feat: support HLS media playback

[daibhin]

Problem

HLS media playback is not supported in Replay right now because the src is not added to the DOM and thus not captured by rrweb

Changes

Implementation as described in #25087 (comment)

Key thing to note is that the media source must be added as a hls-src attribute on the video element (needs to be added to the docs once this is testred)

How did you test this code?

Tested video plays back locally

Before	After

[github-actions]

Size Change: +87 B (+0.01%)

Total Size: 1.1 MB

ℹ️ View Unchanged

Filename	Size	Change
frontend/dist/toolbar.js	1.1 MB	+87 B (+0.01%)

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[pauldambra]

other than the question about the url, this is a great fix

[MannyAdumbire]

@daibhin thanks for the quick fix!

Unfortunately I'm not sure how to test this is working, using the "hobby" docker version of PostHog.
How would I confirm that my local copy of PostHog has loaded this PRs changes?

I added the hls-src attribute on <video> element with .m3u8 HLS video for its value.

Then did the following:

1. pull the latest changes from master branch which contains this merged PR.
2. ran docker-compose up --build -d
3. "record" a couple sessions for replay

Still seeing the original issue after the steps above.

I searched(greped) inside the web, caddy, plugins, worker docker containers, but can't find any reference to "hls-src".
I'm assuming it will take time to be deployed to PostHog cloud, so really appreciate any pointers as to where/how this PR changes would show up on the hobby version.

[daibhin]

Hey @MannyAdumbire, do you have a link to one of the affected recordings? Just trying to recreate this locally on my machine but might be quicker to use one of your examples if you have one to hand

[daibhin]

You're right @MannyAdumbire, I hadn't anticipated that a HLS video would add a src attribute of it's own which is causing an exception to be thrown during playback. The fix requires an update to the SDK so you will need to upgrade once v1.166.1 is live

[MannyAdumbire]

@daibhin I finally figured out how to update the hobby version container to get built with the latest posthog-js.
HLS playback working as expected now. 😭:)
thanks again for your help!

[daibhin]

Amazing! Did it require any changes on your end beyond upgrading the version? I would love to update our docs if there's anything that might help others to make this work

[MannyAdumbire]

Amazing! Did it require any changes on your end beyond upgrading the version? I would love to update our docs if there's anything that might help others to make this work

Sorry that I don't quite remember the key steps 😅
It went something like:

> cd /path/to/posthog/repo
> git pull
> docker build -t  posthog:latest . 
> docker-compose up -d --force-recreate --build

I wish I know what the minimal list of docker services needing to be rebuilt is, but each one I tried complained with some docker message about dependent container being affected.
I will have to take note next times.

This rough upgrade worked fine for a while but then I run into an issue that seemed to only resolve with the full upgrade mentioned in #25262 (comment)
https://posthog.com/docs/self-host#upgrading.
Running the full script wasn't too bad either time-wise to get back up running, other than it wiping some custom configs for my reverse-proxy setup.
Gonna try to avoid losing those configs time by moving them into a docker-compose.override.yml.