DSL: Ash.Resource — ash v2.17.0

attributes.create_timestamp

create_timestamp name

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

Arguments

Name	Type	Default	Docs
name ^*	`atom`		The name of the attribute.

Options

Name	Type	Default	Docs
type	`module`	`Ash.Type.UtcDatetimeUsec`	The type of the attribute. See `Ash.Type` for more.
constraints	`Keyword.t`		Constraints to provide to the type when casting the value. For more, see the [constraints topic](/documentation/topics/constraints.md).
description	`String.t`		An optional description for the attribute.
sensitive?	`boolean`	`false`	Whether or not the attribute value contains sensitive information, like PII. See the [Security guide](/documentation/topics/security.md) for more.
source	`atom`		If the field should be mapped to a different name in the data layer. Support varies by data layer.
always_select?	`boolean`	`false`	Whether or not to ensure this attribute is always selected when reading from the database, regardless of applied select statements.
primary_key?	`boolean`	`false`	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.
allow_nil?	`boolean`	`false`	Whether or not the attribute can be set to nil. If nil value is given error is raised.
generated?	`boolean`	`false`	Whether or not the value may be generated by the data layer.
writable?	`boolean`	`false`	Whether or not the value can be written to. Non-writable attributes can still be written with `Ash.Changeset.force_change_attribute/3`.
private?	`boolean`	`true`	The attribute is not publically writable, and should not be exposed over any public interfaces. See the [security guide](/documentation/topics/security.md) for more.
default	`(-> any) \| mfa \| any()`	`&DateTime.utc_now/0`	A value to be set on all creates, unless a value is being provided already.
update_default	`(-> any) \| mfa \| any()`		A value to be set on all updates, unless a value is being provided already.
filterable?	`boolean \| :simple_equality`	`true`	Whether or not the attribute can be referenced in filters.
match_other_defaults?	`boolean`	`true`	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.

Introspection

attributes.update_timestamp

update_timestamp name

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 :updated_at

Arguments

Name	Type	Default	Docs
name ^*	`atom`		The name of the attribute.

Options

Name	Type	Default	Docs
type	`module`	`Ash.Type.UtcDatetimeUsec`	The type of the attribute. See `Ash.Type` for more.
constraints	`Keyword.t`		Constraints to provide to the type when casting the value. For more, see the [constraints topic](/documentation/topics/constraints.md).
description	`String.t`		An optional description for the attribute.
sensitive?	`boolean`	`false`	Whether or not the attribute value contains sensitive information, like PII. See the [Security guide](/documentation/topics/security.md) for more.
source	`atom`		If the field should be mapped to a different name in the data layer. Support varies by data layer.
always_select?	`boolean`	`false`	Whether or not to ensure this attribute is always selected when reading from the database, regardless of applied select statements.
primary_key?	`boolean`	`false`	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.
allow_nil?	`boolean`	`false`	Whether or not the attribute can be set to nil. If nil value is given error is raised.
generated?	`boolean`	`false`	Whether or not the value may be generated by the data layer.
writable?	`boolean`	`false`	Whether or not the value can be written to. Non-writable attributes can still be written with `Ash.Changeset.force_change_attribute/3`.
private?	`boolean`	`true`	The attribute is not publically writable, and should not be exposed over any public interfaces. See the [security guide](/documentation/topics/security.md) for more.
default	`(-> any) \| mfa \| any()`	`&DateTime.utc_now/0`	A value to be set on all creates, unless a value is being provided already.
update_default	`(-> any) \| mfa \| any()`	`&DateTime.utc_now/0`	A value to be set on all updates, unless a value is being provided already.
filterable?	`boolean \| :simple_equality`	`true`	Whether or not the attribute can be referenced in filters.
match_other_defaults?	`boolean`	`true`	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.

Introspection

attributes.integer_primary_key

integer_primary_key name

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

Arguments

Name	Type	Default	Docs
name ^*	`atom`		The name of the attribute.

Options

Name	Type	Default	Docs
type	`module`	`:integer`	The type of the attribute. See `Ash.Type` for more.
constraints	`Keyword.t`		Constraints to provide to the type when casting the value. For more, see the [constraints topic](/documentation/topics/constraints.md).
description	`String.t`		An optional description for the attribute.
sensitive?	`boolean`	`false`	Whether or not the attribute value contains sensitive information, like PII. See the [Security guide](/documentation/topics/security.md) for more.
source	`atom`		If the field should be mapped to a different name in the data layer. Support varies by data layer.
always_select?	`boolean`	`false`	Whether or not to ensure this attribute is always selected when reading from the database, regardless of applied select statements.
primary_key?	`boolean`	`true`	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.
generated?	`boolean`	`true`	Whether or not the value may be generated by the data layer.
writable?	`boolean`	`false`	Whether or not the value can be written to. Non-writable attributes can still be written with `Ash.Changeset.force_change_attribute/3`.
private?	`boolean`	`false`	The attribute is not publically writable, and should not be exposed over any public interfaces. See the [security guide](/documentation/topics/security.md) for more.
default	`(-> any) \| mfa \| any()`		A value to be set on all creates, unless a value is being provided already.
update_default	`(-> any) \| mfa \| any()`		A value to be set on all updates, unless a value is being provided already.
filterable?	`boolean \| :simple_equality`	`true`	Whether or not the attribute can be referenced in filters.
match_other_defaults?	`boolean`	`false`	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.

Introspection

attributes.uuid_primary_key

uuid_primary_key name

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

Arguments

Name	Type	Default	Docs
name ^*	`atom`		The name of the attribute.

Options

Name	Type	Default	Docs
type	`module`	`:uuid`	The type of the attribute. See `Ash.Type` for more.
constraints	`Keyword.t`		Constraints to provide to the type when casting the value. For more, see the [constraints topic](/documentation/topics/constraints.md).
description	`String.t`		An optional description for the attribute.
sensitive?	`boolean`	`false`	Whether or not the attribute value contains sensitive information, like PII. See the [Security guide](/documentation/topics/security.md) for more.
source	`atom`		If the field should be mapped to a different name in the data layer. Support varies by data layer.
always_select?	`boolean`	`false`	Whether or not to ensure this attribute is always selected when reading from the database, regardless of applied select statements.
primary_key?	`boolean`	`true`	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.
generated?	`boolean`	`false`	Whether or not the value may be generated by the data layer.
writable?	`boolean`	`false`	Whether or not the value can be written to. Non-writable attributes can still be written with `Ash.Changeset.force_change_attribute/3`.
private?	`boolean`	`false`	The attribute is not publically writable, and should not be exposed over any public interfaces. See the [security guide](/documentation/topics/security.md) for more.
default	`(-> any) \| mfa \| any()`	`&Ash.UUID.generate/0`	A value to be set on all creates, unless a value is being provided already.
update_default	`(-> any) \| mfa \| any()`		A value to be set on all updates, unless a value is being provided already.
filterable?	`boolean \| :simple_equality`	`true`	Whether or not the attribute can be referenced in filters.
match_other_defaults?	`boolean`	`false`	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.

Introspection

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

relationships.has_one

has_one name, destination

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

Arguments

Name	Type	Default	Docs
name	`atom`		The name of the relationship
destination	`module`		The destination resource

Options

Name	Type	Default	Docs
manual	`(any, any -> any) \| module`		A module that implements `Ash.Resource.ManualRelationship`. Also accepts a 2 argument function that takes the source records and the context.
no_attributes?	`boolean`		All existing entities are considered related, i.e this relationship is not based on any fields, and `source_attribute` and `destination_attribute` are ignored. See the See the [relationships guide](/documentation/topics/relationships.md) for more.
allow_nil?	`boolean`	`true`	Marks the relationship as required. Has no effect on validations, but can inform extensions that there will always be a related entity.
from_many?	`boolean`	`false`	Signal that this relationship is actually a `has_many` where the first record is given via the `sort`. This will allow data layers to properly deduplicate when necessary.
description	`String.t`		An optional description for the relationship
destination_attribute	`atom`		The attribute on the related resource that should match the `source_attribute` configured on this resource.
validate_destination_attribute?	`boolean`	`true`	Whether or not to validate that the destination field exists on the destination resource
source_attribute	`atom`	`:id`	The field on this resource that should match the `destination_attribute` on the related resource.
relationship_context	`any`		Context to be set on any queries or changesets generated for managing or querying this relationship.
private?	`boolean`	`false`	Whether or not the relationship will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql See the [security guide](/documentation/topics/security.md) for more.
not_found_message	`String.t`		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`	`true`	Whether or not the relationship may be managed.
read_action	`atom`		The read action on the destination resource to use when loading data and filtering.
api	`atom`		The API module to use when working with the related entity.
filter	`any`		A filter to be applied when reading the relationship.
filterable?	`boolean`	`true`	If set to `false`, the relationship will not be usable in filters.
sort	`any`		A sort statement to be applied when loading the relationship.
could_be_related_at_creation?	`boolean`	`false`	Whether or not related values may exist for this relationship at creation.
violation_message	`String.t`		A message to show if there is a conflict with this relationship in the database on destroy.

Introspection

Target: Ash.Resource.Relationships.HasOne

relationships.has_many

has_many name, destination

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

Arguments

Name	Type	Default	Docs
name	`atom`		The name of the relationship
destination	`module`		The destination resource

Options

Name	Type	Default	Docs
manual	`(any, any -> any) \| module`		A module that implements `Ash.Resource.ManualRelationship`. Also accepts a 2 argument function that takes the source records and the context.
no_attributes?	`boolean`		All existing entities are considered related, i.e this relationship is not based on any fields, and `source_attribute` and `destination_attribute` are ignored. See the See the [relationships guide](/documentation/topics/relationships.md) for more.
description	`String.t`		An optional description for the relationship
destination_attribute	`atom`		The attribute on the related resource that should match the `source_attribute` configured on this resource.
validate_destination_attribute?	`boolean`	`true`	Whether or not to validate that the destination field exists on the destination resource
source_attribute	`atom`	`:id`	The field on this resource that should match the `destination_attribute` on the related resource.
relationship_context	`any`		Context to be set on any queries or changesets generated for managing or querying this relationship.
private?	`boolean`	`false`	Whether or not the relationship will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql See the [security guide](/documentation/topics/security.md) for more.
not_found_message	`String.t`		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`	`true`	Whether or not the relationship may be managed.
read_action	`atom`		The read action on the destination resource to use when loading data and filtering.
api	`atom`		The API module to use when working with the related entity.
filter	`any`		A filter to be applied when reading the relationship.
filterable?	`boolean`	`true`	If set to `false`, the relationship will not be usable in filters.
sort	`any`		A sort statement to be applied when loading the relationship.
could_be_related_at_creation?	`boolean`	`false`	Whether or not related values may exist for this relationship at creation.
violation_message	`String.t`		A message to show if there is a conflict with this relationship in the database on destroy.

Introspection

Target: Ash.Resource.Relationships.HasMany

relationships.many_to_many

many_to_many name, destination

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

Arguments

Name	Type	Default	Docs
name	`atom`		The name of the relationship
destination	`module`		The destination resource

Options

Name	Type	Default	Docs
through ^*	`module`		The resource to use as the join resource.
source_attribute_on_join_resource	`atom`		The attribute on the join resource that should line up with `source_attribute` on this resource. Defaults to `_id`.
destination_attribute_on_join_resource	`atom`		The attribute on the join resource that should line up with `destination_attribute` on the related resource. Defaults to `_id`.
join_relationship	`atom`		The has_many relationship to the join resource. Defaults to `_join_assoc`.
description	`String.t`		An optional description for the relationship
destination_attribute	`atom`	`:id`	The attribute on the related resource that should match the `source_attribute` configured on this resource.
validate_destination_attribute?	`boolean`	`true`	Whether or not to validate that the destination field exists on the destination resource
source_attribute	`atom`	`:id`	The field on this resource that should match the `destination_attribute` on the related resource.
relationship_context	`any`		Context to be set on any queries or changesets generated for managing or querying this relationship.
private?	`boolean`	`false`	Whether or not the relationship will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql See the [security guide](/documentation/topics/security.md) for more.
not_found_message	`String.t`		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`	`true`	Whether or not the relationship may be managed.
read_action	`atom`		The read action on the destination resource to use when loading data and filtering.
api	`atom`		The API module to use when working with the related entity.
filter	`any`		A filter to be applied when reading the relationship.
filterable?	`boolean`	`true`	If set to `false`, the relationship will not be usable in filters.
sort	`any`		A sort statement to be applied when loading the relationship.
could_be_related_at_creation?	`boolean`	`false`	Whether or not related values may exist for this relationship at creation.
violation_message	`String.t`		A message to show if there is a conflict with this relationship in the database on destroy.

Introspection

Target: Ash.Resource.Relationships.ManyToMany

relationships.belongs_to

belongs_to name, destination

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

Arguments

Name	Type	Default	Docs
name	`atom`		The name of the relationship
destination	`module`		The destination resource

Options

Name	Type	Default	Docs
primary_key?	`boolean`	`false`	Whether the generated attribute is, or is part of, the primary key of a resource.
allow_nil?	`boolean`	`true`	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.
attribute_writable?	`boolean`	`false`	Whether the generated attribute will be marked as public & writable.
define_attribute?	`boolean`	`true`	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.
attribute_type	`any`	`:uuid`	The type of the generated created attribute. See `Ash.Type` for more.
description	`String.t`		An optional description for the relationship
destination_attribute	`atom`	`:id`	The attribute on the related resource that should match the `source_attribute` configured on this resource.
validate_destination_attribute?	`boolean`	`true`	Whether or not to validate that the destination field exists on the destination resource
source_attribute	`atom`		The field on this resource that should match the `destination_attribute` on the related resource. - Defaults to _id
relationship_context	`any`		Context to be set on any queries or changesets generated for managing or querying this relationship.
private?	`boolean`	`false`	Whether or not the relationship will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql See the [security guide](/documentation/topics/security.md) for more.
not_found_message	`String.t`		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`	`true`	Whether or not the relationship may be managed.
read_action	`atom`		The read action on the destination resource to use when loading data and filtering.
api	`atom`		The API module to use when working with the related entity.
filter	`any`		A filter to be applied when reading the relationship.
filterable?	`boolean`	`true`	If set to `false`, the relationship will not be usable in filters.
sort	`any`		A sort statement to be applied when loading the relationship.
violation_message	`String.t`		A message to show if there is a conflict with this relationship in the database on destroy.

Introspection

Target: Ash.Resource.Relationships.BelongsTo

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.

Nested DSLs

action
- argument
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

Options

Name	Type	Default	Docs
defaults	`list(:create \| :read \| :update \| :destroy)`		Creates a simple action of each specified type, with the same name as the type. These will be `primary?` unless one already exists for that type. Embedded resources, however, have a default of all resource types.
default_accept	`list(atom)`		A default value for the `accept` option for each action. Defaults to all public attributes.

actions.action

action name, returns

Declares a generic action. A combination of arguments, a return type and a run function.

For calling this action, see the Ash.Api documentation.

Nested DSLs

argument

Examples

action :top_user_emails, {:array, :string} do
  argument :limit, :integer, default: 10, allow_nil?: false
  run fn input, context ->
    with {:ok, top_users} <- top_users(input.limit) do
      {:ok, Enum.map(top_users, &(&1.email))}
    end
  end
end

Arguments

Name	Type	Default	Docs
name ^*	`atom`		The name of the action
returns	`module`		The return type of the action. See `Ash.Type` for more.

Options

Name	Type	Default	Docs
constraints	`Keyword.t`		Constraints for the return type. See the [constriants topic](/documentation/topics/constraints.md) for more.
allow_nil?	`boolean`	`false`	Whether or not the action can return nil. Unlike attributes & arguments, this defaults to `false`.
run	`(any, any -> any) \| module`
primary?	`boolean`	`false`	Whether or not this action should be used when no action is specified by the caller.
description	`String.t`		An optional description for the action
transaction?	`boolean`		Whether or not the action should be run in transactions. Reads default to false, while create/update/destroy actions default to `true`.
touches_resources	`list(atom)`		A list of resources that the action may touch, used when building transactions.

actions.action.argument

argument name, type

Declares an argument on the action

Examples

argument :password_confirmation, :string

Arguments

Name	Type	Default	Docs
name ^*	`atom`		The name of the argument
type ^*	`module`		The type of the argument. See `Ash.Type` for more.

Options

Name	Type	Default	Docs
description	`String.t`		An optional description for the argument.
constraints	`Keyword.t`	`[]`	Constraints to provide to the type when casting the value. For more information, see [the constraints topic](/documentation/topics/constraints.md).
allow_nil?	`boolean`	`true`	Whether or not the argument value may be nil (or may be not provided). If nil value is given error is raised.
private?	`boolean`	`false`	Whether or not the argument should be suppliable by the client.
sensitive?	`boolean`	`false`	Whether or not the argument value contains sensitive information, like PII. See the [security guide](/documentation/topics/security.md) for more.
default	`any`		The default value for the argument to take. It can be a zero argument function e.g `&MyMod.my_fun/0` or a value

Introspection

Introspection

Target: Ash.Resource.Actions.Action

actions.create

create name

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

Nested DSLs

change
validate
argument
metadata

Examples

create :register do
  primary? true
end

Arguments

Name	Type	Default	Docs
name ^*	`atom`		The name of the action

Options

Name	Type	Default	Docs
allow_nil_input	`list(atom)`		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	`(any, any -> any) \| module`		Override the creation behavior. Accepts a module or module and opts, or a function that takes the changeset and context. See the [manual actions guide](/documentation/topics/manual-actions.md) for more.
upsert?	`boolean`	`false`	Forces all uses of this action to be treated as an upsert.
upsert_identity	`atom`		The identity to use for the upsert. Cannot be overriden by the caller. Ignored if `upsert?` is not set to `true`.
upsert_fields	`:replace_all \| {:replace, atom \| list(atom)} \| {:replace_all_except, atom \| list(atom)} \| atom \| list(atom)`		The fields to overwrite in the case of an upsert. If not provided, all fields except for fields set by defaults will be overwritten.
primary?	`boolean`	`false`	Whether or not this action should be used when no action is specified by the caller.
description	`String.t`		An optional description for the action
transaction?	`boolean`		Whether or not the action should be run in transactions. Reads default to false, while create/update/destroy actions default to `true`.
touches_resources	`list(atom)`		A list of resources that the action may touch, used when building transactions.
accept	`:all \| list(atom)`		The list of attributes to accept. Defaults to all attributes on the resource
delay_global_validations?	`boolean`	`false`	If true, global validations will be done in a `before_action` hook, regardless of their configuration on the resource.
skip_global_validations?	`boolean`	`false`	If true, global validations will be skipped. Useful for manual actions.
reject	`:all \| list(atom)`		A list of attributes not to accept. If this is specified along with `accept`, these are removed from the `accept` list.
require_attributes	`list(atom)`		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	`mfa`		Sets the error handler on the changeset. See `Ash.Changeset.handle_errors/2` for more
manual?	`boolean`		Instructs Ash to skip the actual update/create/destroy step at the data layer. See the [manual actions guide](/documentation/topics/manual-actions.md) for more.

actions.create.change

change change

A change to be applied to the changeset.

See Ash.Resource.Change for more.

Examples

change relate_actor(:reporter)

change {MyCustomChange, :foo}

Arguments

Name	Type	Default	Docs
change ^*	`(any, any -> any) \| module`		The module and options for a change. Also accepts a function that takes the changeset and the context. See `Ash.Resource.Change.Builtins` for builtin changes.

Options

Name	Type	Default	Docs
only_when_valid?	`boolean`	`false`	If the change should only be run on valid changes. By default, all changes are run unless stated otherwise here.
description	`String.t`		An optional description for the change
where	`list((any -> any) \| module)`	`[]`	Validations that should pass in order for this validation to apply. These validations failing will result in this validation being ignored.

Introspection

actions.create.validate

validate validation

Declares a validation to be applied to the changeset.

See Ash.Resource.Validation for more.

Examples

validate changing(:email)

Arguments

Name	Type	Default	Docs
validation ^*	`(any -> any) \| module`		The module (or module and opts) that implements the `Ash.Resource.Validation` behaviour. Also accepts a one argument function that takes the changeset.

Options

Name	Type	Default	Docs
where	`(any -> any) \| module \| list((any -> any) \| module)`	`[]`	Validations that should pass in order for this validation to apply. Any of these validations failing will result in this validation being ignored.
only_when_valid?	`boolean`	`false`	If the validation should only run on valid changes. Useful for expensive validations or validations that depend on valid data.
message	`String.t`		If provided, overrides any message set by the validation error
description	`String.t`		An optional description for the validation
before_action?	`boolean`	`false`	If set to `true`, the validation will be run in a before_action hook

Introspection

actions.create.argument

argument name, type

Declares an argument on the action

Examples

argument :password_confirmation, :string

Arguments

Name	Type	Default	Docs
name ^*	`atom`		The name of the argument
type ^*	`module`		The type of the argument. See `Ash.Type` for more.

Options

Name	Type	Default	Docs
description	`String.t`		An optional description for the argument.
constraints	`Keyword.t`	`[]`	Constraints to provide to the type when casting the value. For more information, see [the constraints topic](/documentation/topics/constraints.md).
allow_nil?	`boolean`	`true`	Whether or not the argument value may be nil (or may be not provided). If nil value is given error is raised.
private?	`boolean`	`false`	Whether or not the argument should be suppliable by the client.
sensitive?	`boolean`	`false`	Whether or not the argument value contains sensitive information, like PII. See the [security guide](/documentation/topics/security.md) for more.
default	`any`		The default value for the argument to take. It can be a zero argument function e.g `&MyMod.my_fun/0` or a value

Introspection

actions.create.metadata

metadata name, type

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

Arguments

Name	Type	Default	Docs
name ^*	`atom`		The name of the metadata
type ^*	`any`		The type of the metadata. See `Ash.Type` for more.

Options

Name	Type	Default	Docs
constraints	`Keyword.t`	`[]`	Type constraints on the metadata
description	`String.t`		An optional description for the metadata.
allow_nil?	`boolean`	`true`	Whether or not the metadata may return `nil`
default	`any`		The default value for the metadata to take. It can be a zero argument function e.g `&MyMod.my_fun/0` or a value

Introspection

Introspection

Target: Ash.Resource.Actions.Create

actions.read

read name

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

Nested DSLs

argument
prepare
pagination
metadata

Examples

read :read_all do
  primary? true
end

Arguments

Name	Type	Default	Docs
name ^*	`atom`		The name of the action

Options

Name	Type	Default	Docs
filter	`any`		A filter template that will be applied whenever the action is used. See `Ash.Filter` for more on templates
manual	`(any, any, any -> any) \| module`		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](/documentation/topics/manual-actions.md) for more.
get?	`boolean`	`false`	Expresses that this action innately only returns a single result. Used by extensions to validate and/or modify behavior. Causes code interfaces to return a single value instead of a list. See the [code interface guide](/documentation/topics/code-interface.md) for more.
modify_query	`mfa \| (any, any -> any)`		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}`.
get_by	`atom \| list(atom)`		A helper to automatically generate a "get by X" action. Sets `get?` to true, add args for each of the specified fields, and adds a filter for each of the arguments.
primary?	`boolean`	`false`	Whether or not this action should be used when no action is specified by the caller.
description	`String.t`		An optional description for the action
transaction?	`boolean`		Whether or not the action should be run in transactions. Reads default to false, while create/update/destroy actions default to `true`.
touches_resources	`list(atom)`		A list of resources that the action may touch, used when building transactions.

actions.read.argument

argument name, type

Declares an argument on the action

Examples

argument :password_confirmation, :string

Arguments

Name	Type	Default	Docs
name ^*	`atom`		The name of the argument
type ^*	`module`		The type of the argument. See `Ash.Type` for more.

Options

Name	Type	Default	Docs
description	`String.t`		An optional description for the argument.
constraints	`Keyword.t`	`[]`	Constraints to provide to the type when casting the value. For more information, see [the constraints topic](/documentation/topics/constraints.md).
allow_nil?	`boolean`	`true`	Whether or not the argument value may be nil (or may be not provided). If nil value is given error is raised.
private?	`boolean`	`false`	Whether or not the argument should be suppliable by the client.
sensitive?	`boolean`	`false`	Whether or not the argument value contains sensitive information, like PII. See the [security guide](/documentation/topics/security.md) for more.
default	`any`		The default value for the argument to take. It can be a zero argument function e.g `&MyMod.my_fun/0` or a value

Introspection

actions.read.prepare

prepare preparation

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

Examples

prepare build(sort: [:foo, :bar])

Arguments

Name	Type	Default	Docs
preparation ^*	`(any, any -> any) \| module`		The module and options for a preparation. Also accepts functions take the query and the context.

Introspection

Target: Ash.Resource.Preparation

actions.read.pagination

Adds pagination options to a resource

Options

Name	Type	Default	Docs
keyset?	`boolean`	`false`	Whether or not keyset based pagination is supported
offset?	`boolean`	`false`	Whether or not offset based pagination is supported
default_limit	`pos_integer`		The default page size to apply, if one is not supplied
countable	`true \| false \| :by_default`	`false`	Whether not a returned page will have a full count of all records. Use `:by_default` to do it automatically.
max_page_size	`pos_integer`	`250`	The maximum amount of records that can be requested in a single page
required?	`boolean`	`true`	Whether or not pagination can be disabled. Only relevant if some pagination configuration is supplied.

Introspection

Target: Ash.Resource.Actions.Read.Pagination

actions.read.metadata

metadata name, type

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

Arguments

Name	Type	Default	Docs
name ^*	`atom`		The name of the metadata
type ^*	`any`		The type of the metadata. See `Ash.Type` for more.

Options

Name	Type	Default	Docs
constraints	`Keyword.t`	`[]`	Type constraints on the metadata
description	`String.t`		An optional description for the metadata.
allow_nil?	`boolean`	`true`	Whether or not the metadata may return `nil`
default	`any`		The default value for the metadata to take. It can be a zero argument function e.g `&MyMod.my_fun/0` or a value

Introspection

Introspection

Target: Ash.Resource.Actions.Read

actions.update

update name

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

Nested DSLs

change
validate
metadata
argument

Examples

update :flag_for_review, primary?: true

Arguments

Name	Type	Default	Docs
name ^*	`atom`		The name of the action

Options

Name	Type	Default	Docs
manual	`(any, any -> any) \| module`		Override the update behavior. Accepts a module or module and opts, or a function that takes the changeset and context. See the [manual actions guide](/documentation/topics/manual-actions.md) for more.
primary?	`boolean`	`false`	Whether or not this action should be used when no action is specified by the caller.
description	`String.t`		An optional description for the action
transaction?	`boolean`		Whether or not the action should be run in transactions. Reads default to false, while create/update/destroy actions default to `true`.
touches_resources	`list(atom)`		A list of resources that the action may touch, used when building transactions.
accept	`:all \| list(atom)`		The list of attributes to accept. Defaults to all attributes on the resource
delay_global_validations?	`boolean`	`false`	If true, global validations will be done in a `before_action` hook, regardless of their configuration on the resource.
skip_global_validations?	`boolean`	`false`	If true, global validations will be skipped. Useful for manual actions.
reject	`:all \| list(atom)`		A list of attributes not to accept. If this is specified along with `accept`, these are removed from the `accept` list.
require_attributes	`list(atom)`		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	`mfa`		Sets the error handler on the changeset. See `Ash.Changeset.handle_errors/2` for more
manual?	`boolean`		Instructs Ash to skip the actual update/create/destroy step at the data layer. See the [manual actions guide](/documentation/topics/manual-actions.md) for more.

actions.update.change

change change

A change to be applied to the changeset.

See Ash.Resource.Change for more.

Examples

change relate_actor(:reporter)

change {MyCustomChange, :foo}

Arguments

Name	Type	Default	Docs
change ^*	`(any, any -> any) \| module`		The module and options for a change. Also accepts a function that takes the changeset and the context. See `Ash.Resource.Change.Builtins` for builtin changes.

Options

Name	Type	Default	Docs
only_when_valid?	`boolean`	`false`	If the change should only be run on valid changes. By default, all changes are run unless stated otherwise here.
description	`String.t`		An optional description for the change
where	`list((any -> any) \| module)`	`[]`	Validations that should pass in order for this validation to apply. These validations failing will result in this validation being ignored.

Introspection

actions.update.validate

validate validation

Declares a validation to be applied to the changeset.

See Ash.Resource.Validation for more.

Examples

validate changing(:email)

Arguments

Name	Type	Default	Docs
validation ^*	`(any -> any) \| module`		The module (or module and opts) that implements the `Ash.Resource.Validation` behaviour. Also accepts a one argument function that takes the changeset.

Options

Name	Type	Default	Docs
where	`(any -> any) \| module \| list((any -> any) \| module)`	`[]`	Validations that should pass in order for this validation to apply. Any of these validations failing will result in this validation being ignored.
only_when_valid?	`boolean`	`false`	If the validation should only run on valid changes. Useful for expensive validations or validations that depend on valid data.
message	`String.t`		If provided, overrides any message set by the validation error
description	`String.t`		An optional description for the validation
before_action?	`boolean`	`false`	If set to `true`, the validation will be run in a before_action hook

Introspection

actions.update.metadata

metadata name, type

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

Arguments

Name	Type	Default	Docs
name ^*	`atom`		The name of the metadata
type ^*	`any`		The type of the metadata. See `Ash.Type` for more.

Options

Name	Type	Default	Docs
constraints	`Keyword.t`	`[]`	Type constraints on the metadata
description	`String.t`		An optional description for the metadata.
allow_nil?	`boolean`	`true`	Whether or not the metadata may return `nil`
default	`any`		The default value for the metadata to take. It can be a zero argument function e.g `&MyMod.my_fun/0` or a value

Introspection

actions.update.argument

argument name, type

Declares an argument on the action

Examples

argument :password_confirmation, :string

Arguments

Name	Type	Default	Docs
name ^*	`atom`		The name of the argument
type ^*	`module`		The type of the argument. See `Ash.Type` for more.

Options

Name	Type	Default	Docs
description	`String.t`		An optional description for the argument.
constraints	`Keyword.t`	`[]`	Constraints to provide to the type when casting the value. For more information, see [the constraints topic](/documentation/topics/constraints.md).
allow_nil?	`boolean`	`true`	Whether or not the argument value may be nil (or may be not provided). If nil value is given error is raised.
private?	`boolean`	`false`	Whether or not the argument should be suppliable by the client.
sensitive?	`boolean`	`false`	Whether or not the argument value contains sensitive information, like PII. See the [security guide](/documentation/topics/security.md) for more.
default	`any`		The default value for the argument to take. It can be a zero argument function e.g `&MyMod.my_fun/0` or a value

Introspection

Introspection

Target: Ash.Resource.Actions.Update

actions.destroy

destroy name

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

Nested DSLs

change
validate
metadata
argument

Examples

destroy :soft_delete do
  primary? true
end

Arguments

Name	Type	Default	Docs
name ^*	`atom`		The name of the action

Options

Name	Type	Default	Docs
soft?	`atom`	`false`	If specified, the destroy action behaves as an update internally
manual	`(any, any -> any) \| module`		Override the update behavior. Accepts a module or module and opts, or a function that takes the changeset and context. See the [manual actions guide](/documentation/topics/manual-actions.md) for more.
primary?	`boolean`	`false`	Whether or not this action should be used when no action is specified by the caller.
description	`String.t`		An optional description for the action
transaction?	`boolean`		Whether or not the action should be run in transactions. Reads default to false, while create/update/destroy actions default to `true`.
touches_resources	`list(atom)`		A list of resources that the action may touch, used when building transactions.
accept	`:all \| list(atom)`		The list of attributes to accept. Defaults to all attributes on the resource
delay_global_validations?	`boolean`	`false`	If true, global validations will be done in a `before_action` hook, regardless of their configuration on the resource.
skip_global_validations?	`boolean`	`false`	If true, global validations will be skipped. Useful for manual actions.
reject	`:all \| list(atom)`		A list of attributes not to accept. If this is specified along with `accept`, these are removed from the `accept` list.
require_attributes	`list(atom)`		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	`mfa`		Sets the error handler on the changeset. See `Ash.Changeset.handle_errors/2` for more
manual?	`boolean`		Instructs Ash to skip the actual update/create/destroy step at the data layer. See the [manual actions guide](/documentation/topics/manual-actions.md) for more.

actions.destroy.change

change change

A change to be applied to the changeset.

See Ash.Resource.Change for more.

Examples

change relate_actor(:reporter)

change {MyCustomChange, :foo}

Arguments

Name	Type	Default	Docs
change ^*	`(any, any -> any) \| module`		The module and options for a change. Also accepts a function that takes the changeset and the context. See `Ash.Resource.Change.Builtins` for builtin changes.

Options

Name	Type	Default	Docs
only_when_valid?	`boolean`	`false`	If the change should only be run on valid changes. By default, all changes are run unless stated otherwise here.
description	`String.t`		An optional description for the change
where	`list((any -> any) \| module)`	`[]`	Validations that should pass in order for this validation to apply. These validations failing will result in this validation being ignored.

Introspection

actions.destroy.validate

validate validation

Declares a validation to be applied to the changeset.

See Ash.Resource.Validation for more.

Examples

validate changing(:email)

Arguments

Name	Type	Default	Docs
validation ^*	`(any -> any) \| module`		The module (or module and opts) that implements the `Ash.Resource.Validation` behaviour. Also accepts a one argument function that takes the changeset.

Options

Name	Type	Default	Docs
where	`(any -> any) \| module \| list((any -> any) \| module)`	`[]`	Validations that should pass in order for this validation to apply. Any of these validations failing will result in this validation being ignored.
only_when_valid?	`boolean`	`false`	If the validation should only run on valid changes. Useful for expensive validations or validations that depend on valid data.
message	`String.t`		If provided, overrides any message set by the validation error
description	`String.t`		An optional description for the validation
before_action?	`boolean`	`false`	If set to `true`, the validation will be run in a before_action hook

Introspection

actions.destroy.metadata

metadata name, type

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

Arguments

Name	Type	Default	Docs
name ^*	`atom`		The name of the metadata
type ^*	`any`		The type of the metadata. See `Ash.Type` for more.

Options

Name	Type	Default	Docs
constraints	`Keyword.t`	`[]`	Type constraints on the metadata
description	`String.t`		An optional description for the metadata.
allow_nil?	`boolean`	`true`	Whether or not the metadata may return `nil`
default	`any`		The default value for the metadata to take. It can be a zero argument function e.g `&MyMod.my_fun/0` or a value

Introspection

actions.destroy.argument

argument name, type

Declares an argument on the action

Examples

argument :password_confirmation, :string

Arguments

Name	Type	Default	Docs
name ^*	`atom`		The name of the argument
type ^*	`module`		The type of the argument. See `Ash.Type` for more.

Options

Name	Type	Default	Docs
description	`String.t`		An optional description for the argument.
constraints	`Keyword.t`	`[]`	Constraints to provide to the type when casting the value. For more information, see [the constraints topic](/documentation/topics/constraints.md).
allow_nil?	`boolean`	`true`	Whether or not the argument value may be nil (or may be not provided). If nil value is given error is raised.
private?	`boolean`	`false`	Whether or not the argument should be suppliable by the client.
sensitive?	`boolean`	`false`	Whether or not the argument value contains sensitive information, like PII. See the [security guide](/documentation/topics/security.md) for more.
default	`any`		The default value for the argument to take. It can be a zero argument function e.g `&MyMod.my_fun/0` or a value

Introspection

Introspection

Target: Ash.Resource.Actions.Destroy

code_interface

Functions that will be defined on the Api module to interact with this resource. See the code interface guide for more.

Nested DSLs

define
define_calculation

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

Options

Name	Type	Default	Docs
define_for	`module`	`false`	Defines the code interface on the resource module directly, using the provided Api.

code_interface.define

define name

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

Arguments

Name	Type	Default	Docs
name ^*	`atom`		The name of the function that will be defined

Options

Name	Type	Default	Docs
action	`atom`		The name of the action that will be called. Defaults to the same name as the function.
args	`list(atom \| {:optional, atom})`		Map specific arguments to named inputs. Can provide any argument/attributes that the action allows.
not_found_error?	`boolean`	`true`	If the action or interface is configured with `get?: true`, this determines whether or not an error is raised or `nil` is returned.
get?	`boolean`		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	`atom \| list(atom)`		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`		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.

Introspection

Target: Ash.Resource.Interface

code_interface.define_calculation

define_calculation name

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}]

Arguments

Name	Type	Default	Docs
name ^*	`atom`		The name of the function that will be defined

Options

Name	Type	Default	Docs
calculation	`atom`		The name of the calculation that will be evaluated. Defaults to the same name as the function.
args	`any`	`[]`	Supply field or argument values referenced by the calculation, in the form of :name, `{:arg, :name}` and/or `{:ref, :name}`. See the [code interface guide](/documentation/topics/code-interface.md) for more.

Introspection

Target: Ash.Resource.CalculationInterface

resource

General resource configuration

Examples

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

Options

Name	Type	Default	Docs
description	`String.t`		A human readable description of the resource, to be used in generated documentation
base_filter	`any`		A filter statement to be applied to any queries on the resource
default_context	`any`		Default context to apply to any queries/changesets generated for this resource.
trace_name	`String.t`		The name to use in traces. Defaults to the short_name stringified. See the [monitoring guide](/documentation/topics/monitoring.md) for more.
short_name	`atom`		A short identifier for the resource, which should be unique. See the [monitoring guide](/documentation/topics/monitoring.md) for more.
plural_name	`atom`		A pluralized version of the resource short_name. May be used by generators or automated tooling.
simple_notifiers	`list(module)`		A list of notifiers that require no DSL. Can be used to avoid compile time dependencies on notifiers
require_primary_key?	`boolean`	`true`	Allow the resource to be used without any primary key fields. Warning: this option is experimental, and should not be used unless you know what you're doing.

identities

Unique identifiers for the resource

Nested DSLs

identity

Examples

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

identities.identity

identity name, keys

Represents a unique constraint on the resource.

See the identities guide for more.

Examples

identity :name, [:name]

identity :full_name, [:first_name, :last_name]

Arguments

Name	Type	Default	Docs
name ^*	`atom`		The name of the identity.
keys ^*	`atom \| list(atom)`		The names of the attributes that uniquely identify this resource.

Options

Name	Type	Docs
eager_check_with	`module`	Validates that the unique identity provided is unique at validation time, outside of any transactions, using the api module provided.
pre_check_with	`module`	Validates that the unique identity provided is unique in a before_action hook.
description	`String.t`	An optional description for the identity
message	`String.t`	An error message to use when the unique identity would be violated

Introspection

Target: Ash.Resource.Identity

changes

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

See Ash.Resource.Change for more.

Nested DSLs

change

Examples

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

changes.change

change change

A change to be applied to the changeset.

See Ash.Resource.Change for more.

Examples

change relate_actor(:reporter)

change {MyCustomChange, :foo}

Arguments

Name	Type	Default	Docs
change ^*	`(any, any -> any) \| module`		The module and options for a change. Also accepts a function that takes the changeset and the context. See `Ash.Resource.Change.Builtins` for builtin changes.

Options

Name	Type	Default	Docs
on	`:create \| :update \| :destroy \| list(:create \| :update \| :destroy)`	`[:create, :update]`	The action types the validation should run on. Destroy actions are omitted by default as most changes don't make sense for a destroy.
only_when_valid?	`boolean`	`false`	If the change should only be run on valid changes. By default, all changes are run unless stated otherwise here.
description	`String.t`		An optional description for the change
where	`list((any -> any) \| module)`	`[]`	Validations that should pass in order for this validation to apply. These validations failing will result in this validation being ignored.

Introspection

preparations

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

Nested DSLs

prepare

Examples

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

preparations.prepare

prepare preparation

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

Examples

prepare build(sort: [:foo, :bar])

Arguments

Name	Type	Default	Docs
preparation ^*	`(any, any -> any) \| module`		The module and options for a preparation. Also accepts functions take the query and the context.

Introspection

Target: Ash.Resource.Preparation

validations

Declare validations prior to performing actions against the resource

Nested DSLs

validate

Examples

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

validations.validate

validate validation

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])

Arguments

Name	Type	Default	Docs
validation ^*	`(any -> any) \| module`		The module (or module and opts) that implements the `Ash.Resource.Validation` behaviour. Also accepts a one argument function that takes the changeset.

Options

Name	Type	Default	Docs
where	`(any -> any) \| module \| list((any -> any) \| module)`	`[]`	Validations that should pass in order for this validation to apply. Any of these validations failing will result in this validation being ignored.
on	`:create \| :update \| :destroy \| list(:create \| :update \| :destroy)`	`[:create, :update]`	The action types the validation should run on. Many validations don't make sense in the context of deletion, so by default it is not included.
only_when_valid?	`boolean`	`false`	If the validation should only run on valid changes. Useful for expensive validations or validations that depend on valid data.
message	`String.t`		If provided, overrides any message set by the validation error
description	`String.t`		An optional description for the validation
before_action?	`boolean`	`false`	If set to `true`, the validation will be run in a before_action hook

Introspection

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.

Nested DSLs

count
exists
first
sum
list
max
min
avg
custom

Examples

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

aggregates.count

count name, relationship_path

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

Arguments

Name	Type	Default	Docs
name ^*	`atom`		The field to place the aggregate in
relationship_path ^*	`atom \| list(atom)`		The relationship or relationship path to use for the aggregate

Options

Name	Type	Default	Docs
kind ^*	`:count \| :first \| :sum \| :list \| :avg \| :max \| :min \| :exists \| :custom \| {:custom, module}`		The kind of the aggregate
uniq?	`boolean`	`false`	Whether or not to count unique values only
read_action	`atom`		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.
field	`atom`		The field to aggregate. Defaults to the first field in the primary key of the resource
filter	`any`	`[]`	A filter to apply to the aggregate
description	`String.t`		An optional description for the aggregate
default	`any`		A default value to use in cases where nil would be used. Count defaults to `0`.
private?	`boolean`	`false`	Whether or not the aggregate will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql
filterable?	`boolean \| :simple_equality`	`true`	Whether or not the aggregate should be usable in filters.
authorize?	`boolean`	`true`	Whether or not the aggregate query should authorize based on the target action, if the parent query is authorized. Requires filter checks on the target action.

Introspection

aggregates.exists

exists name, relationship_path

Declares a named exists aggregate on the resource

Supports filter, but not sort (because that wouldn't affect if something exists)

See the aggregates guide for more.

Examples

exists :has_ticket, :assigned_tickets

Arguments

Name	Type	Default	Docs
name ^*	`atom`		The field to place the aggregate in
relationship_path ^*	`atom \| list(atom)`		The relationship or relationship path to use for the aggregate

Options

Name	Type	Default	Docs
kind ^*	`:count \| :first \| :sum \| :list \| :avg \| :max \| :min \| :exists \| :custom \| {:custom, module}`		The kind of the aggregate
read_action	`atom`		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.
filter	`any`	`[]`	A filter to apply to the aggregate
description	`String.t`		An optional description for the aggregate
default	`any`		A default value to use in cases where nil would be used. Count defaults to `0`.
private?	`boolean`	`false`	Whether or not the aggregate will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql
filterable?	`boolean \| :simple_equality`	`true`	Whether or not the aggregate should be usable in filters.
authorize?	`boolean`	`true`	Whether or not the aggregate query should authorize based on the target action, if the parent query is authorized. Requires filter checks on the target action.

Introspection

aggregates.first

first name, relationship_path, field

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

Arguments

Name	Type	Docs
name ^*	`atom`	The field to place the aggregate in
relationship_path ^*	`atom \| list(atom)`	The relationship or relationship path to use for the aggregate
field	`atom`	The field to aggregate. Defaults to the first field in the primary key of the resource

Options

Name	Type	Default	Docs
kind ^*	`:count \| :first \| :sum \| :list \| :avg \| :max \| :min \| :exists \| :custom \| {:custom, module}`		The kind of the aggregate
read_action	`atom`		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.
filter	`any`	`[]`	A filter to apply to the aggregate
sort	`any`		A sort to be applied to the aggregate
description	`String.t`		An optional description for the aggregate
default	`any`		A default value to use in cases where nil would be used. Count defaults to `0`.
private?	`boolean`	`false`	Whether or not the aggregate will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql
filterable?	`boolean \| :simple_equality`	`true`	Whether or not the aggregate should be usable in filters.
authorize?	`boolean`	`true`	Whether or not the aggregate query should authorize based on the target action, if the parent query is authorized. Requires filter checks on the target action.

Introspection

aggregates.sum

sum name, relationship_path, field

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

Arguments

Name	Type	Docs
name ^*	`atom`	The field to place the aggregate in
relationship_path ^*	`atom \| list(atom)`	The relationship or relationship path to use for the aggregate
field	`atom`	The field to aggregate. Defaults to the first field in the primary key of the resource

Options

Name	Type	Default	Docs
kind ^*	`:count \| :first \| :sum \| :list \| :avg \| :max \| :min \| :exists \| :custom \| {:custom, module}`		The kind of the aggregate
read_action	`atom`		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.
filter	`any`	`[]`	A filter to apply to the aggregate
description	`String.t`		An optional description for the aggregate
default	`any`		A default value to use in cases where nil would be used. Count defaults to `0`.
private?	`boolean`	`false`	Whether or not the aggregate will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql
filterable?	`boolean \| :simple_equality`	`true`	Whether or not the aggregate should be usable in filters.
authorize?	`boolean`	`true`	Whether or not the aggregate query should authorize based on the target action, if the parent query is authorized. Requires filter checks on the target action.

Introspection

aggregates.list

list name, relationship_path, field

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

Arguments

Name	Type	Docs
name ^*	`atom`	The field to place the aggregate in
relationship_path ^*	`atom \| list(atom)`	The relationship or relationship path to use for the aggregate
field	`atom`	The field to aggregate. Defaults to the first field in the primary key of the resource

Options

Name	Type	Default	Docs
kind ^*	`:count \| :first \| :sum \| :list \| :avg \| :max \| :min \| :exists \| :custom \| {:custom, module}`		The kind of the aggregate
uniq?	`boolean`	`false`	Whether or not to count unique values only
read_action	`atom`		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.
filter	`any`	`[]`	A filter to apply to the aggregate
sort	`any`		A sort to be applied to the aggregate
description	`String.t`		An optional description for the aggregate
default	`any`		A default value to use in cases where nil would be used. Count defaults to `0`.
private?	`boolean`	`false`	Whether or not the aggregate will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql
filterable?	`boolean \| :simple_equality`	`true`	Whether or not the aggregate should be usable in filters.
authorize?	`boolean`	`true`	Whether or not the aggregate query should authorize based on the target action, if the parent query is authorized. Requires filter checks on the target action.

Introspection

aggregates.max

max name, relationship_path, field

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

Arguments

Name	Type	Docs
name ^*	`atom`	The field to place the aggregate in
relationship_path ^*	`atom \| list(atom)`	The relationship or relationship path to use for the aggregate
field	`atom`	The field to aggregate. Defaults to the first field in the primary key of the resource

Options

Name	Type	Default	Docs
kind ^*	`:count \| :first \| :sum \| :list \| :avg \| :max \| :min \| :exists \| :custom \| {:custom, module}`		The kind of the aggregate
read_action	`atom`		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.
filter	`any`	`[]`	A filter to apply to the aggregate
description	`String.t`		An optional description for the aggregate
default	`any`		A default value to use in cases where nil would be used. Count defaults to `0`.
private?	`boolean`	`false`	Whether or not the aggregate will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql
filterable?	`boolean \| :simple_equality`	`true`	Whether or not the aggregate should be usable in filters.
authorize?	`boolean`	`true`	Whether or not the aggregate query should authorize based on the target action, if the parent query is authorized. Requires filter checks on the target action.

Introspection

aggregates.min

min name, relationship_path, field

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

Arguments

Name	Type	Docs
name ^*	`atom`	The field to place the aggregate in
relationship_path ^*	`atom \| list(atom)`	The relationship or relationship path to use for the aggregate
field	`atom`	The field to aggregate. Defaults to the first field in the primary key of the resource

Options

Name	Type	Default	Docs
kind ^*	`:count \| :first \| :sum \| :list \| :avg \| :max \| :min \| :exists \| :custom \| {:custom, module}`		The kind of the aggregate
read_action	`atom`		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.
filter	`any`	`[]`	A filter to apply to the aggregate
description	`String.t`		An optional description for the aggregate
default	`any`		A default value to use in cases where nil would be used. Count defaults to `0`.
private?	`boolean`	`false`	Whether or not the aggregate will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql
filterable?	`boolean \| :simple_equality`	`true`	Whether or not the aggregate should be usable in filters.
authorize?	`boolean`	`true`	Whether or not the aggregate query should authorize based on the target action, if the parent query is authorized. Requires filter checks on the target action.

Introspection

aggregates.avg

avg name, relationship_path, field

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

Arguments

Name	Type	Docs
name ^*	`atom`	The field to place the aggregate in
relationship_path ^*	`atom \| list(atom)`	The relationship or relationship path to use for the aggregate
field	`atom`	The field to aggregate. Defaults to the first field in the primary key of the resource

Options

Name	Type	Default	Docs
kind ^*	`:count \| :first \| :sum \| :list \| :avg \| :max \| :min \| :exists \| :custom \| {:custom, module}`		The kind of the aggregate
read_action	`atom`		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.
filter	`any`	`[]`	A filter to apply to the aggregate
description	`String.t`		An optional description for the aggregate
default	`any`		A default value to use in cases where nil would be used. Count defaults to `0`.
private?	`boolean`	`false`	Whether or not the aggregate will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql
filterable?	`boolean \| :simple_equality`	`true`	Whether or not the aggregate should be usable in filters.
authorize?	`boolean`	`true`	Whether or not the aggregate query should authorize based on the target action, if the parent query is authorized. Requires filter checks on the target action.

Introspection

aggregates.custom

custom name, relationship_path, type

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

Arguments

Name	Type	Docs
name ^*	`atom`	The field to place the aggregate in
relationship_path ^*	`atom \| list(atom)`	The relationship or relationship path to use for the aggregate
type ^*	`module`	The type of the value returned by the aggregate

Options

Name	Type	Default	Docs
implementation ^*	`module`		The module that implements the relevant data layer callbacks
kind ^*	`:count \| :first \| :sum \| :list \| :avg \| :max \| :min \| :exists \| :custom \| {:custom, module}`		The kind of the aggregate
read_action	`atom`		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.
field	`atom`		The field to aggregate. Defaults to the first field in the primary key of the resource
filter	`any`	`[]`	A filter to apply to the aggregate
sort	`any`		A sort to be applied to the aggregate
description	`String.t`		An optional description for the aggregate
default	`any`		A default value to use in cases where nil would be used. Count defaults to `0`.
private?	`boolean`	`false`	Whether or not the aggregate will appear in any interfaces created off of this resource, e.g AshJsonApi and AshGraphql
filterable?	`boolean \| :simple_equality`	`true`	Whether or not the aggregate should be usable in filters.
authorize?	`boolean`	`true`	Whether or not the aggregate query should authorize based on the target action, if the parent query is authorized. Requires filter checks on the target action.

Introspection