Refactor DeerFlow to use Gateway's LangGraph-compatible API

- Updated documentation and comments to reflect the transition from LangGraph Server to Gateway.
- Changed default URLs in ChannelManager and tests to point to Gateway.
- Removed references to LangGraph Server in deployment scripts and configurations.
- Updated Nginx configuration to route API traffic to Gateway.
- Adjusted frontend configurations to utilize Gateway's API.
- Removed LangGraph service from Docker Compose files, consolidating services under Gateway.
- Added regression tests to ensure Gateway integration works as expected.

Co-authored-by: Copilot <copilot@github.com>

docker/docker-compose-dev.yaml

@@ -4,8 +4,7 @@
 # Services:
 #   - nginx: Reverse proxy (port 2026)
 #   - frontend: Frontend Next.js dev server (port 3000)
-#   - gateway: Backend Gateway API (port 8001)
-#   - langgraph: LangGraph server (port 2024)
+#   - gateway: Backend Gateway API + agent runtime (port 8001)
 #   - provisioner (optional): Sandbox provisioner (creates Pods in host Kubernetes)
 #
 # Prerequisites:
@@ -61,9 +60,7 @@ services:
       start_period: 15s
 
   # ── Reverse Proxy ──────────────────────────────────────────────────────
-  # Routes API traffic to gateway/langgraph and (optionally) provisioner.
-  # LANGGRAPH_UPSTREAM and LANGGRAPH_REWRITE control gateway vs standard
-  # routing (processed by envsubst at container start).
+  # Routes API traffic to gateway and (optionally) provisioner.
   nginx:
     image: nginx:alpine
     container_name: deer-flow-nginx
@@ -71,16 +68,12 @@ services:
       - "2026:2026"
     volumes:
       - ./nginx/nginx.conf:/etc/nginx/nginx.conf.template:ro
-    environment:
-      - LANGGRAPH_UPSTREAM=${LANGGRAPH_UPSTREAM:-langgraph:2024}
-      - LANGGRAPH_REWRITE=${LANGGRAPH_REWRITE:-/}
     command:
       - sh
       - -c
       - |
         set -e
-        envsubst '$$LANGGRAPH_UPSTREAM $$LANGGRAPH_REWRITE' \
-          < /etc/nginx/nginx.conf.template > /etc/nginx/nginx.conf
+        cp /etc/nginx/nginx.conf.template /etc/nginx/nginx.conf
         test -e /proc/net/if_inet6 || sed -i '/^[[:space:]]*listen[[:space:]]\+\[::\]:2026;/d' /etc/nginx/nginx.conf
         exec nginx -g 'daemon off;'
     depends_on:
@@ -114,7 +107,6 @@ services:
       - WATCHPACK_POLLING=true
       - CI=true
       - DEER_FLOW_INTERNAL_GATEWAY_BASE_URL=http://gateway:8001
-      - DEER_FLOW_INTERNAL_LANGGRAPH_BASE_URL=http://langgraph:2024
     env_file:
       - ../frontend/.env
     networks:
@@ -147,7 +139,7 @@ services:
       # On macOS/Docker Desktop, uv may fail to create symlinks inside shared
       # host directories, which causes startup-time `uv sync` to crash.
       - gateway-uv-cache:/root/.cache/uv
-      # DooD: same as gateway — AioSandboxProvider runs inside LangGraph process.
+      # DooD: AioSandboxProvider runs inside the Gateway process.
       - /var/run/docker.sock:/var/run/docker.sock
       # CLI auth directories for auto-auth (Claude Code + Codex CLI)
       - type: bind
@@ -166,7 +158,7 @@ services:
     environment:
       - CI=true
       - DEER_FLOW_HOME=/app/backend/.deer-flow
-      - DEER_FLOW_CHANNELS_LANGGRAPH_URL=${DEER_FLOW_CHANNELS_LANGGRAPH_URL:-http://langgraph:2024}
+      - DEER_FLOW_CHANNELS_LANGGRAPH_URL=${DEER_FLOW_CHANNELS_LANGGRAPH_URL:-http://gateway:8001/api}
       - DEER_FLOW_CHANNELS_GATEWAY_URL=${DEER_FLOW_CHANNELS_GATEWAY_URL:-http://gateway:8001}
       - DEER_FLOW_HOST_BASE_DIR=${DEER_FLOW_ROOT}/backend/.deer-flow
       - DEER_FLOW_HOST_SKILLS_PATH=${DEER_FLOW_ROOT}/skills
@@ -180,70 +172,11 @@ services:
       - deer-flow-dev
     restart: unless-stopped
 
-  # Backend - LangGraph Server
-  langgraph:
-    build:
-      context: ../
-      dockerfile: backend/Dockerfile
-      target: dev
-      # cache_from disabled - requires manual setup: mkdir -p /tmp/docker-cache-langgraph
-      args:
-        APT_MIRROR: ${APT_MIRROR:-}
-        UV_IMAGE: ${UV_IMAGE:-ghcr.io/astral-sh/uv:0.7.20}
-        UV_INDEX_URL: ${UV_INDEX_URL:-https://pypi.org/simple}
-    container_name: deer-flow-langgraph
-    command: sh -c "cd backend && { (uv sync || (echo '[startup] uv sync failed; recreating .venv and retrying once' && uv venv --allow-existing .venv && uv sync)) && allow_blocking='' && if [ \"\${LANGGRAPH_ALLOW_BLOCKING:-0}\" = '1' ]; then allow_blocking='--allow-blocking'; fi && uv run langgraph dev --no-browser \${allow_blocking} --host 0.0.0.0 --port 2024 --n-jobs-per-worker \${LANGGRAPH_JOBS_PER_WORKER:-10}; } > /app/logs/langgraph.log 2>&1"
-    volumes:
-      - ../backend/:/app/backend/
-      # Preserve the .venv built during Docker image build — mounting the full backend/
-      # directory above would otherwise shadow it with the (empty) host directory.
-      - langgraph-venv:/app/backend/.venv
-      - ../config.yaml:/app/config.yaml
-      - ../extensions_config.json:/app/extensions_config.json
-      - ../skills:/app/skills
-      - ../logs:/app/logs
-      # Use a Docker-managed uv cache volume instead of a host bind mount.
-      # On macOS/Docker Desktop, uv may fail to create symlinks inside shared
-      # host directories, which causes startup-time `uv sync` to crash.
-      - langgraph-uv-cache:/root/.cache/uv
-      # DooD: same as gateway — AioSandboxProvider runs inside LangGraph process.
-      - /var/run/docker.sock:/var/run/docker.sock
-      # CLI auth directories for auto-auth (Claude Code + Codex CLI)
-      - type: bind
-        source: ${HOME:?HOME must be set}/.claude
-        target: /root/.claude
-        read_only: true
-        bind:
-          create_host_path: true
-      - type: bind
-        source: ${HOME:?HOME must be set}/.codex
-        target: /root/.codex
-        read_only: true
-        bind:
-          create_host_path: true
-    working_dir: /app
-    environment:
-      - CI=true
-      - DEER_FLOW_HOME=/app/backend/.deer-flow
-      - DEER_FLOW_HOST_BASE_DIR=${DEER_FLOW_ROOT}/backend/.deer-flow
-      - DEER_FLOW_HOST_SKILLS_PATH=${DEER_FLOW_ROOT}/skills
-      - DEER_FLOW_SANDBOX_HOST=host.docker.internal
-    env_file:
-      - ../.env
-    extra_hosts:
-      # For Linux: map host.docker.internal to host gateway
-      - "host.docker.internal:host-gateway"
-    networks:
-      - deer-flow-dev
-    restart: unless-stopped
-
 volumes:
   # Persist .venv across container restarts so dependencies installed during
   # image build are not shadowed by the host backend/ directory mount.
   gateway-venv:
-  langgraph-venv:
   gateway-uv-cache:
-  langgraph-uv-cache:
 
 networks:
   deer-flow-dev: