Allow clients to limit the number of times a playlist attempts to reload following an error

[evanfarina]

Description

Addresses the issue of unlimited retries mentioned in issue #983 by allowing clients to control how often a playlist will try to reload following an error. Thanks to @gkatsev for the suggestion of using the playlist object to keep track of number of retries.

Specific Changes proposed

Introduce a new option maxPlaylistRetries which sets a limit on the number of times a playlist will be retried. Once the number of retries is greater than (>) the value set by maxPlaylistRetries, playlist.excludeUntil is set to Infinity.

Note: A property retryCount is set and incremented on Playlist objects. I've found that playlist errors and segment errors follow different paths (playlistRequestError and blacklistCurrentPlaylist, respectfully) so I'm incrementing this property in each of these places. I'd appreciate it if a reviewer could confirm that no error will result in both of these methods being called as that would cause a single error to increment the retryCount twice.

Requirements Checklist

• [ x ] Feature implemented / Bug fixed
• If necessary, more likely in a feature request than a bug fix
  • [ x ] Unit Tests updated or fixed
  • [ x ] Docs/guides updated
  • Example created (starter template on JSBin)
• Reviewed by Two Core Contributors

[codecov]

Codecov Report

Merging #1098 (298508d) into main (5405c18) will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #1098      +/-   ##
==========================================
+ Coverage   86.41%   86.44%   +0.02%     
==========================================
  Files          39       39              
  Lines        9465     9471       +6     
  Branches     2182     2183       +1     
==========================================
+ Hits         8179     8187       +8     
+ Misses       1286     1284       -2     

Impacted Files	Coverage Δ
src/segment-loader.js	96.18% <ø> (ø)
src/manifest.js	93.06% <100.00%> (+0.06%)	⬆️
src/master-playlist-controller.js	94.49% <100.00%> (+0.03%)	⬆️
src/playlist-loader.js	93.73% <0.00%> (+0.62%)	⬆️

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[brandonocasey]

Sorry it took us so long to review. There has been a ton on our plate internally.

[gkatsev]

Aside from the weird test whitespace, LGTM

[gkatsev]

The playback tests look a bit suspicious, they don't seem like the standard timeout issue we see.