TRANSIP: Pause when rate-limited

providers/transip/retry.go

@@ -0,0 +1,76 @@
+package transip
+
+import (
+	"log"
+	"time"
+
+	"github.com/transip/gotransip/v6/rest"
+)
+
+const (
+	initialBackoff = time.Second * 20 // First delay duration
+	maxBackoff     = time.Minute * 4  // Maximum backoff delay
+)
+
+// backoff is the amount of time to sleep if a 429 (or similar) is received.
+// It is doubled after each use.
+var (
+	backoff = initialBackoff
+)
+
+func retryNeeded(err error) bool {
+	if err == nil {
+		return false // Not an error.
+	}
+
+	serr, ok := err.(*rest.Error)
+	if !ok {
+		return false // Not an error we know how to work with.
+	}
+
+	if serr.StatusCode == 200 {
+		backoff = initialBackoff // Reset
+		return false             // Success! No need to retry.
+	}
+
+	if serr.StatusCode != 429 {
+		return false
+	}
+
+	// a simple exponential back-off
+	log.Printf("Pausing due to ratelimit (%03d): %v seconds\n", serr.StatusCode, backoff)
+	time.Sleep(backoff)
+	backoff = backoff + (backoff / 2)
+	if backoff > maxBackoff {
+		backoff = maxBackoff
+	}
+
+	return true // Request the API call be re-tried.
+}
+
+/*
+
+TODO(tlim): Use X-Rate-Limit-Reset to optimize sleep time.
+
+This is a rather lazy implementation.  A better implementation would examine
+the X-Rate-Limit-Reset header and wait until that timestamp, if the timestamp
+seems reasonable.  This implementation just does an exponential back-off.
+
+This is what the documentation says:
+
+> **Rate limit**
+> The rate limit for this API uses a sliding window of 15 minutes. Within this window, a maximum of 1000 requests can be made per user.
+>
+> Every request returns the following headers, indicating the number of requests made within this window, the amount of requests remaining and the reset timestamp.
+>
+> ```text
+> X-Rate-Limit-Limit: 1000
+> X-Rate-Limit-Remaining: 650
+> X-Rate-Limit-Reset: 1485875578
+> ```
+
+> When this rate limit is exceeded, the response contains an error with HTTP status code: `429: Too many requests`.
+
+<https://api.transip.nl/rest/docs.html#header-rate-limit>
+
+*/

providers/transip/transipProvider.go

@@ -99,10 +99,15 @@ func init() {
 func (n *transipProvider) ListZones() ([]string, error) {
 	var domains []string
 
+retry:
 	domainsMap, err := n.domains.GetAll()
+	if retryNeeded(err) {
+		goto retry
+	}
 	if err != nil {
 		return nil, err
 	}
+
 	for _, domainname := range domainsMap {
 		domains = append(domains, domainname.Name)
 	}
@@ -136,7 +141,13 @@ func (n *transipProvider) GetZoneRecordsCorrections(dc *models.DomainConfig, cur
 					return err
 				}
 
-				return n.domains.ReplaceDNSEntries(dc.Name, nativeDNSEntries)
+			retry:
+				err = n.domains.ReplaceDNSEntries(dc.Name, nativeDNSEntries)
+				if retryNeeded(err) {
+					goto retry
+				}
+				return err
+
 			},
 		},
 	}
@@ -146,7 +157,11 @@ func (n *transipProvider) GetZoneRecordsCorrections(dc *models.DomainConfig, cur
 
 // GetZoneRecords returns all records within given zone
 func (n *transipProvider) GetZoneRecords(domainName string, meta map[string]string) (models.Records, error) {
+retry:
 	entries, err := n.domains.GetDNSEntries(domainName)
+	if retryNeeded(err) {
+		goto retry
+	}
 	if err != nil {
 		return nil, err
 	}
@@ -167,10 +182,15 @@ func (n *transipProvider) GetZoneRecords(domainName string, meta map[string]stri
 func (n *transipProvider) GetNameservers(domainName string) ([]*models.Nameserver, error) {
 	var nss []string
 
+retry:
 	entries, err := n.domains.GetNameservers(domainName)
+	if retryNeeded(err) {
+		goto retry
+	}
 	if err != nil {
 		return nil, err
 	}
+
 	for _, entry := range entries {
 		nss = append(nss, entry.Hostname)
 	}