Rarely, we find ourselves needing to explicitly delete some data, eg. something that shouldn't
have been public and should be removed from all records.
It would also be nice if we could "clean up" bad versions of the same segment,
which occasionally come up when downloaders have issues.
With our distributed segment database, this is actually rather difficult as deleting the data
from any one server would cause it to be restored from the others. It was only possible
by stopping all backfill, deleting the data on all servers, then starting backfill again.
Here we introduce a more practical approach. An operator creates an empty flag file
with the same name as the segment to be deleted, but with a `.tombstone` extension.
eg. to delete a file `/segments/desertbus/source/2019-11-13T02/45:51.608000-2.0-full-7IS92rssMzoSBQDIevHStbTNy-URRV3Vw-jzZ6pwOZM.ts`,
you would create a tombstone `/segments/desertbus/source/2019-11-13T02/45:51.608000-2.0-full-7IS92rssMzoSBQDIevHStbTNy-URRV3Vw-jzZ6pwOZM.tombstone`.
These tombstone files do two important things:
* They hide the segment from being listed, which both means:
* It can't be restreamed or put into a video
* It can't be backfilled to other nodes
* The tombstone files themselves do get backfilled to other nodes, so you only need to mark them on one server.
Once the tombstone has propagated to all nodes, the segment file can be deleted independently on each one.
We chose not to have a tombstone automatically trigger a segment deletion for safety reasons.
Previously both restreamer and thrimshim had some complex logic for dealing with
graceful shutdown, in different ways, that was still prone to race conditions.
We replace this with a common method that does it properly.
Fixes#226
When pushed, this tells github to associate the ghcr.io repo that was pushed to
with the github repo specified (the owner needs to match).
This does a few things.
Most importantly, this automatically gives github actions credentials to push to these
repositories when run in the context of the wubloader repo.
This is the simplest case as we can just cut each range like we already do,
then concat the results.
We still allow for the full design in the database and cutter, but error out if transitions
is ever anything but hard cuts or if it's a full cut.
We also update the restreamer to allow accepting ranges, however for usability we still allow
the old "just one start and end" args.
Note this changes the thrimshim API to give and take the new "video_ranges" and "video_transitions" columns.
Check that open() calls for reading and writing use binary modes
Use alpine version with py3-pip package
Use python3 in Dockerfile CMD
Remove sys.setdefaultencoding() "hack"
Simplify ensure_directory() in common.common package
By carefully ensuring most of our dockerfiles are identical in their first few layers,
we only need to build those layers once instead of every time.
In particular, we move installing gevent to before installing common,
so that even when common changes gevent doesn't need to be reinstalled.
This is important because gevent takes ages to install.
Also fixes segment_coverage, which wasn't being installed.
In a fast cut, we edit the first and last segments then concatenate them all.
However, this leads to some tiny but perciptible artifacting around the border
of the first and second (and second-last and last) segments.
A full cut is much slower, but re-encodes the video into the desired format
and is more reliable.
We want both options to be available.
With this commit, we only add the option, we don't use it in restreamer or cutter.
We wrap direct dateutil calls to handle two distinct cases:
* `common.dateutil.parse()`: We want to handle arbitrary timestamps including tz info,
then convert them to UTC.
This is used in HLS parsing, and for command line input for backfiller
* `common.dateutil.parse_utc_only()`: We want to only handle UTC timestamps,
but datetime.strptime isn't flexible enough (eg. can't handle missing fractional component).
This is used for restreamer request params.
Note this moves over the 'experimental' cutter and deletes the original cutter
that concatenates entire videos before cutting.
We may eventually want to revive that method if the experimental cutter turns out
to introduce too many issues.
We move most of the code over verbatim, but adjust it such that it acts
as a generic iterator that can be used in a variety of contexts.
Some other changes made during the move include telling ffmpeg to be quieter
(don't output version info and junk, only log if something goes wrong),
and avoiding errors during cleanup.
Backdoor allows the operator to telnet into the given port, and get a python shell
running inside the process, from which you can debug, modify state (eg. set the log level),
or whatever. This is extremely useful for debugging weird states that you encounter randomly
but can't easily reproduce, without restarting the process and needing to wait until it happens again.
Prom client doesn't like you creating two stats with the same name,
even though they have different labels and this makes perfect sense.
I feel like I just need to re-write the prom client at some point - it doesn't actually
do all that much except get in your way, apart from the actual text encoding which I
can steal.
Anyway, in the meantime, we get around this by breaking up metrics into two names,
a "foo_all" and a "foo_ENDPOINT". The foo_all lacks the detailed labels,
but is still labelled by endpoint and can be used more easily.
The foo_ENDPOINT labels have more information but require messier PromQL as you need to
match on a name regex if you want to look at more than one specific endpoint.
Mike Lang
ElementalAlchemist
HubbeKing
HubbeKing
Mike Lang
Christopher Usher
MasterGunner