adds an action to preview docs

.github/workflows/preview-docs.yml

@@ -0,0 +1,99 @@
+# deploys a preview version of the frontend including example changes
+name: Preview Docs
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  build-preview:
+    name: Build and deploy preview
+    runs-on: ubuntu-20.04
+    env:
+      MODAL_TOKEN_ID: ${{ secrets.MODAL_MODAL_LABS_TOKEN_ID }}
+      MODAL_TOKEN_SECRET: ${{ secrets.MODAL_MODAL_LABS_TOKEN_SECRET }}
+      MODAL_ENVIRONMENT: examples
+
+    steps:
+      - name: Checkout modal repo
+        uses: actions/checkout@v3
+        with:
+          repository: modal-labs/modal
+          token: ${{ secrets.GH_PAT }}
+          fetch-depth: 1
+          path: modal
+          persist-credentials: false
+
+      - name: Install Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.11"
+
+      - name: Install base packages
+        shell: bash
+        run: |
+          pip install uv
+          uv pip install --system setuptools wheel
+
+      - name: Install modal development packages
+        run: |
+          uv pip install --system -r modal/requirements.dev.txt
+
+      - name: Checkout client repo
+        uses: actions/checkout@v3
+        with:
+          repository: modal-labs/modal-client
+          token: ${{ secrets.GH_PAT }}
+          path: client
+          fetch-depth: 1
+          persist-credentials: false
+
+      - name: Install client repo
+        run: |
+          uv pip install --system -e client
+
+      - name: Install node
+        uses: actions/setup-node@v4
+        with:
+          node-version: 18
+
+      - name: Install node packages
+        run: npm ci --include=dev
+        working-directory: modal/frontend
+
+      - name: Compile protos
+        run: |
+          cd client
+          inv protoc type-stubs
+          cd ../modal
+          inv protoc
+
+      - name: Checkout examples repo
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 1
+          path: modal/examples
+
+      - name: Build and deploy preview
+        id: deploy_preview
+        working-directory: modal
+        run: |
+          export DEPLOYMENT_ID=${GITHUB_SHA::7}
+          inv frontend-preview --skip-update --deployment-id $DEPLOYMENT_ID | tee output.txt
+          DEPLOYMENT_URL=$(cat output.txt | grep "$DEPLOYMENT_ID" | grep "modal.run" | tail -n 1)
+          echo "DEPLOYMENT_URL=$DEPLOYMENT_URL" >> $GITHUB_OUTPUT
+
+      - name: Post a comment with the preview URL
+        uses: actions/github-script@v6
+        with:
+          github-token: ${{ secrets.GH_PAT }}
+          script: |
+            const deploymentUrl = `${{ steps.deploy_preview.outputs.DEPLOYMENT_URL }}`;
+            github.rest.issues.createComment({
+              issue_number: context.issue.number,
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              body: `🚀 The docs preview is ready! Check it out here: ${deploymentUrl}`
+            });