Embedding ejabberd in a Phoenix app

If you’re working to embed ejabberd into a Phoenix app, I hope this helps!

I had been following the docs and tutorial (note that the blog post is dated):
https://docs.ejabberd.im/developer/extending-ejabberd/elixir/
https://blog.process-one.net/embedding-ejabberd-into-an-elixir-phoenix-web-application/

I’m using the following versions:

• Phoenix 1.4.10
• ejabberd 19.8

If you’re having Logger/logger/lager issues, see this related thread: https://forum.elixirforum.com/t/getting-ejabberd-to-use-elixir-logger-in-release-build/24252

I had been getting an error on compilation (see below). The solution was to remove the ejabberd dependency from mix.exs, clean out the build, get and compile the other dependencies, then add back ejabberd before a final compilation step. Here’s the full workaround:

# Clean out build; careful with rm -rf ...
rm -rf _build
rm -rf deps
mix deps.clean --all
# In mix.exs, comment out the line in deps {:ejabberd, "~> 19.8"},
mix do deps.get, compile
# In mix.exs, uncomment the ejabberd line in deps
mix do deps.get, compile

Does anyone know why building everything at once causes this task to crash? I’d like to find a better solution. Thanks!

...
==> phoenix_ecto
Compiling 6 files (.ex)
Generated phoenix_ecto app

16:32:04.624 [info]  Application phoenix exited: exited in: Phoenix.start(:normal, [])
    ** (EXIT) exited in: :gen_server.call(:telemetry_handler_table, {:insert, {Phoenix.Logger, [:phoenix, :channel_handled_in]}, [[:phoenix, :channel_handled_in]], #Function<8.17735610/4 in Phoenix.Logger.install/0>, :ok})
        ** (EXIT) no process: the process is not alive or there's no process currently associated with the given name, possibly because its application isn't started

16:32:04.624 [info]  Application eex exited: :stopped
** (MatchError) no match of right hand side value: {:error, {:phoenix, {:bad_return, {{Phoenix, :start, [:normal, []]}, {:EXIT, {:noproc, {:gen_server, :call, [:telemetry_handler_table, {:insert, {Phoenix.Logger, [:phoenix, :channel_handled_in]}, [[:phoenix, :channel_handled_in]], #Function<8.17735610/4 in Phoenix.Logger.install/0>, :ok}]}}}}}}}
    (phoenix) lib/mix/tasks/compile.phoenix.ex:11: Mix.Tasks.Compile.Phoenix.run/1
    (mix) lib/mix/task.ex:331: Mix.Task.run_task/3
    (mix) lib/mix/tasks/compile.all.ex:73: Mix.Tasks.Compile.All.run_compiler/2
    (mix) lib/mix/tasks/compile.all.ex:53: Mix.Tasks.Compile.All.do_compile/4
    (mix) lib/mix/tasks/compile.all.ex:24: anonymous fn/1 in Mix.Tasks.Compile.All.run/1
    (mix) lib/mix/tasks/compile.all.ex:40: Mix.Tasks.Compile.All.with_logger_app/1
    (mix) lib/mix/task.ex:331: Mix.Task.run_task/3
    (mix) lib/mix/tasks/compile.ex:96: Mix.Tasks.Compile.run/1
    (mix) lib/mix/task.ex:331: Mix.Task.run_task/3
    (mix) lib/mix/cli.ex:79: Mix.CLI.run_task/2
    (elixir) lib/code.ex:813: Code.require_file/2

In any case, I hope this workaround helps someone out there!