Add round-robin picker #16
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TCN-1912 Add round-robin picker
To make sure multiple replicas don't iterate connections in the same order (potentially resulting in thundering herd of concurrent requests to each backend), this should shuffle the order of connections before iterating. |
jhump
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Jun 7, 2023
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| // TODO: when possible, it'd be good to test multiple connections to verify | ||
| // that shuffling works and that we get round-robin behavior. |
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Would also be good to do some "white-box" testing: to actually look at the conns slice of the resulting picker and verify it emits connections in actual round-robin sequence.
jhump
reviewed
Jun 7, 2023
jhump
reviewed
Jun 7, 2023
Doesn't look like there's a cleaner way to initialize an atomic wrapper.
Co-authored-by: John Chadwick <jchadwick@buf.build>
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This was as simple as I could manage to make it. Hopefully close to what was in mind.
Per TCN-1912, it shuffles the connections whenever it gets a new list. Since we can't shuffle the Conns in place, I can't just use
rand.Shuffledirectly since it is doing an in-place Fisher-Yates shuffle. However, I believe this is still fine, as it should still yield a result where any permutation is equally likely.