Add trivy workflow

.github/workflows/trivy.yml

@@ -0,0 +1,48 @@
+# This workflow uses actions that are not certified by GitHub.
+# They are provided by a third-party and are governed by
+# separate terms of service, privacy policy, and support
+# documentation.
+
+name: trivy scan
+
+on:
+  # Running on push to main for now. If we decide this uses too many GH Action resources, we can move to a cron job or something.
+  push:
+    branches: [ "main" ]
+  #pull_request:
+    # The branches below must be a subset of the branches above
+    # branches: [ "main" ]
+
+permissions:
+  contents: read
+
+jobs:
+  build:
+    permissions:
+      contents: read # for actions/checkout to fetch code
+      security-events: write # for github/codeql-action/upload-sarif to upload SARIF results
+      actions: read # only required for a private repository by github/codeql-action/upload-sarif to get the Action run status
+    name: Build
+    runs-on: "ubuntu-20.04"
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v3
+
+      - name: Build an image from Dockerfile
+        env:
+          AGENT_IMAGE: 'grafana/agent:${{ github.sha }}'
+        run: |
+          make agent-image
+      - name: Run Trivy vulnerability scanner
+        uses: aquasecurity/trivy-action@7b7aa264d83dc58691451798b4d117d53d21edfe
+        with:
+          image-ref: 'grafana/agent:${{ github.sha }}'
+          format: 'template'
+          template: '@/contrib/sarif.tpl'
+          output: 'trivy-results.sarif'
+          severity: 'CRITICAL,HIGH,MEDIUM,LOW'
+
+      - name: Upload Trivy scan results to GitHub Security tab
+        uses: github/codeql-action/upload-sarif@v2
+        with:
+          sarif_file: 'trivy-results.sarif'