add elixir streams example

Author: VictorGaiva

.gitignore

@@ -18,6 +18,10 @@ ruby*/gems/
 venv/*
 ruby*/rubygems*
 
+elixir-stream/deps
+elixir-stream/_build
+elixir-stream/.elixir_ls
+
 java*/.idea/workspace.xml
 java*/.idea/encodings.xml
 *~

README.md

@@ -30,6 +30,7 @@ The following ports are available:
  * [Common Lisp](./common-lisp)
  * [Dart](./dart)
  * [Elixir](./elixir) 
+ * [Elixir (Streams)](./elixir-stream) 
  * [Erlang](./erlang)
  * [Go](./go)
  * [Haskell](./haskell)

elixir-stream/README.md

@@ -0,0 +1,20 @@
+# Elixir code for RabbitMQ tutorials
+
+Here you can find Elixir code examples from [RabbitMQ tutorials](https://www.rabbitmq.com/getstarted.html).
+
+## Requirements
+
+These examples use the [`VictorGaiva/rabbitmq-stream`](https://github.com/VictorGaiva/rabbitmq-stream) client library.
+
+The dependencies are installed during the exection of the examples using `Mix.install/1`
+
+## Code
+
+Code examples are executed via `elixir`:
+
+Tutorial one: "Hello World!":
+
+    elixir publish.exs
+    elixir consume.exs
+
+To learn more, see [`VictorGaiva/rabbitmq-stream`](https://github.com/VictorGaiva/rabbitmq-stream).

elixir-stream/consume.exs

@@ -0,0 +1,25 @@
+#! /usr/bin/env elixir
+require Logger
+
+# Installing the rabbitmq_stream Library
+Mix.install([
+  {:rabbitmq_stream, "~> 0.4.1"}
+])
+
+# First we start a Connection to the RabbitMQ Server
+{:ok, connection} = RabbitMQStream.Connection.start_link()
+
+# We can assume the stream already exists as this sample is meant to be run after the 'publish.exs' sample
+
+# Now we can subscribe to the stream, receiving up to 1 chunk.
+{:ok, subscription_id} =
+  RabbitMQStream.Connection.subscribe(connection, "my_stream", self(), :first, 1)
+
+# Now we can consume the messages
+receive do
+  # Each 'deliver' data comes inside a Chunk, which may contain multiple messages
+  {:deliver, %{subscription_id: ^subscription_id, osiris_chunk: chunk}} ->
+    for message <- chunk.data_entries do
+      Logger.info("Received: #{inspect(message)}")
+    end
+end

elixir-stream/publish.exs

@@ -0,0 +1,31 @@
+#! /usr/bin/env elixir
+require Logger
+
+# Installing the rabbitmq_stream Library
+Mix.install([
+  {:rabbitmq_stream, "~> 0.4.1"}
+])
+
+# First we start a Connection to the RabbitMQ Server
+{:ok, connection} = RabbitMQStream.Connection.start_link()
+
+# We can assume the stream doesn't exist yet, and attempt to create it. If it already exists,
+# it should be still be good to go.
+RabbitMQStream.Connection.create_stream(connection, "my_stream")
+
+# Before publishing a message, we need to declare a producer. It is required by the
+# RabbitMQ Sever to prevent message duplication.
+{:ok, producer_id} =
+  RabbitMQStream.Connection.declare_producer(connection, "my_stream", "my_producer")
+
+# Each producer has a sequence number, that must must be published with the message, and
+# incremented after each message.
+{:ok, sequence_number} =
+  RabbitMQStream.Connection.query_producer_sequence(connection, "my_stream", "my_producer")
+
+# Now we can publish a message. Note that we only specify the producer_id and sequence number.
+# The target Stream is already tracked by the server based on the producer_id.
+:ok =
+  RabbitMQStream.Connection.publish(connection, producer_id, sequence_number + 1, "Hello, World!")
+
+Logger.info("Published: \"Hello, World!\"")