code coverage: implement JaCoCo report generation in CI

        Motivation:
            To improve test quality visibility and enable coverage tracking, this implements
            JaCoCo coverage report generation for the whole project in the CI pipeline.

        Modifications:
            - CI: Added 3 new jobs to .gitlab-ci.yml:
                  "run_ut_with_coverage" for executing tests and collecting coverage data
                  "get_jacoco_cli" for fetching the JaCoCo CLI tool
                  "generate_jacoco_report" for merging reports and generating final output
            - Scripts: Added 2 new scripts:
                  get-jacoco.sh for caching/downloading JaCoCo CLI
                  generate-jacoco-report.sh for report aggregation
            - RPM job: Disabled tests to prevent overhead.

        Results:
            - Per-module coverage data (.exec files) is generated during test execution
            - A merged HTML coverage report is created and archived as a CI artifact.

        Testing:
            - Validated report generation locally and in CI.

Acked-by: Dmitry Litvintsev
Target: master
Require-book: no
Require-notes: no
Committed:

Author: chubnastia

.gitlab-ci.yml

@@ -94,7 +94,6 @@ default:
     name: dtzar/helm-kubectl:latest
     entrypoint: ['']
 
-
 #
 # default cache konfiguration for maven build jobs
 # Cache downloaded dependencies and plugins between builds.
@@ -116,14 +115,12 @@ default:
   rules:
     - if: $CI_COMMIT_TAG
 
-
-
 rpm:
   stage: build
   image: dcache/maven-java21-rpm-build
   extends: .build_cache
   script:
-    - mvn $MAVEN_CLI_OPTS -Drun.slow.tests -am -pl packages/fhs -P rpm clean package
+    - mvn $MAVEN_CLI_OPTS -DskipTests -Drun.slow.tests -am -pl packages/fhs -P rpm clean package
   artifacts:
     reports:
       junit:
@@ -167,6 +164,21 @@ tar:
       - "packages/tar/target/dcache-*.tar.gz"
     expire_in: 2 days
 
+#Job to create and collect JaCoCo reports
+run_ut_with_coverage:
+  stage: build
+  image: maven:3.9.12-eclipse-temurin-17
+  extends: .build_cache
+  script:
+    # run all tests with the coverage profile
+    - mvn $MAVEN_CLI_OPTS -P code-coverage clean verify -DskipTests=false
+  artifacts:
+    paths:
+      # pass the .exec files AND the compiled classes to the next stage
+      #pass .exec files and compiled classes to the next stage
+      - "**/target/coverage-reports/jacoco-ut.exec"
+      - "**/target/classes/"
+    expire_in: 1 day
 
 spotbugs:
   stage: build
@@ -690,3 +702,42 @@ Run OIDC test:
     - while ! kubectl -n $K8S_NAMESPACE wait --for=condition=Ready pod oidc-tester; do sleep 1; done
     - kubectl -n $K8S_NAMESPACE cp .ci/run-oidc-test.sh oidc-tester:/run-oidc-test.sh
     - kubectl -n $K8S_NAMESPACE exec oidc-tester -- /bin/sh /run-oidc-test.sh
+
+#Job to find JaCoCo CLI in cache or download it
+get_jacoco_cli:
+  stage: build
+  image: eclipse-temurin:17-jre
+  variables:
+    JACOCO_VERSION: "0.8.14"
+  script:
+    - ./get-jacoco.sh
+  cache:
+    key: "jacoco-cli-${JACOCO_VERSION}"  #cache per version
+    paths:
+      - "jacoco-${JACOCO_VERSION}/"      #cache the entire JaCoCo directory
+    policy: pull
+  artifacts:
+    paths:
+      - "jacoco-${JACOCO_VERSION}/lib/jacococli.jar"
+    expire_in: 1 week
+
+# Job to generate JaCoCo report using script
+generate_jacoco_report:
+  stage: build
+  image: eclipse-temurin:17-jre
+  variables:
+    JACOCO_VERSION: "0.8.14"
+  needs:
+    - job: run_ut_with_coverage
+      artifacts: true
+    - job: get_jacoco_cli
+  cache:
+    key: "jacoco-cli-${JACOCO_VERSION}"
+    paths:
+      - "jacoco-${JACOCO_VERSION}/"
+  script:
+    - ./generate-jacoco-report.sh
+  artifacts:
+    paths:
+      - target/coverage-reports/site/
+    expire_in: 1 week

generate-jacoco-report.sh

@@ -0,0 +1,67 @@
+#!/bin/bash
+
+# Define paths
+PROJECT_ROOT="${PROJECT_ROOT:-$(pwd)}"
+JACOCO_VERSION=0.8.14
+JACOCO_DIR="${PROJECT_ROOT}/jacoco-$JACOCO_VERSION"
+JACOCO_CLI_JAR="$JACOCO_DIR/lib/jacococli.jar"
+MERGED_EXEC="$PROJECT_ROOT/target/coverage-reports/merged.exec"
+REPORT_DIR="$PROJECT_ROOT/target/coverage-reports/site"
+
+# Check if JaCoCo CLI JAR exists get-jacoco.sh
+if [ ! -f "$JACOCO_CLI_JAR" ]; then
+    echo "Error: JaCoCo CLI JAR not found at $JACOCO_CLI_JAR"
+    exit 1
+fi
+
+# Ensure the report directory exists
+mkdir -p "$REPORT_DIR"
+
+# Issue 1: Simplified find command (avoiding array initialization)
+EXEC_FILES=$(find "$PROJECT_ROOT" -name "jacoco-ut.exec" -type f)
+
+# Issue 2: Simplified check for empty results using -z
+if [ -z "$EXEC_FILES" ]; then
+    echo "Error: No jacoco-ut.exec files found in $PROJECT_ROOT"
+    exit 1
+fi
+
+# Merge execution data files
+echo "Merging execution data files..."
+# Issue 4: Passing the string directly
+java -jar "$JACOCO_CLI_JAR" merge ${EXEC_FILES} --destfile "$MERGED_EXEC"
+
+if [ $? -ne 0 ]; then
+    echo "Error: Failed to merge execution data files"
+    exit 1
+fi
+
+# Generate the coverage report
+echo "Generating coverage report..."
+
+# Build classfiles and sourcefiles arguments dynamically
+CLASSFILES_ARGS=()
+SOURCEFILES_ARGS=()
+
+# Issue 5: Iterating over the string list instead of an array
+for exec_file in ${EXEC_FILES}; do
+    # Extract module path (e.g., core, dlm, rquota) from the exec file path
+    module_path=$(dirname "$(dirname "$(dirname "$exec_file")")")
+
+    # Add classfiles and sourcefiles arguments
+    CLASSFILES_ARGS+=("--classfiles" "$module_path/target/classes")
+    SOURCEFILES_ARGS+=("--sourcefiles" "$module_path/src/main/java")
+done
+
+# Generate the report with dynamic arguments
+java -jar "$JACOCO_CLI_JAR" report "$MERGED_EXEC" \
+    "${CLASSFILES_ARGS[@]}" \
+    "${SOURCEFILES_ARGS[@]}" \
+    --html "$REPORT_DIR"
+
+if [ $? -ne 0 ]; then
+    echo "Error: Failed to generate coverage report"
+    exit 1
+fi
+
+echo "Coverage report generated successfully at ${REPORT_DIR}/index.html"

get-jacoco.sh

@@ -0,0 +1,32 @@
+#!/bin/bash
+
+apt-get update && apt-get install -y wget unzip
+# Define paths
+PROJECT_ROOT="${PROJECT_ROOT:-$(pwd)}"
+JACOCO_VERSION=0.8.14
+JACOCO_DIR="${PROJECT_ROOT}/jacoco-$JACOCO_VERSION"
+JACOCO_CLI_JAR="$JACOCO_DIR/lib/jacococli.jar"
+
+echo "DEBUG: Checking if $JACOCO_CLI_JAR exists..."
+###
+#
+# Check if JaCoCo CLI JAR exists in the cache directory
+if [ ! -f "$JACOCO_CLI_JAR" ]; then
+    echo "JaCoCo CLI JAR not found in cache directory. Downloading..."
+    mkdir -p "$JACOCO_DIR"
+    wget -q "https://github.com/jacoco/jacoco/releases/download/v$JACOCO_VERSION/jacoco-$JACOCO_VERSION.zip" -O "/tmp/jacoco-$JACOCO_VERSION.zip"
+    unzip -q "/tmp/jacoco-$JACOCO_VERSION.zip" -d "$JACOCO_DIR"
+    rm -f "/tmp/jacoco-$JACOCO_VERSION.zip"
+    echo "DEBUG: Downloaded JaCoCo CLI to $JACOCO_DIR"
+    ls -la "$JACOCO_DIR"
+else
+    echo "DEBUG: JaCoCo CLI JAR found at $JACOCO_CLI_JAR"
+fi
+
+# Check if JaCoCo CLI JAR exists after download
+if [ ! -f "$JACOCO_CLI_JAR" ]; then
+    echo "Error: JaCoCo CLI JAR not found at $JACOCO_CLI_JAR"
+    exit 1
+fi
+
+export JACOCO_CLI_JAR