Docker best practices

Dockerfile

@@ -1,29 +1,10 @@
-
-#
-# Originally Java Dockerfile from https://github.com/dockerfile/java
-#
-
-# Pull base image.
-FROM dockerfile/ubuntu
+FROM ubuntu
 MAINTAINER Ken Mugrage <kmugrage@thoughtworks.com>
 
-# My agents need Ruby
-RUN apt-get install -y ruby1.9.1
-RUN gem install rake
-
-RUN apt-get update && apt-get install -y default-jre-headless
-
-# Modified to wget the agent from the download site. When a package repo
-# is available we can use that and always get the lastest
-RUN cd /tmp && wget -nc -nv http://download01.thoughtworks.com/go/14.1.0/ga/go-agent-14.1.0-18882.deb  
-RUN dpkg -i -E /tmp/go-agent-14.1.0-18882.deb
-
-# This file has my authorization string so that I don't have to approve new agents. 
-ADD autoregister.properties /var/lib/go-agent/config/autoregister.properties
+RUN echo "deb http://dl.bintray.com/gocd/gocd-deb /\n" >> /etc/apt/sources.list
+RUN apt-get update && apt-get install -y --force-yes openjdk-7-jre go-agent
 
-# This file is also very specific to my installation. It tells the Go agent where the Go server
-# is on my internal network.
-ADD go-agent /etc/default/go-agent
+COPY go-agent /etc/default/go-agent
+COPY docker-entrypoint.sh /usr/share/docker-entrypoint.sh
 
-# This should probably be something like supervisord to keep the container running
-CMD /usr/share/go-agent/agent.sh && tail -F /var/log/go-agent/go-agent.log
+CMD /usr/share/go-agent/agent.sh

README.md

@@ -1,22 +1,20 @@
 Go Agent Docker
 ===============
 
-Creating Go CD agents from a dockerfile. 
-
-This is really mostly a spike at this point. I wanted a way to run multiple agents in
-discrete containers on my machine. The files should work for anyone else if you edit
-go-agent and autoregister.properties
+Creating Go CD agents from a Dockerfile.
 
 ## Usage
 
-git clone this repo
+```
+docker build -t gocd/agent .
+docker run -e "GO_SERVER=your_host" -e "GO_SERVER_PORT=8153" gocd/agent
+```
+
+## Autoregister
 
-Build your image
-<code>
-docker build -t your-repo-name/go-agent .
-</code>
+If you want to autoregister, just pass the following environment variables.
 
-This will launch 10 agents in containers
-<code>
-for i in {1..10} ; do docker run -d kmugrage/go-agent ; done
-</code>
+```
+GO_AUTOREGISTER_KEY - the autoregistration key so that your agents are immediately available
+GO_AUTOREGISTER_RESOURCES - [optional] resources to register for your new agent
+```

docker-entrypoint.sh

@@ -0,0 +1,28 @@
+#!/bin/bash
+set -e
+
+if [ -z "$GO_SERVER" ]; then
+    GO_SERVER=127.0.0.1
+fi
+if [ -z "$GO_SERVER_PORT" ]; then
+    GO_SERVER_PORT=8153
+fi
+
+echo "
+GO_SERVER=$GO_SERVER
+export GO_SERVER
+GO_SERVER_PORT=$GO_SERVER_PORT
+export GO_SERVER_PORT
+" >> /etc/default/go-agent
+
+if [ -z "$GO_AUTOREGISTER_KEY" ]; then
+    echo "
+agent.auto.register.key=$GO_AUTOREGISTER_KEY
+agent.auto.register.resources=$GO_AUTOREGISTER_RESOURCES
+" > /var/lib/go-agent/config/autoregister.properties
+fi
+
+# execute the actual command of the image
+# for example, this is likely "foreman start"
+# THIS MUST BE THE LAST LINE OF THIS FILE
+exec "$@"

go-agent

@@ -1,10 +1,6 @@
-GO_SERVER=172.17.42.1
-export GO_SERVER
-GO_SERVER_PORT=8153
-export GO_SERVER_PORT
 AGENT_WORK_DIR=/var/lib/go-agent
 export AGENT_WORK_DIR
-DAEMON=Y
+DAEMON=N
 VNC=N
-JAVA_HOME=/usr/lib/jvm/default-java/jre
+JAVA_HOME=/usr/lib/jvm/java-7-openjdk-amd64/jre
 export JAVA_HOME