Validates that that image exists for commit

Otherwise, falls back to building image and wheel.

Signed-off-by: dougbtv <[email protected]>

Author: dougbtv

buildkite/bootstrap.sh

@@ -191,8 +191,17 @@ if git rev-parse --is-inside-work-tree >/dev/null 2>&1; then
     LCA_COMMIT=$(git merge-base origin/main HEAD)
 fi
 if [[ -n "$LCA_COMMIT" ]]; then
-    DOCKER_IMAGE_OVERRIDE="public.ecr.aws/q9t5s3a7/vllm-ci-postmerge-repo:$LCA_COMMIT"
-    echo "Using Docker image for LCA commit: $DOCKER_IMAGE_OVERRIDE"
+    IMAGE_TAG="public.ecr.aws/q9t5s3a7/vllm-ci-postmerge-repo:$LCA_COMMIT"
+    # Check if the image exists on the registry
+    if docker manifest inspect "$IMAGE_TAG" >/dev/null 2>&1; then
+        DOCKER_IMAGE_OVERRIDE="$IMAGE_TAG"
+        echo "Using Docker image for LCA commit: $DOCKER_IMAGE_OVERRIDE"
+    else
+        DOCKER_IMAGE_OVERRIDE="public.ecr.aws/q9t5s3a7/vllm-ci-postmerge-repo:latest"
+        echo "LCA image not found, falling back to build image"
+        SKIP_IMAGE_BUILD=0
+        VLLM_USE_PRECOMPILED=0
+    fi
 else
     DOCKER_IMAGE_OVERRIDE="public.ecr.aws/q9t5s3a7/vllm-ci-postmerge-repo:latest"
     echo "Could not determine LCA commit, using latest Docker image: $DOCKER_IMAGE_OVERRIDE"