Add BuildKit cache mounts to optimize Docker build performance

- Enable BuildKit syntax directive
- Cache UV and Bun package downloads
- Update docs for cache optimization
- Improve rebuild efficiency

Author: danielaskdd

Dockerfile

@@ -1,3 +1,5 @@
+# syntax=docker/dockerfile:1
+
 # Frontend build stage
 FROM oven/bun:1 AS frontend-builder
 
@@ -7,7 +9,8 @@ WORKDIR /app
 COPY lightrag_webui/ ./lightrag_webui/
 
 # Build frontend assets for inclusion in the API package
-RUN cd lightrag_webui \
+RUN --mount=type=cache,target=/root/.bun/install/cache \
+    cd lightrag_webui \
     && bun install --frozen-lockfile \
     && bun run build
 
@@ -40,7 +43,8 @@ COPY setup.py .
 COPY uv.lock .
 
 # Install base, API, and offline extras without the project to improve caching
-RUN uv sync --frozen --no-dev --extra api --extra offline --no-install-project --no-editable
+RUN --mount=type=cache,target=/root/.local/share/uv \
+    uv sync --frozen --no-dev --extra api --extra offline --no-install-project --no-editable
 
 # Copy project sources after dependency layer
 COPY lightrag/ ./lightrag/
@@ -49,7 +53,8 @@ COPY lightrag/ ./lightrag/
 COPY --from=frontend-builder /app/lightrag/api/webui ./lightrag/api/webui
 
 # Sync project in non-editable mode and ensure pip is available for runtime installs
-RUN uv sync --frozen --no-dev --extra api --extra offline --no-editable \
+RUN --mount=type=cache,target=/root/.local/share/uv \
+    uv sync --frozen --no-dev --extra api --extra offline --no-editable \
     && /app/.venv/bin/python -m ensurepip --upgrade
 
 # Prepare offline cache directory and pre-populate tiktoken data
@@ -81,7 +86,8 @@ ENV PATH=/app/.venv/bin:/root/.local/bin:$PATH
 
 # Install dependencies with uv sync (uses locked versions from uv.lock)
 # And ensure pip is available for runtime installs
-RUN uv sync --frozen --no-dev --extra api --extra offline --no-editable \
+RUN --mount=type=cache,target=/root/.local/share/uv \
+    uv sync --frozen --no-dev --extra api --extra offline --no-editable \
     && /app/.venv/bin/python -m ensurepip --upgrade
 
 # Create persistent data directories AFTER package installation

Dockerfile.lite

@@ -1,3 +1,5 @@
+# syntax=docker/dockerfile:1
+
 # Frontend build stage
 FROM oven/bun:1 AS frontend-builder
 
@@ -7,7 +9,8 @@ WORKDIR /app
 COPY lightrag_webui/ ./lightrag_webui/
 
 # Build frontend assets for inclusion in the API package
-RUN cd lightrag_webui \
+RUN --mount=type=cache,target=/root/.bun/install/cache \
+    cd lightrag_webui \
     && bun install --frozen-lockfile \
     && bun run build
 
@@ -40,7 +43,8 @@ COPY setup.py .
 COPY uv.lock .
 
 # Install project dependencies (base + API extras) without the project to improve caching
-RUN uv sync --frozen --no-dev --extra api --no-install-project --no-editable
+RUN --mount=type=cache,target=/root/.local/share/uv \
+    uv sync --frozen --no-dev --extra api --no-install-project --no-editable
 
 # Copy project sources after dependency layer
 COPY lightrag/ ./lightrag/
@@ -49,7 +53,8 @@ COPY lightrag/ ./lightrag/
 COPY --from=frontend-builder /app/lightrag/api/webui ./lightrag/api/webui
 
 # Sync project in non-editable mode and ensure pip is available for runtime installs
-RUN uv sync --frozen --no-dev --extra api --no-editable \
+RUN --mount=type=cache,target=/root/.local/share/uv \
+    uv sync --frozen --no-dev --extra api --no-editable \
     && /app/.venv/bin/python -m ensurepip --upgrade
 
 # Prepare tiktoken cache directory and pre-populate tokenizer data
@@ -81,7 +86,8 @@ ENV PATH=/app/.venv/bin:/root/.local/bin:$PATH
 
 # Sync dependencies inside the final image using uv
 # And ensure pip is available for runtime installs
-RUN uv sync --frozen --no-dev --extra api --no-editable \
+RUN --mount=type=cache,target=/root/.local/share/uv \
+    uv sync --frozen --no-dev --extra api --no-editable \
     && /app/.venv/bin/python -m ensurepip --upgrade
 
 # Create persistent data directories

docs/DockerDeployment.md

@@ -59,10 +59,19 @@ LightRAG can be configured using environment variables in the `.env` file:
 
 Docker instructions work the same on all platforms with Docker Desktop installed.
 
+### Build Optimization
+
+The Dockerfile uses BuildKit cache mounts to significantly improve build performance:
+
+- **Automatic cache management**: BuildKit is automatically enabled via `# syntax=docker/dockerfile:1` directive
+- **Faster rebuilds**: Only downloads changed dependencies when `uv.lock` or `bun.lock` files are modified
+- **Efficient package caching**: UV and Bun package downloads are cached across builds
+- **No manual configuration needed**: Works out of the box in Docker Compose and GitHub Actions
+
 ### Start LightRAG  server:
 
 ```bash
-docker-compose up -d
+docker compose up -d
 ```
 
 LightRAG Server uses the following paths for data storage:
@@ -77,9 +86,9 @@ data/
 
 To update the Docker container:
 ```bash
-docker-compose pull
-docker-compose down
-docker-compose up
+docker compose pull
+docker compose down
+docker compose up
 ```
 
 ### Offline deployment
@@ -91,10 +100,15 @@ Software packages requiring `transformers`, `torch`, or `cuda` will is not prein
 ### For local development and testing
 
 ```bash
-# Build and run with docker-compose
+# Build and run with Docker Compose (BuildKit automatically enabled)
 docker compose up --build
+
+# Or explicitly enable BuildKit if needed
+DOCKER_BUILDKIT=1 docker compose up --build
 ```
 
+**Note**: BuildKit is automatically enabled by the `# syntax=docker/dockerfile:1` directive in the Dockerfile, ensuring optimal caching performance.
+
 ### For production release
 
  **multi-architecture build and push**: