Add collapsible console sections with marker detection

README.md

@@ -47,6 +47,20 @@ See a live demonstration from a Jenkins Contributor Summit:
 
 ## Pipeline DSL Extensions
 
+### Collapsible Console Sections
+
+Console output can be split into collapsible sections using `##[group]` / `##[endgroup]` markers (Azure DevOps style) or `::group::` / `::endgroup::` (GitHub Actions style):
+
+```groovy
+sh '''
+    echo "##[group]Unit Tests"
+    ./run-tests.sh
+    echo "##[endgroup]"
+'''
+```
+
+Sections with more than 25 lines start collapsed. Nested sections are supported. See [collapsible-console-sections.md](docs/collapsible-console-sections.md) for full details including colored titles with the AnsiColor plugin.
+
 ### Hiding Steps from View
 
 You can mark specific pipeline steps as hidden from the view by wrapping them with the `hideFromView` step:
@@ -74,6 +88,15 @@ pipeline {
 
 The REST API documentation can be found [here](https://editor-next.swagger.io/?url=https://raw.githubusercontent.com/jenkinsci/pipeline-graph-view-plugin/refs/heads/main/openapi.yaml).
 
+## Extending the Plugin
+
+Plugin authors can contribute custom collapsible section rules via two extension points:
+
+- `ConsoleSectionRule` - regex-based, runs client-side. Good for simple delimited output (npm install, pip, Docker builds, etc.).
+- `ConsoleSectionAnnotator` - stateful, runs server-side line by line. Good for context-dependent grouping like stack traces or test suite blocks.
+
+See [extending-console-sections.md](docs/extending-console-sections.md) for examples of both.
+
 ## Contributing
 
 Refer to our [contribution guidelines](./CONTRIBUTING.md).

docs/collapsible-console-sections.md

@@ -0,0 +1,65 @@
+# Collapsible Console Sections
+
+Steps in the Pipeline Graph View console can collapse sections of their output into expandable groups. This makes long logs easier to scan.
+
+## Using markers in your Jenkinsfile
+
+Add `##[group]` and `##[endgroup]` markers to your shell commands. The text after `##[group]` becomes the section title.
+
+```groovy
+stage('Test') {
+    steps {
+        sh '''
+            echo "##[group]Unit Tests"
+            ./run-tests.sh
+            echo "##[endgroup]"
+
+            echo "##[group]Integration Tests"
+            ./run-integration.sh
+            echo "##[endgroup]"
+        '''
+    }
+}
+```
+
+Both Azure DevOps (`##[group]`) and GitHub Actions (`::group::`) syntax are supported and can be mixed freely.
+
+```groovy
+sh '''
+    echo "::group::Dependency install"
+    npm ci
+    echo "::endgroup::"
+'''
+```
+
+## Behavior
+
+- Sections with more than 25 lines start collapsed.
+- Sections with 25 or fewer lines start open.
+- Sections still being written (not yet closed) stay open.
+- Sections can be nested.
+- Lines from `set -x` shell tracing (starting with `+ `) are never treated as markers.
+
+## Colored titles (AnsiColor plugin)
+
+If you install the [AnsiColor plugin](https://plugins.jenkins.io/ansicolor/), wrap your step in `ansiColor('xterm')`. ANSI codes in section titles are rendered as colors.
+
+```groovy
+stage('Build') {
+    steps {
+        ansiColor('xterm') {
+            sh '''#!/bin/bash
+                echo -e "\033[32m##[group]Dependencies\033[0m"
+                npm ci
+                echo "##[endgroup]"
+
+                echo -e "##[group]\033[1;34mCompile\033[0m"
+                npm run build
+                echo "##[endgroup]"
+            '''
+        }
+    }
+}
+```
+
+Note: use `echo -e` in bash (not the default `sh`) so escape sequences are interpreted. Add `#!/bin/bash` at the top of your `sh` block.