Tesla plugin

lib/prom_ex/plugins/tesla.ex

@@ -0,0 +1,142 @@
+if Code.ensure_loaded?(Tesla) do
+  defmodule PromEx.Plugins.Tesla do
+    @moduledoc """
+    This plugin captures HTTP request metrics emitted by Tesla.
+
+    This plugin exposes the following metric group:
+    - `:tesla_http_event_metrics`
+
+    This plugin supports the following options:
+    - `otp_app`: This is a REQUIRED option and is the name of you application in snake case (e.g. :my_cool_app).
+
+    - `metric_prefix`: This option is OPTIONAL and is used to override the default metric prefix of
+      `[otp_app, :prom_ex, :application]`. If this changes you will also want to set `application_metric_prefix`
+      in your `dashboard_assigns` to the snakecase version of your prefix, the default
+      `application_metric_prefix` is `{otp_app}_prom_ex_application`.
+
+
+
+    To use plugin in your application, add the following to your PromEx module:
+
+    ```
+    defmodule WebApp.PromEx do
+      use PromEx, otp_app: :web_app
+
+      @impl true
+      def plugins do
+        [
+          ...
+          PromEx.Plugins.Tesla
+        ]
+      end
+
+      @impl true
+      def dashboards do
+        [
+          ...
+          {:prom_ex, "tesla.json"}
+        ]
+      end
+    end
+    ```
+
+
+    """
+
+    use PromEx.Plugin
+
+    require Logger
+
+    # @start_event [:tesla, :request, :start]
+    @stop_event [:tesla, :request, :stop]
+    @exception_event [:tesla, :request, :exception]
+
+    @impl true
+    def event_metrics(opts) do
+      otp_app = Keyword.fetch!(opts, :otp_app)
+      metric_prefix = Keyword.get(opts, :metric_prefix, PromEx.metric_prefix(otp_app, :tesla))
+
+      [
+        http_events(metric_prefix, opts)
+      ]
+    end
+
+    defp http_events(metric_prefix, _opts) do
+      http_metrics_tags = [:status, :method, :url]
+
+      Event.build(
+        :tesla_http_event_metrics,
+        [
+          distribution(
+            metric_prefix ++ [:http, :request, :duration, :milliseconds],
+            event_name: @stop_event,
+            measurement: :duration,
+            description: "The time it takes for an HTTP request to complete.",
+            reporter_options: [
+              buckets: [10, 100, 500, 1_000, 5_000, 10_000, 30_000]
+            ],
+            tag_values: &get_tags(&1),
+            tags: http_metrics_tags,
+            unit: {:native, :millisecond}
+          ),
+          distribution(
+            metric_prefix ++ [:http, :request, :exception, :duration, :milliseconds],
+            event_name: @exception_event,
+            measurement: :duration,
+            description: "The time it takes for an HTTP request to result in an exception.",
+            reporter_options: [
+              buckets: [10, 100, 500, 1_000, 5_000, 10_000, 30_000]
+            ],
+            tag_values: &get_tags(&1),
+            tags: http_metrics_tags,
+            unit: {:native, :millisecond}
+          ),
+          distribution(
+            metric_prefix ++ [:http, :response, :size, :bytes],
+            event_name: @stop_event,
+            description: "The size of the HTTP response payload.",
+            reporter_options: [
+              buckets: [64, 512, 4_096, 65_536, 262_144, 1_048_576, 4_194_304, 16_777_216]
+            ],
+            measurement: &resp_body_size/2,
+            tag_values: &get_tags(&1),
+            tags: http_metrics_tags,
+            unit: :byte
+          ),
+          counter(
+            metric_prefix ++ [:http, :requests, :total],
+            event_name: @stop_event,
+            description: "The number of requests that have been made.",
+            tag_values: &get_tags(&1),
+            tags: http_metrics_tags
+          )
+        ]
+      )
+    end
+
+    defp get_tags(%{env: %Tesla.Env{status: status, method: method, url: url}}) do
+      %{
+        status: status,
+        method: method,
+        url: url
+      }
+    end
+
+    defp resp_body_size(_, metadata) do
+      case metadata.env.body do
+        nil -> 0
+        _ -> metadata.env.body |> :erlang.term_to_binary() |> :erlang.byte_size()
+      end
+    end
+  end
+else
+  defmodule PromEx.Plugins.Tesla do
+    @moduledoc false
+    use PromEx.Plugin
+
+    @impl true
+    def event_metrics(_opts) do
+      PromEx.Plugin.no_dep_raise(__MODULE__, "Tesla")
+    end
+  end
+end

mix.exs

@@ -61,6 +61,7 @@ defmodule PromEx.MixProject do
       {:oban, ">= 2.4.0", optional: true},
       {:absinthe, ">= 1.6.0", optional: true},
       {:broadway, ">= 1.0.2", optional: true},
+      {:tesla, ">= 1.4.0", optional: true},
 
       # PromEx development related dependencies
       {:bypass, "~> 2.1", only: :test},

mix.lock

@@ -56,5 +56,6 @@
   "telemetry_metrics": {:hex, :telemetry_metrics, "0.6.1", "315d9163a1d4660aedc3fee73f33f1d355dcc76c5c3ab3d59e76e3edf80eef1f", [:mix], [{:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "7be9e0871c41732c233be71e4be11b96e56177bf15dde64a8ac9ce72ac9834c6"},
   "telemetry_metrics_prometheus_core": {:hex, :telemetry_metrics_prometheus_core, "1.0.2", "c98b1c580de637bfeac00db41b9fb91fb4c3548ee3d512a8ed7299172312eaf3", [:mix], [{:telemetry, "~> 0.4 or ~> 1.0.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:telemetry_metrics, "~> 0.6", [hex: :telemetry_metrics, repo: "hexpm", optional: false]}], "hexpm", "48351a0d56f80e38c997b44232b1043e0a081670d16766eee920e6254175b730"},
   "telemetry_poller": {:hex, :telemetry_poller, "1.0.0", "db91bb424e07f2bb6e73926fcafbfcbcb295f0193e0a00e825e589a0a47e8453", [:rebar3], [{:telemetry, "~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "b3a24eafd66c3f42da30fc3ca7dda1e9d546c12250a2d60d7b81d264fbec4f6e"},
+  "tesla": {:hex, :tesla, "1.4.4", "bb89aa0c9745190930366f6a2ac612cdf2d0e4d7fff449861baa7875afd797b2", [:mix], [{:castore, "~> 0.1", [hex: :castore, repo: "hexpm", optional: true]}, {:exjsx, ">= 3.0.0", [hex: :exjsx, repo: "hexpm", optional: true]}, {:finch, "~> 0.3", [hex: :finch, repo: "hexpm", optional: true]}, {:fuse, "~> 2.4", [hex: :fuse, repo: "hexpm", optional: true]}, {:gun, "~> 1.3", [hex: :gun, repo: "hexpm", optional: true]}, {:hackney, "~> 1.6", [hex: :hackney, repo: "hexpm", optional: true]}, {:ibrowse, "4.4.0", [hex: :ibrowse, repo: "hexpm", optional: true]}, {:jason, ">= 1.0.0", [hex: :jason, repo: "hexpm", optional: true]}, {:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:mint, "~> 1.0", [hex: :mint, repo: "hexpm", optional: true]}, {:poison, ">= 1.0.0", [hex: :poison, repo: "hexpm", optional: true]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: true]}], "hexpm", "d5503a49f9dec1b287567ea8712d085947e247cb11b06bc54adb05bfde466457"},
   "unicode_util_compat": {:hex, :unicode_util_compat, "0.7.0", "bc84380c9ab48177092f43ac89e4dfa2c6d62b40b8bd132b1059ecc7232f9a78", [:rebar3], [], "hexpm", "25eee6d67df61960cf6a794239566599b09e17e668d3700247bc498638152521"},
 }

test/prom_ex/plugins/tesla_test.exs

@@ -0,0 +1,45 @@
+defmodule PromEx.Plugins.TeslaTest do
+  use ExUnit.Case, async: false
+
+  alias PromEx.Plugins.Tesla
+  alias PromEx.Test.Support.{Events, Metrics}
+
+  defmodule WebApp.PromEx do
+    use PromEx, otp_app: :web_app
+
+    @impl true
+    def plugins do
+      [Tesla]
+    end
+  end
+
+  test "telemetry works for start/stop" do
+    start_supervised!(WebApp.PromEx)
+    Events.execute_all(:tesla)
+
+    metrics =
+      WebApp.PromEx
+      |> PromEx.get_metrics()
+      |> Metrics.sort()
+
+    assert metrics == Metrics.read_expected(:tesla)
+  end
+
+  describe "event_metrics/1" do
+    test "should return the correct number of metrics" do
+      assert length(Tesla.event_metrics(otp_app: :prom_ex)) == 1
+    end
+  end
+
+  describe "polling_metrics/1" do
+    test "should return the correct number of metrics" do
+      assert Tesla.polling_metrics([]) == []
+    end
+  end
+
+  describe "manual_metrics/1" do
+    test "should return the correct number of metrics" do
+      assert Tesla.manual_metrics(otp_app: :prom_ex) == []
+    end
+  end
+end

test/support/events/tesla.exs

@@ -0,0 +1,58 @@
+[
+  %{
+    event: [:tesla, :request, :start],
+    measurements: %{system_time: 1_654_972_577_479_492_414},
+    metadata: %{
+      env: %Tesla.Env{
+        __client__: %Tesla.Client{adapter: nil, fun: nil, post: [], pre: []},
+        __module__: TestApp,
+        body: nil,
+        headers: [],
+        method: :get,
+        opts: [],
+        query: [],
+        status: nil,
+        url: "/users"
+      }
+    }
+  },
+  %{
+    event: [:tesla, :request, :stop],
+    measurements: %{duration: 100_115_245},
+    metadata: %{
+      env: %Tesla.Env{
+        __client__: %Tesla.Client{adapter: nil, fun: nil, post: [], pre: []},
+        __module__: TestApp,
+        body: [
+          %{
+            "age" => 46,
+            "first_name" => "Frankie",
+            "id" => "7cbd7a74-c09a-4d4d-a5b5-a9c25dab8ed3",
+            "last_name" => "Price",
+            "points" => 0
+          },
+          %{
+            "age" => 26,
+            "first_name" => "Matt",
+            "id" => "0c4a8465-2731-4ecf-9c93-80bfe6d9eac7",
+            "last_name" => "Hermann",
+            "points" => 0
+          }
+        ],
+        headers: [
+          {"cache-control", "max-age=0, private, must-revalidate"},
+          {"date", "Sat, 11 Jun 2022 18:36:16 GMT"},
+          {"server", "Cowboy"},
+          {"content-length", "109512"},
+          {"content-type", "application/json; charset=utf-8"},
+          {"x-request-id", "FvekynXlvJB0pCMAAAGC"}
+        ],
+        method: :get,
+        opts: [],
+        query: [],
+        status: 200,
+        url: "http://127.0.0.1:4000/users"
+      }
+    }
+  }
+]

test/support/metrics/tesla.txt

@@ -0,0 +1,31 @@
+# HELP web_app_prom_ex_prom_ex_status_info Information regarding the PromEx library. Primarily used as a source of truth for Prometheus default labels.
+# HELP web_app_prom_ex_tesla_http_request_duration_milliseconds The time it takes for an HTTP request to complete.
+# HELP web_app_prom_ex_tesla_http_requests_total The number of requests that have been made.
+# HELP web_app_prom_ex_tesla_http_response_size_bytes The size of the HTTP response payload.
+# TYPE web_app_prom_ex_prom_ex_status_info gauge
+# TYPE web_app_prom_ex_tesla_http_request_duration_milliseconds histogram
+# TYPE web_app_prom_ex_tesla_http_requests_total counter
+# TYPE web_app_prom_ex_tesla_http_response_size_bytes histogram
+web_app_prom_ex_prom_ex_status_info 1
+web_app_prom_ex_tesla_http_request_duration_milliseconds_bucket{method="get",status="200",url="http://127.0.0.1:4000/users",le="+Inf"} 1
+web_app_prom_ex_tesla_http_request_duration_milliseconds_bucket{method="get",status="200",url="http://127.0.0.1:4000/users",le="10"} 0
+web_app_prom_ex_tesla_http_request_duration_milliseconds_bucket{method="get",status="200",url="http://127.0.0.1:4000/users",le="100"} 0
+web_app_prom_ex_tesla_http_request_duration_milliseconds_bucket{method="get",status="200",url="http://127.0.0.1:4000/users",le="1000"} 1
+web_app_prom_ex_tesla_http_request_duration_milliseconds_bucket{method="get",status="200",url="http://127.0.0.1:4000/users",le="10000"} 1
+web_app_prom_ex_tesla_http_request_duration_milliseconds_bucket{method="get",status="200",url="http://127.0.0.1:4000/users",le="30000"} 1
+web_app_prom_ex_tesla_http_request_duration_milliseconds_bucket{method="get",status="200",url="http://127.0.0.1:4000/users",le="500"} 1
+web_app_prom_ex_tesla_http_request_duration_milliseconds_bucket{method="get",status="200",url="http://127.0.0.1:4000/users",le="5000"} 1
+web_app_prom_ex_tesla_http_request_duration_milliseconds_count{method="get",status="200",url="http://127.0.0.1:4000/users"} 1
+web_app_prom_ex_tesla_http_request_duration_milliseconds_sum{method="get",status="200",url="http://127.0.0.1:4000/users"} 100.115245
+web_app_prom_ex_tesla_http_requests_total{method="get",status="200",url="http://127.0.0.1:4000/users"} 1
+web_app_prom_ex_tesla_http_response_size_bytes_bucket{method="get",status="200",url="http://127.0.0.1:4000/users",le="+Inf"} 1
+web_app_prom_ex_tesla_http_response_size_bytes_bucket{method="get",status="200",url="http://127.0.0.1:4000/users",le="1048576"} 1
+web_app_prom_ex_tesla_http_response_size_bytes_bucket{method="get",status="200",url="http://127.0.0.1:4000/users",le="16777216"} 1
+web_app_prom_ex_tesla_http_response_size_bytes_bucket{method="get",status="200",url="http://127.0.0.1:4000/users",le="262144"} 1
+web_app_prom_ex_tesla_http_response_size_bytes_bucket{method="get",status="200",url="http://127.0.0.1:4000/users",le="4096"} 1
+web_app_prom_ex_tesla_http_response_size_bytes_bucket{method="get",status="200",url="http://127.0.0.1:4000/users",le="4194304"} 1
+web_app_prom_ex_tesla_http_response_size_bytes_bucket{method="get",status="200",url="http://127.0.0.1:4000/users",le="512"} 1
+web_app_prom_ex_tesla_http_response_size_bytes_bucket{method="get",status="200",url="http://127.0.0.1:4000/users",le="64"} 0
+web_app_prom_ex_tesla_http_response_size_bytes_bucket{method="get",status="200",url="http://127.0.0.1:4000/users",le="65536"} 1
+web_app_prom_ex_tesla_http_response_size_bytes_count{method="get",status="200",url="http://127.0.0.1:4000/users"} 1
+web_app_prom_ex_tesla_http_response_size_bytes_sum{method="get",status="200",url="http://127.0.0.1:4000/users"} 260