feat: add prom_ex to expose system metrics

* Upgrade elixir, erlang, and postgres to their latest versions.
* Fix CI configuration, so tests are executed.
* Migrate project configuration from `Mix.Config` to `Config`.

Reviewed-on: #5

.drone.yml

@@ -6,13 +6,21 @@ name: test
 trigger:
   event:
     include:
-      - push
       - pull_request
 
 steps:
+  - name: database healthcheck
+    image: 'postgres:14.2-alpine'
+    environment:
+      PGUSER: postgres
+      PGPASSWORD: postgres
+      PGHOST: db
+    commands:
+      - while ! pg_isready; do sleep 1; done
   - name: test
-    image: 'elixir:1.21.1'
-    environemnt:
+    image: 'elixir:1.13.4'
+    environment:
+      MIX_ENV: test
       POSTGRES_HOST: db
       POSTGRES_USER: postgres
       POSTGRES_PASS: postgres
@@ -22,7 +30,7 @@ steps:
 
 services:
   - name: db
-    image: 'postgres:13.3-alpine'
+    image: 'postgres:14.2-alpine'
     environment:
       POSTGRES_USER: postgres
       POSTGRES_PASSWORD: postgres

.tool-versions

@@ -1,2 +1,2 @@
-erlang 24.0.2
-elixir 1.12.1-otp-24
+erlang 24.3.3
+elixir 1.13.4-otp-24

config/config.exs

@@ -5,7 +5,7 @@
 # is restricted to this project.
 
 # General application configuration
-use Mix.Config
+import Config
 
 config :wabanex,
   ecto_repos: [Wabanex.Repo]
@@ -14,6 +14,13 @@ config :wabanex, Wabanex.Repo,
   migration_primary_key: [type: :binary_id],
   migration_foreign_key: [type: :binary_id]
 
+config :wabanex, Wabanex.PromEx,
+  disabled: false,
+  manual_metrics_start_delay: :no_delay,
+  drop_metrics_groups: [],
+  grafana: :disabled,
+  metrics_server: :disabled
+
 # Configures the endpoint
 config :wabanex, WabanexWeb.Endpoint,
   url: [host: "localhost"],
@@ -32,4 +39,4 @@ config :phoenix, :json_library, Jason
 
 # Import environment specific config. This must remain at the bottom
 # of this file so it overrides the configuration defined above.
-import_config "#{Mix.env()}.exs"
+import_config "#{config_env()}.exs"

config/dev.exs

@@ -1,11 +1,8 @@
-use Mix.Config
+import Config
 
 # Configure your database
 config :wabanex, Wabanex.Repo,
-  username: System.get_env("POSTGRES_USER") || "postgres",
-  password: System.get_env("POSTGRES_PASS") || "postgres",
   database: "wabanex_dev",
-  hostname: System.get_env("POSTGRES_HOST") || "localhost",
   show_sensitive_data_on_connection_error: true,
   pool_size: 10
 

config/prod.exs

@@ -1,4 +1,4 @@
-use Mix.Config
+import Config
 
 # For production, don't forget to configure the url host
 # to something meaningful, Phoenix uses this information

config/runtime.exs

@@ -0,0 +1,6 @@
+import Config
+
+config :wabanex, Wabanex.Repo,
+  username: System.get_env("POSTGRES_USER") || "postgres",
+  password: System.get_env("POSTGRES_PASS") || "postgres",
+  hostname: System.get_env("POSTGRES_HOST") || "localhost"

config/test.exs

@@ -1,4 +1,4 @@
-use Mix.Config
+import Config
 
 # Configure your database
 #
@@ -6,10 +6,7 @@ use Mix.Config
 # to provide built-in test partitioning in CI environment.
 # Run `mix help test` for more information.
 config :wabanex, Wabanex.Repo,
-  username: System.get_env("POSTGRES_USER") || "postgres",
-  password: System.get_env("POSTGRES_PASS") || "postgres",
   database: "wabanex_test#{System.get_env("MIX_TEST_PARTITION")}",
-  hostname: System.get_env("POSTGRES_HOST") || "localhost",
   pool: Ecto.Adapters.SQL.Sandbox
 
 # We don't run a server during test. If one is required,

docker-compose.yml

@@ -2,7 +2,7 @@
 version: '3.7'
 services:
   db:
-    image: 'postgres:13.3-alpine'
+    image: 'postgres:14.2-alpine'
     hostname: &db_host db
     environment:
       POSTGRES_USER: &db_user postgres
@@ -12,5 +12,40 @@ services:
       - './priv/docker/postgres/init.sql:/docker-entrypoint-initdb.d/init.sql'
       - 'db_data:/var/lib/postgresql/data'
     restart: unless-stopped
+  app:
+    image: 'elixir:1.13.4'
+    hostname: app
+    depends_on:
+      - db
+    init: true
+    environment:
+      POSTGRES_HOST: *db_host
+      POSTGRES_USER: *db_user
+      POSTGRES_PASS: *db_pass
+      POSTGRES_NAME: wabanex_dev
+    volumes:
+      - '.:/opt/app'
+      - 'app_build:/opt/app/_build'
+      - 'app_deps:/opt/app/deps'
+    working_dir: /opt/app
+    entrypoint: sleep
+    command: infinity
+  pgcli:
+    image: 'joaodubas/pgcli:latest'
+    hostname: development
+    depends_on:
+      - db
+    environment:
+      PGUSER: *db_user
+      PGPASSWORD: *db_pass
+      PGHOST: *db_host
+      PGDATABASE: wabanex_dev
+    volumes:
+      - './priv/docker/pgcli:/root/.config/pgcli'
+    restart: unless-stopped
+    entrypoint: sleep
+    command: 3650d
 volumes:
   db_data: {}
+  app_build: {}
+  app_deps: {}

lib/wabanex/application.ex

@@ -7,6 +7,8 @@ defmodule Wabanex.Application do
 
   def start(_type, _args) do
     children = [
+      # Start the PromEx supervisor
+      Wabanex.PromEx,
       # Start the Ecto repository
       Wabanex.Repo,
       # Start the Telemetry supervisor

lib/wabanex/prom_ex.ex

@@ -0,0 +1,102 @@
+defmodule Wabanex.PromEx do
+  @moduledoc """
+  Be sure to add the following to finish setting up PromEx:
+
+  1. Update your configuration (config.exs, dev.exs, prod.exs, releases.exs, etc) to
+     configure the necessary bit of PromEx. Be sure to check out `PromEx.Config` for
+     more details regarding configuring PromEx:
+     ```
+     config :wabanex, Wabanex.PromEx,
+       disabled: false,
+       manual_metrics_start_delay: :no_delay,
+       drop_metrics_groups: [],
+       grafana: :disabled,
+       metrics_server: :disabled
+     ```
+
+  2. Add this module to your application supervision tree. It should be one of the first
+     things that is started so that no Telemetry events are missed. For example, if PromEx
+     is started after your Repo module, you will miss Ecto's init events and the dashboards
+     will be missing some data points:
+     ```
+     def start(_type, _args) do
+       children = [
+         Wabanex.PromEx,
+
+         ...
+       ]
+
+       ...
+     end
+     ```
+
+  3. Update your `endpoint.ex` file to expose your metrics (or configure a standalone
+     server using the `:metrics_server` config options). Be sure to put this plug before
+     your `Plug.Telemetry` entry so that you can avoid having calls to your `/metrics`
+     endpoint create their own metrics and logs which can pollute your logs/metrics given
+     that Prometheus will scrape at a regular interval and that can get noisy:
+     ```
+     defmodule WabanexWeb.Endpoint do
+       use Phoenix.Endpoint, otp_app: :wabanex
+
+       ...
+
+       plug PromEx.Plug, prom_ex_module: Wabanex.PromEx
+
+       ...
+     end
+     ```
+
+  4. Update the list of plugins in the `plugins/0` function return list to reflect your
+     application's dependencies. Also update the list of dashboards that are to be uploaded
+     to Grafana in the `dashboards/0` function.
+  """
+
+  use PromEx, otp_app: :wabanex
+
+  alias PromEx.Plugins
+
+  @impl true
+  def plugins do
+    [
+      # PromEx built in plugins
+      Plugins.Application,
+      Plugins.Beam
+      # {Plugins.Phoenix, router: WabanexWeb.Router, endpoint: WabanexWeb.Endpoint},
+      # Plugins.Ecto,
+      # Plugins.Oban,
+      # Plugins.PhoenixLiveView,
+      # Plugins.Absinthe,
+      # Plugins.Broadway,
+
+      # Add your own PromEx metrics plugins
+      # Wabanex.Users.PromExPlugin
+    ]
+  end
+
+  @impl true
+  def dashboard_assigns do
+    [
+      datasource_id: "WABANEX_SERVICE",
+      default_selected_interval: "30s"
+    ]
+  end
+
+  @impl true
+  def dashboards do
+    [
+      # PromEx built in Grafana dashboards
+      {:prom_ex, "application.json"},
+      {:prom_ex, "beam.json"}
+      # {:prom_ex, "phoenix.json"},
+      # {:prom_ex, "ecto.json"},
+      # {:prom_ex, "oban.json"},
+      # {:prom_ex, "phoenix_live_view.json"},
+      # {:prom_ex, "absinthe.json"},
+      # {:prom_ex, "broadway.json"},
+
+      # Add your dashboard definitions here with the format: {:otp_app, "path_in_priv"}
+      # {:wabanex, "/grafana_dashboards/user_metrics.json"}
+    ]
+  end
+end

mix.exs

@@ -43,6 +43,7 @@ defmodule Wabanex.MixProject do
       {:phoenix, "~> 1.6.0"},
       {:phoenix_ecto, "~> 4.1"},
       {:phoenix_live_dashboard, "~> 0.4"},
+      {:prom_ex, "~> 1.7"},
       {:plug_cowboy, "~> 2.0"},
       {:postgrex, ">= 0.0.0"},
       {:telemetry_metrics, "~> 0.4"},

mix.lock

@@ -39,8 +39,10 @@
   "plug_cowboy": {:hex, :plug_cowboy, "2.5.2", "62894ccd601cf9597e2c23911ff12798a8a18d237e9739f58a6b04e4988899fe", [:mix], [{:cowboy, "~> 2.7", [hex: :cowboy, repo: "hexpm", optional: false]}, {:cowboy_telemetry, "~> 0.3", [hex: :cowboy_telemetry, repo: "hexpm", optional: false]}, {:plug, "~> 1.7", [hex: :plug, repo: "hexpm", optional: false]}], "hexpm", "ea6e87f774c8608d60c8d34022a7d073bd7680a0a013f049fc62bf35efea1044"},
   "plug_crypto": {:hex, :plug_crypto, "1.2.2", "05654514ac717ff3a1843204b424477d9e60c143406aa94daf2274fdd280794d", [:mix], [], "hexpm", "87631c7ad914a5a445f0a3809f99b079113ae4ed4b867348dd9eec288cecb6db"},
   "postgrex": {:hex, :postgrex, "0.16.2", "0f83198d0e73a36e8d716b90f45f3bde75b5eebf4ade4f43fa1f88c90a812f74", [: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]}], "hexpm", "a9ea589754d9d4d076121090662b7afe155b374897a6550eb288f11d755acfa0"},
+  "prom_ex": {:hex, :prom_ex, "1.7.1", "39331ee3fe6f9a8587d8208bf9274a253bb80281700e127dd18786cda5e08c37", [:mix], [{:absinthe, ">= 1.6.0", [hex: :absinthe, repo: "hexpm", optional: true]}, {:broadway, ">= 1.0.2", [hex: :broadway, repo: "hexpm", optional: true]}, {:ecto, ">= 3.5.0", [hex: :ecto, repo: "hexpm", optional: true]}, {:finch, "~> 0.10.2", [hex: :finch, repo: "hexpm", optional: false]}, {:jason, "~> 1.2", [hex: :jason, repo: "hexpm", optional: false]}, {:oban, ">= 2.4.0", [hex: :oban, repo: "hexpm", optional: true]}, {:phoenix, ">= 1.5.0", [hex: :phoenix, repo: "hexpm", optional: true]}, {:phoenix_live_view, ">= 0.14.0", [hex: :phoenix_live_view, repo: "hexpm", optional: true]}, {:plug, ">= 1.12.1", [hex: :plug, repo: "hexpm", optional: true]}, {:plug_cowboy, "~> 2.5.1", [hex: :plug_cowboy, repo: "hexpm", optional: false]}, {:telemetry, "~> 1.0.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:telemetry_metrics, "~> 0.6.1", [hex: :telemetry_metrics, repo: "hexpm", optional: false]}, {:telemetry_metrics_prometheus_core, "~> 1.0.2", [hex: :telemetry_metrics_prometheus_core, repo: "hexpm", optional: false]}, {:telemetry_poller, "~> 1.0.0", [hex: :telemetry_poller, repo: "hexpm", optional: false]}], "hexpm", "4c978872b88a929833925a0f4d0561824804c671fdd04581e765509ed0a6ed08"},
   "ranch": {:hex, :ranch, "1.8.0", "8c7a100a139fd57f17327b6413e4167ac559fbc04ca7448e9be9057311597a1d", [:make, :rebar3], [], "hexpm", "49fbcfd3682fab1f5d109351b61257676da1a2fdbe295904176d5e521a2ddfe5"},
   "telemetry": {:hex, :telemetry, "1.0.0", "0f453a102cdf13d506b7c0ab158324c337c41f1cc7548f0bc0e130bbf0ae9452", [:rebar3], [], "hexpm", "73bc09fa59b4a0284efb4624335583c528e07ec9ae76aca96ea0673850aec57a"},
   "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"},
 }