diff --git a/go/logic/throttler.go b/go/logic/throttler.go index ecc1f2b..ae95b70 100644 --- a/go/logic/throttler.go +++ b/go/logic/throttler.go @@ -8,6 +8,7 @@ package logic import ( "fmt" "net/http" + "strings" "sync/atomic" "time" @@ -18,6 +19,26 @@ import ( "github.com/outbrain/golib/sqlutils" ) +var ( + httpStatusMessages map[int]string = map[int]string{ + 200: "OK", + 404: "Not found", + 417: "Expectation failed", + 429: "Too many requests", + 500: "Internal server error", + } + // See https://github.com/github/freno/blob/master/doc/http.md + httpStatusFrenoMessages map[int]string = map[int]string{ + 200: "OK", + 404: "freno: unknown metric", + 417: "freno: access forbidden", + 429: "freno: threshold exceeded", + 500: "freno: internal error", + } +) + +const frenoMagicHint = "freno" + // Throttler collects metrics related to throttling and makes informed decisison // whether throttling should take place. type Throttler struct { @@ -34,6 +55,17 @@ func NewThrottler(applier *Applier, inspector *Inspector) *Throttler { } } +func (this *Throttler) throttleHttpMessage(statusCode int) string { + statusCodesMap := httpStatusMessages + if throttleHttp := this.migrationContext.GetThrottleHTTP(); strings.Contains(throttleHttp, frenoMagicHint) { + statusCodesMap = httpStatusFrenoMessages + } + if message, ok := statusCodesMap[statusCode]; ok { + return fmt.Sprintf("%s (http=%d)", message, statusCode) + } + return fmt.Sprintf("http=%d", statusCode) +} + // shouldThrottle performs checks to see whether we should currently be throttling. // It merely observes the metrics collected by other components, it does not issue // its own metric collection. @@ -49,7 +81,7 @@ func (this *Throttler) shouldThrottle() (result bool, reason string, reasonHint // HTTP throttle statusCode := atomic.LoadInt64(&this.migrationContext.ThrottleHTTPStatusCode) if statusCode != 0 && statusCode != http.StatusOK { - return true, fmt.Sprintf("http=%d", statusCode), base.NoThrottleReasonHint + return true, this.throttleHttpMessage(int(statusCode)), base.NoThrottleReasonHint } // Replication lag throttle maxLagMillisecondsThrottleThreshold := atomic.LoadInt64(&this.migrationContext.MaxLagMillisecondsThrottleThreshold)