chore: jlink improvements from jenkinsci/docker (#405)

* chore: jlink improvements from jenkinsci/docker

* fixup debian jdk21 preview

alpine/Dockerfile

@@ -24,22 +24,21 @@ ARG JAVA_VERSION=17.0.11_9
 ARG ALPINE_TAG=3.19.1
 FROM eclipse-temurin:"${JAVA_VERSION}"-jdk-alpine AS jre-build
 
-RUN if [ "$TARGETPLATFORM" != 'linux/arm/v7' ]; then \
-    case "$(jlink --version 2>&1)" in \
+RUN case "$(jlink --version 2>&1)" in \
       # jlink version 11 has less features than JDK17+
-      "11."*) strip_java_debug_flags="--strip-debug" ;; \
-      *) strip_java_debug_flags="--strip-java-debug-attributes" ;; \
+      "11."*) set -- "--strip-debug" "--compress=2" ;; \
+      "17."*) set -- "--strip-java-debug-attributes" "--compress=2" ;; \
+      # the compression argument is different for JDK21
+      "21."*) set -- "--strip-java-debug-attributes" "--compress=zip-6" ;; \
+      *) echo "ERROR: unmanaged jlink version pattern" && exit 1 ;; \
     esac; \
     jlink \
+      "$1" \
+      "$2" \
       --add-modules ALL-MODULE-PATH \
-      "$strip_java_debug_flags" \
       --no-man-pages \
       --no-header-files \
-      --compress=2 \
-      --output /javaruntime; \
-  else \
-    cp -r /opt/java/openjdk /javaruntime; \
-  fi
+      --output /javaruntime
 
 FROM alpine:"${ALPINE_TAG}" AS build
 

debian/Dockerfile

@@ -11,27 +11,21 @@ SHELL ["/bin/bash","-e", "-u", "-o", "pipefail", "-c"]
 # Generate smaller java runtime without unneeded files
 # for now we include the full module path to maintain compatibility
 # while still saving space (approx 200mb from the full distribution)
-RUN if test "${TARGETPLATFORM}" != 'linux/arm/v7'; then \
-    case "$(jlink --version 2>/dev/null)" in \
-        # jlink version 11 has less features than JDK17+
-        "11."*) strip_java_debug_flags=("--strip-debug") ;; \
-        *) strip_java_debug_flags=("--strip-java-debug-attributes") ;; \
+RUN case "$(jlink --version 2>&1)" in \
+      # jlink version 11 has less features than JDK17+
+      "11."*) set -- "--strip-debug" "--compress=2" ;; \
+      "17."*) set -- "--strip-java-debug-attributes" "--compress=2" ;; \
+      # the compression argument is different for JDK21
+      "21."*) set -- "--strip-java-debug-attributes" "--compress=zip-6" ;; \
+      *) echo "ERROR: unmanaged jlink version pattern" && exit 1 ;; \
     esac; \
-    if test "${TARGETPLATFORM}" != 'linux/amd/64'; then \
-        # posix_spawn (default for JDK12+) fails erratically with qemu on non x86 CPUs - https://github.com/openzipkin/docker-java/issues/34#issuecomment-721673618
-        export JAVA_TOOL_OPTIONS='-Djdk.lang.Process.launchMechanism=vfork'; \
-    fi; \
     jlink \
-        --add-modules ALL-MODULE-PATH \
-        "${strip_java_debug_flags[@]}" \
-        --no-man-pages \
-        --no-header-files \
-        --compress=2 \
-        --output /javaruntime; \
-    # It is acceptable to have a larger image in arm/v7 (arm 32 bits) environment.
-    # Because jlink fails with the error "jmods: Value too large for defined data type" error.
-    else cp -r /opt/java/openjdk /javaruntime; \
-    fi
+      "$1" \
+      "$2" \
+      --add-modules ALL-MODULE-PATH \
+      --no-man-pages \
+      --no-header-files \
+      --output /javaruntime
 
 FROM debian:"${DEBIAN_RELEASE}"
 

debian/preview/Dockerfile

@@ -20,30 +20,9 @@ RUN apt-get update \
 
 ENV PATH="/opt/jdk-${JAVA_VERSION}/bin:${PATH}"
 
-# Generate smaller java runtime without unneeded files
-# for now we include the full module path to maintain compatibility
-# while still saving space (approx 200mb from the full distribution)
-RUN if test "${TARGETPLATFORM}" != 'linux/arm/v7'; then \
-    case "$(jlink --version 2>/dev/null)" in \
-        # jlink version 11 has less features than JDK17+
-        "11."*) strip_java_debug_flags=("--strip-debug") ;; \
-        *) strip_java_debug_flags=("--strip-java-debug-attributes") ;; \
-    esac; \
-    if test "${TARGETPLATFORM}" != 'linux/amd/64'; then \
-        # posix_spawn (default for JDK12+) fails erratically with qemu on non x86 CPUs - https://github.com/openzipkin/docker-java/issues/34#issuecomment-721673618
-        export JAVA_TOOL_OPTIONS='-Djdk.lang.Process.launchMechanism=vfork'; \
-    fi; \
-    jlink \
-        --add-modules ALL-MODULE-PATH \
-        "${strip_java_debug_flags[@]}" \
-        --no-man-pages \
-        --no-header-files \
-        --compress=2 \
-        --output /javaruntime; \
-    # It is acceptable to have a larger image in arm/v7 (arm 32 bits) environment.
-    # Because jlink fails with the error "jmods: Value too large for defined data type" error.
-    else cp -r "/opt/jdk-${JAVA_VERSION}" /javaruntime; \
-    fi
+# It is acceptable to have a larger image in arm/v7 (arm 32 bits) environment.
+# Because jlink fails with the error "jmods: Value too large for defined data type" error.
+RUN cp -r "/opt/jdk-${JAVA_VERSION}" /javaruntime
 
 FROM debian:"${DEBIAN_RELEASE}"