ci: skip worker build if already built.

.github/workflows/build.yml

@@ -62,13 +62,30 @@ jobs:
               with:
                   node-version: '14'
 
+            - name: Set up Cloud SDK
+              uses: google-github-actions/setup-gcloud@master
+              with:
+                  project_id: ${{ secrets.GCS_PROJECT_ID }}
+                  service_account_key: ${{ secrets.GCS_TF_KEY }}
+                  export_default_credentials: true
+
+            - name: Check if already deployed
+              id: check
+              run: |
+                  gsutil stat gs://roleypoly-artifacts/backend-worker/${{ github.sha }}/script.js \
+                      && echo ::set-output name=skip::0 \
+                      || echo ::set-output name=skip::1
+
             - run: npm i -g @cloudflare/wrangler
+              if: steps.check.outputs.skip == '0'
 
             - name: Get yarn cache directory path
+              if: steps.check.outputs.skip == '0'
               id: yarn-cache-dir-path
               run: echo "::set-output name=dir::$(yarn cache dir)"
 
             - uses: actions/cache@v2
+              if: steps.check.outputs.skip == '0'
               id: yarn-cache # use this to check for `cache-hit` (`steps.yarn-cache.outputs.cache-hit != 'true'`)
               with:
                   path: ${{ steps.yarn-cache-dir-path.outputs.dir }}
@@ -77,13 +94,16 @@ jobs:
                       ${{ runner.os }}-yarn-
 
             - run: yarn install --frozen-lockfile
+              if: steps.check.outputs.skip == '0'
 
             - run: |
                   wrangler init
                   echo 'webpack_config = "src/backend-worker/webpack.config.js"' | tee -a wrangler.toml
                   wrangler build
+              if: steps.check.outputs.skip == '0'
 
             - id: upload-file
+              if: steps.check.outputs.skip == '0'
               uses: google-github-actions/upload-cloud-storage@main
               with:
                   path: worker/script.js