feat(mcp-image-gen): add ComfyUI auto-start health check + systemd service

Option A: Add lifespan context manager to server.py
- _ping_comfyui(): async health check against /system_stats
- check_and_start_comfyui(): ping on startup; if down, launches ComfyUI
  via subprocess.Popen from COMFYUI_DIR (.venv/bin/python main.py)
  with HSA_OVERRIDE_GFX_VERSION=11.0.0 injected for AMD ROCm
- Polls up to 30s for readiness after auto-start
- New env var: COMFYUI_DIR (default ~/ComfyUI)
- FastMCP lifespan= wired in; 34/34 tests still passing

Option B: Add comfyui.service systemd user service file
- Install: cp mcp/mcp-image-gen/comfyui.service ~/.config/systemd/user/
- Enable: systemctl --user enable --now comfyui
- Sets HSA_OVERRIDE_GFX_VERSION=11.0.0, WorkingDirectory=%h/ComfyUI
- Restart=on-failure, logs via journald

docs: Update mcp-image-gen-ComfyUI-Setup.md
- New Step 4: systemd service install + linger instructions
- Step 5: manual start (moved from old Step 4)
- Step 6/7 renumbered; COMFYUI_DIR env var documented
- Architecture diagram added; troubleshooting rows updated
This commit is contained in:
Patrick Plate
2026-04-06 10:43:36 +02:00
parent 0ff3f20589
commit c662a5237b
3 changed files with 222 additions and 43 deletions
+81 -10
View File
@@ -62,7 +62,52 @@ huggingface-cli download comfyanonymous/flux_text_encoders \
--local-dir ~/ComfyUI/models/clip
```
## Step 4: Start ComfyUI
## Step 4: Install the systemd User Service (Recommended)
Installing ComfyUI as a systemd user service ensures it starts automatically on login and restarts on failure.
```bash
# Copy the bundled service file to the systemd user directory
mkdir -p ~/.config/systemd/user
cp ~/pi_mcps/mcp/mcp-image-gen/comfyui.service ~/.config/systemd/user/comfyui.service
# Reload systemd, enable + start the service
systemctl --user daemon-reload
systemctl --user enable --now comfyui
# Verify it is running
systemctl --user status comfyui
```
> ⚠️ `HSA_OVERRIDE_GFX_VERSION=11.0.0` is already set in the service file — it is mandatory for RX 7900 XTX on ROCm. Without it, model loading fails silently.
### Enable lingering (start ComfyUI even without a login session)
```bash
loginctl enable-linger $USER
```
This ensures the service starts at boot even before you log in — recommended for headless / homelab setups.
### Managing the service
```bash
# Follow live logs
journalctl --user -u comfyui -f
# Restart after model changes
systemctl --user restart comfyui
# Stop temporarily
systemctl --user stop comfyui
# Disable autostart
systemctl --user disable comfyui
```
## Step 5: Manual Start (without systemd)
If you prefer to start ComfyUI manually (e.g. for debugging):
```bash
cd ~/ComfyUI
@@ -74,26 +119,36 @@ HSA_OVERRIDE_GFX_VERSION=11.0.0 \
echo "ComfyUI PID: $!"
```
> ⚠️ `HSA_OVERRIDE_GFX_VERSION=11.0.0` is mandatory for RX 7900 XTX on ROCm. Without it, model loading fails silently.
## Step 5: Verify ComfyUI is Running
## Step 6: Verify ComfyUI is Running
```bash
curl http://localhost:8188/system_stats
# Should return JSON with GPU info
```
## Step 6: Configure mcp-image-gen
## Step 7: Configure mcp-image-gen
```bash
cd /home/pplate/pi_mcps/mcp/mcp-image-gen
# Environment variables (set in .roo/mcp.json or shell):
# COMFYUI_URL=http://localhost:8188
# IMAGE_OUTPUT_DIR=~/Pictures/mcp-generated
# COMFYUI_TIMEOUT=120
# COMFYUI_URL=http://localhost:8188 — ComfyUI API endpoint
# IMAGE_OUTPUT_DIR=~/Pictures/mcp-generated — where generated images are saved
# COMFYUI_TIMEOUT=120 — max wait time (seconds) per image
# COMFYUI_DIR=~/ComfyUI — path to ComfyUI install (used by auto-start)
```
### Auto-start behaviour
`mcp-image-gen` includes a **startup health check** in its lifespan. Every time the MCP server starts it:
1. Pings `http://localhost:8188/system_stats`
2. **If reachable** — logs `ComfyUI is already running ✓` and proceeds normally.
3. **If not reachable** — attempts to launch ComfyUI as a background subprocess from `COMFYUI_DIR` using `.venv/bin/python main.py --listen --port 8188` with `HSA_OVERRIDE_GFX_VERSION=11.0.0` injected automatically.
4. Polls up to 30 s for ComfyUI to become ready.
With the systemd service enabled, step 3 is never needed in practice — but the check acts as a safety net.
## Performance
| GPU | Model | Resolution | Steps | Time |
@@ -101,12 +156,28 @@ cd /home/pplate/pi_mcps/mcp/mcp-image-gen
| AMD RX 7900 XTX | FLUX.1-schnell | 1024×1024 | 4 | ~8s |
| AMD RX 7900 XTX | FLUX.1-schnell | 1280×512 | 4 | ~7s |
## Architecture Overview
```
Boot
└─ systemd --user (comfyui.service)
└─ ComfyUI at localhost:8188
VS Code / Roo Code
└─ mcp-image-gen MCP server (stdio)
├─ lifespan startup: ping localhost:8188
│ └─ if down: subprocess.Popen ComfyUI, wait ≤30s
└─ tools: generate_image, list_available_models, …
```
## Troubleshooting
| Problem | Solution |
|---|---|
| `HTTP 401` downloading model | Accept FLUX license on HuggingFace first |
| GPU not detected | Ensure `HSA_OVERRIDE_GFX_VERSION=11.0.0` is set |
| `Connection refused` from mcp-image-gen | Start ComfyUI first, check port 8188 |
| Slow generation (>60s) | ComfyUI may be running on CPU — check ROCm install |
| `Connection refused` from mcp-image-gen | Check `systemctl --user status comfyui`; or set `COMFYUI_DIR` so auto-start can locate the install |
| Slow generation (>60s) | ComfyUI may be running on CPU — check ROCm install and `HSA_OVERRIDE_GFX_VERSION` |
| Ollama image gen | As of April 2026: macOS-only, not available on Linux |
| Auto-start logs | `journalctl --user -u comfyui -f` or check mcp-image-gen server logs |
| Service not starting at boot | Run `loginctl enable-linger $USER` to enable session-less startup |