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Addressing code review feedback.

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This commit is contained in:
Renán Del Valle 2021-05-10 11:13:48 -07:00
parent e709f8405c
commit 7906fd6c67
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GPG key ID: C240AD6D6F443EC9
3 changed files with 39 additions and 25 deletions
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43
retry.go
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@ -114,7 +114,12 @@ func ExponentialBackoff(backoff Backoff, logger logger, condition ConditionFunc)
type auroraThriftCall func() (resp *aurora.Response, err error)
// Verification functions should strive to keep the number of thrift calls to one wherever possible.
// verifyOntimeout defines the type of function that will be used to verify whether a Thirft call to the Scheduler
// made it to the scheduler or not. In general, these types of functions will have to interact with the scheduler
// through the very same Thrift API which previously encountered a time out from the client.
// This means that the functions themselves should be kept to a minimum number of Thrift calls.
// It should also be noted that this is a best effort mechanism and
// is likely to fail for the same reasons that the original call failed.
type verifyOnTimeout func() (*aurora.Response, bool)
// Duplicates the functionality of ExponentialBackoff but is specifically targeted towards ThriftCalls.
@ -171,6 +176,24 @@ func (r *realisClient) thriftCallWithRetries(
return nil, errors.Wrap(clientErr, "permanent connection error")
}
// There exists a corner case where thrift payload was received by Aurora but
// connection timed out before Aurora was able to reply.
// Users can take special action on a timeout by using IsTimedout and reacting accordingly
// if they have configured the client to return on a timeout.
if timedout && returnOnTimeout {
return resp, newTimedoutError(errors.New("client connection closed before server answer"))
}
// In the future, reestablish connection should be able to check if it is actually possible
// to make a thrift call to Aurora. For now, a reconnect should always lead to a retry.
// Ignoring error due to the fact that an error should be retried regardless
reestablishErr := r.ReestablishConn()
if reestablishErr != nil {
r.logger.debugPrintf("error re-establishing connection ", reestablishErr)
}
// If users did not opt for a return on timeout in order to react to a timedout error,
// attempt to verify that the call made it to the scheduler after the connection was re-established.
if timedout {
timeouts++
r.logger.debugPrintf(
@ -182,7 +205,7 @@ func (r *realisClient) thriftCallWithRetries(
// it timed out.
if verifyOnTimeout != nil {
if verifyResp, ok := verifyOnTimeout(); ok {
r.logger.debugPrint("verified that the call went through successfully")
r.logger.Print("verified that the call went through successfully after a client timeout")
// Response here might be different than the original as it is no longer constructed
// by the scheduler but mimicked.
// This is OK since the scheduler is very unlikely to change responses at this point in its
@ -190,22 +213,6 @@ func (r *realisClient) thriftCallWithRetries(
return verifyResp, nil
}
}
if returnOnTimeout {
// There exists a corner case where thrift payload was received by Aurora but
// connection timed out before Aurora was able to reply.
// Users can take special action on a timeout by using IsTimedout and reacting accordingly
// if they have configured the client to return on a timeout.
return resp, newTimedoutError(errors.New("client connection closed before server answer"))
}
}
// In the future, reestablish connection should be able to check if it is actually possible
// to make a thrift call to Aurora. For now, a reconnect should always lead to a retry.
// Ignoring error due to the fact that an error should be retried regardless
reestablishErr := r.ReestablishConn()
if reestablishErr != nil {
r.logger.debugPrintf("error re-establishing connection ", reestablishErr)
}
// Retry the thrift payload