Implementation:Apache Druid OpenRewrite Migration Recipes

Knowledge Sources	Apache_Druid
Domains	Code_Migration, Testing, Build
Last Updated	2026-02-10 10:00 GMT

Overview

rewrite.yml defines OpenRewrite automated code migration recipes used to modernize and standardize the Apache Druid codebase.

Description

This YAML file contains multiple OpenRewrite recipe definitions that automate repetitive code transformations across the Druid project. The top-level recipe org.apache.druid.RewriteRules orchestrates sub-recipes for migrating Calcite-based tests from JUnit 4 to JUnit 5, removing obsolete test runners, upgrading Apache Commons Lang, and converting Jackson Codehaus imports to FasterXML. A detailed custom JUnit4-to-5 migration recipe (org.apache.druid.JUnit4to5Migration) handles annotation updates, assertion migrations, dependency swaps, and plugin version upgrades across the entire Maven build.

Usage

Run these recipes via the OpenRewrite Maven plugin to perform automated code migrations. This is typically done when upgrading test frameworks or libraries across the Druid codebase.

Code Reference

Source Location

• Repository: Apache Druid
• File: rewrite.yml
• Lines: 1-159

Signature

# Top-level composite recipe
type: specs.openrewrite.org/v1beta/recipe
name: org.apache.druid.RewriteRules
recipeList:
  - org.apache.druid.UpgradeCalciteTestsToJunit5
  - org.openrewrite.java.testing.junit5.RemoveObsoleteRunners
  - org.openrewrite.apache.commons.lang.UpgradeApacheCommonsLang_2_3
  - org.openrewrite.java.jackson.CodehausToFasterXML

# Calcite test upgrade (scoped to CalciteTestBase subclasses)
name: org.apache.druid.UpgradeCalciteTestsToJunit5

# EasyMock runner replacement
name: org.apache.druid.EasyMockRunnerToEasyMockExtension

# Custom JUnit 4 to JUnit 5 migration (40+ sub-recipes)
name: org.apache.druid.JUnit4to5Migration

Import

# Execute the rewrite recipes via Maven
mvn rewrite:run -Drewrite.recipeArtifactCoordinates=org.openrewrite:rewrite-testing-frameworks:LATEST \
  -Drewrite.activeRecipes=org.apache.druid.RewriteRules

I/O Contract

Inputs

Name	Type	Required	Description
Java source files	.java	Yes	The Java source and test files in the Druid codebase to be transformed
pom.xml files	XML	Yes	Maven POM files for dependency and plugin version updates
rewrite.yml	YAML	Yes	This recipe definition file, consumed by the OpenRewrite engine

Outputs

Name	Type	Description
Modified Java source files	.java	Updated test files with JUnit 5 annotations, imports, and assertions
Modified pom.xml files	XML	Updated Maven POMs with new dependency versions and removed obsolete dependencies

Usage Examples

Run All Migration Recipes

# Apply all Druid rewrite rules
mvn rewrite:run \
  -Drewrite.activeRecipes=org.apache.druid.RewriteRules

Dry Run to Preview Changes

# Preview what changes would be made without applying them
mvn rewrite:dryRun \
  -Drewrite.activeRecipes=org.apache.druid.RewriteRules

Run Only JUnit Migration

# Apply only the JUnit 4 to 5 migration
mvn rewrite:run \
  -Drewrite.activeRecipes=org.apache.druid.JUnit4to5Migration