nebulex v1.0.0-rc.2 Nebulex.Cache.Hook behaviour View Source

Specifies pre/post hooks callbacks. These are functions that you define and that you direct to execute before or after particular cache action.

Execution strategies

It is possible to configure the strategy how the hooks are evaluated, the available strategies are:

:async - (the default) all hooks are evaluated asynchronously (in parallel) and their results are ignored.
:sync - hooks are evaluated synchronously (sequentially) and their results are ignored.
:pipe - similar to :sync but each hook result is passed to the next one and so on, until the last hook evaluation is returned.

These strategy values applies to the compile-time options :pre_hooks_strategy and :post_hooks_strategy.

Example

config :my_app, MyApp.MyCache,
  adapter: Nebulex.Adapters.Local,
  n_shards: 2,
  pre_hooks_strategy: :async,
  post_hooks_strategy: :pipe

defmodule MyApp.MyCache do
  use Nebulex.Cache, adapter: Nebulex.Adapters.Local

  def pre_hooks do
    [... your pre hook functions ...]
  end

  def post_hooks do
    [... your post hook functions ...]
  end
end

Link to this section Summary

Types

hook_fun()

Callbacks

post_hooks()

Returns a list of hook functions that will be executed after invoke the cache action

pre_hooks()

Returns a list of hook functions that will be executed before invoke the cache action

Link to this section Types

hook_fun()

hook_fun() :: (result :: any(), {Nebulex.Cache.t(), action :: atom(), args :: [any()]} -> any())

Link to this section Callbacks

post_hooks()

post_hooks() :: [hook_fun()]

Returns a list of hook functions that will be executed after invoke the cache action.

Examples

defmodule MyCache do
  use Nebulex.Cache, adapter: Nebulex.Adapters.Local

  def post_hooks do
    [&post_hook/2]
  end

  def post_hook(result, {_, :set, _} = call),
    do: send(:hooked_cache, call)
  def post_hook(_, _),
    do: :noop
end

pre_hooks()

pre_hooks() :: [hook_fun()]

Returns a list of hook functions that will be executed before invoke the cache action.

Examples

defmodule MyCache do
  use Nebulex.Cache, adapter: Nebulex.Adapters.Local

  def pre_hooks do
    pre_hook =
      fn
        (result, {_, :get, _} = call) ->
          # do your stuff ...
        (result, _) ->
          result
      end
    [pre_hook]
  end
end