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94 lines
2.7 KiB
Go
94 lines
2.7 KiB
Go
package gcloud
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import (
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"log"
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"time"
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"google.golang.org/api/googleapi"
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)
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const (
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initialBackoff = time.Second * 10 // First delay duration
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maxBackoff = time.Minute * 3 // Maximum backoff delay
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)
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// backoff is the amount of time to sleep if a 429 or 504 is received.
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// It is doubled after each use.
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var (
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backoff = initialBackoff
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backoff404 = false // Set if the last call requested a retry of a 404
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backoff502 = false // Set if the last call requested a retry of a 502
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)
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func retryNeeded(resp *googleapi.ServerResponse, err error) bool {
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if err == nil {
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return false // Not an error.
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}
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serr, ok := err.(*googleapi.Error)
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if !ok {
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return false // Not a google error.
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}
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if serr.Code == 200 {
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backoff = initialBackoff // Reset
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return false // Success! No need to retry.
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}
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if serr.Code == 404 {
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// serr.Code == 404 happens occasionally when GCLOUD hasn't
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// finished updating the database yet. We pause and retry
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// exactly once. There should be a better way to do this, such as
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// a callback that would tell us a transaction is complete.
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if backoff404 {
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backoff404 = false
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return false // Give up. We've done this already.
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}
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log.Printf("Special 404 pause-and-retry for GCLOUD: Pausing %s\n", backoff)
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time.Sleep(backoff)
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backoff404 = true
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return true // Request a retry.
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}
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backoff404 = false
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if serr.Code == 502 {
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// serr.Code == 502 happens occasionally when "The server
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// encountered a temporary error and could not complete your
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// request. Please try again in 30 seconds. That’s all we know."
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// We pause and retry exactly once.
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if backoff502 {
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backoff502 = false
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return false // Give up. We've done this already.
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}
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log.Printf("Special 502 pause-and-retry for GCLOUD: Pausing %s\n", backoff)
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time.Sleep(31 * time.Second)
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backoff502 = true
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return true // Request a retry.
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}
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backoff502 = false
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if serr.Code != 429 && serr.Code != 503 {
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return false // Not an error that permits retrying.
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}
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// TODO(tlim): In theory, resp.Header has a header that says how
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// long to wait but I haven't been able to capture that header in
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// the wild. If you get these "RUNCHANGE HEAD" messages, please
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// file a bug with the contents!
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if resp != nil {
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log.Printf("NOTE: If you see this message, please file a bug with the output below:\n")
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log.Printf("RUNCHANGE CODE = %+v\n", resp.HTTPStatusCode)
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log.Printf("RUNCHANGE HEAD = %+v\n", resp.Header)
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}
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// a simple exponential back-off
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log.Printf("Pausing due to ratelimit: %v seconds\n", backoff)
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time.Sleep(backoff)
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backoff = backoff + (backoff / 2)
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if backoff > maxBackoff {
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backoff = maxBackoff
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}
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return true // Request the API call be re-tried.
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}
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