Added kingpin vars for exponential backoff config. (Default off)

Defaults are
0 retries (i.e. off)
1 second jitter base
5s max time between retries
10s total http timeout. Same as Prometheus default scrape timeout.

Author: Olve S. Hansen

stackdriver_exporter.go

@@ -15,7 +15,6 @@ import (
 	"golang.org/x/oauth2/google"
 	"google.golang.org/api/monitoring/v3"
 	"gopkg.in/alecthomas/kingpin.v2"
-	"time"
 )
 
 var (
@@ -46,6 +45,26 @@ var (
 	collectorFillMissingLabels = kingpin.Flag(
 		"collector.fill-missing-labels", "Fill missing metrics labels with empty string to avoid label dimensions inconsistent failure ($STACKDRIVER_EXPORTER_COLLECTOR_FILL_MISSING_LABELS).",
 	).Envar("STACKDRIVER_EXPORTER_COLLECTOR_FILL_MISSING_LABELS").Default("true").Bool()
+
+	stackdriverMaxRetries = kingpin.Flag(
+		"stackdriver.max-retries", "Max number of retries that should be attempted on 503 errors from stackdriver. ($STACKDRIVER_EXPORTER_MAX_RETRIES)",
+	).Envar("STACKDRIVER_EXPORTER_MAX_RETRIES").Default("0").Int()
+
+	stackdriverHttpTimeout = kingpin.Flag(
+		"stackdriver.http-timeout", "How long should stackdriver_exporter wait for a result from the Stackdriver API ($STACKDRIVER_EXPORTER_HTTP_TIMEOUT)",
+	).Envar("STACKDRIVER_EXPORTER_HTTP_TIMEOUT").Default("10s").Duration()
+
+	stackdriverMaxBackoffDuration = kingpin.Flag(
+		"stackdriver.http-timeout", "Max time between each request in an exp backoff scenario ($STACKDRIVER_EXPORTER_MAX_BACKOFF_DURATION)",
+	).Envar("STACKDRIVER_EXPORTER_MAX_BACKOFF_DURATION").Default("5s").Duration()
+
+	stackdriverBackoffJitterBase = kingpin.Flag(
+		"stackdriver.http-timeout", "The amount of jitter to introduce in a exp backoff scenario ($STACKDRIVER_EXPORTER_BACKODFF_JITTER_BASE)",
+	).Envar("STACKDRIVER_EXPORTER_BACKODFF_JITTER_BASE").Default("1s").Duration()
+
+	stackdriverRetryStatuses = kingpin.Flag(
+		"stackdriver.retry-statuses", "The HTTP statuses that should trigger a retry (comma separated) ($STACKDRIVER_EXPORTER_RETRY_STATUSES)",
+	).Envar("STACKDRIVER_EXPORTER_RETRY_STATUSES").Default("503").Ints()
 )
 
 func init() {
@@ -56,13 +75,14 @@ func createMonitoringService() (*monitoring.Service, error) {
 	ctx := context.Background()
 
 	googleClient, err := google.DefaultClient(ctx, monitoring.MonitoringReadScope)
-	googleClient.Timeout = time.Second * 10
+
+	googleClient.Timeout = *stackdriverHttpTimeout
 	googleClient.Transport = rehttp.NewTransport(
 		googleClient.Transport, // need to wrap DefaultClient transport
 		rehttp.RetryAll(
-			rehttp.RetryMaxRetries(3),
-			rehttp.RetryStatuses(503)), // Cloud support suggests retrying on 503 errors
-		rehttp.ExpJitterDelay(time.Second, 9*time.Second), // Set timeout to <10s as that is prom default timeout
+			rehttp.RetryMaxRetries(*stackdriverMaxRetries),
+			rehttp.RetryStatuses(*stackdriverRetryStatuses...)), // Cloud support suggests retrying on 503 errors
+		rehttp.ExpJitterDelay(*stackdriverBackoffJitterBase, *stackdriverMaxBackoffDuration), // Set timeout to <10s as that is prom default timeout
 	)
 
 	if err != nil {