build: add dependency caching for bundle builds

Cache pip/npm dependency downloads via BuildKit cache mounts and skip
the postgres pull when the image is already present locally, so a
repeat ./build.sh bundle run does not download dependencies twice.

build.sh

@@ -41,6 +41,8 @@ set -euo pipefail
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 cd "$SCRIPT_DIR"
 
+export DOCKER_BUILDKIT=1
+
 BACKEND_ENV_FILE="$SCRIPT_DIR/backend/.env"
 DIST_ROOT="$SCRIPT_DIR/dist/docker"
 
@@ -158,6 +160,17 @@ get_repo_digest() {
   fi
 }
 
+# Pull an image only if it is not already present locally.
+ensure_image_present() {
+  local source="$1"
+  if docker image inspect "$source" >/dev/null 2>&1; then
+    echo "[bundle] Image ${source} already present, skipping pull"
+    return 0
+  fi
+  docker pull "$source"
+}
+
+
 resolve_app_version() {
   local tag="$1"
   local git_commit
@@ -719,8 +732,8 @@ bundle_release() {
   build_agent "${tag}"
 
   # Pull and tag postgres image
-  echo "[bundle] Pulling postgres image ${postgres_source}..."
+  echo "[bundle] Ensuring postgres image ${postgres_source}..."
-  docker pull "${postgres_source}"
+  ensure_image_present "${postgres_source}"
   docker tag "${postgres_source}" "${postgres_tag}"
 
   # Release gate: fresh PostgreSQL migration + backend boot + restart must pass.
@@ -905,8 +918,8 @@ bundle_embeddings() {
   build_agent_embeddings "${tag}${suffix}"
 
   # Pull and tag postgres image
-  echo "[bundle:embeddings] Pulling postgres image ${postgres_source}..."
+  echo "[bundle:embeddings] Ensuring postgres image ${postgres_source}..."
-  docker pull "${postgres_source}"
+  ensure_image_present "${postgres_source}"
   docker tag "${postgres_source}" "${postgres_tag}"
 
   # Release gate: fresh PostgreSQL migration + backend boot + restart must pass.
@@ -1023,6 +1036,9 @@ Notes:
   - Bundle commands (bundle, bundle:embeddings) now include postgres:16-alpine
     as superset-tools-postgres:<tag> — loaded together with other images
     via 'xz -dc ... | docker load'. No external PostgreSQL required.
+  - pip/npm dependency downloads are cached via BuildKit cache mounts and the
+    postgres pull is skipped when the image is already present locally.
+    Clear the dependency cache with: docker buildx prune
 HELP
 }
 

docker/Dockerfile.agent

@@ -26,12 +26,14 @@ RUN pip install --no-cache-dir -e /app/shared/
 
 # Install agent requirements
 COPY agent/requirements.txt /app/agent/requirements.txt
-RUN pip install --no-cache-dir -r /app/agent/requirements.txt
+RUN --mount=type=cache,target=/root/.cache/pip \
+    pip install -r /app/agent/requirements.txt
 
 # Optional: semantic embedding routing
 COPY agent/requirements-embeddings.txt /app/agent/requirements-embeddings.txt
-RUN if [ "$WITH_EMBEDDINGS" = "true" ]; then \
+RUN --mount=type=cache,target=/root/.cache/pip \
-        pip install --no-cache-dir -r /app/agent/requirements-embeddings.txt; \
+    if [ "$WITH_EMBEDDINGS" = "true" ]; then \
+        pip install -r /app/agent/requirements-embeddings.txt; \
     fi
 
 # Agent source code

docker/all-in-one.Dockerfile

@@ -18,7 +18,8 @@ WORKDIR /app/frontend
 
 # Install deps (layer cache when package.json unchanged)
 COPY frontend/package.json frontend/package-lock.json* ./
-RUN npm ci --prefer-offline --no-audit --no-fund --legacy-peer-deps
+RUN --mount=type=cache,target=/root/.npm \
+    npm ci --prefer-offline --no-audit --no-fund --legacy-peer-deps
 
 # Build frontend
 COPY frontend/ ./
@@ -43,7 +44,8 @@ RUN apt-get update \
 
 # Python deps (NO playwright — saves ~350MB)
 COPY backend/requirements-backend.txt /app/backend/requirements-backend.txt
-RUN pip install --no-cache-dir -r /app/backend/requirements-backend.txt
+RUN --mount=type=cache,target=/root/.cache/pip \
+    pip install -r /app/backend/requirements-backend.txt
 
 # Backend source
 COPY backend/ /app/backend/

docker/backend.Dockerfile

@@ -25,14 +25,16 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 
 # Python зависимости — backend runtime
 COPY backend/requirements-backend.txt /app/backend/requirements-backend.txt
-RUN pip install --no-cache-dir -r /app/backend/requirements-backend.txt
+RUN --mount=type=cache,target=/root/.cache/pip \
+    pip install -r /app/backend/requirements-backend.txt
 
 # Install shared package (LLM health, SSL, cot_logger)
 COPY shared/ /app/shared/
 RUN pip install --no-cache-dir -e /app/shared/
 
 # Install shared LLM deps (openai, httpx for _llm_health)
-RUN pip install --no-cache-dir "openai>=1.0.0" "httpx>=0.28.1"
+RUN --mount=type=cache,target=/root/.cache/pip \
+    pip install "openai>=1.0.0" "httpx>=0.28.1"
 
 # Browser binaries are required only by screenshot-capable deployments. API-only E2E
 # stacks can opt out through INSTALL_PLAYWRIGHT_BROWSERS=0 to reduce image build pressure.

docker/frontend.Dockerfile

@@ -15,7 +15,8 @@ ENV APP_VERSION=${APP_VERSION}
 WORKDIR /app/frontend
 
 COPY frontend/package*.json ./
-RUN npm ci --legacy-peer-deps
+RUN --mount=type=cache,target=/root/.npm \
+    npm ci --legacy-peer-deps
 
 COPY frontend/ ./
 RUN npm run build