actions/importer-labs
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Merge pull request #19 from valet-customers/gitlab/dry-run-lab

Browse Source 
Add GitLab Dry-Run Lab
This commit is contained in:
j-dunham
2022-08-12 12:52:12 -04:00
committed by GitHub
parent 5b44a3f677 9056585b78
commit 62b6e45d65
1 changed files with 266 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files
gitlab/valet-dry-run-lab.md
+266
View File
@@ -0,0 +1,266 @@
# Dry run the migration of an GitLab pipeline to GitHub Actions
In this lab, you will use the Valet `dry-run` command to convert a GitLab pipeline to its equivalent GitHub Actions workflow.
The end result of this command will be the actions workflow written to your local filesystem.
- [Prerequisites](#prerequisites)
- [Perform a dry run](#perform-a-dry-run)
- [Review dry-run output](#review-dry-run-output)
- [Includes Dry-Run](#includes-dry-run)
- [Next Lab](#next-lab)
## Prerequisites
1. Followed [steps](../gitlab#readme) to set up your codespace environment.
2. Completed the [configure lab](../gitlab/valet-configure-lab.md)
## Perform a dry run
We will be performing a dry-run against a preconfigured project in the GitLab instance. Before running the command we need to collect some information:
1. What is the project we want to convert? __basic-pipeline-example__
2. What is the namespace for that project? __Valet. In this case the namespace is the same as the group the project is in__
3. Where do we want to store the result? __./tmp/dry-run-lab. This can be any valid path on the system. In the case of codespaces it is generally best to use `./tmp/SOME_DIRECTORY_HERE` so the files show in explorer__
### Steps
1. Navigate to the codespace terminal
2. Run the dry-run command using the values determined above
```
gh valet dry-run gitlab --output-dir ./tmp/dry-run-lab --namespace valet --project basic-pipeline-example
```
3. When the command finishes the output files should be printed to the terminal.
<img width="1112" alt="dry-run-terminal" src="https://user-images.githubusercontent.com/18723510/184173635-aec28d1c-8c61-4dcf-a743-f86cbdc836c5.png">
4. Open generated actions workflow
- Find `./tmp/dry-run-lab/valet` in the file explorer pane in codespaces.
- Click `basic-pipeline-example.yml` to open
<img width="231" alt="dry-run-explorer" src="https://user-images.githubusercontent.com/18723510/184177477-747905a8-32f3-4c15-8955-32079844a509.png">
## Review dry-run output
The dry-run output will show you the GitHub Actions yaml that would be migrated to GitHub with the `migrate` command. We will now take a quick look at what was generated.
__Click to Expand__
<details>
<summary><em>GitLab Pipeline</em> </summary>
```yaml
stages:
- build
- test
- deploy
image: alpine
build_a:
stage: build
script:
- echo "This job builds something."
- sleep 100
build_b:
stage: build
script:
- echo "This job builds something else."
- sleep 70
test_a:
stage: test
script:
- echo "This job tests something. It will only run when all jobs in the"
- echo "build stage are complete."
test_b:
stage: test
script:
- echo "This job tests something else. It will only run when all jobs in the"
- echo "build stage are complete too. It will start at about the same time as test_a."
- sleep 300
deploy_a:
stage: deploy
script:
- echo "This job deploys something. It will only run when all jobs in the"
- echo "test stage complete."
- sleep 600
deploy_b:
stage: deploy
script:
- echo "This job deploys something else. It will only run when all jobs in the"
- echo "test stage complete. It will start at about the same time as deploy_a."
- sleep 400
```
</details>
<details>
<summary><em>Actions Workflow</em></summary>
```yaml
name: valet/basic-pipeline-example
on:
push:
workflow_dispatch:
concurrency:
group: "${{ github.ref }}"
cancel-in-progress: true
jobs:
build_a:
runs-on: ubuntu-latest
container:
image: alpine
timeout-minutes: 60
steps:
- uses: actions/checkout@v2
with:
fetch-depth: 20
lfs: true
- run: echo "This job builds something."
- run: sleep 100
build_b:
runs-on: ubuntu-latest
container:
image: alpine
timeout-minutes: 60
steps:
- uses: actions/checkout@v2
with:
fetch-depth: 20
lfs: true
- run: echo "This job builds something else."
- run: sleep 70
test_a:
needs:
- build_a
- build_b
runs-on: ubuntu-latest
container:
image: alpine
timeout-minutes: 60
steps:
- uses: actions/checkout@v2
with:
fetch-depth: 20
lfs: true
- run: echo "This job tests something. It will only run when all jobs in the"
- run: echo "build stage are complete."
test_b:
needs:
- build_a
- build_b
runs-on: ubuntu-latest
container:
image: alpine
timeout-minutes: 60
steps:
- uses: actions/checkout@v2
with:
fetch-depth: 20
lfs: true
- run: echo "This job tests something else. It will only run when all jobs in the"
- run: echo "build stage are complete too. It will start at about the same time as test_a."
- run: sleep 300
deploy_a:
needs:
- test_a
- test_b
runs-on: ubuntu-latest
container:
image: alpine
timeout-minutes: 60
steps:
- uses: actions/checkout@v2
with:
fetch-depth: 20
lfs: true
- run: echo "This job deploys something. It will only run when all jobs in the"
- run: echo "test stage complete."
- run: sleep 600
deploy_b:
needs:
- test_a
- test_b
runs-on: ubuntu-latest
container:
image: alpine
timeout-minutes: 60
steps:
- uses: actions/checkout@v2
with:
fetch-depth: 20
lfs: true
- run: echo "This job deploys something else. It will only run when all jobs in the"
- run: echo "test stage complete. It will start at about the same time as deploy_a."
- run: sleep 400
```
</details>
In the GitLab pipeline we had 3 stages and 6 jobs that run on a alpine image
In the Actions workflow we have the same jobs (`build_a`, `build_b`, `test_a`, `test_b`, `deploy_a`, `deploy_b`) and the stages are now being enforced using the `needs` keyword. We can see this if we examine the `needs` for `test_a` and `test_b`, which make the test jobs depend on the build jobs.
```diff
- stages: test
+ needs:
+ - build_a
+ - build_b
```
The `image` in the GitLab pipeline has be transformed to `container` on each of the jobs.
```diff
- image: alpine
+ container:
+ image: alpine
```
And `script` has been transformed to `run`
```diff
- script:
- - echo "This job builds something."
+ run: echo "This job builds something."
```
## Includes Dry-Run
In the previous dry-run we migrated a basic pipeline that mapped very nicely to concepts in GitHub Actions. In this section we will examine the results of a dry-run that does not map directly to Actions using the `included-files-example` pipeline, which looks like
```yaml
include:
- local: /config/build.gitlab-ci.yml
- local: /config/test.gitlab-ci.yml
```
and results in the below yaml. The difference to note here is that Valet transformed the pipeline into a single workflow, it did not create reusable workflows for the `include` files `/config/build.gitlab-ci.yml` and `/config/test.gitlab-ci.yml`. The reason for this is that the dependency graph of how the jobs run could not be guaranteed using reusable workflows. This is an example of how concepts in GitLab don't always map directly to Actions and Valet has to make a decision on the safest path forward. It is likely this could be refactored to use [reusable workflow](https://docs.github.com/en/actions/using-workflows/reusing-workflows) at a later date with a deeper understanding of the pipeline.
```yaml
name: valet/included-files-example
on:
push:
pull_request:
workflow_dispatch:
concurrency:
group: "${{ github.ref }}"
cancel-in-progress: true
jobs:
build:
runs-on: ubuntu-latest
timeout-minutes: 60
steps:
- uses: actions/checkout@v2
with:
fetch-depth: 50
lfs: true
- run: echo "[BEFORE_SCRIPT] this is from test.gitlab-ci.yml"
- run: echo "this is from a local file"
test:
needs: build
runs-on: ubuntu-latest
timeout-minutes: 60
steps:
- uses: actions/checkout@v2
with:
fetch-depth: 50
lfs: true
- run: echo "[BEFORE_SCRIPT] this is from test.gitlab-ci.yml"
- run: echo "this is from a local file"
```
Try constructing and running the `dry-run` command yourself. Hint, you should just have to change the project name.
## Next Lab
[Audit GitLab Pipelines to GitHub Actions](../gitlab/valet-audit-lab.md)