prometheus_ecto

Ecto query duration metrics for Prometheus.

apps/explorer/config/config.exs

@@ -18,7 +18,9 @@ config :explorer, Explorer.ExchangeRates, enabled: true
 
 config :explorer, Explorer.Market.History.Cataloger, enabled: true
 
-config :explorer, Explorer.Repo, migration_timestamps: [type: :utc_datetime]
+config :explorer, Explorer.Repo,
+  loggers: [Explorer.Repo.PrometheusLogger, Ecto.LogEntry],
+  migration_timestamps: [type: :utc_datetime]
 
 config :explorer,
   solc_bin_api_url: "https://solc-bin.ethereum.org"

apps/explorer/config/dev.secret.exs.example

@@ -7,7 +7,7 @@ config :explorer, Explorer.Repo,
   hostname: "localhost",
   username: "postgres",
   password: "<REPLACE WITH THE PASSWORD YOU CHOSE>",
-  loggers: [],
+  loggers: [Explorer.Repo.PrometheusLogger],
   pool_size: 20,
   pool_timeout: 60_000,
   timeout: 80_000

apps/explorer/lib/explorer/application.ex

@@ -5,8 +5,12 @@ defmodule Explorer.Application do
 
   use Application
 
+  alias Explorer.Repo.PrometheusLogger
+
   @impl Application
   def start(_type, _args) do
+    PrometheusLogger.setup()
+
     # Children to start in all environments
     base_children = [
       Explorer.Repo,

apps/explorer/lib/explorer/repo/prometheus_logger.ex

@@ -0,0 +1,9 @@
+defmodule Explorer.Repo.PrometheusLogger do
+  @moduledoc """
+  Log `Ecto` query durations as `Prometheus` metrics.
+  """
+
+  @dialyzer {:no_match, [log: 1, setup: 0]}
+
+  use Prometheus.EctoInstrumenter
+end

apps/explorer/mix.exs

@@ -91,6 +91,8 @@ defmodule Explorer.Mixfile do
       {:mock, "~> 0.3.0", only: [:test], runtime: false},
       {:mox, "~> 0.4", only: [:test]},
       {:postgrex, ">= 0.0.0"},
+      # Prometheus metrics for query duration
+      {:prometheus_ecto, "~> 1.3"},
       {:sobelow, ">= 0.7.0", only: [:dev, :test], runtime: false},
       {:timex, "~> 3.1.24"},
       {:timex_ecto, "~> 3.2.1"}

mix.lock

@@ -70,6 +70,7 @@
   "poolboy": {:hex, :poolboy, "1.5.1", "6b46163901cfd0a1b43d692657ed9d7e599853b3b21b95ae5ae0a777cf9b6ca8", [:rebar], []},
   "postgrex": {:hex, :postgrex, "0.13.5", "3d931aba29363e1443da167a4b12f06dcd171103c424de15e5f3fc2ba3e6d9c5", [:mix], [{:connection, "~> 1.0", [hex: :connection, optional: false]}, {:db_connection, "~> 1.1", [hex: :db_connection, optional: false]}, {:decimal, "~> 1.0", [hex: :decimal, optional: false]}]},
   "prometheus": {:hex, :prometheus, "4.2.0", "06c58bfdfe28d3168b926da614cb9a6d39593deebde648a5480e32dfa3c370e9", [:mix, :rebar3], [], "hexpm"},
+  "prometheus_ecto": {:hex, :prometheus_ecto, "1.3.0", "fe65de16bcfdd6e3c5455194368cd2c7a7034f734a12c12cb9471f4d5e7690c9", [:mix], [{:ecto, "~> 2.0", [hex: :ecto, repo: "hexpm", optional: false]}, {:prometheus_ex, "~> 1.1 or ~> 2.0 or ~> 3.0", [hex: :prometheus_ex, repo: "hexpm", optional: false]}], "hexpm"},
   "prometheus_ex": {:hex, :prometheus_ex, "3.0.3", "5d722263bb1f7a9b1d02554de42e61ea672b4e3c07c3f74e23ce35ab5e111cfa", [:mix], [{:prometheus, "~> 4.0", [hex: :prometheus, repo: "hexpm", optional: false]}], "hexpm"},
   "prometheus_phoenix": {:hex, :prometheus_phoenix, "1.2.1", "964a74dfbc055f781d3a75631e06ce3816a2913976d1df7830283aa3118a797a", [:mix], [{:phoenix, "~> 1.3", [hex: :phoenix, repo: "hexpm", optional: false]}, {:prometheus_ex, "~> 1.3 or ~> 2.0 or ~> 3.0", [hex: :prometheus_ex, repo: "hexpm", optional: false]}], "hexpm"},
   "prometheus_plugs": {:hex, :prometheus_plugs, "1.1.5", "25933d48f8af3a5941dd7b621c889749894d8a1082a6ff7c67cc99dec26377c5", [:mix], [{:accept, "~> 0.1", [hex: :accept, repo: "hexpm", optional: false]}, {:plug, "~> 1.0", [hex: :plug, repo: "hexpm", optional: false]}, {:prometheus_ex, "~> 1.1 or ~> 2.0 or ~> 3.0", [hex: :prometheus_ex, repo: "hexpm", optional: false]}, {:prometheus_process_collector, "~> 1.1", [hex: :prometheus_process_collector, repo: "hexpm", optional: true]}], "hexpm"},