View Source Ash.Calculation behaviour (ash v2.21.12)

The behaviour for a calculation module

Use select/2 to apply a select statement when the calculation is loaded. This does not apply in the case that you are loading on existing resources using MyApi.load. It also doesn't apply when the calculation is used in a filter or sort, because it is not necessary to select fields to power filters done in the data layer.

Summary

Types

context()

opts()

Callbacks

calculate(records, opts, context)

describe(opts)

expression(otps, context)

has_expression?()

init(opts)

load(query, opts, context)

select(query, opts, context)

Types

context()

@type context() :: %{
  :actor => term() | nil,
  :tenant => term(),
  :authorize? => boolean() | nil,
  :tracer => module() | nil,
  optional(atom()) => any()
}

opts()

@type opts() :: Keyword.t()

Callbacks

calculate(records, opts, context)

(optional)

@callback calculate(
  records :: [Ash.Resource.record()],
  opts :: opts(),
  context :: context()
) ::
  {:ok, [term()]} | [term()] | {:error, term()} | :unknown

describe(opts)

@callback describe(opts :: opts()) :: String.t()

expression(otps, context)

(optional)

@callback expression(otps :: opts(), context :: context()) :: any()

has_expression?()

@callback has_expression?() :: boolean()

init(opts)

@callback init(opts :: opts()) :: {:ok, opts()} | {:error, term()}

load(query, opts, context)

@callback load(query :: Ash.Query.t(), opts :: opts(), context :: context()) ::
  atom() | [atom()] | Keyword.t()

select(query, opts, context)

@callback select(query :: Ash.Query.t(), opts :: opts(), context :: context()) :: [atom()]