The Root Cause

On Google Cloud Run, an Nginx timeout error typically occurs when the containerized application takes longer to process a request than Nginx’s configured proxy_read_timeout or proxy_send_timeout directives allow. This often signifies the application is either slow to respond or experiencing a bottleneck, failing to return data to Nginx within its expected timeframe.

Quick Fix (CLI)

While Nginx’s internal configuration is part of your container image and requires a redeployment to change, you can immediately adjust Google Cloud Run’s overall request timeout. This serves as an outer boundary and can prevent Cloud Run from terminating requests before Nginx (or your application) completes, especially if Nginx’s internal timeouts are also being addressed.

gcloud run services update SERVICE_NAME \
  --timeout=600s \
  --region=YOUR_CLOUD_RUN_REGION

Replace SERVICE_NAME with your Cloud Run service name, and YOUR_CLOUD_RUN_REGION with your service’s region (e.g., us-central1). 600s (10 minutes) is an example; adjust as needed, up to 3600s, ensuring it’s greater than your intended Nginx timeouts.

Configuration Check

To fix Nginx’s internal timeout, you need to modify your Nginx configuration file within your Docker image.

File to edit: nginx.conf or a file included by it (e.g., conf.d/default.conf). This file is typically copied into your Docker image.

Lines to change: Add or adjust the proxy_connect_timeout, proxy_send_timeout, and proxy_read_timeout directives within your http, server, or location block, depending on the scope required.

# Example: within the http block to apply globally
http {
    # ... other directives ...
    proxy_connect_timeout 90s; # Time to establish a connection with the upstream server
    proxy_send_timeout 90s;    # Time for a send operation to the upstream server
    proxy_read_timeout 90s;    # Time for a read operation from the upstream server
    # ...
}

# OR, if specific to a server or location block:
server {
    listen 8080; # Cloud Run containers must listen on port 8080
    # ...
    location / {
        proxy_pass http://localhost:YOUR_APP_PORT; # e.g., http://localhost:3000 for your backend app
        proxy_connect_timeout 90s;
        proxy_send_timeout 90s;
        proxy_read_timeout 90s;
        # ...
    }
}

Increase 90s (90 seconds) to a value appropriate for your application’s expected processing time, ensuring it’s less than or equal to your Cloud Run service timeout.

Dockerfile Integration: Ensure your Dockerfile copies the updated Nginx configuration into your container image.

# Example Dockerfile snippet
# ...
COPY ./nginx.conf /etc/nginx/nginx.conf
# OR, if using conf.d:
# COPY ./default.conf /etc/nginx/conf.d/default.conf
# ...

Verification

After making configuration changes, you must rebuild your Docker image and deploy it to Cloud Run.

1. Rebuild and Deploy:

   gcloud builds submit --tag gcr.io/PROJECT_ID/IMAGE_NAME .
   gcloud run deploy SERVICE_NAME \
     --image gcr.io/PROJECT_ID/IMAGE_NAME \
     --region=YOUR_CLOUD_RUN_REGION

   Replace PROJECT_ID with your Google Cloud project ID, IMAGE_NAME with your desired image name (e.g., my-nginx-app), SERVICE_NAME with your Cloud Run service name, and YOUR_CLOUD_RUN_REGION.

2. Test the endpoint: Access the specific endpoint that was previously experiencing timeouts.

   SERVICE_URL=$(gcloud run services describe SERVICE_NAME --region=YOUR_CLOUD_RUN_REGION --format='value(status.url)')
   curl -v "${SERVICE_URL}/your-slow-endpoint"

   Replace your-slow-endpoint with the actual path that was timing out. Verify that you receive a successful HTTP response (e.g., 200 OK) without any timeout errors.