# `Broadway.CallerAcknowledger`
[🔗](https://github.com/dashbitco/broadway/blob/v1.3.0/lib/broadway/caller_acknowledger.ex#L1)

A simple acknowledger that sends a message back to a caller.

If you want to use this acknowledger in messages produced by your
`Broadway.Producer`, you can get its configuration by calling
the `init/0` function. For example, you can use it in
`Broadway.test_message/3`:

    some_ref = make_ref()

    Broadway.test_message(
      MyPipeline,
      "some data",
      acknowledger: Broadway.CallerAcknowledger.init({self(), some_ref}, :ignored)
    )

The first parameter is a tuple with the PID to receive the messages
and a unique identifier (usually a reference). Such unique identifier
is then included in the messages sent to the PID. The second parameter,
which is per message, is ignored.

It sends a message in the format:

    {:ack, ref, successful_messages, failed_messages}

If `Broadway.Message.configure_ack/2` is called on a message that
uses this acknowledger, then the following message is sent:

    {:configure, ref, options}

# `init`

```elixir
@spec init(
  {pid(), ref :: term()},
  ignored_term :: term()
) :: Broadway.Message.acknowledger()
```

Returns the acknowledger metadata.

See the module documentation.

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*Consult [api-reference.md](api-reference.md) for complete listing*