(I also considered the names "capabilities" and "scopes", but I think
"permissions" is the most widely understood.)
This is increasingly necessary as the web API becomes more capable.
Among other things, it allows:
* non-administrator users who can view but not access camera passwords
or change any state
* workers that update signal state based on cameras' built-in motion
detection or a security system's events but don't need to view videos
* control over what can be done without authenticating
Currently session permissions are just copied from user permissions, but
you can also imagine admin sessions vs not, as a checkbox when signing
in. This would match the standard Unix workflow of using a
non-administrative session most of the time.
Relevant to my current signals work (#28) and to the addition of an
administrative API (#35, including #66).
This is mostly untested and useless by itself, but it's a starting
point. In particular:
* there's no way to set up signals or add/remove/update events yet
except by manual changes to the database.
* if you associate a signal with a camera then remove the camera,
hitting /api/ will error out.
This is mostly just "cargo fix --edition" + Cargo.toml changes.
There's one fix for upgrading to NLL in db/writer.rs:
Writer::previously_opened wouldn't build with NLL because of a
double-borrow the previous borrow checker somehow didn't catch.
Restructure to avoid it.
I'll put elective NLL changes in a following commit.
Some caveats:
* it doesn't record the peer IP yet, which makes it harder to verify
sessions are valid. This is a little annoying to do in hyper now
(see hyperium/hyper#1410). The direct peer might not be what we want
right now anyway because there's no TLS support yet (see #27). In
the meantime, the sane way to expose Moonfire NVR to the Internet is
via a proxy server, and recording the proxy's IP is not useful.
Maybe better to interpret a RFC 7239 Forwarded header (and/or
the older X-Forwarded-{For,Proto} headers).
* it doesn't ever use Secure (https-only) cookies, for a similar reason.
It's not safe to use even with a tls proxy until this is fixed.
* there's no "moonfire-nvr config" support for inspecting/invalidating
sessions yet.
* in debug builds, logging in is crazy slow. See libpasta/libpasta#9.
Some notes:
* I removed the Javascript "no-use-before-defined" lint, as some of
the functions form a cycle.
* Fixed#20 along the way. I needed to add support for properly
returning non-OK HTTP statuses to signal unauthorized and such.
* I removed the Access-Control-Allow-Origin header support, which was
at odds with the "SameSite=lax" in the cookie header. The "yarn
start" method for running a local proxy server accomplishes the same
thing as the Access-Control-Allow-Origin support in a more secure
manner.
* separate these out into a new file, writer.rs, as dir.rs was getting
unwieldy.
* extract traits for the parts of SampleFileDir and std::fs::File they needed;
set up mock implementations.
* move clock.rs to a new base crate to be accessible from the db crate.
* add tests that exercise all the retry paths.
* bugfix: account for the new recording's bytes when calculating how much to
delete.
* bugfix: when retrying an unlink failure in collect_garbage, we shouldn't
warn about all the recordings no longer existing. Do this by retrying each
step rather than the whole procedure again.
* avoid double-panic scenarios, which I hit while tweaking the mocks. These
are quite annoying to debug as Rust doesn't print information about either
panic. I ended up using lldb to get a backtrace. Better to be cautious about
what we're doing when already panicking.
* give more context on raw::insert_recording errors, which I hit as well while
tweaking the new tests.
This improves the practicality of having many streams (including the doubling
of streams by having main + sub streams for each camera). With these tuned
properly, extra streams don't cause any extra write cycles in normal or error
cases. Consider the worst case in which each RTSP session immediately sends a
single frame and then fails. Moonfire retries every second, so this would
formerly cause one commit per second per stream. (flush_if_sec=0 preserves
this behavior.) Now the commits can be arbitrarily infrequent by setting
higher values of flush_if_sec.
WARNING: this isn't production-ready! I hacked up dir.rs to make tests pass
and "moonfire-nvr run" work in the best-case scenario, but it doesn't handle
errors gracefully. I've been debating what to do when writing a recording
fails. I considered "abandoning" the recording then either reusing or skipping
its id. (in the latter case, marking the file as garbage if it can't be
unlinked immediately). I think now there's no point in abandoning a recording.
If I can't write to that file, there's no reason to believe another will work
better. It's better to retry that recording forever, and perhaps put the whole
directory into an error state that stops recording until those writes go
through. I'm planning to redesign dir.rs to make this happen.
It should reduce compile time / memory usage to put quite a bit of the code
into a separate crate. I also intend to limit visibility of some things to
only within the db crate, but that's for a future change. This is the smallest
move that will compile.
