Add 1 second buffer to expiry to correct throttles #85
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The logic looks sound to me, but without the context of this pull request the extra A comment explaining why it's there or a reference to this PR would be nice :) |
Fixes #69. There was a race condition when `Time.now.to_i` changes between when `epoch_time` is computed in line 18, and the cache request is made (and the `key` is expired). I.e., a throttle check starts at t0, but doesn’t reach the cache until t1, the cache will have expired the throttle count. The request will likely be allowed, even if the request exceeded the limit. This has the effect of keeping keys in cache about 1 second longer than strictly necessary. But the extra cache space seems like a good trade-off for correct throttling.
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Thanks @zmillman. Added a comment to the commit. |
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Add 1 second buffer to expiry to correct throttles
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Fixes #69.
There was a race condition when
Time.now.to_ichanges between whenepoch_timeis computed in line 18, and the cache request is made (andthe
keyis expired).I.e., a throttle check starts at t0, but doesn’t reach the cache until
t1, the cache will have expired the throttle count. The request will
likely be allowed, even if the request exceeded the limit.
This has the effect of keeping keys in cache about 1 second longer than
strictly necessary. But the extra cache space seems like a good
trade-off for correct throttling.
Looking for a sanity check/:+1: from @zmillman before merging.