Hi, I've noticed that narinfo baking is triggered by user requests when the '--cache' option of 'guix publish' is used. It means that the first user who will want it will get the 404 response and will have to build it manually. (See guix/scripts/publish.scm, make-request-handler.)
I was reluctant to send this email to [email protected] because it's fairly well documented, but I don't like this behaviour... As a matter of fact I'm often the first user downloading substitutes on my 'guix publish' server. Would it be possible to trigger the baking right after the build is done? So that every user can be sure that they will get the substitute once they know that Cuirass has built it. If 'guix publish' has no way to get the notification that a build is done, maybe Cuirass could trigger the baking? (But that would be hackish in my opinion.) Cheers, Clément --8<---------------cut here---------------start------------->8--- ‘--cache=DIRECTORY’ ‘-c DIRECTORY’ Cache archives and meta-data (‘.narinfo’ URLs) to DIRECTORY and only serve archives that are in cache. When this option is omitted, archives and meta-data are created on-the-fly. This can reduce the available bandwidth, especially when compression is enabled, since this may become CPU-bound. Another drawback of the default mode is that the length of archives is not known in advance, so ‘guix publish’ does not add a ‘Content-Length’ HTTP header to its responses, which in turn prevents clients from knowing the amount of data being downloaded. Conversely, when ‘--cache’ is used, the first request for a store item (via a ‘.narinfo’ URL) returns 404 and triggers a background process to “bake” the archive—computing its ‘.narinfo’ and compressing the archive, if needed. Once the archive is cached in DIRECTORY, subsequent requests succeed and are served directly from the cache, which guarantees that clients get the best possible bandwidth. The “baking” process is performed by worker threads. By default, one thread per CPU core is created, but this can be customized. See ‘--workers’ below. When ‘--ttl’ is used, cached entries are automatically deleted when they have expired. --8<---------------cut here---------------end--------------->8---
