Sample Java buildpack #3
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java-buildpack/bin/build
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| mkdir -p $launch_dir/jdk/.profile.d | ||
| cat << EOF > $launch_dir/jdk/.profile.d/jdk.sh | ||
| export JAVA_HOME=$launch_dir/jdk | ||
| export PATH=\$JAVA_HOME/bin:\$PATH |
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Interesting. I hadn't thought about this need, but it makes sense. The updates to the path can't happen until after the layer has been created.
java-buildpack/bin/build
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| echo "---> Installing Maven" | ||
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| mkdir -p $cache_dir/maven/.m2 |
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Granted that we don't do builds, but if we did I'd absolutely require the use of mvnw and gradlew to avoid any conflicts here.
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for sure, in the next interation. i plan to support both (although i might kill the default mvn install).
java-buildpack/bin/build
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| echo "---> Running Maven" | ||
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| MAVEN_OPTS="${MAVEN_OPTS:-"-Xmx1024m -Duser.home=$cache_dir -Dmaven.repo.local=$cache_dir/.m2/repository"}" |
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Traditionally we've symlinked a cached directory to $HOME/.m2 because there's no combination of environment variables and system properties that will move all caches (say the mvnw download cache). @sclevine would there be any problems doing that, knowing that the symlink would disappear when the container was disposed and that'd be fine?
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Should work great. /home/pack ($HOME) is intended for this purpose -- an ephemeral home directory that is not preserved.
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@nebhale in the Heroku Java buildpack we let it do whatever in /app and then move it to the cache after the build runs. I'm just being lazy here (and was expecting this to change when i support mvnw).
@sclevine I'm not sure how I feel about relying on $HOME. I don't think we've made that a part of the API, and today on Heroku $HOME is actually the /app dir.
If it's ok with y'all, I'll merge this as is, so I have a baseline to iterate from.
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Interesting point about $HOME. CF is super weird with this: it's /home/vcap at build, but /home/vcap/app (symlinked to /app) at launch. I think it should be the same in both cases, and I think I have a slight preference for /home/pack, because it prevents auto-generated settings/cache from various CLI tools from persisting (ex. ~/.bundle).
@nebhale any thoughts about this?
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@jkutner I'm totally okay with you adding any samples to this repo directly 😄
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I’d agree with definitely ditching the CF insanity, and also lean towards home being somewhere other than the app directory. My anecdotal experience tells me that there are enough packages that write to $HOME that it’s a vector for vulnerabilities. Choosing a “safer” location seems like a prudent safety measure, but I am sensitive to compatibility.
java-buildpack/bin/build
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| mkdir -p $launch_dir/jdk | ||
| jdk_url="https://cdn.azul.com/zulu/bin/zulu8.28.0.1-jdk8.0.163-linux_x64.tar.gz" | ||
| curl -sfL "$jdk_url" | tar pxz -C $launch_dir/jdk --strip-components=1 | ||
| mkdir -p $launch_dir/jdk/.profile.d |
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@jkutner this should be profile.d instead of .profile.d
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Could we define the openjdk version to be installed such as the distro ?
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@cmoulliard yea, absolutely. I only grabbed Zulu 8u163 to get something working.
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I don't know anything about Java anymore, but could this eventually use something like Jib to produce images which can be built incrementally very quickly, with unchanged layers cached in the registry? |
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@imjasonh yea, definitely possible. Although I think it might make more sense as a |
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Maybe such files could help us to define the build and run steps by providing env var to configure the JVM, ... run : https://github.com/fabric8io-images/s2i/blob/master/java/images/centos/s2i/run |
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@cmoulliard can you elaborate on what those scripts do? They look useful, but i'm a little fuzzy on the intent. |
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I merged this and create issues for the ideas @imjasonh and @cmoulliard brought up. |
A very basic Java buildpack that runs Maven to compile an app.