2960: Merge branch 'main' into 2960-keepstore-streaming

[arvados.git] / sdk / go / keepclient / support.go

diff --git a/sdk/go/keepclient/support.go b/sdk/go/keepclient/support.go
index 6acaf64baa34caa265eb10bafcbf36a70d308d9b..d3d799dc5dc2c229d8303d215328fea577c61c10 100644 (file)
--- a/sdk/go/keepclient/support.go
+++ b/sdk/go/keepclient/support.go
@@ -13,10 +13,12 @@ import (
        "io"
        "io/ioutil"
        "log"
+       "math/rand"
        "net/http"
        "os"
        "strconv"
        "strings"
+       "time"
 
        "git.arvados.org/arvados.git/sdk/go/arvados"
        "git.arvados.org/arvados.git/sdk/go/arvadosclient"
@@ -218,6 +220,7 @@ func (kc *KeepClient) httpBlockWrite(ctx context.Context, req arvados.BlockWrite
                replicasPerThread = req.Replicas
        }
 
+       delay := delayCalculator{InitialMaxDelay: kc.RetryDelay}
        retriesRemaining := req.Attempts
        var retryServers []string
 
@@ -306,14 +309,17 @@ func (kc *KeepClient) httpBlockWrite(ctx context.Context, req arvados.BlockWrite
                        }
 
                        if status.statusCode == 0 || status.statusCode == 408 || status.statusCode == 429 ||
-                               (status.statusCode >= 500 && status.statusCode != 503) {
+                               (status.statusCode >= 500 && status.statusCode != http.StatusInsufficientStorage) {
                                // Timeout, too many requests, or other server side failure
-                               // Do not retry when status code is 503, which means the keep server is full
+                               // (do not auto-retry status 507 "full")
                                retryServers = append(retryServers, status.url[0:strings.LastIndex(status.url, "/")])
                        }
                }
 
                sv = retryServers
+               if len(sv) > 0 {
+                       time.Sleep(delay.Next())
+               }
        }
 
        return resp, nil
@@ -345,3 +351,37 @@ func parseStorageClassesConfirmedHeader(hdr string) (map[string]int, error) {
        }
        return classesStored, nil
 }
+
+// delayCalculator calculates a series of delays for implementing
+// exponential backoff with jitter.  The first call to Next() returns
+// a random duration between MinimumRetryDelay and the specified
+// InitialMaxDelay (or DefaultRetryDelay if 0).  The max delay is
+// doubled on each subsequent call to Next(), up to 10x the initial
+// max delay.
+type delayCalculator struct {
+       InitialMaxDelay time.Duration
+       n               int // number of delays returned so far
+       nextmax         time.Duration
+       limit           time.Duration
+}
+
+func (dc *delayCalculator) Next() time.Duration {
+       if dc.nextmax <= MinimumRetryDelay {
+               // initialize
+               if dc.InitialMaxDelay > 0 {
+                       dc.nextmax = dc.InitialMaxDelay
+               } else {
+                       dc.nextmax = DefaultRetryDelay
+               }
+               dc.limit = 10 * dc.nextmax
+       }
+       d := time.Duration(rand.Float64() * float64(dc.nextmax))
+       if d < MinimumRetryDelay {
+               d = MinimumRetryDelay
+       }
+       dc.nextmax *= 2
+       if dc.nextmax > dc.limit {
+               dc.nextmax = dc.limit
+       }
+       return d
+}