Fix plugin build logic

For reasons to me unknown, the build logic was unable to package and
run the plugin against the broker anymore.

As the build logic is incredibly overengineerd and complicated, the
following hacks were done to make it work.

1. We target against a fixed (and stable version) by switching from
the main branch to the versioned one.
2. We build the `.ez` archive ourselves via `mix` and copy both the
plugin and its dependencies within the `plugins` folder.
3. We override an internal variable `EXTRA_DIST_EZS` to avoid RMQ
Makefiles from removing the copied plugins.

This logic is brittle to say the least, I am not sure for how long I
will manage to maintain this package as every time things are more
complicated and less documented...

Signed-off-by: Matteo Cafasso <[email protected]>

.github/workflows/action.yml

@@ -17,12 +17,7 @@ jobs:
           sudo apt install -y --allow-downgrades esl-erlang=${{ matrix.erlang }}
       - name: Install Elixir
         run: |
-          sudo apt install -y elixir=1.13.4-1
-      - name: Install RMQ requirements
-        run: |
-          wget https://github.com/rabbitmq/mix_task_archive_deps/releases/download/0.5.0/mix_task_archive_deps-0.5.0.ez
-          mix archive.install --force ./mix_task_archive_deps-0.5.0.ez
-          rm mix_task_archive_deps-0.5.0.ez
+          sudo apt install -y elixir=1.15.7-1
       - name: Run tests
         run: |
           git checkout -b v3.12.x

Makefile

@@ -1,25 +1,37 @@
 PROJECT = rabbitmq_message_deduplication
 
-BUILD_DEPS = rabbitmq_cli
-DEPS = rabbit_common rabbit
+DEPS = rabbit_common rabbit rabbitmq_management
 TEST_DEPS = rabbitmq_ct_helpers rabbitmq_ct_client_helpers amqp_client
 
 DEP_PLUGINS = rabbit_common/mk/rabbitmq-plugin.mk
+DEP_EARLY_PLUGINS = rabbit_common/mk/rabbitmq-early-plugin.mk
 
+# Mix customizations
+
+MIX_ENV      ?= dev
 override MIX := mix
 elixir_srcs  := mix.exs
 
+# RMQ `dist` target removes anything within the `plugins` folder
+# which is not managed by erlang.mk.
+# We need to instruct the `rabbitmq-dist:do-dist` target to not
+# remove our plugin and related dependencies.
+ELIXIR_VERSION  := $(shell elixir --version | grep Elixir | cut -d ' ' -f 2)
+PROJECT_VERSION := $(shell git describe --tags --abbrev=0)
+EXTRA_DIST_EZS  := plugins/elixir-$(ELIXIR_VERSION).ez plugins/$(PROJECT)-$(PROJECT_VERSION).ez
+
 app:: $(elixir_srcs) deps
 	$(MIX) make_all
+	cp -r _build/$(MIX_ENV)/archives/elixir-*.ez plugins/
+	cp -r _build/$(MIX_ENV)/archives/$(PROJECT)-*.ez plugins/
 
 tests:: $(elixir_srcs) deps
 	MIX_ENV=test $(MIX) make_tests
 
-# FIXME: Use erlang.mk patched for RabbitMQ, while waiting for PRs to be
-# reviewed and merged.
+clean::
+	@rm -fr _build
 
-ERLANG_MK_REPO = https://github.com/rabbitmq/erlang.mk.git
-ERLANG_MK_COMMIT = rabbitmq-tmp
+# erlang.mk modules
 
 include rabbitmq-components.mk
 include erlang.mk

mix.exs

@@ -15,22 +15,7 @@ defmodule RabbitMQ.MessageDeduplicationPlugin.Mixfile do
       deps_path: deps_dir,
       deps: deps(deps_dir),
       aliases: aliases(),
-      xref: [
-        exclude: [
-          :amqqueue,
-          :rabbit_amqqueue,
-          :rabbit_backing_queue,
-          :rabbit_exchange,
-          :rabbit_router,
-          :rabbit_binary_parser,
-          :rabbit_exchange_type,
-          :rabbit_log,
-          :rabbit_misc,
-          :rabbit_policy_validator,
-          :rabbit_registry,
-          :rabbit_policy
-        ]
-      ]
+      # elixirc_paths: ["src"],
     ]
   end
 
@@ -42,12 +27,16 @@ defmodule RabbitMQ.MessageDeduplicationPlugin.Mixfile do
 
     [
       applications: applications,
+      registered: [RabbitMQMessageDeduplication],
       mod: {RabbitMQMessageDeduplication, []}
     ]
   end
 
   defp deps(deps_dir) do
     [
+      {
+        :mix_task_archive_deps, "~> 1.0"
+      },
       {
         :rabbit,
         path: Path.join(deps_dir, "rabbit"),
@@ -77,7 +66,9 @@ defmodule RabbitMQ.MessageDeduplicationPlugin.Mixfile do
       make_all: [
         "deps.get",
         "deps.compile",
-        "compile"
+        "compile",
+        "archive.build.elixir",
+        "archive.build.all"
       ],
       make_tests: [
         "test"