ci: Add workflow for building ai-runner image

Author: yondonfu

.github/workflows/ai-runner-docker.yaml

@@ -0,0 +1,69 @@
+name: Build Docker image for ai-runner
+
+on:
+  pull_request:
+  push:
+    branches:
+      - main
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
+jobs:
+  docker:
+    name: Docker image generation
+    if: github.event_name == 'push' || github.event.pull_request.head.repo.full_name == github.repository
+    permissions:
+      packages: write
+      contents: read
+    runs-on: ubuntu-20.04
+    steps:
+      - name: Check out code
+        uses: actions/[email protected]
+        with:
+          fetch-depth: 0
+          # Check https://github.com/livepeer/go-livepeer/pull/1891
+          # for ref value discussion
+          ref: ${{ github.event.pull_request.head.sha }}
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Login to DockerHub
+        uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.CI_DOCKERHUB_USERNAME }}
+          password: ${{ secrets.CI_DOCKERHUB_TOKEN }}
+
+      - name: Extract metadata (tags, labels) for Docker
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: |
+            livepeer/ai-runner
+          tags: |
+            type=sha
+            type=ref,event=pr
+            type=ref,event=tag
+            type=sha,format=long
+            type=ref,event=branch
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=semver,pattern={{version}},prefix=v
+            type=semver,pattern={{major}}.{{minor}},prefix=v
+            type=raw,value=latest,enable={{is_default_branch}}
+            type=raw,value=${{ github.event.pull_request.head.ref }}
+            type=raw,value=stable,enable=${{ startsWith(github.event.ref, 'refs/tags/v') }}
+
+      - name: Build and push runner docker image
+        uses: docker/build-push-action@v5
+        with:
+          context: "{{defaultContext}}:runner"
+          platforms: linux/amd64
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          file: "Dockerfile"
+          labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=registry,ref=livepeerci/build:cache
+          cache-to: type=registry,ref=livepeerci/build:cache,mode=max