Add Dataloader instrumentation library (#137)

* Add Dataloader instrumentation library

* Move call to set context to @run_start event

---------

Co-authored-by: Tristan Sloughter <t@crashfast.com>

.github/workflows/elixir.yml

@@ -344,7 +344,52 @@ jobs:
         run: mix format --check-formatted
       - name: Test
         run: mix test
+  opentelemetry-dataloader:
+    needs: [test-matrix]
+    if: (contains(github.event.pull_request.labels.*.name, 'elixir') && contains(github.event.pull_request.labels.*.name, 'opentelemetry_dataloader'))
+    env:
+      app: 'opentelemetry_dataloader'
+    defaults:
+      run:
+        working-directory: instrumentation/${{ env.app }}
+    runs-on: ubuntu-20.04
+    name: Opentelemetry Dataloader test on Elixir ${{ matrix.elixir_version }} (OTP ${{ matrix.otp_version }})
+    strategy:
+      fail-fast: false
+      matrix: ${{ fromJson(needs.test-matrix.outputs.matrix) }}
+    services:
+      postgres:
+        image: circleci/postgres:13.3-ram
+        ports: ['5432:5432']
+        options: --health-cmd pg_isready --health-interval 10s --health-timeout 5s --health-retries 5
+        env:
+          POSTGRES_USER: postgres
+          POSTGRES_PASSWORD: postgres
+          POSTGRES_DB: opentelemetry_dataloader_test
 
+    steps:
+      - uses: actions/checkout@v3
+      - uses: erlef/setup-beam@v1
+        with:
+          otp-version: ${{ matrix.otp_version }}
+          elixir-version: ${{ matrix.elixir_version }}
+          rebar3-version: ${{ matrix.rebar3_version }}
+      - name: Cache
+        uses: actions/cache@v3
+        with:
+          path: |
+            ~/deps
+            ~/_build
+          key: ${{ runner.os }}-build-${{ matrix.otp_version }}-${{ matrix.elixir_version }}-v3-${{ hashFiles('**/mix.lock') }}
+      - name: Fetch deps
+        if: steps.deps-cache.outputs.cache-hit != 'true'
+        run: mix deps.get
+      - name: Compile project
+        run: mix compile --warnings-as-errors
+      - name: Check formatting
+        run: mix format --check-formatted
+      - name: Test
+        run: mix test
   opentelemetry-process-propagator:
     needs: [test-matrix]
     if: (contains(github.event.pull_request.labels.*.name, 'elixir') && contains(github.event.pull_request.labels.*.name, 'opentelemetry_process_propagator'))

instrumentation/opentelemetry_dataloader/.formatter.exs

@@ -0,0 +1,4 @@
+# Used by "mix format"
+[
+  inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"]
+]

instrumentation/opentelemetry_dataloader/.gitignore

@@ -0,0 +1,26 @@
+# The directory Mix will write compiled artifacts to.
+/_build/
+
+# If you run "mix test --cover", coverage assets end up here.
+/cover/
+
+# The directory Mix downloads your dependencies sources to.
+/deps/
+
+# Where third-party dependencies like ExDoc output generated docs.
+/doc/
+
+# Ignore .fetch files in case you like to edit your project deps locally.
+/.fetch
+
+# If the VM crashes, it generates a dump, let's ignore it too.
+erl_crash.dump
+
+# Also ignore archive artifacts (built via "mix archive.build").
+*.ez
+
+# Ignore package tarball (built via "mix hex.build").
+opentelemetry_dataloader-*.tar
+
+# Temporary files, for example, from tests.
+/tmp/

instrumentation/opentelemetry_dataloader/README.md

@@ -0,0 +1,27 @@
+# OpentelemetryDataloader
+
+Telemetry handler that creates Opentelemetry spans from Dataloader events.
+
+After installing, setup the handler in your application behaviour before your
+top-level supervisor starts.
+
+```elixir
+OpentelemetryDataloader.setup()
+```
+
+## Installation
+
+If [available in Hex](https://hex.pm/docs/publish), the package can be installed
+by adding `opentelemetry_dataloader` to your list of dependencies in `mix.exs`:
+
+```elixir
+def deps do
+  [
+    {:opentelemetry_dataloader, "~> 1.0.0"}
+  ]
+end
+```
+
+Documentation can be generated with [ExDoc](https://github.com/elixir-lang/ex_doc)
+and published on [HexDocs](https://hexdocs.pm). Once published, the docs can
+be found at <https://hexdocs.pm/opentelemetry_dataloader>.

instrumentation/opentelemetry_dataloader/config/config.exs

@@ -0,0 +1,34 @@
+# This file is responsible for configuring your application
+# and its dependencies with the aid of the Mix.Config module.
+import Config
+
+# This configuration is loaded before any dependency and is restricted
+# to this project. If another project depends on this project, this
+# file won't be loaded nor affect the parent project. For this reason,
+# if you want to provide default values for your application for
+# third-party users, it should be done in your "mix.exs" file.
+
+# You can configure your application as:
+#
+#     config :opentelemetry_ecto, key: :value
+#
+# and access this configuration in your application as:
+#
+#     Application.get_env(:opentelemetry_ecto, :key)
+#
+# You can also configure a third-party app:
+#
+#     config :logger, level: :info
+#
+
+# It is also possible to import configuration files, relative to this
+# directory. For example, you can emulate configuration per environment
+# by uncommenting the line below and defining dev.exs, test.exs and such.
+# Configuration from the imported file will override the ones defined
+# here (which is why it is important to import them last).
+#
+try do
+  import_config "#{Mix.env()}.exs"
+rescue
+  _ -> :ok
+end

instrumentation/opentelemetry_dataloader/config/test.exs

@@ -0,0 +1,14 @@
+import Config
+
+config :opentelemetry_dataloader,
+  ecto_repos: [OpentelemetryDataloader.TestRepo]
+
+config :opentelemetry_dataloader, OpentelemetryDataloader.TestRepo,
+  hostname: "localhost",
+  username: "postgres",
+  password: "postgres",
+  database: "opentelemetry_dataloader_test",
+  pool: Ecto.Adapters.SQL.Sandbox
+
+config :opentelemetry,
+  processors: [{:otel_simple_processor, %{}}]

instrumentation/opentelemetry_dataloader/docker-compose.yml

@@ -0,0 +1,11 @@
+version: "3.7"
+
+services:
+  postgres:
+    image: postgres:13.3
+    environment:
+      - POSTGRES_USER=postgres
+      - POSTGRES_PASSWORD=postgres
+      - POSTGRES_DB=opentelemetry_dataloader_test
+    ports:
+      - 5432:5432

instrumentation/opentelemetry_dataloader/lib/opentelemetry_dataloader.ex

@@ -0,0 +1,99 @@
+defmodule OpentelemetryDataloader do
+  @moduledoc """
+  Module for automatic instrumentation of Dataloader.
+
+  It works by listening to `[:dataloader, :source, :run/:batch, :start/:stop]` telemetry events.
+  """
+
+  @tracer_id __MODULE__
+
+  @run_start [:dataloader, :source, :run, :start]
+  @run_stop [:dataloader, :source, :run, :stop]
+
+  @batch_start [:dataloader, :source, :batch, :run, :start]
+  @batch_stop [:dataloader, :source, :batch, :run, :stop]
+
+  @doc """
+  Initializes and configures the telemetry handlers.
+  """
+  def setup(_opts \\ []) do
+    config = %{
+      tracer_id: @tracer_id
+    }
+
+    :telemetry.attach_many(
+      {__MODULE__, :run},
+      [
+        @run_start,
+        @run_stop
+      ],
+      &__MODULE__.handle_event/4,
+      config
+    )
+
+    :telemetry.attach_many(
+      {__MODULE__, :batch},
+      [
+        @batch_start,
+        @batch_stop
+      ],
+      &__MODULE__.handle_event/4,
+      config
+    )
+  end
+
+  def handle_event(event, measurements, metadata, config)
+
+  def handle_event(@run_start, _measurements, metadata, config) do
+    parent_ctx = OpentelemetryProcessPropagator.fetch_parent_ctx(4, :"$callers")
+
+    if parent_ctx != :undefined do
+      OpenTelemetry.Ctx.attach(parent_ctx)
+    end
+
+    OpentelemetryTelemetry.start_telemetry_span(
+      config.tracer_id,
+      "dataloader.run",
+      metadata,
+      %{
+        kind: :client
+      }
+    )
+  end
+
+  def handle_event(@run_stop, _measurements, metadata, config) do
+    OpentelemetryTelemetry.set_current_telemetry_span(config.tracer_id, metadata)
+
+    OpentelemetryTelemetry.end_telemetry_span(config.tracer_id, metadata)
+  end
+
+  def handle_event(@batch_start, _measurements, metadata, config) do
+    parent_ctx = OpentelemetryProcessPropagator.fetch_parent_ctx(4, :"$callers")
+
+    if parent_ctx != :undefined do
+      OpenTelemetry.Ctx.attach(parent_ctx)
+    end
+
+    {batch_name, _batch_args} = metadata.batch
+
+    attributes = %{
+      "dataloader.batch_key" => inspect(batch_name)
+    }
+
+    OpentelemetryTelemetry.start_telemetry_span(
+      config.tracer_id,
+      "dataloader.batch",
+      metadata,
+      %{
+        kind: :client,
+        attributes: attributes
+      }
+    )
+  end
+
+  def handle_event(@batch_stop, _measurements, metadata, config) do
+    OpentelemetryTelemetry.set_current_telemetry_span(config.tracer_id, metadata)
+
+    OpentelemetryTelemetry.end_telemetry_span(config.tracer_id, metadata)
+  end
+end

instrumentation/opentelemetry_dataloader/mix.exs

@@ -0,0 +1,62 @@
+defmodule OpentelemetryDataloader.MixProject do
+  use Mix.Project
+
+  def project do
+    [
+      app: :opentelemetry_dataloader,
+      description: "Trace Dataloader with OpenTelemetry.",
+      version: "1.0.0",
+      elixir: "~> 1.14",
+      start_permanent: Mix.env() == :prod,
+      deps: deps(),
+      aliases: aliases(),
+      elixirc_paths: elixirc_paths(Mix.env()),
+      package: package(),
+      source_url:
+        "https://github.com/open-telemetry/opentelemetry-erlang-contrib/tree/main/instrumentation/opentelemetry_dataloader"
+    ]
+  end
+
+  defp package do
+    [
+      files: ~w(lib .formatter.exs mix.exs README* LICENSE* CHANGELOG*),
+      licenses: ["Apache-2.0"],
+      links: %{
+        "GitHub" =>
+          "https://github.com/open-telemetry/opentelemetry-erlang-contrib/tree/main/instrumentation/opentelemetry_dataloader",
+        "OpenTelemetry Erlang" => "https://github.com/open-telemetry/opentelemetry-erlang",
+        "OpenTelemetry Erlang Contrib" =>
+          "https://github.com/open-telemetry/opentelemetry-erlang-contrib",
+        "OpenTelemetry.io" => "https://opentelemetry.io"
+      }
+    ]
+  end
+
+  def application do
+    []
+  end
+
+  defp elixirc_paths(:test), do: ["lib", "test/support"]
+  defp elixirc_paths(_), do: ["lib"]
+
+  defp aliases() do
+    [test: ["ecto.drop -q", "ecto.create -q", "ecto.migrate --quiet", "test"]]
+  end
+
+  # Run "mix help deps" to learn about dependencies.
+  defp deps do
+    [
+      {:telemetry, "~> 0.4 or ~> 1.0"},
+      {:opentelemetry_api, "~> 1.0"},
+      {:opentelemetry_telemetry, "~> 1.0"},
+      {:dataloader, "~> 1.0.8"},
+      {:opentelemetry_exporter, "~> 1.0", only: [:dev, :test]},
+      {:opentelemetry, "~> 1.0", only: [:dev, :test]},
+      {:ex_doc, "~> 0.29", only: [:dev], runtime: false},
+      {:ecto_sql, ">= 3.0.0", only: [:dev, :test]},
+      {:postgrex, ">= 0.15.0", only: [:dev, :test]},
+      {:dialyxir, "~> 1.1", only: [:dev, :test], runtime: false},
+      {:opentelemetry_process_propagator, "~> 0.2"}
+    ]
+  end
+end

instrumentation/opentelemetry_dataloader/mix.lock

@@ -0,0 +1,32 @@
+%{
+  "acceptor_pool": {:hex, :acceptor_pool, "1.0.0", "43c20d2acae35f0c2bcd64f9d2bde267e459f0f3fd23dab26485bf518c281b21", [:rebar3], [], "hexpm", "0cbcd83fdc8b9ad2eee2067ef8b91a14858a5883cb7cd800e6fcd5803e158788"},
+  "chatterbox": {:hex, :ts_chatterbox, "0.13.0", "6f059d97bcaa758b8ea6fffe2b3b81362bd06b639d3ea2bb088335511d691ebf", [:rebar3], [{:hpack, "~> 0.2.3", [hex: :hpack_erl, repo: "hexpm", optional: false]}], "hexpm", "b93d19104d86af0b3f2566c4cba2a57d2e06d103728246ba1ac6c3c0ff010aa7"},
+  "connection": {:hex, :connection, "1.1.0", "ff2a49c4b75b6fb3e674bfc5536451607270aac754ffd1bdfe175abe4a6d7a68", [:mix], [], "hexpm", "722c1eb0a418fbe91ba7bd59a47e28008a189d47e37e0e7bb85585a016b2869c"},
+  "ctx": {:hex, :ctx, "0.6.0", "8ff88b70e6400c4df90142e7f130625b82086077a45364a78d208ed3ed53c7fe", [:rebar3], [], "hexpm", "a14ed2d1b67723dbebbe423b28d7615eb0bdcba6ff28f2d1f1b0a7e1d4aa5fc2"},
+  "dataloader": {:hex, :dataloader, "1.0.10", "a42f07641b1a0572e0b21a2a5ae1be11da486a6790f3d0d14512d96ff3e3bbe9", [:mix], [{:ecto, ">= 3.4.3 and < 4.0.0", [hex: :ecto, repo: "hexpm", optional: true]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "54cd70cec09addf4b2ace14cc186a283a149fd4d3ec5475b155951bf33cd963f"},
+  "db_connection": {:hex, :db_connection, "2.4.3", "3b9aac9f27347ec65b271847e6baeb4443d8474289bd18c1d6f4de655b70c94d", [:mix], [{:connection, "~> 1.0", [hex: :connection, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "c127c15b0fa6cfb32eed07465e05da6c815b032508d4ed7c116122871df73c12"},
+  "decimal": {:hex, :decimal, "2.0.0", "a78296e617b0f5dd4c6caf57c714431347912ffb1d0842e998e9792b5642d697", [:mix], [], "hexpm", "34666e9c55dea81013e77d9d87370fe6cb6291d1ef32f46a1600230b1d44f577"},
+  "dialyxir": {:hex, :dialyxir, "1.2.0", "58344b3e87c2e7095304c81a9ae65cb68b613e28340690dfe1a5597fd08dec37", [:mix], [{:erlex, ">= 0.2.6", [hex: :erlex, repo: "hexpm", optional: false]}], "hexpm", "61072136427a851674cab81762be4dbeae7679f85b1272b6d25c3a839aff8463"},
+  "earmark_parser": {:hex, :earmark_parser, "1.4.29", "149d50dcb3a93d9f3d6f3ecf18c918fb5a2d3c001b5d3305c926cddfbd33355b", [:mix], [], "hexpm", "4902af1b3eb139016aed210888748db8070b8125c2342ce3dcae4f38dcc63503"},
+  "ecto": {:hex, :ecto, "3.9.2", "017db3bc786ff64271108522c01a5d3f6ba0aea5c84912cfb0dd73bf13684108", [:mix], [{:decimal, "~> 1.6 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "21466d5177e09e55289ac7eade579a642578242c7a3a9f91ad5c6583337a9d15"},
+  "ecto_sql": {:hex, :ecto_sql, "3.9.1", "9bd5894eecc53d5b39d0c95180d4466aff00e10679e13a5cfa725f6f85c03c22", [:mix], [{:db_connection, "~> 2.4.1 or ~> 2.5", [hex: :db_connection, repo: "hexpm", optional: false]}, {:ecto, "~> 3.9.0", [hex: :ecto, repo: "hexpm", optional: false]}, {:myxql, "~> 0.6.0", [hex: :myxql, repo: "hexpm", optional: true]}, {:postgrex, "~> 0.16.0 or ~> 1.0", [hex: :postgrex, repo: "hexpm", optional: true]}, {:tds, "~> 2.1.1 or ~> 2.2", [hex: :tds, repo: "hexpm", optional: true]}, {:telemetry, "~> 0.4.0 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "5fd470a4fff2e829bbf9dcceb7f3f9f6d1e49b4241e802f614de6b8b67c51118"},
+  "erlex": {:hex, :erlex, "0.2.6", "c7987d15e899c7a2f34f5420d2a2ea0d659682c06ac607572df55a43753aa12e", [:mix], [], "hexpm", "2ed2e25711feb44d52b17d2780eabf998452f6efda104877a3881c2f8c0c0c75"},
+  "ex_doc": {:hex, :ex_doc, "0.29.1", "b1c652fa5f92ee9cf15c75271168027f92039b3877094290a75abcaac82a9f77", [:mix], [{:earmark_parser, "~> 1.4.19", [hex: :earmark_parser, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.14", [hex: :makeup_elixir, repo: "hexpm", optional: false]}, {:makeup_erlang, "~> 0.1", [hex: :makeup_erlang, repo: "hexpm", optional: false]}], "hexpm", "b7745fa6374a36daf484e2a2012274950e084815b936b1319aeebcf7809574f6"},
+  "gproc": {:hex, :gproc, "0.8.0", "cea02c578589c61e5341fce149ea36ccef236cc2ecac8691fba408e7ea77ec2f", [:rebar3], [], "hexpm", "580adafa56463b75263ef5a5df4c86af321f68694e7786cb057fd805d1e2a7de"},
+  "grpcbox": {:hex, :grpcbox, "0.16.0", "b83f37c62d6eeca347b77f9b1ec7e9f62231690cdfeb3a31be07cd4002ba9c82", [:rebar3], [{:acceptor_pool, "~> 1.0.0", [hex: :acceptor_pool, repo: "hexpm", optional: false]}, {:chatterbox, "~> 0.13.0", [hex: :ts_chatterbox, repo: "hexpm", optional: false]}, {:ctx, "~> 0.6.0", [hex: :ctx, repo: "hexpm", optional: false]}, {:gproc, "~> 0.8.0", [hex: :gproc, repo: "hexpm", optional: false]}], "hexpm", "294df743ae20a7e030889f00644001370a4f7ce0121f3bbdaf13cf3169c62913"},
+  "hpack": {:hex, :hpack_erl, "0.2.3", "17670f83ff984ae6cd74b1c456edde906d27ff013740ee4d9efaa4f1bf999633", [:rebar3], [], "hexpm", "06f580167c4b8b8a6429040df36cc93bba6d571faeaec1b28816523379cbb23a"},
+  "makeup": {:hex, :makeup, "1.1.0", "6b67c8bc2882a6b6a445859952a602afc1a41c2e08379ca057c0f525366fc3ca", [:mix], [{:nimble_parsec, "~> 1.2.2 or ~> 1.3", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "0a45ed501f4a8897f580eabf99a2e5234ea3e75a4373c8a52824f6e873be57a6"},
+  "makeup_elixir": {:hex, :makeup_elixir, "0.16.0", "f8c570a0d33f8039513fbccaf7108c5d750f47d8defd44088371191b76492b0b", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}, {:nimble_parsec, "~> 1.2.3", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "28b2cbdc13960a46ae9a8858c4bebdec3c9a6d7b4b9e7f4ed1502f8159f338e7"},
+  "makeup_erlang": {:hex, :makeup_erlang, "0.1.1", "3fcb7f09eb9d98dc4d208f49cc955a34218fc41ff6b84df7c75b3e6e533cc65f", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}], "hexpm", "174d0809e98a4ef0b3309256cbf97101c6ec01c4ab0b23e926a9e17df2077cbb"},
+  "nimble_parsec": {:hex, :nimble_parsec, "1.2.3", "244836e6e3f1200c7f30cb56733fd808744eca61fd182f731eac4af635cc6d0b", [:mix], [], "hexpm", "c8d789e39b9131acf7b99291e93dae60ab48ef14a7ee9d58c6964f59efb570b0"},
+  "opentelemetry": {:hex, :opentelemetry, "1.1.2", "77ba2fd2fee67bebde590851a4afeda45b3f298310aa410a2a3804b364cb598a", [:rebar3], [{:opentelemetry_api, "~> 1.1", [hex: :opentelemetry_api, repo: "hexpm", optional: false]}], "hexpm", "5c60be189d6aed64a9fd17055f72c93eab144be441e625276c3c95533e6bb4c7"},
+  "opentelemetry_api": {:hex, :opentelemetry_api, "1.1.1", "3b43877c456c8a7f5448a95d9bf4fb4bb8cc2abbbea2c62d5f8e8c538b4af14f", [:mix, :rebar3], [], "hexpm", "a9554b3208b60a70043318d051ea78fbbc7a1b8f4c418ebc16ccb40015995675"},
+  "opentelemetry_exporter": {:hex, :opentelemetry_exporter, "1.2.2", "3966c56656627ef7db6c34c4ce28d44ac8629dcd065a310d7c33712fc2a1cfe3", [:rebar3], [{:grpcbox, ">= 0.0.0", [hex: :grpcbox, repo: "hexpm", optional: false]}, {:opentelemetry, "~> 1.1", [hex: :opentelemetry, repo: "hexpm", optional: false]}, {:opentelemetry_api, "~> 1.1", [hex: :opentelemetry_api, repo: "hexpm", optional: false]}, {:tls_certificate_check, "~> 1.11", [hex: :tls_certificate_check, repo: "hexpm", optional: false]}], "hexpm", "5c11adeda19e0d203a04efe92cdd7a183da4b09ae8acaba7608e9303fa258e74"},
+  "opentelemetry_process_propagator": {:hex, :opentelemetry_process_propagator, "0.2.1", "20ac37648faf7175cade16fda8d58e6f1ff1b7f2a50a8ef9d70a032c41aba315", [:mix, :rebar3], [{:opentelemetry_api, "~> 1.0", [hex: :opentelemetry_api, repo: "hexpm", optional: false]}], "hexpm", "f317237e39636d4f6140afa5d419e85ed3dc9e9a57072e7cd442df42af7b8aac"},
+  "opentelemetry_telemetry": {:hex, :opentelemetry_telemetry, "1.0.0", "d5982a319e725fcd2305b306b65c18a86afdcf7d96821473cf0649ff88877615", [:mix, :rebar3], [{:opentelemetry_api, "~> 1.0", [hex: :opentelemetry_api, repo: "hexpm", optional: false]}, {:telemetry, "~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:telemetry_registry, "~> 0.3.0", [hex: :telemetry_registry, repo: "hexpm", optional: false]}], "hexpm", "3401d13a1d4b7aa941a77e6b3ec074f0ae77f83b5b2206766ce630123a9291a9"},
+  "postgrex": {:hex, :postgrex, "0.16.5", "fcc4035cc90e23933c5d69a9cd686e329469446ef7abba2cf70f08e2c4b69810", [:mix], [{:connection, "~> 1.1", [hex: :connection, repo: "hexpm", optional: false]}, {:db_connection, "~> 2.1", [hex: :db_connection, repo: "hexpm", optional: false]}, {:decimal, "~> 1.5 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:table, "~> 0.1.0", [hex: :table, repo: "hexpm", optional: true]}], "hexpm", "edead639dc6e882618c01d8fc891214c481ab9a3788dfe38dd5e37fd1d5fb2e8"},
+  "ssl_verify_fun": {:hex, :ssl_verify_fun, "1.1.6", "cf344f5692c82d2cd7554f5ec8fd961548d4fd09e7d22f5b62482e5aeaebd4b0", [:make, :mix, :rebar3], [], "hexpm", "bdb0d2471f453c88ff3908e7686f86f9be327d065cc1ec16fa4540197ea04680"},
+  "telemetry": {:hex, :telemetry, "1.1.0", "a589817034a27eab11144ad24d5c0f9fab1f58173274b1e9bae7074af9cbee51", [:rebar3], [], "hexpm", "b727b2a1f75614774cff2d7565b64d0dfa5bd52ba517f16543e6fc7efcc0df48"},
+  "telemetry_registry": {:hex, :telemetry_registry, "0.3.0", "6768f151ea53fc0fbca70dbff5b20a8d663ee4e0c0b2ae589590e08658e76f1e", [:mix, :rebar3], [{:telemetry, "~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "492e2adbc609f3e79ece7f29fec363a97a2c484ac78a83098535d6564781e917"},
+  "tls_certificate_check": {:hex, :tls_certificate_check, "1.16.0", "45b05e3b993dbace2e4ebccb666eadbd038f1da8f4db9691f4f34a274dfb0bd7", [:rebar3], [{:ssl_verify_fun, "1.1.6", [hex: :ssl_verify_fun, repo: "hexpm", optional: false]}], "hexpm", "3dc0508c749619b8d6a5e21aca4d719c184f065541795b0556398c8e574a3064"},
+}

instrumentation/opentelemetry_dataloader/priv/test_repo/migrations/1_setup_tables.exs

@@ -0,0 +1,9 @@
+defmodule OpentelemetryDataloader.TestRepo.Migrations.SetupTables do
+  use Ecto.Migration
+
+  def change do
+    create table(:posts) do
+      add(:body, :text)
+    end
+  end
+end

instrumentation/opentelemetry_dataloader/test/opentelemetry_dataloader_test.exs

@@ -0,0 +1,69 @@
+defmodule OpentelemetryDataloaderTest do
+  use ExUnit.Case
+
+  require OpenTelemetry.Tracer
+
+  alias OpentelemetryDataloader.TestRepo, as: Repo
+  alias OpentelemetryDataloader.TestModels.Post
+
+  require Record
+
+  for {name, spec} <- Record.extract_all(from_lib: "opentelemetry/include/otel_span.hrl") do
+    Record.defrecord(name, spec)
+  end
+
+  setup do
+    :application.stop(:opentelemetry)
+    :application.set_env(:opentelemetry, :tracer, :otel_tracer_default)
+
+    :application.set_env(:opentelemetry, :processors, [
+      {:otel_batch_processor, %{scheduled_delay_ms: 1}}
+    ])
+
+    :application.start(:opentelemetry)
+
+    :otel_batch_processor.set_exporter(:otel_exporter_pid, self())
+
+    OpenTelemetry.Tracer.start_span("test")
+
+    on_exit(fn ->
+      OpenTelemetry.Tracer.end_span()
+      :telemetry.detach({__MODULE__, :batch})
+      :telemetry.detach({__MODULE__, :run})
+    end)
+  end
+
+  test "captures dataloader ecto source events" do
+    OpentelemetryDataloader.setup()
+
+    source = Dataloader.Ecto.new(Repo)
+
+    loader = Dataloader.new() |> Dataloader.add_source(:db, source)
+
+    loader =
+      loader
+      |> Dataloader.load(:db, Post, 1)
+      |> Dataloader.load_many(:db, Post, [4, 9])
+
+    Dataloader.run(loader)
+
+    assert_receive {:span,
+                    span(
+                      name: "dataloader.run",
+                      attributes: attributes,
+                      kind: :client
+                    )}
+
+    assert %{} = :otel_attributes.map(attributes)
+
+    assert_receive {:span,
+                    span(
+                      name: "dataloader.batch",
+                      attributes: attributes,
+                      kind: :client
+                    )}
+
+    assert %{"dataloader.batch_key" => key} = :otel_attributes.map(attributes)
+    assert key =~ ~r/OpentelemetryDataloader.TestModels.Post/
+  end
+end

instrumentation/opentelemetry_dataloader/test/support/models/post.ex

@@ -0,0 +1,7 @@
+defmodule OpentelemetryDataloader.TestModels.Post do
+  use Ecto.Schema
+
+  schema "posts" do
+    field(:body, :string)
+  end
+end

instrumentation/opentelemetry_dataloader/test/support/test_repo.ex

@@ -0,0 +1,5 @@
+defmodule OpentelemetryDataloader.TestRepo do
+  use Ecto.Repo,
+    otp_app: :opentelemetry_dataloader,
+    adapter: Ecto.Adapters.Postgres
+end

instrumentation/opentelemetry_dataloader/test/test_helper.exs

@@ -0,0 +1,5 @@
+OpentelemetryDataloader.TestRepo.start_link()
+
+ExUnit.start(capture_log: true)
+
+Ecto.Adapters.SQL.Sandbox.mode(OpentelemetryDataloader.TestRepo, {:shared, self()})