Setup PR Preview workflow (#175)

* Setup PR Preview workflow

* Fix trailing whitespace

* Update .github/workflows/preview.yaml

Co-authored-by: Anderson Banihirwe <[email protected]>

* Fix syntax error

* Fix another indent

* Add step summary

* Add preview url formatting and manual PR comment

* Remove trying to do PR comment, looks like it doesn't work for fork PR

* Remove trailing whitespace

---------

Co-authored-by: Anderson Banihirwe <[email protected]>
Co-authored-by: Deepak Cherian <[email protected]>

Author: 3 people

.github/workflows/preview.yaml

@@ -0,0 +1,60 @@
+name: PR Preview
+
+on: [pull_request]
+
+permissions:
+  pull-requests: write # allow surge-preview to create/update PR comments
+
+jobs:
+  preview:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      - name: Setup JupyterBook Cache
+        uses: actions/cache@v3
+        with:
+          path: _build
+          # NOTE: change key to "jupyterbook-DATE" to force rebuilding cache
+          key: jupyterbook-20230613
+
+      - name: Install Conda environment with Micromamba
+        uses: mamba-org/setup-micromamba@v1
+        with:
+          environment-file: conda/conda-lock.yml
+          environment-name: xarray-tutorial
+          cache-environment: true
+
+      - name: Build JupyterBook
+        # NOTE: login shell activates conda environment
+        shell: bash -l {0}
+        run: |
+          jupyter-book build ./ --warningiserror --keep-going
+
+      - name: Dump Build Logs
+        if: always()
+        run: |
+          if (test -a _build/html/reports/*log); then cat _build/html/reports/*log ; fi
+
+      - name: Publish to Surge
+        id: preview_step
+        uses: afc163/surge-preview@v1
+        with:
+          surge_token: ${{ secrets.SURGE_TOKEN }}
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          dist: _build/html
+          build: |
+            npm install surge
+
+      - name: Format preview url
+        id: format_url
+        run: |
+          echo "url_text=:rocket: Preview deployed at https://${{ steps.preview_step.outputs.preview_url }}" >> $GITHUB_OUTPUT
+
+      - name: Get the preview_url
+        run: echo "${{ steps.format_url.outputs.url_text }}"
+
+      - name: Generate summary
+        run: |
+          echo "#### ${{ steps.format_url.outputs.url_text }}" >> $GITHUB_STEP_SUMMARY