Do you have this build script that with a single command builds your software? Does this still apply on a brand new PC? This presentation takes you on the journey to construct complex build environments using Docker. The journey follows our lessons learned and experiences going from hand crafted to Dockerized build environments. We will look at different patterns to build modular containers, ways to chain containers and the specialties of Windows containers.

1. The fairy tale of
the one command
build script
Tobias Getrost
Senior Developer CI/CD
GN Hearing

2. Agenda

3. About me
● Since January 2017 working @ GN
● Driving CI and CD in embedded
software development
● Software Craftsman
● CI / CD Enthusiast
● Speaker and author

4. ./build.sh

5. Pattern
Single container

6. # Maven build
docker run -it --rm
-v "$PWD":/usr/src/myproject
-w /usr/src/myproject
maven:3-jdk-9 mvn clean install

7. # Gradle build
docker run -it --rm
-v "$PWD":/usr/src/myproject
-w /usr/src/myproject
openjdk-8-jdk ./gradlew clean build

8. When to use?
● Most tools provided by package
manager
● Seldom changes to the tool chain
● Local builds

9. Advantages
● No modifications to the build script
● Easy to restore build environments for
old versions
● Test new version of the tools

10. Is your Dockerfile
getting too long?

11. Does changing one tool
cause a rebuild of
many images?

12. Pattern
One container per tool
(chain)

13. HTML & JS
frontend
Backend Generate
thumbnails
Build
container

14. Approaches
● Use a CI server to do the plumbing
● Modify your build script to run the
containers

15. pipeline {
agent none
stages {
stage('Build') {
agent {
docker ‘java:8-jdk'
}
steps {
sh './gradlew clean build'
}
}
}
}

16. To consider
● CI pipeline glues together the build steps
○ How to deal with local builds?
○ Alternative: Make single steps accessible from build
script
● Can speed up the builds by providing enough
computing power on the build server

17. task genThumbnails(type:Exec) {
commandLine "docker run -it --rm -v ${rootDir}:${ws} -w ${ws} " +
"python:2.7 python genThumbnails.py"
}
> ./gradlew genThumbnails

18. tasks.addRule("Pattern: docker<TaskName>: docker") { String taskName ->
if (taskName.startsWith("docker")) {
def taskNameToCall = (taskName - 'docker').toLowerCase()
def taskToCall = tasks.findByName(taskNameToCall)
if (taskToCall && taskToCall instanceof Exec) {
def cmd = ['docker', 'run', '--rm', '-v', "${taskToCall.workingDir.name}:${ws}",
'-w', "${ws}", 'python:2.7']
cmd.addAll(taskToCall.commandLine)
task(taskName, type: Exec, {
commandLine cmd
})
}}}
> ./gradlew dockerGenthumbnails

19. Advantages
● Higher modularity
● Testing new versions of a tool is easy
● Higher reuse of existing images

20. Windows

21. What about this?

22. FROM microsoft/windowsservercore
ENV url https://www.python.org/ftp/python/2.7.14/python-2.7.14.amd64.msi
RUN $MsiFile = $env:Temp + 'ipython.msi' ;
(New-Object Net.WebClient).DownloadFile($url, $MsiFile) ;
Start-Process msiexec.exe -ArgumentList '/i', $MsiFile, '/quiet', '/norestart',
'/jm' -NoNewWindow -Wait
Installing an MSI
… if it supports silent install

23. Once upon a time
devs needed to
spend long time
before they could
do their first
build…

24. … , then they added Docker to their builds and …

25. … and they
developed
happily ever
after.

26. tobias@getrost.de
www.xing.com/profile/Tobias_Getrost
www.linkedin.com/in/tobias-getrost
https://github.com/getrostt
getrost.org
Tobias Getrost