Re: Hosting pgAdmin4 behind nginx and at /pgdmin, for mortals

Dave,

Thanks for taking this forward, I look forward to 4.4! I also noted with interest that we can use "pgAdmin4:app" rather than my hacky link to the pgAdmin4.wsgi, so that means a completely hack-free solution :-).

Shaheed

On Mon, 4 Mar 2019 at 16:33, Dave Page <dpage@pgadmin.org> wrote:

Hi

On Fri, Mar 1, 2019 at 9:30 AM Shaheed Haque <srhaque@theiet.org> wrote:

OK, I got it working. This is how...

On Mon, 25 Feb 2019 at 23:25, Shaheed Haque <srhaque@theiet.org> wrote:
>
> Hi,
>
> I'm a relative noob when it comes to the world of nginx, wsgi and so forth, but I do have several other things working (a Django app under gunicorn and the RabbitMQ web UI directly behind nginx). However, I'm rather stuck getting pgAdmin4 to run at http://mydomain.com:80/pgadmin behind nginx. Is there a simple, up-to-date example of how to do this (I'm running the latest, v4.2, of pgAdmin4)?
>
> I'm aware of threads such as https://www.postgresql.org/message-id/2197768425D7F5479A0FFB3FEC212F7FF602B871%40aesmail.surcouf.local, and several others but not been able to come up with a clear approach:
>
> One of the several variables I'm struggling to understand is the choice of whether to run pgAdmin4.py on port 5050 directly behind nginx, or as a WSGI app under gunicorn. I assume the latter should be easier to set up, but I've tried both (modelled on what I have working, and various references). One combination I tried was:
>
> - Creating a softlink from pgadmin4.py to pgAdmin4.wsgi
> - Using gunicorn to run the pgadmin4.py to a unix domain socket like this:
>
>     $ /usr/local/bin/gunicorn -w 1 --bind unix:/home/ubuntu/pgadmin.sock pgadmin4:application
>
> - Serving behind nginx like this:
>
>     location /pgadmin {
>         rewrite ^/pgadmin/(.*) /$1 break;
>         include proxy_params;
>         proxy_pass http://unix:/home/ubuntu/pgadmin.sock;
>     }
>
> But all I get is a stubborn 404. Any pointers welcome...

First, I got over the 404s (caused, it seems, by me forgetting just how much my browser had cached :-0). The next problem was with the nginx config fragment: as soon as pgAdmin responded, it of course started the browser looking for top level URLs such as /browser and /static which are obviously not under /pgadmin. The to this key was a piece of code in https://stackoverflow.com/a/50515636/6332554, which basically adds the concept of a SCRIPT_NAME by hacking a small wodge of code into pgAdmin4.py.

The SCRIPT_NAME is set by an nginx fragment like this:

    location /pgadmin {
        rewrite ^/pgadmin/(.*)$ /\$1 break;
        include proxy_params;
        proxy_pass http://unix:/home/$CLOUD_USER/pgadmin.sock;
        proxy_set_header X-Script-Name /pgadmin;
    }

In addition to that change, as previously noted, I needed to create a link to pgAdmin4.wsgi to allow gunicorn to pick it up. I change the name I used so I ended up with the link being "wsgi.py" -> "pgAdmin4.py", so the the corresponding gunicorn command is something like this:

    gunicorn ... --bind unix:/.../pgadmin.sock wsgi:application

Now, IIUC, the notion of SCRIPT_NAME is somewhat standard, and needed to solve this issue of running pgAdmin in server mode, but sharing the domain with other applications. Would there be interest in making the needed code an integral part of pgAdmin? If so, I'd be happy to file a feature request.

Thanks, Shaheed

Thanks for your work on this.

I've committed a change to add the reverse proxy code, and to put some more examples in the docs: https://redmine.postgresql.org/projects/pgadmin4/repository/revisions/f401def044c8b47974d58c71ff9e6f71f34ef41d

FWIW, I think the reason that this was an issue for so long is that you don't need the extra code if you use mod_wsgi or uWSGI - it's only needed with Gunicorn. I'll let you guess which of those technologies I'm most familiar with!

Unfortunately this commit won't make the 4.3 release later this week, but it will be in 4.4. The instructions will still be good for scenarios other than Gunicorn in a sub-directory though.

--

Dave Page
Blog: http://pgsnake.blogspot.com
Twitter: @pgsnake

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