> ## Documentation Index
> Fetch the complete documentation index at: https://notes.kodekloud.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Demo Perform Dry run Migration of a Jenkins Job 2
> Demonstrates dry-run migration of a Jenkins Pipeline to GitHub Actions using gh actions-importer, showing converted workflows, placeholders for unsupported steps, and guidance on custom transformers and full migration.
This lesson demonstrates a dry-run migration of a Jenkins Pipeline job to GitHub Actions. It continues from the dry-run and production migration concepts typically used for Jenkins Freestyle projects and shows how the `gh actions-importer` tool translates pipeline stages and steps into a GitHub Actions workflow file.
## Source Jenkins Pipeline (pipeline portion of config.xml)
For this demo we used the Pipeline Project 2 located under `Folder One → Folder Two`. Below is the pipeline stage structure (scripted/declarative) from the job's `config.xml`:
```groovy theme={null}
stages {
stage('First Stage') {
steps {
echo 'Starting the first stage...'
sleep 5
echo 'First stage completed.'
}
}
stage('Second Stage') {
steps {
echo 'Starting the second stage...'
sleep 2
echo 'Second stage completed.'
}
}
}
```
## Dry-run vs Migrate
* Dry-run: translates and writes workflow files locally without modifying the target repository or creating pull requests.
* Migrate: performs a full migration and can push changes to a target repo or open PRs.
Use the `gh actions-importer` subcommands for both operations.
## Example: Full migration command
```bash theme={null}
gh actions-importer migrate jenkins \
--target-url https://github.com/:owner/:repo \
--output-dir tmp/migrate \
--source-url my-jenkins-project
```
Replace `:owner` and `:repo` with your GitHub organization/user and repository.
## Example: Dry-run command used in this lesson
This dry-run writes translated workflows to `tmp/dry-run` without pushing anything:
```bash theme={null}
gh actions-importer dry-run jenkins \
--source-url http://139.84.149.83:8080/job/folder-1/job/folder-2/job/pipeline-project-2 \
--output-dir tmp/dry-run
```
## Actual dry-run invocation (console output)
The demo's console output shows the dry-run invocation and the generated output path:
```bash theme={null}
root@jenkins in /home
# run dry-run
gh actions-importer dry-run jenkins \
--source-url http://139.84.149.83:8080/job/folder-1/job/folder-2/job/pipeline-project-2 \
--output-dir tmp/dry-run
[2025-05-22 10:36:34] Logs: 'tmp/dry-run/log/valet-20250522-103634.log'
[2025-05-22 10:36:35] Output file(s):
tmp/dry-run/folder-1/folder-2/pipeline-project-2/.github/workflows/pipeline-project-2.yml
root@jenkins in /home took 23s
```
## Generated workflow (abridged)
After the dry-run, the importer created a GitHub Actions workflow YAML. The converter successfully mapped `echo` statements to `run` steps and injected a `checkout` step. Jenkins `sleep` calls did not have a built-in transformer and are emitted as commented placeholders:
```yaml theme={null}
name: folder-1/folder-2/pipeline-project-2
on:
workflow_dispatch:
jobs:
First_Stage:
name: First Stage
runs-on: ubuntu-latest
steps:
- name: checkout
uses: actions/checkout@v4.1.0
- name: echo message
run: echo Starting the first stage...
# This item has no matching transformer
# - sleep:
# - key: time
# value:
# isLiteral: true
# value: 5
- name: echo message
run: echo First stage completed.
Second_Stage:
name: Second Stage
runs-on: ubuntu-latest
needs: First_Stage
steps:
- name: checkout
uses: actions/checkout@v4.1.0
- name: echo message
run: echo Starting the second stage...
# This item has no matching transformer
# - sleep:
# - key: time
# value:
# isLiteral: true
# value: 2
- name: echo message
run: echo Second stage completed.
```
## What the importer did (summary)
| Jenkins construct | Result in converted workflow | Action required |
| --------------------- | ---------------------------------------------------------------------------- | ------------------------------------------------------- |
| `echo` | Converted to `- run: echo ...` steps | No action needed |
| `checkout` (implicit) | Added via `actions/checkout@v4.1.0` | No action needed |
| `sleep` | Emitted as commented placeholder (`# This item has no matching transformer`) | Create a custom transformer or manually update workflow |
The dry-run log reveals these internal steps: the importer fetched the job's `config.xml`, converted XML to an intermediate JSON representation, applied configured transformers, and emitted workflow YAML. Transformers were found for `echo` but not for `sleep`, so `sleep` entries appear as comments.
The importer emits commented placeholders for Jenkins constructs that lack matching transformers. To retain or convert such steps (for example, `sleep`), create a custom transformer that maps the Jenkins keyword/function to an equivalent GitHub Actions step (for instance, `run: sleep 5`). Custom transformers let you tailor conversions for team-specific pipeline usage.
Before running a full `migrate`:
* Validate the dry-run output under `tmp/dry-run` and manually review any commented placeholders.
* Add or author transformers for unsupported keywords if you need automated conversions.
* Only push or open PRs after confirming the generated workflows are functionally equivalent.
## Next steps
1. Implement custom transformers for unsupported Jenkins constructs (e.g., `sleep` → `run: sleep
## Source Jenkins Pipeline (pipeline portion of config.xml)
For this demo we used the Pipeline Project 2 located under `Folder One → Folder Two`. Below is the pipeline stage structure (scripted/declarative) from the job's `config.xml`:
```groovy theme={null}
stages {
stage('First Stage') {
steps {
echo 'Starting the first stage...'
sleep 5
echo 'First stage completed.'
}
}
stage('Second Stage') {
steps {
echo 'Starting the second stage...'
sleep 2
echo 'Second stage completed.'
}
}
}
```
## Dry-run vs Migrate
* Dry-run: translates and writes workflow files locally without modifying the target repository or creating pull requests.
* Migrate: performs a full migration and can push changes to a target repo or open PRs.
Use the `gh actions-importer` subcommands for both operations.
## Example: Full migration command
```bash theme={null}
gh actions-importer migrate jenkins \
--target-url https://github.com/:owner/:repo \
--output-dir tmp/migrate \
--source-url my-jenkins-project
```
Replace `:owner` and `:repo` with your GitHub organization/user and repository.
## Example: Dry-run command used in this lesson
This dry-run writes translated workflows to `tmp/dry-run` without pushing anything:
```bash theme={null}
gh actions-importer dry-run jenkins \
--source-url http://139.84.149.83:8080/job/folder-1/job/folder-2/job/pipeline-project-2 \
--output-dir tmp/dry-run
```
## Actual dry-run invocation (console output)
The demo's console output shows the dry-run invocation and the generated output path:
```bash theme={null}
root@jenkins in /home
# run dry-run
gh actions-importer dry-run jenkins \
--source-url http://139.84.149.83:8080/job/folder-1/job/folder-2/job/pipeline-project-2 \
--output-dir tmp/dry-run
[2025-05-22 10:36:34] Logs: 'tmp/dry-run/log/valet-20250522-103634.log'
[2025-05-22 10:36:35] Output file(s):
tmp/dry-run/folder-1/folder-2/pipeline-project-2/.github/workflows/pipeline-project-2.yml
root@jenkins in /home took 23s
```
## Generated workflow (abridged)
After the dry-run, the importer created a GitHub Actions workflow YAML. The converter successfully mapped `echo` statements to `run` steps and injected a `checkout` step. Jenkins `sleep` calls did not have a built-in transformer and are emitted as commented placeholders:
```yaml theme={null}
name: folder-1/folder-2/pipeline-project-2
on:
workflow_dispatch:
jobs:
First_Stage:
name: First Stage
runs-on: ubuntu-latest
steps:
- name: checkout
uses: actions/checkout@v4.1.0
- name: echo message
run: echo Starting the first stage...
# This item has no matching transformer
# - sleep:
# - key: time
# value:
# isLiteral: true
# value: 5
- name: echo message
run: echo First stage completed.
Second_Stage:
name: Second Stage
runs-on: ubuntu-latest
needs: First_Stage
steps:
- name: checkout
uses: actions/checkout@v4.1.0
- name: echo message
run: echo Starting the second stage...
# This item has no matching transformer
# - sleep:
# - key: time
# value:
# isLiteral: true
# value: 2
- name: echo message
run: echo Second stage completed.
```
## What the importer did (summary)
| Jenkins construct | Result in converted workflow | Action required |
| --------------------- | ---------------------------------------------------------------------------- | ------------------------------------------------------- |
| `echo` | Converted to `- run: echo ...` steps | No action needed |
| `checkout` (implicit) | Added via `actions/checkout@v4.1.0` | No action needed |
| `sleep` | Emitted as commented placeholder (`# This item has no matching transformer`) | Create a custom transformer or manually update workflow |
The dry-run log reveals these internal steps: the importer fetched the job's `config.xml`, converted XML to an intermediate JSON representation, applied configured transformers, and emitted workflow YAML. Transformers were found for `echo` but not for `sleep`, so `sleep` entries appear as comments.