CAMEL-21208: Replace manual string-based code generation with FreeMarker templates by gnodet · Pull Request #22200 · apache/camel

gnodet · 2026-03-23T15:15:38Z

JIRA: CAMEL-21208

Summary

Add FreeMarker 2.3.34 as a template engine dependency to camel-jbang-core
Replace 23 .tmpl files with .ftl FreeMarker templates using square-bracket syntax ([=var], [#if], [#list]) to avoid conflicts with Maven ${...} and XML <...> syntax
Create TemplateHelper utility class that configures FreeMarker with SQUARE_BRACKET_INTERPOLATION_SYNTAX and SQUARE_BRACKET_TAG_SYNTAX, and strips <#-- --> license headers from output
Refactor ExportCamelMain, ExportSpringBoot, ExportQuarkus, Export, Run, and KubernetesExport to build model maps and call TemplateHelper.processTemplate() instead of manual regex/string replacements
Extract shared helpers into ExportBaseCommand: buildRepositoryList(), buildDependencyList(), formatBuildProperties()
Remove 4 unreferenced template fragments (main-docker-*.tmpl, main-jkube-pom.tmpl), consolidating their logic into main-pom.ftl
Maintain backward compatibility in ExportSpringBoot for catalog-provided .tmpl templates (falls back to legacy regex processing)
Maintain backward compatibility in Init.java for both old {{ .Name }} and new [=Name] placeholder syntax
Keep bind templates (.tmpl with TemplateProvider interface) unchanged — separate subsystem
Comprehensive unit tests for all 23 templates: FreeMarker-processed and Init (raw text) templates, covering license header stripping, placeholder resolution, conditional rendering, list iteration, Maven ${...} passthrough, Kamelet {{...}} passthrough, and error handling

Test plan

Unit tests for all FreeMarker-processed templates via TemplateHelper.processTemplate()
Unit tests for all Init templates via raw text loading + header stripping + placeholder replacement
Verify Maven ${...} expressions pass through untouched in POM templates
Verify Kamelet {{...}} expressions pass through untouched in kamelet templates
Verify missing template throws IOException
CI green on JDK 17, 21, 25

github-actions · 2026-03-23T15:16:15Z

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github-actions · 2026-03-23T15:44:43Z

🧪 CI tested the following changed modules:

dsl/camel-jbang/camel-jbang-core
dsl/camel-jbang/camel-jbang-plugin-kubernetes

⚠️ Some tests are disabled on GitHub Actions (@DisabledIfSystemProperty(named = "ci.env.name")) and require manual verification:

dsl/camel-jbang/camel-jbang-core: 1 test(s) disabled on GitHub Actions
dsl/camel-jbang/camel-jbang-plugin-kubernetes: 8 test(s) disabled on GitHub Actions

💡 Manual integration tests recommended:

You modified dsl/camel-jbang/camel-jbang-core, dsl/camel-jbang/camel-jbang-plugin-kubernetes. The related integration tests in dsl/camel-jbang/camel-jbang-it are excluded from CI. Consider running them manually:
mvn verify -f dsl/camel-jbang/camel-jbang-it -Djbang-it-test

⚙️ View full build and test results

Croway · 2026-03-23T15:44:51Z

...el-jbang/camel-jbang-core/src/main/java/org/apache/camel/dsl/jbang/core/commands/Export.java

+        String ftlName = "Dockerfile" + javaVersion + ".ftl";
+        String context;
+        try {
+            Map<String, Object> model = new HashMap<>();


can this be extracted to avoid code duplication?

Claude Code on behalf of Guillaume Nodet

Good catch. Looking at this more carefully — the Dockerfile template rendering now uses FreeMarker through the base class, and the Quarkus override handles the fast-jar vs uber-jar distinction which genuinely needs different logic. So the apparent duplication in Export.java line 311 is the shared base implementation. Will add a clarifying comment.

apupier · 2026-03-25T09:07:59Z

Hey AI agent, please rebase and resolve the conflict

orpiske

Thanks for looking at this ... it's great to see this cleanup on the code base.

orpiske · 2026-03-27T12:46:26Z

...ng/camel-jbang-core/src/main/java/org/apache/camel/dsl/jbang/core/common/TemplateHelper.java

+     * @param  model        the data model
+     * @return              the processed template output
+     */
+    public static String processTemplate(String templateName, Map<String, Object> model) throws IOException {


Maybe cover this one with a brief test to ensure future work doesn't break it?

Added TemplateHelperTest with 6 tests covering: simple interpolation, license header stripping, conditional rendering ([#if]), list rendering ([#list]), Maven expression pass-through (${...}), and missing template error handling.

Claude Code on behalf of Guillaume Nodet

apupier · 2026-04-02T07:58:35Z

What's the status? Is it ready for another review round? If yes, you should re-request a review from Croway so that he can be aware of it

gnodet · 2026-04-03T06:12:33Z

What's the status? Is it ready for another review round? If yes, you should re-request a review from Croway so that he can be aware of it

Yes it is.
@Croway

Croway · 2026-04-03T09:48:59Z

@gnodet I just did a rerun of all the jobs, by any chance did you run dsl/camel-jbang/camel-jbang-it tests? otherwise we can go YOLO and test on the Jenkins CI directly

gnodet · 2026-04-09T14:45:17Z

Claude Code on behalf of Guillaume Nodet

@Croway Yes, I ran the dsl/camel-jbang/camel-jbang-it tests locally with:

mvn verify -B -Djbang-it-test -Dcamel-cli.instance.type=local-camel-cli-process -Dit.test=ExportITCase

ExportITCase results: 11 tests run, 0 failures, 0 errors, 2 skipped (the skipped tests require custom Quarkus system properties or container-only tags).

All export scenarios pass — Spring Boot, Quarkus, Camel Main, export with files, export with agent, export with JMX management, export with CLI connector, and export with Camel config.

gnodet · 2026-04-09T19:00:36Z

Claude Code on behalf of Guillaume Nodet

CI failures are unrelated to this PR — camel-langchain4j-embeddings LangChain4jEmbeddingsComponentInfinispanTargetIT fails with Infinispan SocketTimeoutException (flaky infra test). The camel-jbang-core module was never reached due to the early failure. Needs a rerun.

…ker templates in camel-jbang - Add FreeMarker 2.3.34 dependency to camel-jbang-core - Create TemplateHelper utility using square bracket syntax ([=var], [#if]...[/#if]) to avoid conflicts with ${...} (Maven) and <...> (XML) in generated content - Convert all 23 .tmpl template files to .ftl FreeMarker templates - Refactor Export*, Run, and Init commands to use TemplateHelper instead of manual StringBuilder/replaceAll/replaceFirst code generation - Extract shared helpers (buildRepositoryList, buildDependencyList, formatBuildProperties, mavenGavComparator) into ExportBaseCommand - Maintain backward compatibility for catalog-provided templates in ExportSpringBoot - Remove 4 unreferenced templates (main-docker-*.tmpl, main-jkube-pom.tmpl) - Keep deprecated bind templates (.tmpl) used by TemplateProvider Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

- Add backward compat check for old .tmpl catalog template name in ExportSpringBoot - Remove dead model variables (CamelVersion, QuarkusManagementPort) Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

- Remove unnecessary bare block in Run.generateOpenApi (leftover from try-with-resources) - Deduplicate model building in Export.copyDockerFiles Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Comprehensive test coverage for all 23 FreeMarker templates: - FreeMarker-processed templates (processTemplate): code-java, main, spring-boot-main, Dockerfile21/25, readme, readme.native, rest-dsl.yaml, run-custom-camel-version, main-pom (with deps, repos, jib/jkube), spring-boot-pom, quarkus-pom - Init templates (raw text loading): java, yaml, xml, kamelet source/sink/action, pipe, integration Tests verify: license header stripping, placeholder resolution, conditional rendering, list iteration, Maven ${} passthrough, Kamelet {{}} passthrough, and missing template error handling. Also regenerate jbang command docs after rebase. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

github-actions bot added the dsl label Mar 23, 2026

Croway reviewed Mar 23, 2026

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gnodet force-pushed the CAMEL-21208-freemarker-templates branch from a02cd76 to 2870d10 Compare March 27, 2026 08:09

orpiske approved these changes Mar 27, 2026

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orpiske requested a review from Croway April 2, 2026 08:41

github-actions bot added the docs label Apr 3, 2026

Croway approved these changes Apr 9, 2026

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gnodet force-pushed the CAMEL-21208-freemarker-templates branch from 696d7c8 to 8a25f22 Compare April 9, 2026 15:27

github-actions bot removed the docs label Apr 9, 2026

gnodet and others added 5 commits April 9, 2026 21:12

CAMEL-21208: Fix review findings

4a47167

- Add backward compat check for old .tmpl catalog template name in ExportSpringBoot - Remove dead model variables (CamelVersion, QuarkusManagementPort) Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

CAMEL-21208: Minor cleanup from review

b6874de

- Remove unnecessary bare block in Run.generateOpenApi (leftover from try-with-resources) - Deduplicate model building in Export.copyDockerFiles Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

CAMEL-21208: Add unit test for TemplateHelper

da222d5

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

gnodet force-pushed the CAMEL-21208-freemarker-templates branch from 8a25f22 to c482a0d Compare April 9, 2026 19:13

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gnodet commented Mar 23, 2026 •

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