ex_data_hoover v0.1.0 ExDataHoover.Nozzle

Nozzle exposes a public API around the concept of event sourcing.

The Nozzle provides a basic server implementation that allows to absorb an event.

You have the possibility to use your own Bag to implements what happened after the absortion.

Example

For example, the following nozzle will absorb an event to a simple bag:

ExDataHoover.Nozzle.start_link(:simple_noozle, ExDataHoover.Bag.Simple)

ExDataHoover.Nozzle.sync_absorb(
  :simple_noozle,
  trackee: %{"type" => "User", "id" => 1},
  event: "authenticated",
  props: %{"at" => "2018-11-14 10:00:00"}
)

#=> {:ok,
      %{
        event: "authenticated",
        properties: %{"at" => "2018-11-14 10:00:00"},
        trackee: %{"id" => 1, "type" => "User"},
        trackee_id: "6b86b273ff34fce19d6b804eff5a3f5747ada4eaa22f1d49c01e52ddb7875b4b",
        traits: %{"id" => 1, "type" => "User"}
      }
    }

Link to this section Summary

Functions

Absorb an event, trackee, and props. The implementation will call the bag.wrap under the hood

Returns a specification to start this module under a supervisor

Invoked when the server is started. start_link/3 or start/3 will block until it returns

Starts a nozzle linked to the current process

Absorb an event, trackee, and props. The call is made in a synchronized way. The implementation is identical as the absorb function but it will return the bag.wrap result

Link to this section Functions

Link to this function absorb(name \\ __MODULE__, list)
absorb(atom(), [{:event, any()} | {:props, any()} | {:trackee, any()}, ...]) ::
  :ok

Absorb an event, trackee, and props. The implementation will call the bag.wrap under the hood.

Link to this function child_spec(arg)

Returns a specification to start this module under a supervisor.

See Supervisor.

Invoked when the server is started. start_link/3 or start/3 will block until it returns.

args is the argument term (second argument) passed to start_link/3.

Returning {:ok, state} will cause start_link/3 to return {:ok, pid} and the process to enter its loop.

Returning {:ok, state, timeout} is similar to {:ok, state} except handle_info(:timeout, state) will be called after timeout milliseconds if no messages are received within the timeout.

Returning {:ok, state, :hibernate} is similar to {:ok, state} except the process is hibernated before entering the loop. See c:handle_call/3 for more information on hibernation.

Returning {:ok, state, {:continue, continue}} is similar to {:ok, state} except that immediately after entering the loop the c:handle_continue/2 callback will be invoked with the value continue as first argument.

Returning :ignore will cause start_link/3 to return :ignore and the process will exit normally without entering the loop or calling c:terminate/2. If used when part of a supervision tree the parent supervisor will not fail to start nor immediately try to restart the GenServer. The remainder of the supervision tree will be started and so the GenServer should not be required by other processes. It can be started later with Supervisor.restart_child/2 as the child specification is saved in the parent supervisor. The main use cases for this are:

  • The GenServer is disabled by configuration but might be enabled later.
  • An error occurred and it will be handled by a different mechanism than the Supervisor. Likely this approach involves calling Supervisor.restart_child/2 after a delay to attempt a restart.

Returning {:stop, reason} will cause start_link/3 to return {:error, reason} and the process to exit with reason reason without entering the loop or calling c:terminate/2.

Callback implementation for GenServer.init/1.

Link to this function start_link(name \\ __MODULE__, bag, traits \\ &(&1))

Starts a nozzle linked to the current process.

Argument expected is bag. The bag has to include ExDataHoover.Bag as @behaviour.

Link to this function sync_absorb(name \\ __MODULE__, list)
sync_absorb(atom(), trackee: any(), event: String.t(), props: map()) ::
  {:ok, any()} | {:error | any()}

Absorb an event, trackee, and props. The call is made in a synchronized way. The implementation is identical as the absorb function but it will return the bag.wrap result.