nginx: how to try multiple roots successively

As part of developing this new version of this site, I've needed to mess with nginx a lot to switch from Ghost to Gatsby, especially when related to hosting files out of multiple directories.

Specifically, this site is deployed by rsyncing the production version of the site onto the server hosting it. I want to be able to use --delete to get rid of any old files for reliability reasons (don't want to rely on stuff that's not supposed to be there accidentally). Additionally, I like being able to host random files on the server, which I don't want to manage with Gatsby.

What this means is that I need the server to try in order:

• serve the file from the Gatsby directory
• attempt to serve it as a directory and return index.html
• serve it from the untracked static files
• 404

There are countless StackOverflow posts on this exact issue, but none were quite right for my use case.

One popular suggestion is to set the root to some directory above both content directories then use something like try_files dir1$uri dir1$uri/ dir2$uri =404;. This works... nearly.

It works properly for all direct paths, but the directory functionality is broken: it sends a 301 to the browser with dir1/subdir/, which, once followed, 404s since the nginx server will then try to serve dir1/dir1/subdir/index.html which it can't find. Further, this redirection behaviour seems not to be documented anywhere.

The solution here is to just do try_files dir1$uri dir1$uri/index.html dir2$uri =404; and bypass the nginx index directive entirely.