GitHub Action that deploys previews of pull requests to GitHub Pages. Works on any repository with a GitHub Pages site.
Features:
- Creates and deploys previews of pull requests to your GitHub Pages site
- Leaves a comment on the pull request with a link to the preview so that you and your team can collaborate on new features faster
- Updates the deployment and the comment whenever new commits are pushed to the pull request
- Cleans up after itself — removes deployed previews when the pull request is closed
- Can be configured to override any of these behaviours
Preview URLs look like this:
https://[owner].github.io/[repo]/pr-preview/pr-[number]/
A GitHub Actions workflow is required to use this Action.
All the workflow needs to do first is checkout the repository and build the Pages site.
If your GitHub pages site is deployed from the gh-pages branch, built
with e.g. an npm script to the ./build/ dir, and you're happy with the
default settings, usage is very simple:
# .github/workflows/preview.yml
name: Deploy PR previews
on:
pull_request:
types:
- opened
- reopened
- synchronize
- closed
concurrency: preview-${{ github.ref }}
jobs:
deploy-preview:
runs-on: ubuntu-20.04
steps:
- name: Checkout
uses: actions/checkout@v2
- name: Install and Build
run: |
npm install
npm run build
- name: Deploy preview
uses: rossjrw/pr-preview-action@v1
with:
source-dir: ./build/Consider limiting this workflow to run only when relevant files are edited to avoid deploying previews unnecessarily.
Be sure to pick the right event
types
for the pull_request event. It only comes with opened, reopened, and
synchronize by default — but this Action assumes by default that
the preview should be removed during the closed event, which it only sees
if you explicitly add it to the workflow.
I highly recommend setting a concurrency
group
scoped to each PR using github.ref as above, which should prevent the
preview and comment from desynchronising if you are e.g. committing very
frequently.
Important: If your root directory on the GitHub Pages deployment branch
(or docs/ on the main branch) is generated automatically (e.g. on pushes
to the main branch, with a tool such as Webpack), you will need to configure
it not to remove the umbrella directory (pr-preview/ by default, see
configuration below).
For example, if you are using
JamesIves/github-pages-deploy-action
to deploy your build, you can implement this using its clean-exclude
parameter:
# .github/workflows/build-deploy-pages-site.yml
steps:
...
- uses: JamesIves/github-pages-deploy-action@v4
...
with:
clean-exclude: pr-preview/
...If you don't do this, your main deployment may delete all of your currently-existing PR previews.
The following configuration settings are provided, which can be passed to
the with parameter.
-
source-dir: Directory containing files to deploy.E.g. if your project builds to
./dist/you would put./dist/(or justdist) here. For the root directory of your project, put.here.Equivalent to JamesIves/github-pages-deploy-action 'folder' setting.
Will be ignored when removing a preview.
Default:
. -
preview-branch: Branch on which the previews will be deployed. This should be the same branch that your GitHub Pages site is deployed from.Default:
gh-pages -
umbrella-dir: Name of the directory containing all previews. All previews will be created inside this directory.The umbrella directory is used to namespace previews from your main branch's deployment on GitHub Pages.
Set to
.to place preview directories into the root directory, but be aware that this may cause your main branch's deployment to interfere with your preview deployments (and vice-versa!)Default:
pr-preview -
(Advanced)
action: Determines what this action will do when it is executed. Supported values:deploy,remove,none,auto.deploy: will attempt to deploy the preview and overwrite any existing preview in that location.remove: will attempt to remove the preview in that location.auto: the action will try to determine whether to deploy or remove the preview based on the emitted event. It will deploy the preview onpull_request.types.opened,.reopenedand.synchronizeevents; and remove it onpull_request.types.closedevents. It will not do anything for all other events, even if you explicitly specify that the workflow should run on them.noneand all other values: the action will not do anything.
Default value:
auto
Full example with all default values added:
# .github/workflows/preview.yml
name: Deploy PR previews
concurrency: preview-${{ github.ref }}
on:
pull_request:
types:
- opened
- reopened
- synchronize
- closed
jobs:
deploy-preview:
runs-on: ubuntu-20.04
steps:
- uses: actions/checkout@v2
- run: npm i && npm run build
- uses: rossjrw/pr-preview-action@v1
with:
source-dir: .
preview-branch: gh-pages
umbrella-dir: pr-preview
action: autoIf your Pages site is built to build/ and deployed from the docs/
directory on the main branch:
# .github/workflows/preview.yml
steps:
...
- uses: rossjrw/pr-preview-action@v1
with:
source-dir: build
preview-branch: main
umbrella-dir: docs/pr-previewInformation from the context and conditionals can be used to make more complex decisions about what to do with previews; for example, removing only those associated with unmerged PRs when they are closed:
# .github/workflows/preview.yml
steps:
...
- uses: rossjrw/pr-preview-action@v1
if: contains(['opened', 'reopened', 'synchronize'], github.event.action)
with:
source-dir: ./build/
action: deploy
- uses: rossjrw/pr-preview-action@v1
if: github.event.action == "closed" && !github.event.pull_request.merged
with:
source-dir: ./build/
action: removeIf you want to keep PR previews around forever, even after the associated
PR has been closed, you don't want the cleanup behaviour of auto —
call deploy and never call remove:
# .github/workflows/everlasting-preview.yml
name: Deploy everlasting PR preview
concurrency: preview-${{ github.ref }}
on:
pull_request:
types:
- opened
- synchronize
jobs:
deploy-preview:
runs-on: ubuntu-20.04
steps:
- uses: actions/checkout@v2
- run: npm i && npm run build
- uses: rossjrw/pr-preview-action@v1
with:
source-dir: ./build/
action: deployBig thanks to the following:
- shlinkio/deploy-preview-action (MIT), prior art that informed the direction of this Action
- JamesIves/github-pages-deploy-action (MIT), used by this Action to deploy previews
- marocchino/sticky-pull-request-comment (MIT), used by this Action to leave a sticky comment on pull requests