boolean/0) - Whether or not the attribute value contains sensitive information, like PII. Using this option will cause the attribute to be ** Redacted ** from the resource when logging or inspecting. See the Security guide for more. The default value is false.

  • :source (atom/0) - If the field should be mapped to a different name in the data layer. Support varies by data layer.

  • :always_select? (boolean/0) - Whether or not to ensure this attribute is always selected when reading from the database.
    When this option is true and performing a read action, the attribute will always be selected even if it was explicitly selected out of the query. For example say there is a resource with two attributes :foo and :bar. Say :foo has always_select? true set. The query Ash.Query.select(MyResource, [:bar]) would return both :foo and :bar even though :foo was not selected in the query. The default value is false.

  • :primary_key? (boolean/0) - Whether the attribute is the primary key. Composite primary key is also possible by using primary_key? true in more than one attribute. If primary_key? is true, allow_nil? must be false. The default value is false.

  • :allow_nil? (boolean/0) - Whether or not the attribute can be set to nil. If nil value is given error is raised. The default value is true.

  • :generated? (boolean/0) - Whether or not the value may be generated by the data layer. The default value is false.

  • :writable? (boolean/0) - Whether or not the value can be written to. If writable? false then attribute is read-only and cannot be written to even when creating a record. This can be overridden with Ash.Changeset.force_change_attribute/3. The default value is true.

  • :private? (boolean/0) - If private? true then attribute is read-only and cannot be written to even when creating a record. Additionally it tells other extensions (e.g. AshJsonApi or AshGraphql) not to expose these attributes through the API. The value of the attribute can be overridden with Ash.Changeset.force_change_attribute/3.
    See the security guide for more. The default value is false.

  • :default - A value to be set on all creates, unless a value is being provided already.

  • :update_default - A value to be set on all updates, unless a value is being provided already.

  • :filterable? - Whether or not the attribute can be referenced in filters. Can be used to prevent filtering on large text columns with no indexing. The default value is true.

  • :match_other_defaults? (boolean/0) - Ensures that other attributes that use the same "lazy" default (a function or an mfa), use the same default value. Has no effect unless default is a zero argument function. For example, create and update timestamps use this option, and have the same lazy function &DateTime.utc_now/0, so they get the same value, instead of having slightly different timestamps. The default value is false.

create_timestamp

 create_timestamp

Declares a non-writable attribute with a create default of &DateTime.utc_now/0

Accepts all the same options as Ash.Resource.Dsl.attributes.attribute, except it sets the following different defaults:

  writable? false
  private? true
  default &DateTime.utc_now/0
  match_other_defaults? true
  type Ash.Type.UTCDatetimeUsec
  allow_nil? false

Examples:

create_timestamp :inserted_at
  • :name (atom/0) - The name of the attribute.

update_timestamp

 update_timestamp

Declares a non-writable attribute with a create and update default of &DateTime.utc_now/0

Accepts all the same options as Ash.Resource.Dsl.attributes.attribute, except it sets the following different defaults:

  writable? false
  private? true
  default &DateTime.utc_now/0
  match_other_defaults? true
  update_default &DateTime.utc_now/0
  type Ash.Type.UTCDatetimeUsec
  allow_nil? false

Examples:

update_timestamp :inserted_at
  • :name (atom/0) - The name of the attribute.

integer_primary_key

 integer_primary_key

Declares a generated, non writable, non-nil, primary key column of type integer.

Generated integer primary keys must be supported by the data layer.

Accepts all the same options as Ash.Resource.Dsl.attributes.attribute, except for allow_nil?, but it sets the following different defaults:

  writable? false
  primary_key? true
  generated? true
  type :integer

Examples:

integer_primary_key :id
  • :name (atom/0) - The name of the attribute.

uuid_primary_key

 uuid_primary_key

Declares a non writable, non-nil, primary key column of type uuid, which defaults to Ash.UUID.generate/0.

Accepts all the same options as Ash.Resource.Dsl.attributes.attribute, except for allow_nil?, but it sets the following different defaults:

  writable? false
  default &Ash.UUID.generate/0
  primary_key? true
  generated? true
  type :uuid

Examples:

uuid_primary_key :id
  • :name (atom/0) - The name of the attribute.

relationships

 relationships

A section for declaring relationships on the resource.

Relationships are a core component of resource oriented design. Many components of Ash will use these relationships. A simple use case is loading relationships (done via the Ash.Query.load/2).

See the relationships guide for more.

Examples:

relationships do
  belongs_to :post, MyApp.Post do
    primary_key? true
  end

  belongs_to :category, MyApp.Category do
    primary_key? true
  end
end

relationships do
  belongs_to :author, MyApp.Author

  many_to_many :categories, MyApp.Category do
    through MyApp.PostCategory
    destination_attribute_on_join_resource :category_id
    source_attribute_on_join_resource :post_id
  end
end

relationships do
  has_many :posts, MyApp.Post do
    destination_attribute :author_id
  end

  has_many :composite_key_posts, MyApp.CompositeKeyPost do
    destination_attribute :author_id
  end
end

Imports:

has_one

 has_one

Declares a has_one relationship. In a relational database, the foreign key would be on the other table.

Generally speaking, a has_one also implies that the destination table is unique on that foreign key.

See the relationships guide for more.

Examples:

# In a resource called `Word`
has_one :dictionary_entry, DictionaryEntry do
  source_attribute :text
  destination_attribute :word_text
end

  • :manual - A module that implements Ash.Resource.ManualRelationship. Also accepts a 2 argument function that takes the source records and the context.

  • :no_attributes? (boolean/0) - If true, all existing entities are considered related, i.e this relationship is not based on any fields, and source_attribute and destination_attribute are ignored.
    This can be very useful when combined with multitenancy. Specifically, if you have a tenant resource like Organization, you can use no_attributes? to do things like has_many :employees, Employee, no_attributes?: true, which lets you avoid having an unnecessary organization_id field on Employee. The same works in reverse: has_one :organization, Organization, no_attributes?: true allows relating the employee to their organization.
    Some important caveats here:

    1. You can still manage relationships from one to the other, but "relate" and "unrelate" will have no effect, because there are no fields to change.
    2. Loading the relationship on a list of resources will not behave as expected in all circumstances involving multitenancy. For example, if you get a list of Organization and then try to load employees, you would need to set a single tenant on the load query, meaning you'll get all organizations back with the set of employees from one tenant. This could eventually be solved, but for now it is considered an edge case.

  • :allow_nil? (boolean/0) - Marks the relationship as required. Has no effect on validations, but can inform extensions that there will always be a related entity. The default value is true.

  • :name (atom/0) - The name of the relationship

  • :destination (atom/0) - The destination resource

  • :description (String.t/0) - An optional description for the relationship

  • :destination_attribute (atom/0) - The attribute on the related resource that should match the source_attribute configured on this resource.

  • :validate_destination_attribute? (boolean/0) - Whether or not to validate that the destination field exists on the destination resource The default value is true.

  • :source_attribute (atom/0) - The field on this resource that should match the destination_attribute on the related resource. The default value is :id.

  • :relationship_context (term/0) - Context to be set on any queries or changesets generated for managing or querying this relationship.

  • :private? (boolean/0) - Whether or not the relationship will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql
    See the security guide for more. The default value is false.

  • :not_found_message (String.t/0) - A message to show if there is a conflict with this relationship in the database on update or create, or when managing relationships.

  • :writable? (boolean/0) - Whether or not the relationship may be managed. The default value is true.

  • :read_action (atom/0) - The read action on the destination resource to use when loading data and filtering.

  • :api (atom/0) - The API module to use when working with the related entity.

  • :filter (term/0) - A filter to be applied when reading the relationship.

  • :filterable? (boolean/0) - If set to false, the relationship will not be usable in filters. The default value is true.

  • :sort (term/0) - A sort statement to be applied when loading the relationship.

  • :could_be_related_at_creation? (boolean/0) - Whether or not related values may exist for this relationship at creation. The default value is false.

  • :violation_message (String.t/0) - A message to show if there is a conflict with this relationship in the database on destroy. For example, if a record is deleted while related records still exist (and aren't configured to cascade deletes)

has_many

 has_many

Declares a has_many relationship. There can be any number of related entities.

See the relationships guide for more.

Examples:

# In a resource called `Word`
has_many :definitions, DictionaryDefinition do
  source_attribute :text
  destination_attribute :word_text
end

  • :manual - A module that implements Ash.Resource.ManualRelationship. Also accepts a 2 argument function that takes the source records and the context.

  • :no_attributes? (boolean/0) - If true, all existing entities are considered related, i.e this relationship is not based on any fields, and source_attribute and destination_attribute are ignored.
    This can be very useful when combined with multitenancy. Specifically, if you have a tenant resource like Organization, you can use no_attributes? to do things like has_many :employees, Employee, no_attributes?: true, which lets you avoid having an unnecessary organization_id field on Employee. The same works in reverse: has_one :organization, Organization, no_attributes?: true allows relating the employee to their organization.
    Some important caveats here:

    1. You can still manage relationships from one to the other, but "relate" and "unrelate" will have no effect, because there are no fields to change.
    2. Loading the relationship on a list of resources will not behave as expected in all circumstances involving multitenancy. For example, if you get a list of Organization and then try to load employees, you would need to set a single tenant on the load query, meaning you'll get all organizations back with the set of employees from one tenant. This could eventually be solved, but for now it is considered an edge case.

  • :name (atom/0) - The name of the relationship

  • :destination (atom/0) - The destination resource

  • :description (String.t/0) - An optional description for the relationship

  • :destination_attribute (atom/0) - The attribute on the related resource that should match the source_attribute configured on this resource.

  • :validate_destination_attribute? (boolean/0) - Whether or not to validate that the destination field exists on the destination resource The default value is true.

  • :source_attribute (atom/0) - The field on this resource that should match the destination_attribute on the related resource. The default value is :id.

  • :relationship_context (term/0) - Context to be set on any queries or changesets generated for managing or querying this relationship.

  • :private? (boolean/0) - Whether or not the relationship will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql
    See the security guide for more. The default value is false.

  • :not_found_message (String.t/0) - A message to show if there is a conflict with this relationship in the database on update or create, or when managing relationships.

  • :writable? (boolean/0) - Whether or not the relationship may be managed. The default value is true.

  • :read_action (atom/0) - The read action on the destination resource to use when loading data and filtering.

  • :api (atom/0) - The API module to use when working with the related entity.

  • :filter (term/0) - A filter to be applied when reading the relationship.

  • :filterable? (boolean/0) - If set to false, the relationship will not be usable in filters. The default value is true.

  • :sort (term/0) - A sort statement to be applied when loading the relationship.

  • :could_be_related_at_creation? (boolean/0) - Whether or not related values may exist for this relationship at creation. The default value is false.

  • :violation_message (String.t/0) - A message to show if there is a conflict with this relationship in the database on destroy. For example, if a record is deleted while related records still exist (and aren't configured to cascade deletes)

many_to_many

 many_to_many

Declares a many_to_many relationship. Many to many relationships require a join resource.

A join resource is a resource that consists of a relationship to the source and destination of the many to many.

See the relationships guide for more.

Examples:

# In a resource called `Word`
many_to_many :books, Book do
  through BookWord
  source_attribute :text
  source_attribute_on_join_resource :word_text
  destination_attribute :id
  destination_attribute_on_join_resource :book_id
end

# And in `BookWord` (the join resource)
belongs_to :book, Book, primary_key?: true, allow_nil?: false
belongs_to :word, Word, primary_key?: true, allow_nil?: false

  • :source_attribute_on_join_resource (atom/0) - Required. The attribute on the join resource that should line up with source_attribute on this resource.

  • :destination_attribute_on_join_resource (atom/0) - Required. The attribute on the join resource that should line up with destination_attribute on the related resource.

  • :through (atom/0) - Required. The resource to use as the join resource.

  • :join_relationship (atom/0) - The has_many relationship to the join resource. Defaults to <relationship_name>_join_assoc

  • :name (atom/0) - The name of the relationship

  • :destination (atom/0) - The destination resource

  • :description (String.t/0) - An optional description for the relationship

  • :destination_attribute (atom/0) - The attribute on the related resource that should match the source_attribute configured on this resource. The default value is :id.

  • :validate_destination_attribute? (boolean/0) - Whether or not to validate that the destination field exists on the destination resource The default value is true.

  • :source_attribute (atom/0) - The field on this resource that should match the destination_attribute on the related resource. The default value is :id.

  • :relationship_context (term/0) - Context to be set on any queries or changesets generated for managing or querying this relationship.

  • :private? (boolean/0) - Whether or not the relationship will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql
    See the security guide for more. The default value is false.

  • :not_found_message (String.t/0) - A message to show if there is a conflict with this relationship in the database on update or create, or when managing relationships.

  • :writable? (boolean/0) - Whether or not the relationship may be managed. The default value is true.

  • :read_action (atom/0) - The read action on the destination resource to use when loading data and filtering.

  • :api (atom/0) - The API module to use when working with the related entity.

  • :filter (term/0) - A filter to be applied when reading the relationship.

  • :filterable? (boolean/0) - If set to false, the relationship will not be usable in filters. The default value is true.

  • :sort (term/0) - A sort statement to be applied when loading the relationship.

  • :could_be_related_at_creation? (boolean/0) - Whether or not related values may exist for this relationship at creation. The default value is false.

  • :violation_message (String.t/0) - A message to show if there is a conflict with this relationship in the database on destroy. For example, if a record is deleted while related records still exist (and aren't configured to cascade deletes)

belongs_to

 belongs_to

Declares a belongs_to relationship. In a relational database, the foreign key would be on the source table.

This creates a field on the resource with the corresponding name and type, unless define_attribute?: false is provided.

See the relationships guide for more.

Examples:

# In a resource called `Word`
belongs_to :dictionary_entry, DictionaryEntry do
  source_attribute :text,
  destination_attribute :word_text
end

  • :primary_key? (boolean/0) - Whether the generated attribute is, or is part of, the primary key of a resource. The default value is false.

  • :allow_nil? (boolean/0) - Whether this relationship must always be present, e.g: must be included on creation, and never removed (it may be modified). The generated attribute will not allow nil values. The default value is true.

  • :attribute_writable? (boolean/0) - Whether the generated attribute will be marked as public & writable. The default value is false.

  • :define_attribute? (boolean/0) - If set to false an attribute is not created on the resource for this relationship, and one must be manually added in attributes, invalidating many other options. The default value is true.

  • :attribute_type (term/0) - The type of the generated created attribute. See Ash.Type for more. The default value is :uuid.

  • :name (atom/0) - The name of the relationship

  • :destination (atom/0) - The destination resource

  • :description (String.t/0) - An optional description for the relationship

  • :destination_attribute (atom/0) - The attribute on the related resource that should match the source_attribute configured on this resource. The default value is :id.

  • :validate_destination_attribute? (boolean/0) - Whether or not to validate that the destination field exists on the destination resource The default value is true.

  • :source_attribute (atom/0) - The field on this resource that should match the destination_attribute on the related resource. - Defaults to <name>_id

  • :relationship_context (term/0) - Context to be set on any queries or changesets generated for managing or querying this relationship.

  • :private? (boolean/0) - Whether or not the relationship will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql
    See the security guide for more. The default value is false.

  • :not_found_message (String.t/0) - A message to show if there is a conflict with this relationship in the database on update or create, or when managing relationships.

  • :writable? (boolean/0) - Whether or not the relationship may be managed. The default value is true.

  • :read_action (atom/0) - The read action on the destination resource to use when loading data and filtering.

  • :api (atom/0) - The API module to use when working with the related entity.

  • :filter (term/0) - A filter to be applied when reading the relationship.

  • :filterable? (boolean/0) - If set to false, the relationship will not be usable in filters. The default value is true.

  • :sort (term/0) - A sort statement to be applied when loading the relationship.

  • :violation_message (String.t/0) - A message to show if there is a conflict with this relationship in the database on destroy. For example, if a record is deleted while related records still exist (and aren't configured to cascade deletes)

actions

 actions

A section for declaring resource actions.

All manipulation of data through the underlying data layer happens through actions. There are four types of action: create, read, update, and destroy. You may recognize these from the acronym CRUD. You can have multiple actions of the same type, as long as they have different names. This is the primary mechanism for customizing your resources to conform to your business logic. It is normal and expected to have multiple actions of each type in a large application.

  • create
    • change
    • validate
    • argument
    • metadata
  • read
    • argument
    • prepare
    • pagination
    • metadata
  • update
    • change
    • validate
    • metadata
    • argument
  • destroy
    • change
    • validate
    • metadata
    • argument

Examples:

actions do
  create :signup do
    argument :password, :string
    argument :password_confirmation, :string
    validate confirm(:password, :password_confirmation)
    change {MyApp.HashPassword, []} # A custom implemented Change
  end

  read :me do
    # An action that auto filters to only return the user for the current user
    filter [id: actor(:id)]
  end

  update :update do
    accept [:first_name, :last_name]
  end

  destroy do
    change set_attribute(:deleted_at, &DateTime.utc_now/0)
    # This tells it that even though this is a delete action, it
    # should be treated like an update because `deleted_at` is set.
    # This should be coupled with a `base_filter` on the resource
    # or with the read actions having a `filter` for `is_nil: :deleted_at`
    soft? true
  end
end

  • :defaults - Creates a simple action of each specified type, with the same name as the type. These actions will be the primary actions, unless you've declared a different action of the same type that is explicitly set as primary.
    By default, resources have no default actions. Embedded resources, however, have a default of all resource types.

  • :default_accept (list of atom/0) - A default value for the accept option for each action. Defaults to all public attributes.

create

 create

Declares a create action. For calling this action, see the Ash.Api documentation.

Examples:

create :register do
  primary? true
end

  • :allow_nil_input (list of atom/0) - A list of attributes that would normally be required, but should not be for this action. They will still be validated just before the record is created.

  • :manual - Override the creation behavior. See the manual action guides for more. Accepts a module or module and opts, or a function that takes the changeset and context.
    See the manual actions guide for more.

  • :upsert? (boolean/0) - Wether or not this action is always an upsert.
    If this is false, the action can still be used as an upsert by passing upsert?: true when using it. This option forces all uses of this action to be treated as an upsert The default value is false.

  • :upsert_identity (atom/0) - The identity to use for the upsert. Cannot be overriden by the caller. Ignored if upsert? is not set to true. The default value is false.

  • :name (atom/0) - Required. The name of the action

  • :primary? (boolean/0) - Whether or not this action should be used when no action is specified by the caller. The default value is false.

  • :description (String.t/0) - An optional description for the action

  • :transaction? (boolean/0) - Whether or not the action should be run in transactions. Reads default to false, while create/update/destroy actions default to true.
    Has no effect if the data layer does not support transactions, or if that data layer is already in a transaction.

  • :touches_resources (list of atom/0) - A list of resources that the action may touch, used when building transactions.

  • :accept - The list of attributes to accept. Defaults to all attributes on the resource

  • :delay_global_validations? (boolean/0) - If true, global validations will be done in a before_action hook, regardless of their configuration on the resource. The default value is false.

  • :skip_global_validations? (boolean/0) - If true, global validations will be skipped. Useful for manual actions. The default value is false.

  • :reject - A list of attributes not to accept. This is useful if you want to say 'accept all but x'
    If this is specified along with accept, then everything in the accept list minus any matches in the reject list will be accepted.

  • :require_attributes (list of atom/0) - A list of attributes that would normally allow_nil?, to require for this action.
    No need to include attributes that already do not allow nil?

  • :error_handler - Sets the error handler on the changeset. See Ash.Changeset.handle_errors/2 for more

  • :manual? (boolean/0) - Instructs Ash to skip the actual update/create/destroy step at the data layer. See the manual action guides for more.
    See the manual actions guide for more.

change

A change to be applied to the changeset.

See Ash.Resource.Change for more.

Examples:

change relate_actor(:reporter)
change {MyCustomChange, :foo}

  • :only_when_valid? (boolean/0) - If the change should only be run on valid changes. By default, all changes are run unless stated otherwise here. The default value is false.

  • :description (String.t/0) - An optional description for the change

  • :change - Required. The module and options for a change. Also accepts a function that takes the changeset and the context.
    See Ash.Resource.Change.Builtins for more.

  • :where - Validations that should pass in order for this validation to apply. These validations failing will not invalidate the changes, but instead just result in this change being ignored. Also accepts functions take the changeset. The default value is [].

validate

Declares a validation to be applied to the changeset.

See Ash.Resource.Validation for more.

Examples:

validate changing(:email)

  • :validation - Required. The module (or module and opts) that implements the Ash.Resource.Validation behaviour. Also accepts a one argument function that takes the changeset.

  • :where - Validations that should pass in order for this validation to apply. These validations failing will not invalidate the changes, but will instead result in this validation being ignored. Accepts a module, module and opts, or a 1 argument function that takes the changeset. The default value is [].

  • :only_when_valid? (boolean/0) - If the validation should only run on valid changes. Useful for expensive validations or validations that depend on valid data. The default value is false.

  • :message (String.t/0) - If provided, overrides any message set by the validation error

  • :description (String.t/0) - An optional description for the validation

  • :before_action? (boolean/0) - If set to true, the validation will be run in a before_action hook The default value is false.

argument

Declares an argument on the action

Examples:

argument :password_confirmation, :string

  • :name (atom/0) - Required. The name of the argument

  • :type (term/0) - Required. The type of the argument. See Ash.Type for more.

  • :description (String.t/0) - An optional description for the argument.

  • :constraints (keyword/0) - Constraints to provide to the type when casting the value. For more information see the specific type's documentation, for general type information see Ash.Type and for practical example see the constraints topic. The default value is [].

  • :allow_nil? (boolean/0) - Whether or not the argument value may be nil (or may be not provided) If nil value is given error is raised. The default value is true.

  • :private? (boolean/0) - Whether or not the argument should be suppliable by the client. The default value is false.

  • :sensitive? (boolean/0) - Whether or not the argument value contains sensitive information, like PII. Using this option will cause the argument to be ** Redacted ** from the resource when logging or inspecting. See the security guide for more. The default value is false.

  • :default (term/0) - The default value for the argument to take. It can be a zero argument function e.g &MyMod.my_fun/0 or a value

metadata

A special kind of attribute that is only added to specific actions. Nothing sets this value, it must be set in a custom change via Ash.Resource.Info.put_metadata/3.

Examples:

metadata :api_token, :string, allow_nil?: false

metadata :operation_id, :string, allow_nil?: false

  • :name (atom/0) - Required. The name of the metadata

  • :type (term/0) - Required. The type of the metadata. See Ash.Type for more.

  • :constraints (keyword/0) - Type constraints on the metadata The default value is [].

  • :description (String.t/0) - An optional description for the metadata.

  • :allow_nil? (boolean/0) - Whether or not the metadata may return nil The default value is true.

  • :default (term/0) - The default value for the metadata to take. It can be a zero argument function e.g &MyMod.my_fun/0 or a value

read

 read

Declares a read action. For calling this action, see the Ash.Api documentation.

Examples:

read :read_all do
  primary? true
end

  • :filter (term/0) - A filter template that will be applied whenever the action is used. See Ash.Filter for more on templates

  • :manual - Delegates running of the query to the provided module. Accepts a module or module and opts, or a function that takes the changeset and context.
    See the manual actions guide for more.

  • :get? (boolean/0) - Expresses that this action innately only returns a single result. Can be used by extensions to validate that you have not hooked something up that expects a list to an action that can only return one thing. Used by the code interface when defining functions for read actions.
    See the code interface guide for more. The default value is false.

  • :modify_query - Allows direct manipulation of the data layer query via an MFA.
    The ash query and the data layer query will be provided as additional arguments. The result must be {:ok, new_data_layer_query} | {:error, error}.
    Here be dragons.

  • :get_by - A helper to automatically generate a "get by X" action.
    Using this option will set get? to true, add arguments for each of the specified fields, and add a filter to the underlying query for each of the arguments. The default value is nil.

  • :name (atom/0) - Required. The name of the action

  • :primary? (boolean/0) - Whether or not this action should be used when no action is specified by the caller. The default value is false.

  • :description (String.t/0) - An optional description for the action

  • :transaction? (boolean/0) - Whether or not the action should be run in transactions. Reads default to false, while create/update/destroy actions default to true.
    Has no effect if the data layer does not support transactions, or if that data layer is already in a transaction.

  • :touches_resources (list of atom/0) - A list of resources that the action may touch, used when building transactions.

argument

Declares an argument on the action

Examples:

argument :password_confirmation, :string

  • :name (atom/0) - Required. The name of the argument

  • :type (term/0) - Required. The type of the argument. See Ash.Type for more.

  • :description (String.t/0) - An optional description for the argument.

  • :constraints (keyword/0) - Constraints to provide to the type when casting the value. For more information see the specific type's documentation, for general type information see Ash.Type and for practical example see the constraints topic. The default value is [].

  • :allow_nil? (boolean/0) - Whether or not the argument value may be nil (or may be not provided) If nil value is given error is raised. The default value is true.

  • :private? (boolean/0) - Whether or not the argument should be suppliable by the client. The default value is false.

  • :sensitive? (boolean/0) - Whether or not the argument value contains sensitive information, like PII. Using this option will cause the argument to be ** Redacted ** from the resource when logging or inspecting. See the security guide for more. The default value is false.

  • :default (term/0) - The default value for the argument to take. It can be a zero argument function e.g &MyMod.my_fun/0 or a value

prepare

Declares a preparation, which can be used to prepare a query for a read action.

Examples:

prepare build(sort: [:foo, :bar])
  • :preparation - Required. The module and options for a preparation. Also accepts functions take the query and the context.
pagination

Adds pagination options to a resource

  • :keyset? (boolean/0) - Whether or not keyset based pagination is supported The default value is false.

  • :offset? (boolean/0) - Whether or not offset based pagination is supported The default value is false.

  • :default_limit (pos_integer/0) - The default page size to apply, if one is not supplied

  • :countable - Whether not a returned page will have a full count of all records. Use :by_default to do it automatically. The default value is false.

  • :max_page_size (pos_integer/0) - The maximum amount of records that can be requested in a single page The default value is 250.

  • :required? (boolean/0) - Whether or not pagination can be disabled. Only relevant if some pagination configuration is supplied. The default value is true.

metadata

A special kind of attribute that is only added to specific actions. Nothing sets this value, it must be set in a custom change via Ash.Resource.Info.put_metadata/3.

Examples:

metadata :api_token, :string, allow_nil?: false

metadata :operation_id, :string, allow_nil?: false

  • :name (atom/0) - Required. The name of the metadata

  • :type (term/0) - Required. The type of the metadata. See Ash.Type for more.

  • :constraints (keyword/0) - Type constraints on the metadata The default value is [].

  • :description (String.t/0) - An optional description for the metadata.

  • :allow_nil? (boolean/0) - Whether or not the metadata may return nil The default value is true.

  • :default (term/0) - The default value for the metadata to take. It can be a zero argument function e.g &MyMod.my_fun/0 or a value

update

 update

Declares a update action. For calling this action, see the Ash.Api documentation.

Examples:

update :flag_for_review, primary?: true

  • :manual - Override the update behavior. See the manual action guides for more. Accepts a module or module and opts, or a function that takes the changeset and context.
    See the manual actions guide for more.

  • :name (atom/0) - Required. The name of the action

  • :primary? (boolean/0) - Whether or not this action should be used when no action is specified by the caller. The default value is false.

  • :description (String.t/0) - An optional description for the action

  • :transaction? (boolean/0) - Whether or not the action should be run in transactions. Reads default to false, while create/update/destroy actions default to true.
    Has no effect if the data layer does not support transactions, or if that data layer is already in a transaction.

  • :touches_resources (list of atom/0) - A list of resources that the action may touch, used when building transactions.

  • :accept - The list of attributes to accept. Defaults to all attributes on the resource

  • :delay_global_validations? (boolean/0) - If true, global validations will be done in a before_action hook, regardless of their configuration on the resource. The default value is false.

  • :skip_global_validations? (boolean/0) - If true, global validations will be skipped. Useful for manual actions. The default value is false.

  • :reject - A list of attributes not to accept. This is useful if you want to say 'accept all but x'
    If this is specified along with accept, then everything in the accept list minus any matches in the reject list will be accepted.

  • :require_attributes (list of atom/0) - A list of attributes that would normally allow_nil?, to require for this action.
    No need to include attributes that already do not allow nil?

  • :error_handler - Sets the error handler on the changeset. See Ash.Changeset.handle_errors/2 for more

  • :manual? (boolean/0) - Instructs Ash to skip the actual update/create/destroy step at the data layer. See the manual action guides for more.
    See the manual actions guide for more.

change

A change to be applied to the changeset.

See Ash.Resource.Change for more.

Examples:

change relate_actor(:reporter)
change {MyCustomChange, :foo}

  • :only_when_valid? (boolean/0) - If the change should only be run on valid changes. By default, all changes are run unless stated otherwise here. The default value is false.

  • :description (String.t/0) - An optional description for the change

  • :change - Required. The module and options for a change. Also accepts a function that takes the changeset and the context.
    See Ash.Resource.Change.Builtins for more.

  • :where - Validations that should pass in order for this validation to apply. These validations failing will not invalidate the changes, but instead just result in this change being ignored. Also accepts functions take the changeset. The default value is [].

validate

Declares a validation to be applied to the changeset.

See Ash.Resource.Validation for more.

Examples:

validate changing(:email)

  • :validation - Required. The module (or module and opts) that implements the Ash.Resource.Validation behaviour. Also accepts a one argument function that takes the changeset.

  • :where - Validations that should pass in order for this validation to apply. These validations failing will not invalidate the changes, but will instead result in this validation being ignored. Accepts a module, module and opts, or a 1 argument function that takes the changeset. The default value is [].

  • :only_when_valid? (boolean/0) - If the validation should only run on valid changes. Useful for expensive validations or validations that depend on valid data. The default value is false.

  • :message (String.t/0) - If provided, overrides any message set by the validation error

  • :description (String.t/0) - An optional description for the validation

  • :before_action? (boolean/0) - If set to true, the validation will be run in a before_action hook The default value is false.

metadata

A special kind of attribute that is only added to specific actions. Nothing sets this value, it must be set in a custom change via Ash.Resource.Info.put_metadata/3.

Examples:

metadata :api_token, :string, allow_nil?: false

metadata :operation_id, :string, allow_nil?: false

  • :name (atom/0) - Required. The name of the metadata

  • :type (term/0) - Required. The type of the metadata. See Ash.Type for more.

  • :constraints (keyword/0) - Type constraints on the metadata The default value is [].

  • :description (String.t/0) - An optional description for the metadata.

  • :allow_nil? (boolean/0) - Whether or not the metadata may return nil The default value is true.

  • :default (term/0) - The default value for the metadata to take. It can be a zero argument function e.g &MyMod.my_fun/0 or a value

argument

Declares an argument on the action

Examples:

argument :password_confirmation, :string

  • :name (atom/0) - Required. The name of the argument

  • :type (term/0) - Required. The type of the argument. See Ash.Type for more.

  • :description (String.t/0) - An optional description for the argument.

  • :constraints (keyword/0) - Constraints to provide to the type when casting the value. For more information see the specific type's documentation, for general type information see Ash.Type and for practical example see the constraints topic. The default value is [].

  • :allow_nil? (boolean/0) - Whether or not the argument value may be nil (or may be not provided) If nil value is given error is raised. The default value is true.

  • :private? (boolean/0) - Whether or not the argument should be suppliable by the client. The default value is false.

  • :sensitive? (boolean/0) - Whether or not the argument value contains sensitive information, like PII. Using this option will cause the argument to be ** Redacted ** from the resource when logging or inspecting. See the security guide for more. The default value is false.

  • :default (term/0) - The default value for the argument to take. It can be a zero argument function e.g &MyMod.my_fun/0 or a value

destroy

 destroy

Declares a destroy action. For calling this action, see the Ash.Api documentation.

Examples:

destroy :soft_delete do
  primary? true
end

  • :soft? (atom/0) - If specified, the destroy action behaves as an update internally The default value is false.

  • :manual - Override the update behavior. See the manual action guides for more. Accepts a module or module and opts, or a function that takes the changeset and context.
    See the manual actions guide for more.

  • :name (atom/0) - Required. The name of the action

  • :primary? (boolean/0) - Whether or not this action should be used when no action is specified by the caller. The default value is false.

  • :description (String.t/0) - An optional description for the action

  • :transaction? (boolean/0) - Whether or not the action should be run in transactions. Reads default to false, while create/update/destroy actions default to true.
    Has no effect if the data layer does not support transactions, or if that data layer is already in a transaction.

  • :touches_resources (list of atom/0) - A list of resources that the action may touch, used when building transactions.

  • :accept - The list of attributes to accept. Defaults to all attributes on the resource

  • :delay_global_validations? (boolean/0) - If true, global validations will be done in a before_action hook, regardless of their configuration on the resource. The default value is false.

  • :skip_global_validations? (boolean/0) - If true, global validations will be skipped. Useful for manual actions. The default value is false.

  • :reject - A list of attributes not to accept. This is useful if you want to say 'accept all but x'
    If this is specified along with accept, then everything in the accept list minus any matches in the reject list will be accepted.

  • :require_attributes (list of atom/0) - A list of attributes that would normally allow_nil?, to require for this action.
    No need to include attributes that already do not allow nil?

  • :error_handler - Sets the error handler on the changeset. See Ash.Changeset.handle_errors/2 for more

  • :manual? (boolean/0) - Instructs Ash to skip the actual update/create/destroy step at the data layer. See the manual action guides for more.
    See the manual actions guide for more.

change

A change to be applied to the changeset.

See Ash.Resource.Change for more.

Examples:

change relate_actor(:reporter)
change {MyCustomChange, :foo}

  • :only_when_valid? (boolean/0) - If the change should only be run on valid changes. By default, all changes are run unless stated otherwise here. The default value is false.

  • :description (String.t/0) - An optional description for the change

  • :change - Required. The module and options for a change. Also accepts a function that takes the changeset and the context.
    See Ash.Resource.Change.Builtins for more.

  • :where - Validations that should pass in order for this validation to apply. These validations failing will not invalidate the changes, but instead just result in this change being ignored. Also accepts functions take the changeset. The default value is [].

validate

Declares a validation to be applied to the changeset.

See Ash.Resource.Validation for more.

Examples:

validate changing(:email)

  • :validation - Required. The module (or module and opts) that implements the Ash.Resource.Validation behaviour. Also accepts a one argument function that takes the changeset.

  • :where - Validations that should pass in order for this validation to apply. These validations failing will not invalidate the changes, but will instead result in this validation being ignored. Accepts a module, module and opts, or a 1 argument function that takes the changeset. The default value is [].

  • :only_when_valid? (boolean/0) - If the validation should only run on valid changes. Useful for expensive validations or validations that depend on valid data. The default value is false.

  • :message (String.t/0) - If provided, overrides any message set by the validation error

  • :description (String.t/0) - An optional description for the validation

  • :before_action? (boolean/0) - If set to true, the validation will be run in a before_action hook The default value is false.

metadata

A special kind of attribute that is only added to specific actions. Nothing sets this value, it must be set in a custom change via Ash.Resource.Info.put_metadata/3.

Examples:

metadata :api_token, :string, allow_nil?: false

metadata :operation_id, :string, allow_nil?: false

  • :name (atom/0) - Required. The name of the metadata

  • :type (term/0) - Required. The type of the metadata. See Ash.Type for more.

  • :constraints (keyword/0) - Type constraints on the metadata The default value is [].

  • :description (String.t/0) - An optional description for the metadata.

  • :allow_nil? (boolean/0) - Whether or not the metadata may return nil The default value is true.

  • :default (term/0) - The default value for the metadata to take. It can be a zero argument function e.g &MyMod.my_fun/0 or a value

argument

Declares an argument on the action

Examples:

argument :password_confirmation, :string

  • :name (atom/0) - Required. The name of the argument

  • :type (term/0) - Required. The type of the argument. See Ash.Type for more.

  • :description (String.t/0) - An optional description for the argument.

  • :constraints (keyword/0) - Constraints to provide to the type when casting the value. For more information see the specific type's documentation, for general type information see Ash.Type and for practical example see the constraints topic. The default value is [].

  • :allow_nil? (boolean/0) - Whether or not the argument value may be nil (or may be not provided) If nil value is given error is raised. The default value is true.

  • :private? (boolean/0) - Whether or not the argument should be suppliable by the client. The default value is false.

  • :sensitive? (boolean/0) - Whether or not the argument value contains sensitive information, like PII. Using this option will cause the argument to be ** Redacted ** from the resource when logging or inspecting. See the security guide for more. The default value is false.

  • :default (term/0) - The default value for the argument to take. It can be a zero argument function e.g &MyMod.my_fun/0 or a value

code_interface

 code_interface

Functions that will be defined on the Api module to interact with this resource.

See the code interface guide for more.

Examples:

code_interface do
  define_for MyApp.Api
  define :create_user, action: :create
  define :get_user_by_id, action: :get_by_id, args: [:id], get?: true
end
  • :define_for (atom/0) - Defines the code interface on the resource module directly, using the provided Api. The default value is false.

define

 define

Defines a function with the corresponding name and arguments.

See the code interface guide for more.

Examples:

define :get_user_by_id, action: :get_by_id, args: [:id], get?: true

  • :name (atom/0) - Required. The name of the function that will be defined

  • :action (atom/0) - The name of the action that will be called. Defaults to the same name as the function.

  • :args - Map specific arguments to named inputs. Can provide any argument/attributes that the action allows.

  • :not_found_error? (boolean/0) - If the action or interface is configured with get?: true, this determines whether or not an error is raised or nil is returned. The default value is true.

  • :get? (boolean/0) - Expects to only receive a single result from a read action, and returns a single result instead of a list. Ignored for other action types.

  • :get_by (list of atom/0) - Takes a list of fields and adds those fields as arguments, which will then be used to filter. Sets get? to true automatically. Ignored for non-read actions.

  • :get_by_identity (atom/0) - Only relevant for read actions. Takes an identity, and gets its field list, performing the same logic as get_by once it has the list of fields.

define_calculation

 define_calculation

Defines a function with the corresponding name and arguments, that evaluates a calculation.

Use :_record to take an instance of a record.

See the code interface guide for more.

Examples:

define_calculation :referral_link, args: [:id]
define_calculation :referral_link, args: [{:arg, :id}, {:ref, :id}]

  • :name (atom/0) - Required. The name of the function that will be defined

  • :calculation (atom/0) - The name of the calculation that will be evaluated. Defaults to the same name as the function.

  • :args (term/0) - Supply field or argument values referenced by the calculation.
    By default, the value will be provided for any matching named reference and argument. This is normally fine, but in the case that you have an argument and a reference with the same name, you can specify it by supplying {:arg, :name} and {:ref, :name}. For example: 

      define_calculation :id_matches, args: [{:arg, :id}, {:ref, :id}]

    To make arguments optional, wrap them in {:optional, ..}, for example: 

      define_calculation :id_matches, args: [{:arg, :id}, {:optional, {:ref, :id}}]
  ``` The default value is `[]`.

resource

 resource

General resource configuration

Examples:

resource do
  description "A description of this resource"
  base_filter [is_nil: :deleted_at]
end

Imports:

  • :description (String.t/0) - A human readable description of the resource, to be used in generated documentation

  • :base_filter (term/0) - A filter statement to be applied to any queries on the resource

  • :default_context (term/0) - Default context to apply to any queries/changesets generated for this resource.

  • :trace_name (String.t/0) - The name to use in traces. Defaults to the short_name stringified.
    See the monitoring guide for more.

  • :short_name (atom/0) - A short identifier for the resource, which should be unique.
    See the monitoring guide for more.

  • :simple_notifiers (list of atom/0) - A list of notifiers that require no DSL. Can be used to avoid compile time dependencies on notifiers

identities

 identities

Unique identifiers for the resource

Examples:

identities do
  identity :full_name, [:first_name, :last_name]
  identity :email, [:email]
end

identity

 identity

Represents a unique constraint on the resource.

See the identities guide for more.

Examples:

identity :name, [:name]
identity :full_name, [:first_name, :last_name]

  • :name (atom/0) - Required. The name of the identity.

  • :keys - Required. The names of the attributes that uniquely identify this resource.

  • :eager_check_with (atom/0) - Validates that the unique identity provided is unique at validation time, outside of any transactions, using the api module provided.

  • :pre_check_with (atom/0) - Validates that the unique identity provided is unique in a before_action hook.

  • :description (String.t/0) - An optional description for the identity

  • :message (String.t/0) - An error message to use when the unique identity would be violated

changes

 changes

Declare changes that occur on create/update/destroy actions against the resource

See Ash.Resource.Change for more.

Examples:

changes do
  change {Mod, [foo: :bar]}
  change set_context(%{some: :context})
end

Imports:

change

 change

A change to be applied to the changeset.

See Ash.Resource.Change for more.

Examples:

change relate_actor(:reporter)
change {MyCustomChange, :foo}

  • :on - The action types the validation should run on. Destroy actions are omitted by default as most changes don't make sense for a destroy. The default value is [:create, :update].

  • :only_when_valid? (boolean/0) - If the change should only be run on valid changes. By default, all changes are run unless stated otherwise here. The default value is false.

  • :description (String.t/0) - An optional description for the change

  • :change - Required. The module and options for a change. Also accepts a function that takes the changeset and the context.
    See Ash.Resource.Change.Builtins for more.

  • :where - Validations that should pass in order for this validation to apply. These validations failing will not invalidate the changes, but instead just result in this change being ignored. Also accepts functions take the changeset. The default value is [].

preparations

 preparations

Declare preparations that occur on all read actions for a given resource

Examples:

preparations do
  prepare {Mod, [foo: :bar]}
  prepare set_context(%{some: :context})
end

Imports:

prepare

 prepare

Declares a preparation, which can be used to prepare a query for a read action.

Examples:

prepare build(sort: [:foo, :bar])
  • :preparation - Required. The module and options for a preparation. Also accepts functions take the query and the context.

validations

 validations

Declare validations prior to performing actions against the resource

Examples:

validations do
  validate {Mod, [foo: :bar]}
  validate at_least_one_of_present([:first_name, :last_name])
end

Imports:

validate

 validate

Declares a validation for creates and updates.

See Ash.Resource.Change for more.

Examples:

validate {Mod, [foo: :bar]}
validate at_least_one_of_present([:first_name, :last_name])

  • :validation - Required. The module (or module and opts) that implements the Ash.Resource.Validation behaviour. Also accepts a one argument function that takes the changeset.

  • :where - Validations that should pass in order for this validation to apply. These validations failing will not invalidate the changes, but will instead result in this validation being ignored. Accepts a module, module and opts, or a 1 argument function that takes the changeset. The default value is [].

  • :on - The action types the validation should run on.
    Many validations don't make sense in the context of deletion, so by default it is left out of the list. The default value is [:create, :update].

  • :only_when_valid? (boolean/0) - If the validation should only run on valid changes. Useful for expensive validations or validations that depend on valid data. The default value is false.

  • :message (String.t/0) - If provided, overrides any message set by the validation error

  • :description (String.t/0) - An optional description for the validation

  • :before_action? (boolean/0) - If set to true, the validation will be run in a before_action hook The default value is false.

aggregates

 aggregates

Declare named aggregates on the resource.

These are aggregates that can be loaded only by name using Ash.Query.load/2. They are also available as top level fields on the resource.

See the aggregates guide for more.

Examples:

aggregates do
  count :assigned_ticket_count, :reported_tickets do
    filter [active: true]
  end
end

Imports:

count

 count

Declares a named count aggregate on the resource

Supports filter, but not sort (because that wouldn't affect the count)

See the aggregates guide for more.

Examples:

count :assigned_ticket_count, :assigned_tickets do
  filter [active: true]
end

  • :uniq? (boolean/0) - Wether or not to count unique values only The default value is false.

  • :name (atom/0) - Required. The field to place the aggregate in

  • :read_action (atom/0) - The read action to use when building the aggregate
    Defaults to the primary read action. Keep in mind this action must not have any required arguments.

  • :relationship_path - Required. The relationship or relationship path to use for the aggregate

  • :kind - Required. The kind of the aggregate

  • :field (atom/0) - The field to aggregate. Defaults to the first field in the primary key of the resource

  • :filter (term/0) - A filter to apply to the aggregate The default value is [].

  • :description (String.t/0) - An optional description for the aggregate

  • :default (term/0) - A default value to use in cases where nil would be used. Count defaults to 0.

  • :private? (boolean/0) - Whether or not the aggregate will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql The default value is false.

  • :filterable? - Whether or not the aggregate should be usable in filters. The default value is true.

  • :authorize? (boolean/0) - Wether or not the aggregate query should authorize based on the target action.
    If you are using filter checks or simple checks that don't depend on arguments on the destination resource, then this should be set to true. Additionally, you can set read_action to a separate action that does have filter checks. Otherwise, you can set authorize? false on the aggregate.
    If the parent query is not being authorized, then the aggregate not be authorized either regardless of the setting. The default value is true.

first

 first

Declares a named first aggregate on the resource

First aggregates return the first value of the related record that matches. Supports both filter and sort.

See the aggregates guide for more.

Examples:

first :first_assigned_ticket_subject, :assigned_tickets, :subject do
  filter [active: true]
  sort [:subject]
end

  • :name (atom/0) - Required. The field to place the aggregate in

  • :read_action (atom/0) - The read action to use when building the aggregate
    Defaults to the primary read action. Keep in mind this action must not have any required arguments.

  • :relationship_path - Required. The relationship or relationship path to use for the aggregate

  • :kind - Required. The kind of the aggregate

  • :field (atom/0) - The field to aggregate. Defaults to the first field in the primary key of the resource

  • :filter (term/0) - A filter to apply to the aggregate The default value is [].

  • :sort (term/0) - A sort to be applied to the aggregate

  • :description (String.t/0) - An optional description for the aggregate

  • :default (term/0) - A default value to use in cases where nil would be used. Count defaults to 0.

  • :private? (boolean/0) - Whether or not the aggregate will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql The default value is false.

  • :filterable? - Whether or not the aggregate should be usable in filters. The default value is true.

  • :authorize? (boolean/0) - Wether or not the aggregate query should authorize based on the target action.
    If you are using filter checks or simple checks that don't depend on arguments on the destination resource, then this should be set to true. Additionally, you can set read_action to a separate action that does have filter checks. Otherwise, you can set authorize? false on the aggregate.
    If the parent query is not being authorized, then the aggregate not be authorized either regardless of the setting. The default value is true.

sum

 sum

Declares a named sum aggregate on the resource

Supports filter, but not sort (because that wouldn't affect the sum)

See the aggregates guide for more.

Examples:

sum :assigned_ticket_price_sum, :assigned_tickets, :price do
  filter [active: true]
end

  • :name (atom/0) - Required. The field to place the aggregate in

  • :read_action (atom/0) - The read action to use when building the aggregate
    Defaults to the primary read action. Keep in mind this action must not have any required arguments.

  • :relationship_path - Required. The relationship or relationship path to use for the aggregate

  • :kind - Required. The kind of the aggregate

  • :field (atom/0) - The field to aggregate. Defaults to the first field in the primary key of the resource

  • :filter (term/0) - A filter to apply to the aggregate The default value is [].

  • :description (String.t/0) - An optional description for the aggregate

  • :default (term/0) - A default value to use in cases where nil would be used. Count defaults to 0.

  • :private? (boolean/0) - Whether or not the aggregate will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql The default value is false.

  • :filterable? - Whether or not the aggregate should be usable in filters. The default value is true.

  • :authorize? (boolean/0) - Wether or not the aggregate query should authorize based on the target action.
    If you are using filter checks or simple checks that don't depend on arguments on the destination resource, then this should be set to true. Additionally, you can set read_action to a separate action that does have filter checks. Otherwise, you can set authorize? false on the aggregate.
    If the parent query is not being authorized, then the aggregate not be authorized either regardless of the setting. The default value is true.

list

 list

Declares a named list aggregate on the resource.

A list aggregate selects the list of all values for the given field and relationship combination.

See the aggregates guide for more.

Examples:

list :assigned_ticket_prices, :assigned_tickets, :price do
  filter [active: true]
end

  • :uniq? (boolean/0) - Wether or not to count unique values only The default value is false.

  • :name (atom/0) - Required. The field to place the aggregate in

  • :read_action (atom/0) - The read action to use when building the aggregate
    Defaults to the primary read action. Keep in mind this action must not have any required arguments.

  • :relationship_path - Required. The relationship or relationship path to use for the aggregate

  • :kind - Required. The kind of the aggregate

  • :field (atom/0) - The field to aggregate. Defaults to the first field in the primary key of the resource

  • :filter (term/0) - A filter to apply to the aggregate The default value is [].

  • :sort (term/0) - A sort to be applied to the aggregate

  • :description (String.t/0) - An optional description for the aggregate

  • :default (term/0) - A default value to use in cases where nil would be used. Count defaults to 0.

  • :private? (boolean/0) - Whether or not the aggregate will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql The default value is false.

  • :filterable? - Whether or not the aggregate should be usable in filters. The default value is true.

  • :authorize? (boolean/0) - Wether or not the aggregate query should authorize based on the target action.
    If you are using filter checks or simple checks that don't depend on arguments on the destination resource, then this should be set to true. Additionally, you can set read_action to a separate action that does have filter checks. Otherwise, you can set authorize? false on the aggregate.
    If the parent query is not being authorized, then the aggregate not be authorized either regardless of the setting. The default value is true.

max

 max

Declares a named max aggregate on the resource

Supports filter, but not sort (because that wouldn't affect the max)

See the aggregates guide for more.

Examples:

max :first_assigned_ticket_subject, :assigned_tickets, :severity do
  filter [active: true]
end

  • :name (atom/0) - Required. The field to place the aggregate in

  • :read_action (atom/0) - The read action to use when building the aggregate
    Defaults to the primary read action. Keep in mind this action must not have any required arguments.

  • :relationship_path - Required. The relationship or relationship path to use for the aggregate

  • :kind - Required. The kind of the aggregate

  • :field (atom/0) - The field to aggregate. Defaults to the first field in the primary key of the resource

  • :filter (term/0) - A filter to apply to the aggregate The default value is [].

  • :description (String.t/0) - An optional description for the aggregate

  • :default (term/0) - A default value to use in cases where nil would be used. Count defaults to 0.

  • :private? (boolean/0) - Whether or not the aggregate will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql The default value is false.

  • :filterable? - Whether or not the aggregate should be usable in filters. The default value is true.

  • :authorize? (boolean/0) - Wether or not the aggregate query should authorize based on the target action.
    If you are using filter checks or simple checks that don't depend on arguments on the destination resource, then this should be set to true. Additionally, you can set read_action to a separate action that does have filter checks. Otherwise, you can set authorize? false on the aggregate.
    If the parent query is not being authorized, then the aggregate not be authorized either regardless of the setting. The default value is true.

min

 min

Declares a named min aggregate on the resource

Supports filter, but not sort (because that wouldn't affect the min)

See the aggregates guide for more.

Examples:

min :first_assigned_ticket_subject, :assigned_tickets, :severity do
  filter [active: true]
end

  • :name (atom/0) - Required. The field to place the aggregate in

  • :read_action (atom/0) - The read action to use when building the aggregate
    Defaults to the primary read action. Keep in mind this action must not have any required arguments.

  • :relationship_path - Required. The relationship or relationship path to use for the aggregate

  • :kind - Required. The kind of the aggregate

  • :field (atom/0) - The field to aggregate. Defaults to the first field in the primary key of the resource

  • :filter (term/0) - A filter to apply to the aggregate The default value is [].

  • :description (String.t/0) - An optional description for the aggregate

  • :default (term/0) - A default value to use in cases where nil would be used. Count defaults to 0.

  • :private? (boolean/0) - Whether or not the aggregate will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql The default value is false.

  • :filterable? - Whether or not the aggregate should be usable in filters. The default value is true.

  • :authorize? (boolean/0) - Wether or not the aggregate query should authorize based on the target action.
    If you are using filter checks or simple checks that don't depend on arguments on the destination resource, then this should be set to true. Additionally, you can set read_action to a separate action that does have filter checks. Otherwise, you can set authorize? false on the aggregate.
    If the parent query is not being authorized, then the aggregate not be authorized either regardless of the setting. The default value is true.

avg

 avg

Declares a named avg aggregate on the resource

Supports filter, but not sort (because that wouldn't affect the avg)

See the aggregates guide for more.

Examples:

avg :assigned_ticket_price_sum, :assigned_tickets, :price do
  filter [active: true]
end

  • :name (atom/0) - Required. The field to place the aggregate in

  • :read_action (atom/0) - The read action to use when building the aggregate
    Defaults to the primary read action. Keep in mind this action must not have any required arguments.

  • :relationship_path - Required. The relationship or relationship path to use for the aggregate

  • :kind - Required. The kind of the aggregate

  • :field (atom/0) - The field to aggregate. Defaults to the first field in the primary key of the resource

  • :filter (term/0) - A filter to apply to the aggregate The default value is [].

  • :description (String.t/0) - An optional description for the aggregate

  • :default (term/0) - A default value to use in cases where nil would be used. Count defaults to 0.

  • :private? (boolean/0) - Whether or not the aggregate will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql The default value is false.

  • :filterable? - Whether or not the aggregate should be usable in filters. The default value is true.

  • :authorize? (boolean/0) - Wether or not the aggregate query should authorize based on the target action.
    If you are using filter checks or simple checks that don't depend on arguments on the destination resource, then this should be set to true. Additionally, you can set read_action to a separate action that does have filter checks. Otherwise, you can set authorize? false on the aggregate.
    If the parent query is not being authorized, then the aggregate not be authorized either regardless of the setting. The default value is true.

custom

 custom

Declares a named custom aggregate on the resource

Supports filter and sort.

Custom aggregates provide an implementation which must implement data layer specific callbacks.

See the relevant data layer documentation and the aggregates guide for more.

Examples:

custom :author_names, :authors, :string do
  implementation {StringAgg, delimiter: ","}
end

  • :implementation - Required. The module that implements the relevant data layer callbacks

  • :type (atom/0) - Required. The type of the value returned by the aggregate

  • :name (atom/0) - Required. The field to place the aggregate in

  • :read_action (atom/0) - The read action to use when building the aggregate
    Defaults to the primary read action. Keep in mind this action must not have any required arguments.

  • :relationship_path - Required. The relationship or relationship path to use for the aggregate

  • :kind - Required. The kind of the aggregate

  • :field (atom/0) - The field to aggregate. Defaults to the first field in the primary key of the resource

  • :filter (term/0) - A filter to apply to the aggregate The default value is [].

  • :sort (term/0) - A sort to be applied to the aggregate

  • :description (String.t/0) - An optional description for the aggregate

  • :default (term/0) - A default value to use in cases where nil would be used. Count defaults to 0.

  • :private? (boolean/0) - Whether or not the aggregate will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql The default value is false.

  • :filterable? - Whether or not the aggregate should be usable in filters. The default value is true.

  • :authorize? (boolean/0) - Wether or not the aggregate query should authorize based on the target action.
    If you are using filter checks or simple checks that don't depend on arguments on the destination resource, then this should be set to true. Additionally, you can set read_action to a separate action that does have filter checks. Otherwise, you can set authorize? false on the aggregate.
    If the parent query is not being authorized, then the aggregate not be authorized either regardless of the setting. The default value is true.

calculations

 calculations

Declare named calculations on the resource.

These are calculations that can be loaded only by name using Ash.Query.load/2. They are also available as top level fields on the resource.

See the calculations guide for more.

Examples:

calculations do
  calculate :full_name, :string, MyApp.MyResource.FullName
end

Imports:

calculate

 calculate

Declares a named calculation on the resource.

Takes a module that must adopt the Ash.Calculation behaviour. See that module for more information.

To ensure that the necessary fields are selected:

1.) Specifying the select option on a calculation in the resource. 2.) Define a select/2 callback in the calculation module 3.) Set always_select? on the attribute in question

See the calculations guide for more.

Examples: Ash.Calculation implementation example:

calculate :full_name, :string, {MyApp.FullName, keys: [:first_name, :last_name]}, select: [:first_name, :last_name]

expr/1 example:

calculate :full_name, :string, expr(first_name <> " " <> last_name)

  • :name (atom/0) - Required. The field name to use for the calculation value

  • :type (term/0) - Required. The type of the calculation. See Ash.Type for more.

  • :constraints (keyword/0) - Constraints to provide to the type. See Ash.Type for more. The default value is [].

  • :calculation - Required. The module or {module, opts} to use for the calculation Also accepts a function that takes the list of records and the context.

  • :description (String.t/0) - An optional description for the calculation

  • :private? (boolean/0) - Whether or not the calculation will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql
    See the security guide for more. The default value is false.

  • :select (list of atom/0) - A list of fields to ensure selected if the calculation is used. The default value is [].

  • :load (term/0) - A load statement to be applied if the calculation is used. The default value is [].

  • :allow_nil? (boolean/0) - Whether or not the calculation can return nil. The default value is true.

  • :filterable? - Whether or not the calculation should be usable in filters. The default value is true.

argument

An argument to be passed into the calculation's arguments map

See the calculations guide for more.

Examples:

argument :params, :map do
  default %{}
end

argument :retries, :integer do
  allow_nil? false
end

  • :name (atom/0) - Required. The name of the argument

  • :type (term/0) - Required. The type of the argument. See Ash.Type for more.

  • :default - A default value to use for the argument if not provided

  • :allow_nil? (boolean/0) - Whether or not the argument value may be nil (or may be not provided) The default value is true.

  • :allow_expr? (boolean/0) - Allow passing expressions as argument values. Expressions cannot be type validated. The default value is false.

  • :constraints (keyword/0) - Constraints to provide to the type when casting the value. See the type's documentation and Ash.Type for more. The default value is [].

multitenancy

 multitenancy

Options for configuring the multitenancy behavior of a resource.

To specify a tenant, use Ash.Query.set_tenant/2 or Ash.Changeset.set_tenant/2 before passing it to an operation.

See the multitenancy guide

Examples:

multitenancy do
  strategy :attribute
  attribute :organization_id
  global? true
end

  • :strategy - Determine if multitenancy is performed with attribute filters or using data layer features. The default value is :context.

  • :attribute (atom/0) - If using the attribute strategy, the attribute to use, e.g org_id

  • :global? (boolean/0) - Whether or not the data also exists outside of each tenant. The default value is false.

  • :parse_attribute - An mfa ({module, function, args}) pointing to a function that takes a tenant and returns the attribute value The default value is {Ash.Resource.Dsl, :identity, []}.

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changes(body)

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