Adds KAFKA_ADVERTISED_HOST_NAME and example kafka file

Tested with brave-resteasy-example with Docker Toolbox on OS/X

Fixes #85

README.md

@@ -74,6 +74,20 @@ To start the MySQL-backed configuration, run:
 
     $ docker-compose -f docker-compose.yml -f docker-compose-mysql.yml up
 
+### Kafka
+
+The docker-compose configuration can be extended to host a test Kafka broker
+using the `docker-compose-kafka.yml` file. That file employs
+[docker-compose overrides](https://docs.docker.com/compose/extends/#multiple-compose-files)
+to add a Kafka+ZooKeeper container and relevant settings.
+
+To start the Cassandra+Kafka configuration, run:
+
+    $ docker-compose -f docker-compose.yml -f docker-compose-kafka.yml up
+
+By default, this assumes your Docker host IP is 192.168.99.100, which is what
+you would use for the broker IP when configuring application instrumentation.
+
 ### Legacy
 
 The Cassandra and MySQL docker-compose files described above use version 2 of

docker-compose-kafka.yml

@@ -0,0 +1,25 @@
+# This file uses the version 2 docker-compose file format, described here:
+# https://docs.docker.com/compose/compose-file/#version-2
+#
+# It extends the default configuration from docker-compose.yml to run the
+# zipkin-mysql container instead of the zipkin-cassandra container.
+
+version: '2'
+
+services:
+  kafka-zookeeper:
+    build: kafka
+    image: openzipkin/zipkin-kafka:1.4.3
+    container_name: kafka-zookeeper
+    environment:
+      # corresponds to your docker machine and your producer's broker list
+      - KAFKA_ADVERTISED_HOST_NAME=192.168.99.100
+    ports:
+      - 2181:2181
+      - 9092:9092
+
+  zipkin:
+    environment:
+      - KAFKA_ZOOKEEPER=kafka-zookeeper
+    depends_on:
+      - kafka-zookeeper

kafka/Dockerfile

@@ -3,7 +3,7 @@ FROM openzipkin/jre-full:1.8.0_72
 MAINTAINER OpenZipkin "http://zipkin.io/"
 
 ENV SCALA_VERSION 2.11
-ENV KAFKA_VERSION 0.9.0.0
+ENV KAFKA_VERSION 0.9.0.1
 ENV ZOOKEEPER_VERSION 3.4.6
 
 WORKDIR /kafka

kafka/install.sh

@@ -36,10 +36,14 @@ EOF
 
 # create runit config, dependent on zookeeper, that advertises the container ip
 mkdir -p /etc/service/kafka
-cat > /etc/service/kafka/run <<-EOF
+cat > /etc/service/kafka/run <<-"EOF"
 #!/bin/sh
 sv start zookeeper || exit 1
-echo advertised.host.name=$(route -n | awk '/UG[ \t]/{print $2}') >> /kafka/config/server.properties
+if [[ -z "$KAFKA_ADVERTISED_HOST_NAME" ]]; then
+  echo advertised.host.name=$(route -n | awk '/UG[ \t]/{print $2}') >> /kafka/config/server.properties
+else
+  echo advertised.host.name=$KAFKA_ADVERTISED_HOST_NAME >> /kafka/config/server.properties
+fi
 exec sh /kafka/bin/kafka-run-class.sh -name kafkaServer -loggc kafka.Kafka /kafka/config/server.properties
 EOF
 chmod +x /etc/service/kafka/run