Package OAP Distribution & Docker Image

Rebuilding the Docker image after a source-code change has a two-step dependency: rebuild the dist tarball, then rebuild the image. Skipping the first step silently produces an image with stale jars — the Docker build still "succeeds," the image has a fresh timestamp, but the embedded jar is the one from your previous build.

Why this matters

make docker.oap in the root Makefile is defined as:

docker.% push.docker.%: $(CONTEXT)/$(DIST) $(SW_ROOT)/docker/%/*
    $(DOCKER_RULE)

It depends on $(CONTEXT)/$(DIST) (the dist tarball) as a file prerequisite. If that tarball already exists, make does not regenerate it — it just copies whatever is on disk into dist/docker_build/oap/ and runs docker buildx build. There is no dependency that rebuilds the tarball from source.

Only make docker triggers the full chain (init → build.all → docker.all). So:

flatten:flatten — always run it before package/install

SkyWalking's poms use ${revision} as a placeholder version (e.g., 10.5.0-SNAPSHOT). The flatten-maven-plugin resolves ${revision} into concrete versions and writes a .flattened-pom.xml. Without it:

• Installed artifacts carry the literal string ${revision} in their coordinates and cannot be resolved as dependencies.
• Downstream modules (including apm-dist) see an inconsistent dependency graph.
• Symptoms are subtle: -pl <module> -am may succeed in isolation but fail or pull in stale transitive artifacts when the same module is consumed by another build invocation in the same session.

Always run flatten:flatten in the same goal chain as package or install. The CI dist-tar job and the compile skill both do this. Example:

./mvnw clean flatten:flatten package -Pbackend,dist -DskipTests

Not optional — treat it as part of package.

Pick the right command

Changed OAP source → want a new image

# Recommended: full chain
make docker

or, faster and equivalent for backend-only changes (skips UI):

./mvnw -pl apm-dist -am -o clean flatten:flatten package -Pbackend,dist -DskipTests -Dcheckstyle.skip=true -Dmaven.javadoc.skip=true
make docker.oap

Do not just run make docker.oap after a code edit — the image will look rebuilt but your change will not be in the jars. Do not skip flatten:flatten — see the section above.

Changed only the dist packaging (e.g., apm-dist/, log4j2.xml)

./mvnw -pl apm-dist -am -o clean flatten:flatten package -Pbackend,dist -DskipTests
make docker.oap

Changed only Dockerfile / entrypoint (docker/oap/*)

The tarball is untouched, so make docker.oap alone is correct:

make docker.oap

Verify the fix reached the image

Docker's "image created" timestamp updates even when the content is stale (because --no-cache is used). Don't trust the timestamp. Verify the jar contents directly:

# Copy the jar out of the container
docker cp <container-name>:/skywalking/oap-libs/<module>-<version>.jar /tmp/verify.jar

# Extract the specific class
cd /tmp && jar -xf verify.jar <path/to/YourClass.class>

# Grep for a string your fix introduced (unique literal, method name, etc.)
grep -oa "myFixSignature" <path/to/YourClass.class>

If grep finds nothing, the image does not contain your fix — you forgot to rebuild the dist. Re-run with the correct chain.

Common pitfalls

• make docker.oap after ./mvnw package: The module jar is fresh in oap-server/.../target/, but the dist tarball at dist/apache-skywalking-apm-bin.tar.gz is untouched. Image uses the old jar.
• Cancelling a make docker mid-flight: leaves the dist half-rebuilt. Re-run make docker or delete dist/ first.
• Stale buildx cache: not usually the issue (the Makefile passes --no-cache), but if you suspect it, run docker buildx prune.
• Trusting image timestamps: docker images shows when the image was tagged, not when its content actually changed. A no-op rebuild still updates the timestamp.
• Interactive buildx hangs: if docker buildx build sits silent for minutes with no stdout, kill it and retry. The buildx container driver occasionally stalls; a restart is faster than waiting.

The golden rule

After any Java source edit that affects code shipped in oap-libs/, run one of:

1. make docker (full, safest)
2. ./mvnw -pl apm-dist -am -o package -Pbackend,dist -DskipTests -Dcheckstyle.skip=true && make docker.oap (fast)

Then verify the fix is in the image's jar before running e2e. Don't assume.