Now each syncer has a binary heap of the times it plans to do a flush.
When one of those times arrives, it rechecks if there's something to do.
Seems more straightforward than rechecking each stream's first
uncommitted recording, especially with the logic to retry failed flushes
every minute.
Also improved the info! log for each flush to see the actual recordings
being flushed for better debuggability.
No new tests right now. :-( They're tricky to write. One problem is that
it's hard to get the timing right: a different flush has to happen
after Syncer::save's database operations and before Syncer::run calls
SimulatedClocks::recv_timeout with an empty channel[*], advancing the
time. I've thought of a few ways of doing this:
* adding a new SyncerCommand to run something, but it's messy (have
to add it from the mock of one of the actions done by the save),
and Box<dyn FnOnce() + 'static> not working (see
rust-lang/rust#28796) makes it especially annoying.
* replacing SimulatedClocks with something more like MockClocks.
Lots of boilerplate. Maybe I need to find a good general-purpose
Rust mock library. (mockers sounds good but I want something that
works on stable Rust.)
* bypassing the Syncer::run loop, instead manually running iterations
from the test.
Maybe the last way is the best for now. I'm likely to try it soon.
[*] actually, it's calling Receiver::recv_timeout directly;
Clocks::recv_timeout is dead code now? oops.
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.
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.
Scott Lamb