ci: add skip directives for long tests (#3151)

This PR introduces many CI optimizations:

1. The `[ci-skip]` PR body directive to skip the Postgres and end to end tests
2. Improved caching that cuts the Go test matrix in half
3. Increasing Go test parallelism for ~20% gains
4. Enable caching in webpack (4x frontend build)

.github/workflows/coder.yaml

@@ -60,13 +60,31 @@ jobs:
           echo "${{ toJSON(steps.filter )}}"
 
   # Debug step
-  show-changes:
-    needs: changes
+  debug-inputs:
+    needs:
+      - changes
+      - pr-context
     runs-on: ubuntu-latest
     steps:
       - id: log
         run: |
-          echo "${{ toJSON(needs.changes) }}"
+          echo "${{ toJSON(needs) }}"
+          echo "${{ contains(needs.pr-context.outputs.skips, 'postgres') }} "
+
+  pr-context:
+    runs-on: ubuntu-latest
+    outputs:
+      skips: ${{ steps.pr-context.outputs.skips }}
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-go@v3
+        with:
+          go-version: "~1.18"
+      - id: pr-context
+        env:
+          GITHUB_CONTEXT: ${{ toJSON(github) }}
+        run: |
+          go run github.com/coder/coder/.github/workflows/prcontext
 
   style-lint-golangci:
     name: style/lint/golangci
@@ -157,6 +175,25 @@ jobs:
       - uses: actions/setup-go@v3
         with:
           go-version: "~1.18"
+
+      - name: Echo Go Cache Paths
+        id: go-cache-paths
+        run: |
+          echo "::set-output name=go-build::$(go env GOCACHE)"
+          echo "::set-output name=go-mod::$(go env GOMODCACHE)"
+
+      - name: Go Build Cache
+        uses: actions/cache@v3
+        with:
+          path: ${{ steps.go-cache-paths.outputs.go-build }}
+          key: ${{ github.job }}-go-build-${{ hashFiles('**/go.sum', '**/**.go') }}
+
+      - name: Go Mod Cache
+        uses: actions/cache@v3
+        with:
+          path: ${{ steps.go-cache-paths.outputs.go-mod }}
+          key: ${{ github.job }}-go-mod-${{ hashFiles('**/go.sum') }}
+
       - run: |
           curl -sSL https://github.com/kyleconroy/sqlc/releases/download/v1.13.0/sqlc_1.13.0_linux_amd64.tar.gz | sudo tar -C /usr/bin -xz sqlc
 
@@ -229,7 +266,7 @@ jobs:
         uses: actions/cache@v3
         with:
           path: ${{ steps.go-cache-paths.outputs.go-build }}
-          key: ${{ runner.os }}-go-build-${{ hashFiles('**/go.sum') }}
+          key: ${{ runner.os }}-go-build-${{ hashFiles('**/go.**', '**.go') }}
 
       - name: Go Mod Cache
         uses: actions/cache@v3
@@ -251,14 +288,23 @@ jobs:
           terraform_wrapper: false
 
       - name: Test with Mock Database
+        id: test
         shell: bash
-        run: gotestsum --junitfile="gotests.xml" --packages="./..." --
-          -covermode=atomic -coverprofile="gotests.coverage"
-          -coverpkg=./...,github.com/coder/coder/codersdk
-          -timeout=5m -short -failfast
+        run: |
+          # Code coverage is more computationally expensive and also
+          # prevents test caching, so we disable it on alternate operating
+          # systems.
+          if [ "${{ matrix.os }}" == "ubuntu-latest" ]; then
+            echo ::set-output name=cover::true
+            export COVERAGE_FLAGS='-covermode=atomic -coverprofile="gotests.coverage" -coverpkg=./...,github.com/coder/coder/codersdk'
+          else
+            echo ::set-output name=cover::false
+          fi
+          set -x
+          gotestsum --junitfile="gotests.xml" --packages="./..." -- -parallel=8 -timeout=5m -short -failfast $COVERAGE_FLAGS
 
       - name: Upload DataDog Trace
-        if: always() && github.actor != 'dependabot[bot]' && !github.event.pull_request.head.repo.fork
+        if: github.actor != 'dependabot[bot]' && !github.event.pull_request.head.repo.fork
         env:
           DATADOG_API_KEY: ${{ secrets.DATADOG_API_KEY }}
           DD_DATABASE: fake
@@ -272,7 +318,7 @@ jobs:
         # that is no guarantee, see:
         # https://github.com/codecov/codecov-action/issues/788
         continue-on-error: true
-        if: github.actor != 'dependabot[bot]' && !github.event.pull_request.head.repo.fork
+        if: steps.test.outputs.cover && github.actor != 'dependabot[bot]' && !github.event.pull_request.head.repo.fork
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
           files: ./gotests.coverage
@@ -280,8 +326,12 @@ jobs:
 
   test-go-postgres:
     name: "test/go/postgres"
-    needs: changes
-    if: needs.changes.outputs.docs-only == 'false'
+    needs:
+      - changes
+      - pr-context
+    if: >
+      needs.changes.outputs.docs-only == 'false' &&
+      contains(needs.pr-context.outputs.skips, github.job) == 'false'
     runs-on: ubuntu-latest
     # This timeout must be greater than the timeout set by `go test` in
     # `make test-postgres` to ensure we receive a trace of running
@@ -305,7 +355,7 @@ jobs:
         uses: actions/cache@v3
         with:
           path: ${{ steps.go-cache-paths.outputs.go-build }}
-          key: ${{ runner.os }}-go-build-${{ hashFiles('**/go.sum') }}
+          key: ${{ runner.os }}-go-build-${{ hashFiles('**/go.sum', '**/**.go') }}
 
       - name: Go Mod Cache
         uses: actions/cache@v3
@@ -517,8 +567,10 @@ jobs:
 
   test-e2e:
     name: "test/e2e/${{ matrix.os }}"
-    needs: changes
-    if: needs.changes.outputs.docs-only == 'false'
+    needs:
+      - changes
+      - pr-context
+    if: needs.changes.outputs.docs-only == 'false' && !contains(needs.pr-context.outputs.skips, 'test/e2e')
     runs-on: ${{ matrix.os }}
     timeout-minutes: 20
     strategy:
@@ -535,9 +587,7 @@ jobs:
           path: |
             **/node_modules
             .eslintcache
-          key: js-${{ runner.os }}-test-${{ hashFiles('**/yarn.lock') }}
-          restore-keys: |
-            js-${{ runner.os }}-
+          key: js-${{ runner.os }}-e2e-${{ hashFiles('**/yarn.lock') }}
 
       # Go is required for uploading the test results to datadog
       - uses: actions/setup-go@v3
@@ -573,6 +623,7 @@ jobs:
 
       - name: Build
         run: |
+          sudo npm install -g prettier
           make -B site/out/index.html
 
       - run: yarn playwright:install