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34 lines
1.1 KiB
Markdown
34 lines
1.1 KiB
Markdown
# Inspecting The Process Message Queue
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A core tenant of Elixir is message passing between processes. So, if a
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process is sent a message, where does that message go? What happens if it
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gets sent many messages? The `Process.info/2` function allows us to inspect
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the message queue.
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First, let's send some messages (to ourself) and then keep an eye on the
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length of the message queue as we go.
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```elixir
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> send self(), {:error, "this is bad"}
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{:error, "this is bad"}
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> Process.info(self(), :message_queue_len)
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{:message_queue_len, 1}
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> send self(), {:hello, "world"}
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{:hello, "world"}
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> Process.info(self(), :message_queue_len)
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{:message_queue_len, 2}
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```
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Now, I am curious what those specific messages are. Let's ask
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`Process.info/2` for the messages that are in the message queue.
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```elixir
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> Process.info(self(), :messages)
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{:messages, [error: "this is bad", hello: "world"]}
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```
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There are a lot of other things that `Process.info/2` can tell us about a
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process. See [the Erlang docs for
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`process_info`](http://erlang.org/doc/man/erlang.html#process_info-2) for
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more details.
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