Port example from opentelemetry-examples (#31)

* Copy opentelemetry-examples/basic_elixir over

* Bump opentelemtry and opentelemetry_exporter to 1,0.0-rc.3

* Remove OpenTelemetry.register_application_tracer

* Update example to be consistent with opentelemetry.io docs

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

examples/basic_elixir/.dockerignore

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+# The directory Mix will write compiled artifacts to.
+_build/
+
+# The directory Mix downloads your dependencies sources to.
+deps/
+
+# If the VM crashes, it generates a dump, let's ignore it too.
+erl_crash.dump
+

examples/basic_elixir/.formatter.exs

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

examples/basic_elixir/.gitignore

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+# 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").
+basic_elixir-*.tar
+

examples/basic_elixir/Dockerfile

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+FROM elixir:1.9-alpine as builder
+RUN mix local.hex --force && mix local.rebar --force
+WORKDIR /app
+COPY . /app
+RUN mix deps.get
+RUN MIX_ENV=prod mix release
+
+FROM alpine:latest as app
+RUN apk add bash openssl
+WORKDIR /app
+COPY --from=builder /app/_build/prod/rel/basic_elixir .
+CMD bin/basic_elixir start
+

examples/basic_elixir/README.md

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+# Basic Elixir Example
+
+This is a sample repository that demo how to setup a basic Elixir application
+with `opentelemetry-api` and `opentelemetry_exporter`. Here, we are using
+`opentelemetry_exporter` to export the traces to [OpenTelemetry Collector][0].
+The collector in turn export the traces to [Zipkin][1] and [Jaeger][2]
+respectively.
+
+## Getting Stated
+
+Assuming you already have Docker and Docker Compose installed:
+
+1. Run `docker-compose up` to start the application, OpenTelemetry Collector,
+   Zipkin and Jaeger.
+2. Visit Zipkin at http://localhost:9411 and hit `Run Query` to look the the sample trace.
+3. Visit Jaeger UI at http://localhost:16686 and click `Find Trace` to look at the sample
+   trace.
+
+[0]: https://github.com/open-telemetry/opentelemetry-collector/
+[1]: https://zipkin.io/
+[2]: https://www.jaegertracing.io/

examples/basic_elixir/config/releases.exs

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+import Config
+
+config :opentelemetry,
+       :processors,
+       otel_batch_processor: %{
+         # Using `otel` here since we are starting through docker-compose where
+         # otel refer to the hostname of the OpenCollector,
+         #
+         # If you are running it locally, kindly change it to the correct
+         # hostname such as `localhost`, `0.0.0.0` and etc.
+         exporter: {:opentelemetry_exporter, %{endpoints: [{:http, 'otel', 55681, []}]}}
+       }

examples/basic_elixir/docker-compose.yml

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+version: '3'
+services:
+  elixir:
+    build: .
+
+  otel:
+    image: otel/opentelemetry-collector-contrib-dev:latest
+    command: ["--config=/etc/otel-collector-config.yaml"]
+    ports:
+      - '55681:55681'
+      - '55680:55680'
+    volumes:
+      - ./otel-collector-config.yaml:/etc/otel-collector-config.yaml
+
+  zipkin:
+    image: openzipkin/zipkin-slim
+    ports:
+      - '9411:9411'
+
+  # Jaeger
+  jaeger-all-in-one:
+    image: jaegertracing/all-in-one:latest
+    ports:
+      - "16686:16686"
+      - "14268"
+      - "14250"
+
+

examples/basic_elixir/lib/basic_elixir.ex

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+defmodule BasicElixir do
+  @moduledoc """
+  Documentation for BasicElixir.
+  """
+
+  @doc """
+  Hello world.
+
+  ## Examples
+
+      iex> BasicElixir.hello()
+      :world
+
+  """
+  def hello do
+    :world
+  end
+end

examples/basic_elixir/lib/basic_elixir/application.ex

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+defmodule BasicElixir.Application do
+  # See https://hexdocs.pm/elixir/Application.html
+  # for more information on OTP Applications
+  @moduledoc false
+
+  use Application
+
+  def start(_type, _args) do
+    children = [
+      # Starts a worker by calling: BasicElixir.Worker.start_link(arg)
+      {BasicElixir.Worker, []}
+    ]
+
+    # See https://hexdocs.pm/elixir/Supervisor.html
+    # for other strategies and supported options
+    opts = [strategy: :one_for_one, name: BasicElixir.Supervisor]
+    Supervisor.start_link(children, opts)
+  end
+end

examples/basic_elixir/lib/basic_elixir/worker.ex

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+defmodule BasicElixir.Worker do
+  use GenServer
+  require Logger
+  require OpenTelemetry.Tracer, as: Tracer
+  require OpenTelemetry.Span
+
+  # Client
+  def start_link(default) when is_list(default) do
+    Tracer.with_span "start_link" do
+      Tracer.add_event("Nice operation!", [{"bogons", 100}])
+      Tracer.set_attributes([{:another_key, "yes"}])
+
+      Tracer.with_span "Sub operation..." do
+        Tracer.set_attributes([{:lemons_key, "five"}])
+        Tracer.add_event("Sub span event!", [])
+      end
+
+      GenServer.start_link(__MODULE__, default)
+    end
+  end
+
+  def push(pid, element) do
+    GenServer.cast(pid, {:push, element})
+  end
+
+  def pop(pid) do
+    GenServer.call(pid, :pop)
+  end
+
+  # Server (callbacks)
+  @impl true
+  def init(stack) do
+    Tracer.with_span "init" do
+      Logger.info("Starting #{__MODULE__}...")
+      {:ok, stack}
+    end
+  end
+
+  @impl true
+  def handle_call(:pop, _from, [head | tail]) do
+    {:reply, head, tail}
+  end
+
+  @impl true
+  def handle_cast({:push, element}, state) do
+    {:noreply, [element | state]}
+  end
+end

examples/basic_elixir/mix.exs

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+defmodule BasicElixir.MixProject do
+  use Mix.Project
+
+  def project do
+    [
+      app: :basic_elixir,
+      version: "0.1.0",
+      elixir: "~> 1.9",
+      start_permanent: Mix.env() == :prod,
+      deps: deps(),
+      releases: [
+        basic_elixir: [
+          applications: [opentelemetry: :temporary]
+        ]
+      ]
+    ]
+  end
+
+  # Run "mix help compile.app" to learn about applications.
+  def application do
+    [
+      extra_applications: [:logger],
+      mod: {BasicElixir.Application, []}
+    ]
+  end
+
+  # Run "mix help deps" to learn about dependencies.
+  defp deps do
+    [
+      {:opentelemetry, "~> 1.0.0-rc.3"},
+      {:opentelemetry_exporter, "~> 1.0.0-rc.3"},
+    ]
+  end
+end

examples/basic_elixir/mix.lock

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+%{
+  "acceptor_pool": {:hex, :acceptor_pool, "1.0.0", "43c20d2acae35f0c2bcd64f9d2bde267e459f0f3fd23dab26485bf518c281b21", [:rebar3], [], "hexpm", "0cbcd83fdc8b9ad2eee2067ef8b91a14858a5883cb7cd800e6fcd5803e158788"},
+  "chatterbox": {:hex, :ts_chatterbox, "0.11.0", "b8f372c706023eb0de5bf2976764edb27c70fe67052c88c1f6a66b3a5626847f", [:rebar3], [{:hpack, "~>0.2.3", [hex: :hpack_erl, repo: "hexpm", optional: false]}], "hexpm", "722fe2bad52913ab7e87d849fc6370375f0c961ffb2f0b5e6d647c9170c382a6"},
+  "ctx": {:hex, :ctx, "0.6.0", "8ff88b70e6400c4df90142e7f130625b82086077a45364a78d208ed3ed53c7fe", [:rebar3], [], "hexpm", "a14ed2d1b67723dbebbe423b28d7615eb0bdcba6ff28f2d1f1b0a7e1d4aa5fc2"},
+  "gproc": {:hex, :gproc, "0.8.0", "cea02c578589c61e5341fce149ea36ccef236cc2ecac8691fba408e7ea77ec2f", [:rebar3], [], "hexpm", "580adafa56463b75263ef5a5df4c86af321f68694e7786cb057fd805d1e2a7de"},
+  "grpcbox": {:hex, :grpcbox, "0.14.0", "3eb321bcd2275baf8b54cf381feb7b0559a50c02544de28fda039c7f2f9d1a7a", [:rebar3], [{:acceptor_pool, "~>1.0.0", [hex: :acceptor_pool, repo: "hexpm", optional: false]}, {:chatterbox, "~>0.11.0", [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", "e24159b7b6d3f9869bbe528845c0125fed2259366ba908fd04a1f45fe81d0660"},
+  "hpack": {:hex, :hpack_erl, "0.2.3", "17670f83ff984ae6cd74b1c456edde906d27ff013740ee4d9efaa4f1bf999633", [:rebar3], [], "hexpm", "06f580167c4b8b8a6429040df36cc93bba6d571faeaec1b28816523379cbb23a"},
+  "opentelemetry": {:hex, :opentelemetry, "1.0.0-rc.3", "d2698bee882c354274563ee85d097bb736a9adb8d8ed376a4deea0cd3a14bb31", [:rebar3], [{:opentelemetry_api, "~> 1.0.0-rc.3", [hex: :opentelemetry_api, repo: "hexpm", optional: false]}], "hexpm", "c9105933df0d783d94cf08d79206eb8d6578abc0bcbd498d0b497ec62a4e30a8"},
+  "opentelemetry_api": {:hex, :opentelemetry_api, "1.0.0-rc.3.2", "588ebf85fa7d18eba8db297b7d0a2a654f680f35c4466cd0045cd12a6fda27d7", [:mix, :rebar3], [], "hexpm", "1e0ba55db6718d5797e72c00e3821e60e02f7829e3fb64dc1a7c96f7c2776a58"},
+  "opentelemetry_exporter": {:hex, :opentelemetry_exporter, "1.0.0-rc.3", "76f5657d4c94a12003d9ed2c8da1023c815e98f5553184dbb0cdaeec76db676d", [:rebar3], [{:grpcbox, ">= 0.0.0", [hex: :grpcbox, repo: "hexpm", optional: false]}, {:opentelemetry, "~> 1.0.0-rc.3", [hex: :opentelemetry, repo: "hexpm", optional: false]}, {:opentelemetry_api, "~> 1.0.0-rc.3", [hex: :opentelemetry_api, repo: "hexpm", optional: false]}], "hexpm", "267f0e4c3f1f5557cc7ad6ac71d66b8eaf7b3b56fde942c21f8a0bc96174fe1e"},
+}

examples/basic_elixir/otel-collector-config.yaml

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+receivers:
+  otlp:
+    protocols:
+      grpc:
+        endpoint: "0.0.0.0:55680"
+      http:
+        endpoint: "0.0.0.0:55681"
+processors:
+  batch:
+    send_batch_size: 1024
+    timeout: 5s
+exporters:
+  zipkin:
+    endpoint: "http://zipkin:9411/api/v2/spans"
+  jaeger:
+    endpoint: jaeger-all-in-one:14250
+    insecure: true
+extensions:
+  zpages: {}
+service:
+  extensions: [zpages]
+  pipelines:
+    traces:
+      receivers: [otlp]
+      processors: [batch]
+      exporters: [zipkin, jaeger]
+

examples/basic_elixir/test/basic_elixir_test.exs

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+defmodule BasicElixirTest do
+  use ExUnit.Case
+  doctest BasicElixir
+
+  test "greets the world" do
+    assert BasicElixir.hello() == :world
+  end
+end

examples/basic_elixir/test/test_helper.exs

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+ExUnit.start()