feat: add Process.set_label/1 to Broadway stages

.github/workflows/ci.yml

@@ -16,9 +16,11 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          # Earliest-supported versions.
-          - elixir: "1.7.4"
-            otp: "21.3.8.17"
+          # Minimum supported versions on ubuntu-22.04.
+          # OTP 24.2 is the earliest available on ubuntu-22.04.
+          # Elixir 1.12 is the earliest version compatible with OTP 24.
+          - elixir: "1.12"
+            otp: "24.2"
 
           # Latest versions.
           - elixir: "1.18"
@@ -34,6 +36,7 @@ jobs:
         with:
           otp-version: ${{matrix.otp}}
           elixir-version: ${{matrix.elixir}}
+          version-type: strict
 
       - name: Cache Mix dependencies
         uses: actions/cache@v3

lib/broadway/process.ex

@@ -0,0 +1,20 @@
+defmodule Broadway.Process do
+  @moduledoc false
+
+  # TODO: Remove this module once we require Elixir 1.17+.
+  # Process.set_label/1 was added in Elixir 1.17.0.
+
+  if function_exported?(Process, :set_label, 1) do
+    def set_label(label) do
+      Process.set_label(label)
+    end
+
+    def labels_supported?, do: true
+  else
+    def set_label(_label) do
+      :ok
+    end
+
+    def labels_supported?, do: false
+  end
+end

lib/broadway/topology/batch_processor_stage.ex

@@ -29,6 +29,8 @@ defmodule Broadway.Topology.BatchProcessorStage do
       producer: args[:producer]
     }
 
+    Broadway.Process.set_label({:broadway_batch_processor, state.topology_name, state.partition})
+
     {:consumer, state, []}
   end
 

lib/broadway/topology/batcher_stage.ex

@@ -45,6 +45,8 @@ defmodule Broadway.Topology.BatcherStage do
       context: args[:context]
     }
 
+    Broadway.Process.set_label({:broadway_batcher, state.topology_name, state.batcher})
+
     {:producer_consumer, state, dispatcher: dispatcher}
   end
 

lib/broadway/topology/processor_stage.ex

@@ -33,6 +33,10 @@ defmodule Broadway.Topology.ProcessorStage do
       producer: args[:producer]
     }
 
+    Broadway.Process.set_label(
+      {:broadway_processor, state.topology_name, state.processor_key, state.partition}
+    )
+
     case type do
       :consumer ->
         {:consumer, state, []}

lib/broadway/topology/producer_stage.ex

@@ -61,6 +61,9 @@ defmodule Broadway.Topology.ProducerStage do
       rate_limiting: rate_limiting_state
     }
 
+    topology_name = args[:broadway][:name]
+    Broadway.Process.set_label({:broadway_producer, topology_name, index})
+
     case module.init(arg) do
       {:producer, module_state} ->
         {:producer, %{state | module_state: module_state}, dispatcher: dispatcher}

test/broadway/topology/batch_processor_stage_test.exs

@@ -0,0 +1,32 @@
+defmodule Broadway.Topology.BatchProcessorStageTest do
+  use ExUnit.Case, async: true
+
+  test "sets process label with topology name and partition" do
+    topology_name = :test_topology
+    partition = 3
+
+    {:ok, pid} =
+      Broadway.Topology.BatchProcessorStage.start_link(
+        [
+          topology_name: topology_name,
+          name: :test_batch_processor,
+          module: __MODULE__,
+          context: %{},
+          terminator: __MODULE__,
+          resubscribe: :never,
+          partition: partition,
+          batcher: :test_batcher,
+          producer: nil
+        ],
+        []
+      )
+
+    if Broadway.Process.labels_supported?() do
+      label = Process.info(pid, :label)
+      assert label == {:label, {:broadway_batch_processor, topology_name, partition}}
+    else
+      # Labels not supported in this Elixir version, skip assertion
+      :ok
+    end
+  end
+end

test/broadway/topology/batcher_stage_test.exs

@@ -22,4 +22,34 @@ defmodule Broadway.Topology.BatcherStageTest do
     %{state: state} = :sys.get_state(pid)
     assert state.subscription_options[:max_demand] == 123
   end
+
+  test "sets process label with topology name and batcher key" do
+    topology_name = :test_topology
+    batcher_key = :my_batcher
+
+    {:ok, pid} =
+      Broadway.Topology.BatcherStage.start_link(
+        [
+          topology_name: topology_name,
+          name: :test_batcher,
+          context: %{},
+          terminator: __MODULE__,
+          resubscribe: :never,
+          batcher: batcher_key,
+          processors: [:some_processor],
+          batch_size: 10,
+          batch_timeout: 1000,
+          partition: batcher_key
+        ],
+        []
+      )
+
+    if Broadway.Process.labels_supported?() do
+      label = Process.info(pid, :label)
+      assert label == {:label, {:broadway_batcher, topology_name, batcher_key}}
+    else
+      # Labels not supported in this Elixir version, skip assertion
+      :ok
+    end
+  end
 end

test/broadway/topology/processor_stage_test.exs

@@ -22,4 +22,38 @@ defmodule Broadway.Topology.ProcessorStageTest do
     assert state.subscription_options[:min_demand] == 3
     assert state.subscription_options[:max_demand] == 6
   end
+
+  test "sets process label with topology name, processor key, and partition" do
+    topology_name = :test_topology
+    processor_key = :default
+    partition = 5
+
+    {:ok, pid} =
+      Broadway.Topology.ProcessorStage.start_link(
+        [
+          topology_name: topology_name,
+          name: :test_processor,
+          module: __MODULE__,
+          context: %{},
+          type: :consumer,
+          terminator: __MODULE__,
+          resubscribe: :never,
+          processor_config: [min_demand: 1, max_demand: 10],
+          processor_key: processor_key,
+          producers: [:sample],
+          partition: partition,
+          batchers: :none,
+          producer: nil
+        ],
+        []
+      )
+
+    if Broadway.Process.labels_supported?() do
+      label = Process.info(pid, :label)
+      assert label == {:label, {:broadway_processor, topology_name, processor_key, partition}}
+    else
+      # Labels not supported in this Elixir version, skip assertion
+      :ok
+    end
+  end
 end

test/broadway/topology/producer_stage_test.exs

@@ -184,4 +184,27 @@ defmodule Broadway.Topology.ProducerStageTest do
       assert ProducerStage.terminate(:normal, state) == :ok
     end
   end
+
+  test "sets process label with topology name and index" do
+    topology_name = :test_topology
+    index = 2
+
+    args = %{
+      module: {FakeProducer, []},
+      broadway: [name: topology_name, index: index],
+      transformer: nil,
+      dispatcher: GenStage.DemandDispatcher,
+      rate_limiter: nil
+    }
+
+    {:ok, pid} = ProducerStage.start_link(args, index)
+
+    if Broadway.Process.labels_supported?() do
+      label = Process.info(pid, :label)
+      assert label == {:label, {:broadway_producer, topology_name, index}}
+    else
+      # Labels not supported in this Elixir version, skip assertion
+      :ok
+    end
+  end
 end