当代理NodeJS服务器不工作时，Nginx重定向到静态html（离线）

Question

I have setup a NodeJS server on an Amazon Instance serving some king of web app. I am using Nginx server to handle and route requests internally to the Node server. Everything is working correctly with this setup I am using for Nginx:

server {
    listen 80;

    server_name mydomain.com;

    location / {
        proxy_pass http://localhost:8000;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        proxy_set_header Host $host;
        proxy_cache_bypass $http_upgrade;
    }
    location ~* \.(js|ico|css|jpg|jpeg|eot|svg|ttf|woff)$ {
        root /home/user/webapp/public;
    }
}

What I want to do now, is serve a static html file whenever the node.js server isn't responding. Like when I update the code and need to restart the node.js server or something similar.

How would this be possible with nginx configuration?

Thank you

Answer 1

after searching a little bit more careful, I found the answer...

When the node server is down and nginx tries to redirect traffic to it, a 502 BAD GATEWAY response is triggered. So we can handle this response in order to serve the alternative maintenance page with the command:

error_page 502 503 /maintenance.html;

We can call "maintenance.html" whatever we want. This is the URI that the client will be redirected when this error occurs. Below we handle the redire uri in an other location object.

So the changed configuration is:

server {
    listen 80;

    server_name mydomain.com;

    error_page 502 503 /maintenance.html;

    location / {
        proxy_pass http://localhost:8000;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        proxy_set_header Host $host;
        proxy_cache_bypass $http_upgrade;
    }
    location ~* \.(js|ico|css|jpg|jpeg|eot|svg|ttf|woff)$ {
        root /home/user/webapp/public;
    }
    location = /maintenance.html {
        root /PATH_TO_MAINTENANCE_HTML_FILE;
    }
}