View Source Ash.Resource.Dsl (ash v2.0.0-rc.13)

The built in resource DSL.

dsl-documentation
DSL Documentation

index
Index

attributes
- attribute
- create_timestamp
- update_timestamp
- integer_primary_key
- uuid_primary_key
relationships
- has_one
- has_many
- many_to_many
- belongs_to
actions
- create
  - change
  - validate
  - argument
  - metadata
- read
  - argument
  - prepare
  - pagination
- update
  - change
  - validate
  - metadata
  - argument
- destroy
  - change
  - validate
  - metadata
  - argument
code_interface
- define
resource
identities
- identity
changes
- change
preparations
- prepare
validations
- validate
aggregates
- count
- first
- sum
- list
calculations
- calculate
  - argument
multitenancy

docs
Docs

attributes
attributes

A section for declaring attributes on the resource.

attribute
create_timestamp
update_timestamp
integer_primary_key
uuid_primary_key

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:

Ash.Resource.Attribute.Helpers

attribute
attribute

Declares an attribute on the resource.

Examples:

attribute :name, :string do
  allow_nil? false
end

:name - The name of the attribute.
:type - The type of the attribute.
:constraints - Constraints to provide to the type when casting the value. See the type's documentation for more information.
:description - An optional description for the attribute.
:sensitive? - Whether or not the attribute value contains sensitive information, like PII. The default value is false.
:source - If the field should be mapped to a different name in the data layer. Support varies by data layer.
:always_select? - Whether or not to ensure this attribute is always selected when reading from the database. The default value is false.
:primary_key? - Whether or not the attribute is part of the primary key (one or more fields that uniquely identify a resource)." If primary_key? is true, allow_nil? must be false. The default value is false.
:allow_nil? - Whether or not the attribute can be set to nil. The default value is true.
:generated? - Whether or not the value may be generated by the data layer. The default value is false.
:writable? - Whether or not the value can be written to. The default value is true.
:private? - Whether or not the attribute can be provided as input, or will be shown when extensions work with the resource (i.e won't appear in a web api). 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. The default value is true.
:match_other_defaults? - 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

Examples:

create_timestamp :inserted_at

:name - The name of the attribute.
:type - The type of the attribute. The default value is Ash.Type.UtcDatetimeUsec.
:constraints - Constraints to provide to the type when casting the value. See the type's documentation for more information.
:description - An optional description for the attribute.
:sensitive? - Whether or not the attribute value contains sensitive information, like PII. The default value is false.
:source - If the field should be mapped to a different name in the data layer. Support varies by data layer.
:always_select? - Whether or not to ensure this attribute is always selected when reading from the database. The default value is false.
:primary_key? - Whether or not the attribute is part of the primary key (one or more fields that uniquely identify a resource)." If primary_key? is true, allow_nil? must be false. The default value is false.
:allow_nil? - Whether or not the attribute can be set to nil. The default value is false.
:generated? - Whether or not the value may be generated by the data layer. The default value is false.
:writable? - Whether or not the value can be written to. The default value is false.
:private? - Whether or not the attribute can be provided as input, or will be shown when extensions work with the resource (i.e won't appear in a web api). The default value is true.
:default - A value to be set on all creates, unless a value is being provided already. The default value is &DateTime.utc_now/0.
: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. The default value is true.
:match_other_defaults? - 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 true.

update_timestamp
update_timestamp

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

Examples:

update_timestamp :inserted_at

:name - The name of the attribute.
:type - The type of the attribute. The default value is Ash.Type.UtcDatetimeUsec.
:constraints - Constraints to provide to the type when casting the value. See the type's documentation for more information.
:description - An optional description for the attribute.
:sensitive? - Whether or not the attribute value contains sensitive information, like PII. The default value is false.
:source - If the field should be mapped to a different name in the data layer. Support varies by data layer.
:always_select? - Whether or not to ensure this attribute is always selected when reading from the database. The default value is false.
:primary_key? - Whether or not the attribute is part of the primary key (one or more fields that uniquely identify a resource)." If primary_key? is true, allow_nil? must be false. The default value is false.
:allow_nil? - Whether or not the attribute can be set to nil. The default value is false.
:generated? - Whether or not the value may be generated by the data layer. The default value is false.
:writable? - Whether or not the value can be written to. The default value is false.
:private? - Whether or not the attribute can be provided as input, or will be shown when extensions work with the resource (i.e won't appear in a web api). The default value is true.
:default - A value to be set on all creates, unless a value is being provided already. The default value is &DateTime.utc_now/0.
:update_default - A value to be set on all updates, unless a value is being provided already. The default value is &DateTime.utc_now/0.
:filterable? - Whether or not the attribute can be referenced in filters. The default value is true.
:match_other_defaults? - 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 true.

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.

Examples:

integer_primary_key :id

:name - The name of the attribute.
:type - The type of the attribute. The default value is :integer.
:constraints - Constraints to provide to the type when casting the value. See the type's documentation for more information.
:description - An optional description for the attribute.
:sensitive? - Whether or not the attribute value contains sensitive information, like PII. The default value is false.
:source - If the field should be mapped to a different name in the data layer. Support varies by data layer.
:always_select? - Whether or not to ensure this attribute is always selected when reading from the database. The default value is false.
:primary_key? - Whether or not the attribute is part of the primary key (one or more fields that uniquely identify a resource)." If primary_key? is true, allow_nil? must be false. The default value is true.
:generated? - Whether or not the value may be generated by the data layer. The default value is true.
:writable? - Whether or not the value can be written to. The default value is false.
:private? - Whether or not the attribute can be provided as input, or will be shown when extensions work with the resource (i.e won't appear in a web api). 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. The default value is true.
:match_other_defaults? - 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.

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.

Examples:

uuid_primary_key :id

:name - The name of the attribute.
:type - The type of the attribute. The default value is :uuid.
:constraints - Constraints to provide to the type when casting the value. See the type's documentation for more information.
:description - An optional description for the attribute.
:sensitive? - Whether or not the attribute value contains sensitive information, like PII. The default value is false.
:source - If the field should be mapped to a different name in the data layer. Support varies by data layer.
:always_select? - Whether or not to ensure this attribute is always selected when reading from the database. The default value is false.
:primary_key? - Whether or not the attribute is part of the primary key (one or more fields that uniquely identify a resource)." If primary_key? is true, allow_nil? must be false. The default value is true.
:generated? - Whether or not the value may be generated by the data layer. The default value is false.
:writable? - Whether or not the value can be written to. The default value is false.
:private? - Whether or not the attribute can be provided as input, or will be shown when extensions work with the resource (i.e won't appear in a web api). The default value is false.
:default - A value to be set on all creates, unless a value is being provided already. The default value is &Ash.UUID.generate/0.
: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. The default value is true.
:match_other_defaults? - 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.

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).

has_one
has_many
many_to_many
belongs_to

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:

Ash.Filter.TemplateHelpers

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.

Examples:

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

:manual - Allows for relationships that are fetched manually. WARNING: EXPERIMENTAL
Manual relationships do not support filters or aggregates at the moment. In the future, what we may do is allow the data layer to be configured with a hook that expresses how to implement this manual relationship at the data layer level, like providing a custom ecto join for ash_postgres. This is the simple groundwork for that.

# in the resource
relationships do
  has_many :somethings, MyApp.Something do
    manual {MyApp.FetchSomethings, [opt1: :value]}
    # or if there are no opts
    # manual MyApp.FetchSomethings
  end
end  
# the implementation
defmodule MyApp.FetchSomethings do
  use Ash.Resource.ManualRelationship  
  def load(records, _opts, %{relationship: relationship}) do
    # Return a map of primary keys of the records to the related records.
    # This example is likely suboptimal because it does a separate fetch for
    # each record, whereas you likely want to try to fetch them all at once,
    # and then create the mapping from pkey values to related records
    # For example:  
    # get the primary key
    primary_key = Ash.Resource.Info.primary_key(relationship.source)
    # e.g [:id]  
    # key the records by primary key and the related records with that primary key
    {:ok,
      Map.new(records, fn record ->
        # the key is the pkey values, e.g `%{id: 1}`
        # the value is the related records for that record
        {Map.take(record, primary_key), get_related_records(record)}
      end)}
  end
end

:no_attributes? - 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:

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.
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? - 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 - The name of the relationship
:destination - The destination resource
:description - An optional description for the relationship
:destination_attribute - The attribute on the related resource that should match the source_attribute configured on this resource.
:validate_destination_attribute? - Whether or not to validate that the destination field exists on the destination resource The default value is true.
:source_attribute - The field on this resource that should match the destination_attribute on the related resource. The default value is :id.
:relationship_context - Context to be set on any queries or changesets generated for managing or querying this relationship.
:private? - Whether or not the relationship will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql The default value is false.
:not_found_message - A message to show if there is a conflict with this relationship in the database on update or create, or when managing relationships.
:writable? - Whether or not the relationship may be managed. The default value is true.
:read_action - The read action on the destination resource to use when loading data and filtering.
:api - The API module to use when working with the related entity.
:filter - A filter to be applied when reading the relationship.
:filterable? - If set to false, the relationship will not be usable in filters. The default value is true.
:sort - A sort statement to be applied when loading the relationship.
:could_be_related_at_creation? - Whether or not related values may exist for this relationship at creation. The default value is false.
:violation_message - 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.

Examples:

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

# in the resource
relationships do
  has_many :somethings, MyApp.Something do
    manual {MyApp.FetchSomethings, [opt1: :value]}
    # or if there are no opts
    # manual MyApp.FetchSomethings
  end
end  
# the implementation
defmodule MyApp.FetchSomethings do
  use Ash.Resource.ManualRelationship  
  def load(records, _opts, %{relationship: relationship}) do
    # Return a map of primary keys of the records to the related records.
    # This example is likely suboptimal because it does a separate fetch for
    # each record, whereas you likely want to try to fetch them all at once,
    # and then create the mapping from pkey values to related records
    # For example:  
    # get the primary key
    primary_key = Ash.Resource.Info.primary_key(relationship.source)
    # e.g [:id]  
    # key the records by primary key and the related records with that primary key
    {:ok,
      Map.new(records, fn record ->
        # the key is the pkey values, e.g `%{id: 1}`
        # the value is the related records for that record
        {Map.take(record, primary_key), get_related_records(record)}
      end)}
  end
end

:no_attributes? - 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:

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.
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 - The name of the relationship
:destination - The destination resource
:description - An optional description for the relationship
:destination_attribute - The attribute on the related resource that should match the source_attribute configured on this resource.
:validate_destination_attribute? - Whether or not to validate that the destination field exists on the destination resource The default value is true.
:source_attribute - The field on this resource that should match the destination_attribute on the related resource. The default value is :id.
:relationship_context - Context to be set on any queries or changesets generated for managing or querying this relationship.
:private? - Whether or not the relationship will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql The default value is false.
:not_found_message - A message to show if there is a conflict with this relationship in the database on update or create, or when managing relationships.
:writable? - Whether or not the relationship may be managed. The default value is true.
:read_action - The read action on the destination resource to use when loading data and filtering.
:api - The API module to use when working with the related entity.
:filter - A filter to be applied when reading the relationship.
:filterable? - If set to false, the relationship will not be usable in filters. The default value is true.
:sort - A sort statement to be applied when loading the relationship.
:could_be_related_at_creation? - Whether or not related values may exist for this relationship at creation. The default value is false.
:violation_message - 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.

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 - Required. The attribute on the join resource that should line up with source_attribute on this resource.
:destination_attribute_on_join_resource - Required. The attribute on the join resource that should line up with destination_attribute on the related resource.
:through - Required. The resource to use as the join resource.
:join_relationship - The has_many relationship to the join resource. Defaults to <relationship_name>_join_assoc
:name - The name of the relationship
:destination - The destination resource
:description - An optional description for the relationship
:destination_attribute - The attribute on the related resource that should match the source_attribute configured on this resource. The default value is :id.
:validate_destination_attribute? - Whether or not to validate that the destination field exists on the destination resource The default value is true.
:source_attribute - The field on this resource that should match the destination_attribute on the related resource. The default value is :id.
:relationship_context - Context to be set on any queries or changesets generated for managing or querying this relationship.
:private? - Whether or not the relationship will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql The default value is false.
:not_found_message - A message to show if there is a conflict with this relationship in the database on update or create, or when managing relationships.
:writable? - Whether or not the relationship may be managed. The default value is true.
:read_action - The read action on the destination resource to use when loading data and filtering.
:api - The API module to use when working with the related entity.
:filter - A filter to be applied when reading the relationship.
:filterable? - If set to false, the relationship will not be usable in filters. The default value is true.
:sort - A sort statement to be applied when loading the relationship.
:could_be_related_at_creation? - Whether or not related values may exist for this relationship at creation. The default value is false.
:violation_message - 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.

Examples:

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

:primary_key? - Whether the generated attribute is, or is part of, the primary key of a resource. The default value is false.
:allow_nil? - 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? - Whether the generated attribute will be marked as public & writable. The default value is false.
:define_attribute? - 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 - The type of the generated created attribute. The default value is :uuid.
:name - The name of the relationship
:destination - The destination resource
:description - An optional description for the relationship
:destination_attribute - The attribute on the related resource that should match the source_attribute configured on this resource. The default value is :id.
:validate_destination_attribute? - Whether or not to validate that the destination field exists on the destination resource The default value is true.
:source_attribute - The field on this resource that should match the destination_attribute on the related resource. - Defaults to <name>_id
:relationship_context - Context to be set on any queries or changesets generated for managing or querying this relationship.
:private? - Whether or not the relationship will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql The default value is false.
:not_found_message - A message to show if there is a conflict with this relationship in the database on update or create, or when managing relationships.
:writable? - Whether or not the relationship may be managed. The default value is true.
:read_action - The read action on the destination resource to use when loading data and filtering.
:api - The API module to use when working with the related entity.
:filter - A filter to be applied when reading the relationship.
:filterable? - If set to false, the relationship will not be usable in filters. The default value is true.
:sort - A sort statement to be applied when loading the relationship.
:violation_message - 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
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

Imports:

: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 - 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.

change
validate
argument
metadata

Examples:

create :register do
  primary? true
end

:allow_nil_input - 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.
:name - Required. The name of the action
:primary? - Whether or not this action should be used when no action is specified by the caller. The default value is false.
:description - An optional description for the action
:transaction? - 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 - 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
: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 - 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? - Instructs Ash to skip the actual update/create/destroy step at the data layer. See the manual action guides for more.

change

A change to be applied to the changeset.

Examples:

change relate_actor(:reporter)

change {MyCustomChange, :foo}

:only_when_valid? - 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 - An optional description for the change
:change - Required. The module and options for a change.
: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. The default value is [].

validate

Declares a validation to be applied to the changeset.

Examples:

validate changing(:email)

:validation - Required. The module/opts pair of the validation
: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. The default value is [].
:only_when_valid? - 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 - If provided, overrides any message set by the validation error
:description - An optional description for the validation
:before_action? - 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 - Required. The name of the argument
:type - Required. The type of the argument
:description - An optional description for the argument.
:constraints - Type constraints on the argument The default value is [].
:allow_nil? - Whether or not the argument value may be nil (or may be not provided) The default value is true.
:private? - Whether or not the argument should be suppliable by the client. The default value is false.
:sensitive? - Whether or not the attribute value contains sensitive information, like PII. The default value is false.
:default - 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 - Required. The name of the metadata
:type - Required. The type of the metadata
:constraints - Type constraints on the metadata The default value is [].
:description - An optional description for the metadata.
:allow_nil? - Whether or not the metadata may return nil The default value is true.
:default - 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.

argument
prepare
pagination

Examples:

read :read_all do
  primary? true
end

:filter - 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.
:get? - 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. 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.
:name - Required. The name of the action
:primary? - Whether or not this action should be used when no action is specified by the caller. The default value is false.
:description - An optional description for the action
:transaction? - 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 - 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 - Required. The name of the argument
:type - Required. The type of the argument
:description - An optional description for the argument.
:constraints - Type constraints on the argument The default value is [].
:allow_nil? - Whether or not the argument value may be nil (or may be not provided) The default value is true.
:private? - Whether or not the argument should be suppliable by the client. The default value is false.
:sensitive? - Whether or not the attribute value contains sensitive information, like PII. The default value is false.
:default - 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.

pagination

Adds pagination options to a resource

:keyset? - Whether or not keyset based pagination is supported The default value is false.
:offset? - Whether or not offset based pagination is supported The default value is false.
:default_limit - 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 - The maximum amount of records that can be requested in a single page The default value is 250.
:required? - Whether or not pagination can be disabled. Only relevant if some pagination configuration is supplied. The default value is true.

update
update

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

change
validate
metadata
argument

Examples:

update :flag_for_review, primary?: true

:name - Required. The name of the action
:primary? - Whether or not this action should be used when no action is specified by the caller. The default value is false.
:description - An optional description for the action
:transaction? - 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 - 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
: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 - 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? - Instructs Ash to skip the actual update/create/destroy step at the data layer. See the manual action guides for more.

change

A change to be applied to the changeset.

Examples:

change relate_actor(:reporter)

change {MyCustomChange, :foo}

:only_when_valid? - 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 - An optional description for the change
:change - Required. The module and options for a change.
: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. The default value is [].

validate

Declares a validation to be applied to the changeset.

Examples:

validate changing(:email)

:validation - Required. The module/opts pair of the validation
: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. The default value is [].
:only_when_valid? - 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 - If provided, overrides any message set by the validation error
:description - An optional description for the validation
:before_action? - 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 - Required. The name of the metadata
:type - Required. The type of the metadata
:constraints - Type constraints on the metadata The default value is [].
:description - An optional description for the metadata.
:allow_nil? - Whether or not the metadata may return nil The default value is true.
:default - 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 - Required. The name of the argument
:type - Required. The type of the argument
:description - An optional description for the argument.
:constraints - Type constraints on the argument The default value is [].
:allow_nil? - Whether or not the argument value may be nil (or may be not provided) The default value is true.
:private? - Whether or not the argument should be suppliable by the client. The default value is false.
:sensitive? - Whether or not the attribute value contains sensitive information, like PII. The default value is false.
:default - 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.

change
validate
metadata
argument

Examples:

destroy :soft_delete do
  primary? true
end

:soft? - If specified, the destroy action behaves as an update internally
:name - Required. The name of the action
:primary? - Whether or not this action should be used when no action is specified by the caller. The default value is false.
:description - An optional description for the action
:transaction? - 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 - 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
: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 - 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? - Instructs Ash to skip the actual update/create/destroy step at the data layer. See the manual action guides for more.

change

A change to be applied to the changeset.

Examples:

change relate_actor(:reporter)

change {MyCustomChange, :foo}

:only_when_valid? - 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 - An optional description for the change
:change - Required. The module and options for a change.
: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. The default value is [].

validate

Declares a validation to be applied to the changeset.

Examples:

validate changing(:email)

:validation - Required. The module/opts pair of the validation
: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. The default value is [].
:only_when_valid? - 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 - If provided, overrides any message set by the validation error
:description - An optional description for the validation
:before_action? - 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 - Required. The name of the metadata
:type - Required. The type of the metadata
:constraints - Type constraints on the metadata The default value is [].
:description - An optional description for the metadata.
:allow_nil? - Whether or not the metadata may return nil The default value is true.
:default - 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 - Required. The name of the argument
:type - Required. The type of the argument
:description - An optional description for the argument.
:constraints - Type constraints on the argument The default value is [].
:allow_nil? - Whether or not the argument value may be nil (or may be not provided) The default value is true.
:private? - Whether or not the argument should be suppliable by the client. The default value is false.
:sensitive? - Whether or not the attribute value contains sensitive information, like PII. The default value is false.
:default - 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.

define

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 - Defines the code interface on the resource module directly, using the provided Api. The default value is false.

define
define

Defines a function on the Api with the corresponding name and arguments.

Examples:

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

:name - Required. The name of the function that will be defined
:action - 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.
:get? - 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 - 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 - 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.

resource
resource

General Resource Configuration

Examples:

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

Imports:

Ash.Filter.TemplateHelpers

:description - A human readable description of the resource, to be used in generated documentation
:base_filter - A filter statement to be applied to any queries on the resource
:default_context - Default context to apply to any queries/changesets generated for this resource.
:trace_name - The name to use in traces. Defaults to the short_name stringified
:short_name - A short identifier for the resource, which should be unique.

identities
identities

Unique identifiers for the resource

identity

Examples:

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

identity
identity

Represents a unique constraint on the resource.

Examples:

identity :name, [:name]

identity :full_name, [:first_name, :last_name]

:name - Required. The name of the identity.
:keys - Required. The names of the attributes that uniquely identify this resource.
:eager_check_with - Validates that the unique identity provided is unique at validation time, outside of any transactions, using the api module provided.
:pre_check_with - Validates that the unique identity provided is unique in a before_action hook.
:description - An optional description for the identity
:message - 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

change

Examples:

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

Imports:

change
change

A change to be applied to the changeset.

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? - 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 - An optional description for the change
:change - Required. The module and options for a change.
: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. The default value is [].

preparations
preparations

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

prepare

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.

validations
validations

Declare validations prior to performing actions against the resource

validate

Examples:

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

Imports:

Ash.Resource.Validation.Builtins

validate
validate

Declares a validation for creates and updates.

Examples:

validate {Mod, [foo: :bar]}

validate at_least_one_of_present([:first_name, :last_name])

:validation - Required. The module/opts pair of the validation
: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. 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? - 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 - If provided, overrides any message set by the validation error
:description - An optional description for the validation
:before_action? - 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.

count
first
sum
list

Examples:

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

Imports:

Ash.Filter.TemplateHelpers

count
count

Declares a named count aggregate on the resource

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

Examples:

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

:name - Required. The field to place the aggregate in
:relationship_path - Required. The relationship or relationship path to use for the aggregate
:kind - Required. The kind of the aggregate
:field - The field to aggregate. Defaults to the first field in the primary key of the resource
:filter - A filter to apply to the aggregate The default value is [].
:description - An optional description for the aggregate
:default - A default value to use in cases where nil would be used. Count defaults to 0 but first and count do not have defaults.
:private? - 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.

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.

Examples:

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

:name - Required. The field to place the aggregate in
:relationship_path - Required. The relationship or relationship path to use for the aggregate
:kind - Required. The kind of the aggregate
:field - The field to aggregate. Defaults to the first field in the primary key of the resource
:filter - A filter to apply to the aggregate The default value is [].
:sort - A sort to be applied to the aggregate
:description - An optional description for the aggregate
:default - A default value to use in cases where nil would be used. Count defaults to 0 but first and count do not have defaults.
:private? - 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.

sum
sum

Declares a named sum aggregate on the resource

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

Examples:

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

:name - Required. The field to place the aggregate in
:relationship_path - Required. The relationship or relationship path to use for the aggregate
:kind - Required. The kind of the aggregate
:field - The field to aggregate. Defaults to the first field in the primary key of the resource
:filter - A filter to apply to the aggregate The default value is [].
:description - An optional description for the aggregate
:default - A default value to use in cases where nil would be used. Count defaults to 0 but first and count do not have defaults.
:private? - 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.

list
list

Declares a named list aggregate on the resource.

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

Examples:

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

:name - Required. The field to place the aggregate in
:relationship_path - Required. The relationship or relationship path to use for the aggregate
:kind - Required. The kind of the aggregate
:field - The field to aggregate. Defaults to the first field in the primary key of the resource
:filter - A filter to apply to the aggregate The default value is [].
:sort - A sort to be applied to the aggregate
:description - An optional description for the aggregate
:default - A default value to use in cases where nil would be used. Count defaults to 0 but first and count do not have defaults.
:private? - 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.

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.

calculate
- argument

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

argument

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 - Required. The field name to use for the calculation value
:type - Required. The type of the calculation
:constraints - Constraints to provide to the type. The default value is [].
:allow_async? - If set to true, then the calculation may be run after the main query. The default value is false.
:calculation - Required. The module or {module, opts} to use for the calculation
:description - An optional description for the calculation
:private? - Whether or not the calculation will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql The default value is false.
:select - A list of fields to ensure selected if the calculation is used. The default value is [].
:load - A load statement to be applied if the calculation is used. The default value is [].
:allow_nil? - 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

Examples:

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

argument :retries, :integer do
  allow_nil? false
end

:name - Required. The name of the argument
:type - Required. The type of the argument
:default - A default value to use for the argument if not provided
:allow_nil? - Whether or not the argument value may be nil (or may be not provided) The default value is true.
:constraints - Constraints to provide to the type when casting the value. See the type's documentation for more information. 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.

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 - If using the attribute strategy, the attribute to use, e.g org_id
:global? - 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, []}.

Settings View Source Ash.Resource.Dsl (ash v2.0.0-rc.13)

dsl-documentation DSL Documentation

index Index

docs Docs

attributes attributes

attribute attribute

create_timestamp create_timestamp

update_timestamp update_timestamp

integer_primary_key integer_primary_key

uuid_primary_key uuid_primary_key

relationships relationships

has_one has_one

has_many has_many

many_to_many many_to_many

belongs_to belongs_to

actions actions

create create

change

validate

argument

metadata

read read

argument

prepare

pagination

update update

change

validate

metadata

argument

destroy destroy

change

validate

metadata

argument

code_interface code_interface

define define

resource resource

identities identities

identity identity

changes changes

change change

preparations preparations

prepare prepare

validations validations

validate validate

aggregates aggregates

count count

first first

sum sum

list list

calculations calculations

calculate calculate

argument

multitenancy multitenancy

View Source Ash.Resource.Dsl (ash v2.0.0-rc.13)

dsl-documentation
DSL Documentation

index
Index

docs
Docs

attributes
attributes

attribute
attribute

create_timestamp
create_timestamp

update_timestamp
update_timestamp

integer_primary_key
integer_primary_key

uuid_primary_key
uuid_primary_key

relationships
relationships

has_one
has_one

has_many
has_many

many_to_many
many_to_many

belongs_to
belongs_to

actions
actions

create
create

read
read

update
update

destroy
destroy

code_interface
code_interface

define
define

resource
resource

identities
identities

identity
identity

changes
changes

change
change

preparations
preparations

prepare
prepare

validations
validations

validate
validate

aggregates
aggregates

count
count

first
first

sum
sum

list
list

calculations
calculations

calculate
calculate

multitenancy
multitenancy