After a frustrating search for a suitable channel to use for shutdown
(tokio::sync:⌚:Receiver and
futures::future::Shared<tokio::sync::oneshot::Receiver> didn't look
quite right) in which I rethought my life decisions, I finally just made
my own (server/base/shutdown.rs). We can easily poll it or wait for it
in async or sync contexts. Most importantly, it's convenient; not that
it really matters here, but it's also efficient.
We now do a slightly better job of propagating a "graceful" shutdown
signal, and this channel will give us tools to improve it over time.
* Shut down even when writer or syncer operations are stuck. Fixes#117
* Not done yet: streamers should instantly shut down without waiting for
a connection attempt or frame or something. I'll probably
implement that when removing --rtsp-library=ffmpeg. The code should be
cleaner then.
* Not done yet: fix a couple places that sleep for up to a second when
they could shut down immediately. I just need to do the plumbing for
mock clocks to work.
I also implemented an immediate shutdown mode, activated by a second
signal. I think this will mitigate the streamer wait situation.
I saw this recently while working on new-schema. It was probably due
to some manual upgrade or downgrade I did rather than an actual bug.
Improve debuggability a little nonetheless.
* upgrade to Retina 0.3.1 which automatically tears down sessions
* wait out stale sessions before reconnecting
* wait for teardown to complete before shutting down
This adds some pressure on #117: it will keep waiting for the stale
session to expire even if the user has requested shutdown. I'll try
to address that next.
This mostly affects .mp4 init segments (#146), which currently set the
Last-Modified: date to the epoch. It could also affect other resources
(static files, other .mp4 changes) but only if the clock has gone
backwards.
I forgot to do this in 27395ec resulting in #146. Bump the version now,
and update the digest used in the tests so they will remind me to
bump the version any time the headers change.
As written in the changelog: Live streams formerly worked around a
Firefox pixel aspect ratio bug by forcing all videos to 16:9, which
dramatically distorted 9:16 camera views. Playback didn't, so anamorphic
videos looked correct on Chrome but slightly stretched on Firefox. Now
both live streams and playback are fully correct on all browsers.
Fixes#136
Before:
```
E20210803 09:00:31.161 main moonfire_nvr] panic at '/Users/slamb/.cargo/registry/src/github.com-1ecc6299db9ec823/hyper-0.14.10/src/server/server.rs:68:17': error binding to 0.0.0.0:80: error creating server listener: Address already in use (os error 48)
(set environment variable RUST_BACKTRACE=1 to see backtraces)
...potentially unrelated log msgs from other threads before exiting...
```
After:
```
E20210803 09:06:02.633 main moonfire_nvr] Exiting due to error: unable to bind --http-addr=0.0.0.0:80
caused by: error creating server listener: Address already in use (os error 48)
(set environment variable RUST_BACKTRACE=1 to see backtraces)
```
For #136. I'm also going to make this particular case no longer panic,
but there will surely be other affected panics.
Before:
```
E20210803 08:58:31.606 main moonfire_nvr] panic at '/Users/slamb/.cargo/registry/src/github.com-1ecc6299db9ec823/hyper-0.14.10/src/server/server.rs:68:17'
```
After:
```
E20210803 08:59:51.319 main moonfire_nvr] panic at '/Users/slamb/.cargo/registry/src/github.com-1ecc6299db9ec823/hyper-0.14.10/src/server/server.rs:68:17': error binding to 0.0.0.0:80: error creating server listener: Address already in use (os error 48)
```
While I'm here, return a clean error if a non-initial video frame
includes a parameter change, rather than doing something crazy (#42).
It's still broken under ffmpeg, it's untested, and it's not as clean
as seamlessly starting a new recording with the new parameters, but
it's better than nothing.
* have a timeout for opening the connection and getting the next
video frame. The former is quite important. The latter is arguably
redundant with the keepalive timer, but this ensures we actually
get a full frame in this timespan rather than some keepalive
responses, RTCP sender reports, or partial frames.
* don't drop extra stuff on loss; just note it. I'm not sure what the
right behavior is but I think I shouldn't change too much at once.
I see a lot of yields and such in CPU profiles. I think the workers
are frequently waking up, finding there's not much to do, and going back
to sleep. Reducing the number of worker threads seems reasonable.
Moonfire NVR has some enforcement on its own; this makes retina vs
ffmpeg more of an apples-to-apples comparison.
I'm also thinking of dropping enforcement from retina; enough things
have sketchy timestamps that this policy doesn't make much sense anyway.
This isn't well-tested and doesn't yet support an initial connection
timeout. But in a quick test, it successfully returns video!
I'd like to do some more aggressive code restructuring for zero-copy
and to have only one writer thread per sample file directory (rather
than the syncer thread + one writer thread per RTSP stream). But I'll
likely wait until I drop support for ffmpeg entirely.
This is (slightly) complicating the switch from ffmpeg to retina
as the RTSP client. And it's not really that close to what I want
to end up with for analytics:
* I'd prefer the analytics happen in a separate process for
several reasons
* Feeding the entire frame to the object detector doesn't produce
good results.
* It doesn't do anything with the results yet anyway.
This caused served chunks to be truncated. On seek, nginx sometimes
served 502 errors, chrome sometimes returned
ERR_CONTENT_LENGTH_MISMATCH, and videos weren't playing properly.
