Dice game example

examples/roll_dice/.formatter.exs

@@ -0,0 +1,4 @@
+[
+  import_deps: [:phoenix],
+  inputs: ["*.{ex,exs}", "{config,lib,test}/**/*.{ex,exs}"]
+]

examples/roll_dice/.gitignore

@@ -0,0 +1,27 @@
+# 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 3rd-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
+
+# Temporary files, for example, from tests.
+/tmp/
+
+# Ignore package tarball (built via "mix hex.build").
+roll_dice-*.tar
+

examples/roll_dice/README.md

@@ -0,0 +1,84 @@
+# RollDice
+
+The following example uses a basic [Phoenix](https://www.phoenixframework.org/)
+web application. For more elaborate examples, see [examples](/docs/instrumentation/erlang/examples/).
+
+To start your Phoenix server:
+
+  * Run `mix setup` to install and setup dependencies
+  * Start the opentelemetry collector and Jaeger front-end with `docker-compose up -d`
+  * Set your service name `export OTEL_SERVICE_NAME="roll_dice"`
+  * Start Phoenix endpoint with `mix phx.server` or inside IEx with `iex -S mix phx.server`
+
+To generate and view traces:
+
+  * Visit the new API endpoint with `curl http://localhost:4000/api/rolldice` or in your browser
+  * Visit [`localhost:16686`](http://localhost:16686) to see the traces in Jaeger
+
+For more information on the OpenTelemetry instrumentation in this example, check out the guide for getting started with [OpenTelemetry](https://opentelemetry.io/docs/instrumentation/erlang/getting-started/)
+
+## How did we get here?
+
+To begin, use the `phx` generator to create a new project. To keep things simple we'll leave out the database and html for now with the `--no-ecto` and `--no-html` flags.
+In a real app, you'll probably want to include ecto configured for your preferred database with the `--database` flag (`postgres` by default).
+
+```shell
+mix phx.new --no-ecto --no-html roll_dice
+```
+
+### Rolling The Dice
+
+Now we'll add an API endpoint that will let us roll the dice and return a random
+number between 1 and 6.
+
+To start, we'll add a route to the `/api` scope in your router
+
+```elixir
+# lib/roll_dice_web/router.ex
+scope "/api", DiceGameWeb do
+  pipe_through :api
+
+  get "/rolldice", DiceController, :roll
+end
+```
+
+Then we'll create a new file in the controllers folder for that module. We told
+the router that we will define a roll function, so we'll do that. It will return
+a `200` response code and the result of a `dice_roll` function, which we will
+emit a span for. We also want to set the value of the generated roll as an
+attribute on the span.
+
+```elixir
+# lib/roll_dice_web/controllers/dice_controller.ex
+defmodule DiceGameWeb.DiceController do
+  use DiceGameWeb, :controller
+  require OpenTelemetry.Tracer, as: Tracer
+
+  def roll(conn, _params) do
+    send_resp(conn, 200, roll_dice())
+  end
+
+  defp roll_dice do
+    Tracer.with_span("roll_dice") do
+      roll = Enum.random(1..6)
+
+      Tracer.set_attribute("roll.value", roll)
+
+      to_string(roll)
+    end
+  end
+end
+
+```
+
+If you point your browser/curl/etc. to [`localhost:4000/api/rolldice`](http://localhost:4000/api/rolldice) you should get a random number in response.
+
+Ready to run in production? Please [check our deployment guides](https://hexdocs.pm/phoenix/deployment.html).
+
+## Learn more
+
+  * Official website: https://www.phoenixframework.org/
+  * Guides: https://hexdocs.pm/phoenix/overview.html
+  * Docs: https://hexdocs.pm/phoenix
+  * Forum: https://elixirforum.com/c/phoenix-forum
+  * Source: https://github.com/phoenixframework/phoenix

examples/roll_dice/config/config.exs

@@ -0,0 +1,30 @@
+# This file is responsible for configuring your application
+# and its dependencies with the aid of the Config module.
+#
+# This configuration file is loaded before any dependency and
+# is restricted to this project.
+
+# General application configuration
+import Config
+
+# Configures the endpoint
+config :roll_dice, RollDiceWeb.Endpoint,
+  url: [host: "localhost"],
+  render_errors: [
+    formats: [json: RollDiceWeb.ErrorJSON],
+    layout: false
+  ],
+  pubsub_server: RollDice.PubSub,
+  live_view: [signing_salt: "F/DlUt0K"]
+
+# Configures Elixir's Logger
+config :logger, :console,
+  format: "$time $metadata[$level] $message\n",
+  metadata: [:request_id]
+
+# Use Jason for JSON parsing in Phoenix
+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 "#{config_env()}.exs"

examples/roll_dice/config/dev.exs

@@ -0,0 +1,53 @@
+import Config
+
+# For development, we disable any cache and enable
+# debugging and code reloading.
+#
+# The watchers configuration can be used to run external
+# watchers to your application. For example, we can use it
+# to bundle .js and .css sources.
+config :roll_dice, RollDiceWeb.Endpoint,
+  # Binding to loopback ipv4 address prevents access from other machines.
+  # Change to `ip: {0, 0, 0, 0}` to allow access from other machines.
+  http: [ip: {127, 0, 0, 1}, port: 4000],
+  check_origin: false,
+  code_reloader: true,
+  debug_errors: true,
+  secret_key_base: "4zhqnz+sDpekY/MD3u0QNJpzg8PRWarEI0u+NfSqzwtKp/byfGUWwka4ALZ36yqz",
+  watchers: []
+
+# ## SSL Support
+#
+# In order to use HTTPS in development, a self-signed
+# certificate can be generated by running the following
+# Mix task:
+#
+#     mix phx.gen.cert
+#
+# Run `mix help phx.gen.cert` for more information.
+#
+# The `http:` config above can be replaced with:
+#
+#     https: [
+#       port: 4001,
+#       cipher_suite: :strong,
+#       keyfile: "priv/cert/selfsigned_key.pem",
+#       certfile: "priv/cert/selfsigned.pem"
+#     ],
+#
+# If desired, both `http:` and `https:` keys can be
+# configured to run both http and https servers on
+# different ports.
+
+# Enable dev routes for dashboard and mailbox
+config :roll_dice, dev_routes: true
+
+# Do not include metadata nor timestamps in development logs
+config :logger, :console, format: "[$level] $message\n"
+
+# Set a higher stacktrace during development. Avoid configuring such
+# in production as building large stacktraces may be expensive.
+config :phoenix, :stacktrace_depth, 20
+
+# Initialize plugs at runtime for faster development compilation
+config :phoenix, :plug_init_mode, :runtime

examples/roll_dice/config/prod.exs

@@ -0,0 +1,7 @@
+import Config
+
+# Do not print debug messages in production
+config :logger, level: :info
+
+# Runtime production configuration, including reading
+# of environment variables, is done on config/runtime.exs.

examples/roll_dice/config/runtime.exs

@@ -0,0 +1,91 @@
+import Config
+
+# config/runtime.exs is executed for all environments, including
+# during releases. It is executed after compilation and before the
+# system starts, so it is typically used to load production configuration
+# and secrets from environment variables or elsewhere. Do not define
+# any compile-time configuration in here, as it won't be applied.
+# The block below contains prod specific runtime configuration.
+
+# ## Using releases
+#
+# If you use `mix release`, you need to explicitly enable the server
+# by passing the PHX_SERVER=true when you start it:
+#
+#     PHX_SERVER=true bin/roll_dice start
+#
+# Alternatively, you can use `mix phx.gen.release` to generate a `bin/server`
+# script that automatically sets the env var above.
+if System.get_env("PHX_SERVER") do
+  config :roll_dice, RollDiceWeb.Endpoint, server: true
+end
+
+if config_env() == :prod do
+  # The secret key base is used to sign/encrypt cookies and other secrets.
+  # A default value is used in config/dev.exs and config/test.exs but you
+  # want to use a different value for prod and you most likely don't want
+  # to check this value into version control, so we use an environment
+  # variable instead.
+  secret_key_base =
+    System.get_env("SECRET_KEY_BASE") ||
+      raise """
+      environment variable SECRET_KEY_BASE is missing.
+      You can generate one by calling: mix phx.gen.secret
+      """
+
+  host = System.get_env("PHX_HOST") || "example.com"
+  port = String.to_integer(System.get_env("PORT") || "4000")
+
+  config :roll_dice, RollDiceWeb.Endpoint,
+    url: [host: host, port: 443, scheme: "https"],
+    http: [
+      # Enable IPv6 and bind on all interfaces.
+      # Set it to  {0, 0, 0, 0, 0, 0, 0, 1} for local network only access.
+      # See the documentation on https://hexdocs.pm/plug_cowboy/Plug.Cowboy.html
+      # for details about using IPv6 vs IPv4 and loopback vs public addresses.
+      ip: {0, 0, 0, 0, 0, 0, 0, 0},
+      port: port
+    ],
+    secret_key_base: secret_key_base
+
+  config :opentelemetry,
+         span_processor: :batch,
+         traces_exporter: :otlp
+
+  config :opentelemetry_exporter,
+         otlp_protocol: :http_protobuf,
+         otlp_endpoint: "http://localhost:4317"
+
+
+  # ## SSL Support
+  #
+  # To get SSL working, you will need to add the `https` key
+  # to your endpoint configuration:
+  #
+  #     config :roll_dice, RollDiceWeb.Endpoint,
+  #       https: [
+  #         ...,
+  #         port: 443,
+  #         cipher_suite: :strong,
+  #         keyfile: System.get_env("SOME_APP_SSL_KEY_PATH"),
+  #         certfile: System.get_env("SOME_APP_SSL_CERT_PATH")
+  #       ]
+  #
+  # The `cipher_suite` is set to `:strong` to support only the
+  # latest and more secure SSL ciphers. This means old browsers
+  # and clients may not be supported. You can set it to
+  # `:compatible` for wider support.
+  #
+  # `:keyfile` and `:certfile` expect an absolute path to the key
+  # and cert in disk or a relative path inside priv, for example
+  # "priv/ssl/server.key". For all supported SSL configuration
+  # options, see https://hexdocs.pm/plug/Plug.SSL.html#configure/1
+  #
+  # We also recommend setting `force_ssl` in your endpoint, ensuring
+  # no data is ever sent via http, always redirecting to https:
+  #
+  #     config :roll_dice, RollDiceWeb.Endpoint,
+  #       force_ssl: [hsts: true]
+  #
+  # Check `Plug.SSL` for all available options in `force_ssl`.
+end

examples/roll_dice/config/test.exs

@@ -0,0 +1,14 @@
+import Config
+
+# We don't run a server during test. If one is required,
+# you can enable the server option below.
+config :roll_dice, RollDiceWeb.Endpoint,
+  http: [ip: {127, 0, 0, 1}, port: 4002],
+  secret_key_base: "ZclS6l1Z5RRwC1QKG8uIr4zgwQGkUYMB1AARGv3iaiC4GGRbATFBgKGKURgWPAMa",
+  server: false
+
+# Print only warnings and errors during test
+config :logger, level: :warning
+
+# Initialize plugs at runtime for faster test compilation
+config :phoenix, :plug_init_mode, :runtime

examples/roll_dice/docker-compose.yml

@@ -0,0 +1,23 @@
+version: "3"
+services:
+  otel:
+    image: otel/opentelemetry-collector-contrib:0.76.1
+    command: ["--config=/conf/otel-collector-config.yaml"]
+    privileged: true
+    ports:
+      - 4317:4317
+      - 4318:4318
+      - 55679:55679
+    volumes:
+      - ./otel-collector-config.yaml:/conf/otel-collector-config.yaml
+    links:
+      - jaeger-all-in-one
+
+  jaeger-all-in-one:
+    image: jaegertracing/all-in-one:1.45
+    restart: always
+    environment:
+      COLLECTOR_OTLP_ENABLED: true
+    ports:
+      - "16686:16686"
+      - "4317"

examples/roll_dice/lib/roll_dice.ex

@@ -0,0 +1,9 @@
+defmodule RollDice do
+  @moduledoc """
+  RollDice keeps the contexts that define your domain
+  and business logic.
+
+  Contexts are also responsible for managing your data, regardless
+  if it comes from the database, an external API or others.
+  """
+end

examples/roll_dice/lib/roll_dice/application.ex

@@ -0,0 +1,37 @@
+defmodule RollDice.Application do
+  # See https://hexdocs.pm/elixir/Application.html
+  # for more information on OTP Applications
+  @moduledoc false
+
+  use Application
+
+  @impl true
+  def start(_type, _args) do
+    :opentelemetry_cowboy.setup()
+    OpentelemetryPhoenix.setup(adapter: :cowboy2)
+
+    children = [
+      # Start the Telemetry supervisor
+      RollDiceWeb.Telemetry,
+      # Start the PubSub system
+      {Phoenix.PubSub, name: RollDice.PubSub},
+      # Start the Endpoint (http/https)
+      RollDiceWeb.Endpoint
+      # Start a worker by calling: RollDice.Worker.start_link(arg)
+      # {RollDice.Worker, arg}
+    ]
+
+    # See https://hexdocs.pm/elixir/Supervisor.html
+    # for other strategies and supported options
+    opts = [strategy: :one_for_one, name: RollDice.Supervisor]
+    Supervisor.start_link(children, opts)
+  end
+
+  # Tell Phoenix to update the endpoint configuration
+  # whenever the application is updated.
+  @impl true
+  def config_change(changed, _new, removed) do
+    RollDiceWeb.Endpoint.config_change(changed, removed)
+    :ok
+  end
+end