[AMD CI] Populate image cache in nightly docker release. (#11822)

.github/workflows/release-docker-amd-nightly.yml

@@ -63,3 +63,75 @@ jobs:
 
           docker build . -f docker/Dockerfile.rocm --build-arg BUILD_TYPE=${{ matrix.build_type }} --build-arg GPU_ARCH=${{ matrix.gpu_arch }} -t rocm/sgl-dev:${tag}-${{ env.DATE }}${tag_suffix} --no-cache
           docker push rocm/sgl-dev:${tag}-${{ env.DATE }}${tag_suffix}
+
+  cache:
+    if: github.repository == 'sgl-project/sglang'
+    runs-on: linux-mi300-gpu-1
+    environment: 'prod'
+    needs: publish
+    strategy:
+      matrix:
+        gpu_arch: ['gfx942', 'gfx942-rocm700']
+        build_type: ['all']
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: "Set Date"
+        run: |
+          echo "DATE=$(date +%Y%m%d)" >> $GITHUB_ENV
+
+      - name: Login to Docker Hub
+        uses: docker/login-action@v2
+        with:
+          username: ${{ secrets.DOCKERHUB_AMD_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_AMD_TOKEN }}
+
+      - name: Pull and Save Docker Image to Cache
+        run: |
+          set -euxo pipefail
+
+          version=$(cat python/sglang/version.py | cut -d'"' -f2)
+
+          if [ "${{ matrix.gpu_arch }}" = "gfx942" ]; then
+            rocm_tag="rocm630-mi30x"
+          elif [ "${{ matrix.gpu_arch }}" = "gfx942-rocm700" ]; then
+            rocm_tag="rocm700-mi30x"
+          else
+            echo "Unsupported gfx arch"
+            exit 1
+          fi
+
+          tag=v${version}-${rocm_tag}
+
+          if [ "${{ matrix.build_type }}" = "all" ]; then
+            tag_suffix=""
+          else
+            echo "Unsupported build type"
+            exit 1
+          fi
+
+          image="rocm/sgl-dev:${tag}-${{ env.DATE }}${tag_suffix}"
+
+          # Determine target cache file name based on ROCm variant
+          if [[ "${rocm_tag}" == rocm630* ]]; then
+            final_path="/home/runner/sgl-data/docker/image.tar"
+          elif [[ "${rocm_tag}" == rocm700* ]]; then
+            final_path="/home/runner/sgl-data/docker/image-700.tar"
+          else
+            echo "Unexpected ROCm tag: ${rocm_tag}"
+            exit 1
+          fi
+
+          tmp_path="${final_path}.tmp"
+
+          echo "Pulling image: ${image}"
+          docker pull "${image}"
+
+          echo "Saving to temp file: ${tmp_path}"
+          docker save "${image}" -o "${tmp_path}"
+
+          echo "Moving to final path: ${final_path}"
+          mv -f "${tmp_path}" "${final_path}"
+
+          echo "Cache populated successfully at ${final_path}"