In particular, if there are recordings in progress when the process
dies, they may still be around when check runs. They are easily
identifiable by having an id > cum_recordings and get automatically
deleted on startup, so there's no reason to complain about them.
Inspired by the poor error message here:
https://github.com/scottlamb/moonfire-nvr/issues/107#issuecomment-777587727
* print the friendlier Display version of the error rather than Debug.
Eg, "EROFS: Read-only filesystem" rather than "Sys(EROFS)". Do this
everywhere: on command exit, on syncer retries, and on stream
retries.
* print the most immediate problem and additional lines for each
cause.
* print the backtrace or an advertisement for RUST_BACKTRACE=1 if it's
unavailable.
* also mention RUST_BACKTRACE=1 in the troubleshooting guide.
* add context in various places, including pathnames. There are surely
many places more it'd be helpful, but this is a start.
* allow subcommands to return failure without an Error.
In particular, "moonfire-nvr check" does its own error printing
because it wants to print all the errors it finds. Printing "see
earlier errors" with a meaningless stack trace seems like it'd just
confuse. But I also want to get rid of the misleading "Success" at
the end and 0 return to the OS.
* give a rule of thumb for update time in the documentation
* log the SQLite3 version, which can affect performance
* do the vacuum in non-WAL mode, to correctly set the page size and to
avoid very slow behavior on older SQLite3 versions. Larger page sizes
are generally faster (including subsequent vacuum operations).
This won't help much for the first vacuum after this change, but it
will help afterward.
* likewise, set the page size properly on "moonfire-nvr init".
Besides being more clear about what belongs to which, this helps with
docker caching. The server and ui parts are only rebuilt when their
respective subdirectories change.
Extend this a bit further by making the webpack build not depend on
the target architecture. And adding cache dirs so parts of the server
and ui build process can be reused when layer-wide caching fails.
Scott Lamb