= Pack (alpha) ifdef::env-github[] :toc: :toclevels: 4 endif::[]

Package up Clojure projects in various ways, based on a deps.edn file.

Want to have a chat before opening a ticket? Need help or support from the community? Find us in the link:https://clojurians.zulipchat.com/#narrow/stream/151045-JUXT[Clojurians Zulipchat #JUXT] stream.

== Usage

=== Auto-add to project

Pack can add itself to your deps.edn automatically. It will not modify your indentation style at all. This is alpha, but so is everything else in this project.

It can be run at later times, in order to automatically bump the sha in your deps.edn. It will continue to work even if you rename the default :pack alias to something else.

NOTE: This isn't infallible. Please let me know if I break your indentation.

[source,clojure]

$ clojure -Sdeps '{:deps {pack/pack.alpha {:git/url "https://github.com/juxt/pack.alpha.git" :sha "dccf2134bcf03726a9465d2b9997c42e5cd91bff"}}}' -m mach.pack.alpha.inject 'e518d9b2b70f4292c9988d2792b8667d88a6f4df'

TIP: Latest stable sha is e518d9b2b70f4292c9988d2792b8667d88a6f4df.

The following examples assume you have run this.

=== Lambda

The lambda approach will generate a zip which can be uploaded to AWS.

[source,bash] .Example call

$ clj -A:pack mach.pack.alpha.aws-lambda -e classes lambda.zip

In this example:

• lambda.zip is where to write the package to.
• build_dir is a directory containing extra paths to add, for example it may be where you compile classes to, or write built css to.

[source]

Usage: clj -m mach.pack.alpha.aws-lambda [options] <path/to/output.zip>

Options: -A ALIASES Concatenated aliases of any kind, ex: -A:dev:mem -R ALIASES Concatenated resolve-deps aliases, ex: -R:bench:1.9 -C ALIASES Concatenated make-classpath aliases, ex: -C:dev --Sdeps EDN {} Deps data to use as the last deps map to be merged by tool.deps when pulling dependencies at build time. Equivalent to clj -Sdeps EDN. -e, --extra-path STRING Add directory to classpath for building. Same as :extra-paths -h, --help show this help

output.zip is where to put the output zip. Leading directories will be created.

[TIP]

Lambda (and by extension, lambada) requires java classes. To generate these you will need to AOT your program.

Try this alias:

[source,clojure]

{:aot {:extra-paths ["classes"] :main-opts ["-e" "(compile,'example.lambda)"]}}

Then your build process will be like so:

[source,shell]

$ mkdir -p classes $ clojure -A:aot $ clojure -A:pack mach.pack.alpha.aws-lambda -C:aot lambda.zip

====

=== Uberjar

"Uberjar-ing" consists of packaging you application into one all-encompassing JAR (Java ARchive) file, called an "Uberjar", which can then be executed using java -jar myapp.jar ARG1 ARG2 ARG3....

Pack provides several approaches for creating an Uberjar:

==== Capsule

This consists of building an Uberjar using http://www.capsule.io/[Parallel Universe's Capsule].

[source,clojure]

$ clj -A:pack mach.pack.alpha.capsule uberjar.jar -e build-dir --application-id mycoolapp --application-version "$(git describe)" -m myapp.main $ java -jar uberjar.jar

[source]

Usage: clj -m mach.pack.alpha.capsule [options] <path/to/output.jar> -m, --main SYMBOL main namespace --application-id STRING globally unique name for application, used for caching --application-version STRING unique version for this uberjar, used for caching --system-properties STRING space-separated list of propName=value pairs, specifying JVM System Properties which will be passed to the application. Maps to the 'System-Properties' entry in the Capsule Manifest. --jvm-args STRING space-separated list of JVM argument that will be used to launch the application (e.g "-server -Xms200m -Xmx600m"). Maps to the 'JVM-Args' entry in the Capsule Manifest. -e, --extra-path STRING add directory to classpath for building --Sdeps EDN {} Deps data to use as the last deps map to be merged by tool.deps when pulling dependencies at build time. Equivalent to clj -Sdeps EDN. -M, --manifest-entry STRING a "Key: Value" pair that will be appended to the Capsule Manifest; useful for conveying arbitrary Manifest entries to the Capsule Manifest. Can be repeated to supply several entries. -h, --help show this help

The main does not need :gen-class, it follows the same semantics as clojure.main's -m main. If main is not specified, it will default to clojure.main, meaning it can take options like -m or -r. extra-path is useful for adding clojurescript & css to the resulting jar. It can be used multiple times.

[CAUTION] .Executing a Capsule JAR with JVM args / System Properties

As mentioned in the http://www.capsule.io/user-guide/#the-capsule-execution-process[Capsule docs], when you execute a Capsule-packaged Uberjar, 2 Java processes are actually run: the Capsule launcher, and your application process.

In particular, JVM args and System Properties passed to the java command will apply to both processes, which if you're not careful can result in waste of resources and collisions; for example:

• If you pass the -Xms2g JVM arg, you've just allocated 2 Gigabytes of unnecessary RAM for the Capsule launcher
• If you pass the -Dcom.sun.management.jmxremote.port=7091 System Property you will get an error, as both Java processes try to use the 7091 port for JMX.

The way to prevent this is to pass special options that will only apply to the application process. See the http://www.capsule.io/user-guide/#jvm-arguments-system-properties-environment-variables-and-agents[related Capsule documentation].

INFO: In the future I will extend Capsule support to include capsule-specific features, such as caplets and many of the related manifest attributes.

==== OneJAR

link:http://one-jar.sourceforge.net/[OneJAR] builder. This is a suitable replacement for jdsoft JCL, without the GPL license. It's especially practical where you can't extract into a ~/.capsule directory, or don't need to bake in JVM args.

[source]

Usage: clj -m mach.pack.alpha.one-jar [options] <path/to/output.jar>

Options: -e, --extra-path STRING add directory to classpath for building -d, --deps STRING deps.edn deps.edn file location --Sdeps EDN {} Deps data to use as the last deps map to be merged by tool.deps when pulling dependencies at build time. Equivalent to clj -Sdeps EDN. -m, --main STRING clojure.main Override the default main of clojure.main. You MUST use AOT compilation with this. -h, --help show this help

output.jar is where to put the output uberjar. Leading directories will be created.

Example:

[source,bash]

$ clj -A:pack mach.pack.alpha.one-jar output.jar $ java -jar output.jar

==== jdsoft JarClassLoader

WARNING: This has been removed due to my own licensing concerns about co-locating the source with my own.

=== Skinny JAR

Output a classpath, or subset of it, into directories or jars.

[source]

Usage: clj -m mach.pack.alpha.skinny [options]

Options: --no-libs Skip lib outputs --no-project Skip project outputs --lib-dir PATH target/lib Where to place the output libraries --lib-type STRING :jar Lib type format to use, keep or jar. Keep will keep in original format (jar or dir) --project-path PATH target/app.jar Where to place the project output, if it ends with .jar then the project will automatically output as a jar also. -A ALIASES Concatenated aliases of any kind, ex: -A:dev:mem -R ALIASES Concatenated resolve-deps aliases, ex: -R:bench:1.9 -C ALIASES Concatenated make-classpath aliases, ex: -C:dev --Sdeps EDN {} Deps data to use as the last deps map to be merged by tool.deps when pulling dependencies at build time. Equivalent to clj -Sdeps EDN. -e, --extra-path STRING Add directory to classpath for building. Same as :extra-paths -h, --help show this help

.Put the entire classpath into jars and run from the filesystem

[source,shell] $ clj -A:pack mach.pack.alpha.skinny $ java -cp "target/app.jar:target/lib/*" clojure.main

====

.Output only project files into a single jar

[source,shell] $ clj -A:pack mach.pack.alpha.skinny --no-libs

====

==== Uploading to Clojars (or Maven)

Using skinny jars, pack can be used to upload artifacts to Clojars. This example should be easily modified to work with Maven repositories too, but I haven't tried. A full example can be found at link:https://github.com/SevereOverfl0w/super-duper-octo-barnacle[super-duper-octo-barnacle].

. Follow link:https://github.com/clojars/clojars-web/wiki/Pushing#maven[Clojars maven guide] for "settings.xml" only

. You can generate your jar by passing the --no-libs option to your jar. Also in this example is --project-path, although this is not strictly required. I highly recommend putting this in a Makefile or shell script. + [source,bash]

clojure -Sdeps '{:deps {pack/pack.alpha {:git/url "https://github.com/juxt/pack.alpha.git" :sha "2769a6224bfb938e777906ea311b3daf7d2220f5"}}}' -m mach.pack.alpha.skinny --no-libs --project-path my-cool-lib.jar

. You will also need a pom.xml, you can generate one with clojure: + [source,bash]

clojure -Spom

. Update the pom.xml as necessary to correct your groupId or version. Future calls to pom.xml won't change them back. . Use mvn command line to deploy + [source,bash]

mvn deploy:deploy-file -Dfile=my-cool-lib.jar -DrepositoryId=clojars -Durl=https://clojars.org/repo -DpomFile=pom.xml

=== Docker image

Create a Docker image via link:https://github.com/GoogleContainerTools/jib[Jib]. Supports building to local Docker daemon (--image-type docker), tarball (--image-type tar) and uploading to Docker registries authenticated via $USER_HOME/.docker/config.json (--image-type registry).

[source]

Usage: clj -m mach.pack.alpha.jib [options]

Options: --image-name NAME Name of the image --image-type TYPE docker Type of the image, one of: tar, registry, docker --tar-file FILE Tarball file name --base-image BASE-IMAGE gcr.io/distroless/java:11 Base Docker image to use --include [src:]dest Include file or directory, relative to container root --additional-tag TAG Additional tag for the image, e.g latest. Repeat to add multiple tags --label LABEL=VALUE Set a label for the image, e.g. GIT_COMMIT=${CI_COMMIT_SHORT_SHA}. Repeat to add multiple labels. --user USER Set the user and group to run the container as. Valid formats are: user, uid, user:group, uid:gid, uid:group, user:gid --creation-time CREATION_TIME_EPOCH Set creation time of image in epoch seconds, e.g. $(git log -1 --pretty=format:%ct) Defaults to 0. --from-registry-username USER Set the username to use when pulling base image from registry, e.g. gitlab-ci-token. --from-registry-password PASSWORD Set the password to use when pulling base image from registry, e.g. ${CI_JOB_TOKEN}. --to-registry-username USER Set the username to use when deploying to registry, e.g. gitlab-ci-token. --to-registry-password PASSWORD Set the password to use when deploying to registry, e.g. ${CI_JOB_TOKEN}. -q, --quiet Don't print a progress bar nor a start of build message -v, --verbose Print status of image building --extra-java-args JAVA_ARGS Extra arguments to pass to the java command, e.g. --extra-java-args "-Dfoo=bar -ea" -m, --main SYMBOL Main namespace -A ALIASES Concatenated aliases of any kind, ex: -A:dev:mem -R ALIASES Concatenated resolve-deps aliases, ex: -R:bench:1.9 -C ALIASES Concatenated make-classpath aliases, ex: -C:dev --Sdeps EDN {} Deps data to use as the last deps map to be merged by tool.deps when pulling dependencies at build time. Equivalent to clj -Sdeps EDN. -e, --extra-path STRING Add directory to classpath for building. Same as :extra-paths -h, --help show this help

For example, to deploy to Google Container Registry, first perform link:https://cloud.google.com/container-registry/docs/advanced-authentication[authentication] and then specify registry, repository and tag in the image name:

[source]

clj -A:pack mach.pack.alpha.jib \ --image-name eu.gcr.io/my-example-project/my-app:1234
--image-type registry
-m my.main

In order to pass Java system properties to the running container, JAVA_TOOL_OPTIONS environment variable can be used. See example in link:https://github.com/GoogleContainerTools/jib/blob/master/docs/faq.md#jvm-flags[Jib FAQ].

==== AOT for better startup speed

For larger apps, link:https://www.clojure.org/guides/deps_and_cli#aot_compilation[Ahead-of-time (AOT)] compilation can signifficantly speedup startup time. This can be done by first compiling Clojure source code to bytecode and then including the bytecode into the Docker image via the -e option, for example:

[source]

$ mkdir classes $ clojure -e "(compile 'my.main)" $ clj -A:pack mach.pack.alpha.jib \ --image-name eu.gcr.io/my-example-project/my-app:1234
--image-type registry
-e classes
-m my.main