Adding fanout publishing script for the picture upload example

sylvilagus/jruby/lib/sylvilagus/ch04/fanout_publisher.rb

@@ -0,0 +1,43 @@
+require 'sylvilagus/init'
+require 'sylvilagus/ch04'
+require 'json'
+require 'rabbitmq-client.jar'
+
+class Sylvilagus::Ch04::FanoutPublisher
+  def main(argv = ARGV.clone)
+    unless argv.length == 3
+      STDERR.puts "Usage: #{File.basename($0)} <image-id> <user-id> <image-path>"
+      return 1
+    end
+    message = {
+      'image_id' => Integer(argv.fetch(0)),
+      'user_id' => Integer(argv.fetch(1)),
+      'image_path' => argv.fetch(2)
+    }
+
+    factory = Java::ComRabbitmqClient::ConnectionFactory.new
+    factory.uri = ENV.fetch('SYLVILAGUS_AMQP_URI')
+    @conn = factory.new_connection
+    channel = @conn.create_channel
+    channel.exchange_declare(
+      'upload-pictures', 'fanout', false, true, false, nil
+    )
+
+    props = Java::ComRabbitmqClient::AMQP::BasicProperties.new
+    props.content_type = 'application/json'
+    props.delivery_mode = 2
+
+    json_msg = JSON.dump({'message' => message})
+    channel.basic_publish('upload-pictures', '', props, json_msg.to_java_bytes)
+
+    puts "Sent message #{json_msg.inspect} tagged " <<
+         'exchange "upload-pictures" on vhost "/".'
+    return 0
+  ensure
+    @conn.close if @conn
+  end
+end
+
+if $0 == __FILE__
+  exit Sylvilagus::Ch04::FanoutPublisher.new.main
+end