Maven Build for Apache Druid

Build Command Reference

Full Build (from instructions)

cd /root/druid
mvn clean package \
  -DskipTests \
  -Dcheckstyle.skip=true \
  -Dpmd.skip=true \
  -Dforbiddenapis.skip=true \
  -Dspotbugs.skip=true \
  -Danimal.sniffer.skip=true \
  -Denforcer.skip=true \
  -Djacoco.skip=true \
  -Ddependency-check.skip=true \
  -pl '!web-console' \
  -pl indexing-service \
  -am

Flag Explanations

Flag	Purpose
clean	Remove previous build artifacts
package	Compile and package into JAR/WAR
-DskipTests	Skip unit test execution
-Dcheckstyle.skip=true	Skip code style checking
-Dpmd.skip=true	Skip PMD analysis
-Dforbiddenapis.skip=true	Skip forbidden API checking
-Dspotbugs.skip=true	Skip SpotBugs (FindBugs) analysis
-Danimal.sniffer.skip=true	Skip JDK version compatibility checks
-Denforcer.skip=true	Skip Maven Enforcer rules
-Djacoco.skip=true	Skip code coverage analysis
-Ddependency-check.skip=true	Skip OWASP dependency checking
-pl '!web-console'	Exclude web-console module (memory constraint)
-pl indexing-service	Include indexing-service module
-am	Also make dependencies of selected projects

Memory Management

Memory Issues

If you encounter OOM (Out of Memory) errors:

# Increase heap size
export MAVEN_OPTS="-Xmx2g -Xms1g"

# Very aggressive heap limit
export MAVEN_OPTS="-Xmx1g -Xms512m"

Parallel Builds

To speed up builds with multiple cores:

mvn clean package -T 1C  # 1 thread per core

Output Artifacts

After successful build:

druid/indexing-service/target/druid-indexing-service-0.20.0-SNAPSHOT.jar
druid/distribution/target/apache-druid-0.20.0-SNAPSHOT/lib/

Verifying Build

# Check if JAR was created
ls -la indexing-service/target/*.jar

# Check build log for errors
tail -100 build.log

# Verify specific file was included
jar tf indexing-service/target/*.jar | grep "JavaScriptFilter"

Maven Troubleshooting

Module Not Found

# Verify module exists
ls -la indexing-service/pom.xml

# Rebuild parent projects
mvn clean install -pl '!web-console'

Compilation Errors

# Detailed error output
mvn clean package -X 2>&1 | tail -50

# Compile only (no packaging)
mvn clean compile

Selective Compilation

# Build specific module and dependencies
mvn clean package -pl indexing-service -am

# Build without tests but with other checks
mvn clean package -DskipTests

# Minimal build for testing
mvn clean package -DskipTests -Denforcer.skip=true