Fix Odoo Gevent Worker Crash: Longpolling, WebSocket, and Chat Issues

The Gevent Worker Problem

Odoo uses a separate gevent-based worker for longpolling and WebSocket connections. This worker handles real-time features: live chat, Discuss messaging, push notifications, and presence detection. When it crashes or is misconfigured, these features silently stop working.

Symptoms of Gevent Worker Issues

• Live chat widget does not appear or shows "offline"
• Discuss messages do not appear in real-time (requires page refresh)
• Notifications do not pop up
• Browser console shows WebSocket connection errors
• "Bus" errors in Odoo logs
• High CPU usage from reconnection loops

What the Errors Look Like

# In Odoo logs:
ERROR odoo.service.server: gevent worker pid XXXX exited with status 1
WARNING odoo.service.server: Gevent mode requires the gevent library

# In browser console:
WebSocket connection to 'wss://your-domain.com/websocket' failed
poll error: timeout
bus service: connection lost, reconnecting...

# In nginx error log:
upstream timed out (110: Connection timed out) while reading response header
  from upstream, client: x.x.x.x, upstream: "http://127.0.0.1:8072/websocket"

How Gevent Workers Work in Odoo

When workers > 0 in odoo.conf, Odoo spawns:

• HTTP workers (multi-processing) on port 8069 — handle regular web requests
• Gevent worker (single, async) on port 8072 — handles longpolling/WebSocket

If workers = 0 (threaded mode), everything runs in one process and gevent is not used. This works for development but not production.

Cause 1: Gevent Not Installed

# Check if gevent is installed
python3 -c "import gevent; print(gevent.__version__)"

# If not installed:
pip3 install gevent

# For Odoo's requirements:
pip3 install gevent gevent-websocket

Cause 2: Workers Set to 0

With workers = 0, Odoo runs in threaded mode. The gevent worker is not spawned, and longpolling uses a fallback that does not scale.

# In odoo.conf — enable multi-processing:
workers = 4

# Gevent worker is spawned automatically when workers > 0
# It listens on the longpolling port (default 8072)
gevent_port = 8072

Cause 3: Nginx Not Proxying WebSocket

The most common production issue. Nginx must proxy /websocket and /longpolling to port 8072.

# In nginx server block:

# Odoo 16+ uses WebSocket
location /websocket {
    proxy_pass http://127.0.0.1:8072;
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection $connection_upgrade;
    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-Forwarded-Proto $scheme;
    proxy_read_timeout 86400;  # 24 hours for long-lived connections
}

# Odoo 15 and earlier use longpolling
location /longpolling {
    proxy_pass http://127.0.0.1:8072;
    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_read_timeout 86400;
}

# Required at the http level:
map $http_upgrade $connection_upgrade {
    default upgrade;
    '' close;
}

Cause 4: Memory Limit Kills Gevent Worker

The gevent worker is subject to the same memory limits as HTTP workers. With many concurrent connections, it can exceed limits and get killed.

# In odoo.conf — increase limits for gevent:
limit_memory_hard = 2684354560   # 2.5 GB
limit_memory_soft = 2147483648   # 2 GB

# The gevent worker handles many connections in one process
# It needs more memory than a regular worker

Cause 5: Port 8072 Conflict

# Check if something else is using port 8072
ss -tlnp | grep 8072

# If another process is using it, change Odoo's gevent port:
# In odoo.conf:
gevent_port = 8073

# Then update nginx to proxy to the new port

Cause 6: Gevent Version Incompatibility

Certain gevent versions have bugs that cause crashes with specific Python versions.

# Check versions
python3 --version
python3 -c "import gevent; print(gevent.__version__)"

# Known good combinations:
# Python 3.10 + gevent 22.10+
# Python 3.11 + gevent 23.7+
# Python 3.12 + gevent 24.2+

# Upgrade gevent:
pip3 install --upgrade gevent

Diagnosing Gevent Issues

# 1. Check if gevent worker is running
ps aux | grep gevent
# Should show a process with 'gevent' in the command

# 2. Check if port 8072 is listening
ss -tlnp | grep 8072

# 3. Test longpolling directly
curl -v http://127.0.0.1:8072/websocket
# Should get a 426 Upgrade Required (means it is working)

# 4. Check Odoo logs for gevent errors
grep -i gevent /var/log/odoo/odoo-server.log | tail -20

# 5. Check nginx error log
tail -20 /var/log/nginx/error.log | grep -i 'upstream\|websocket'

Quick Fix Checklist

1. Ensure workers > 0 in odoo.conf
2. Ensure gevent is installed: pip3 install gevent
3. Ensure nginx proxies /websocket to port 8072 with WebSocket headers
4. Set proxy_read_timeout 86400 in nginx for long-lived connections
5. Increase memory limits if the gevent worker keeps dying
6. Restart both Odoo and nginx after changes