Making stackdriver exporter options configurable in env var

pkg/observability/config.go

@@ -15,6 +15,8 @@
 // Package observability sets up and configures observability tools.
 package observability
 
+import "time"
+
 // ExporterType represents a type of observability exporter.
 type ExporterType string
 
@@ -60,4 +62,16 @@ type StackdriverConfig struct {
 	// Allows for providing a real Google Cloud location when running locally for development.
 	// This is ignored if a real location was found during discovery.
 	LocationOverride string `env:"DEV_STACKDRIVER_LOCATION"`
+
+	// The following options are mostly for tuning the metrics reporting
+	// behavior. You normally should not change these values.
+	// ReportingInterval: should be >=60s as stackdriver enforces 60s minimal
+	// interval.
+	// BundleDelayThreshold / BundleCountThreshold: the stackdriver exporter
+	// uses https://google.golang.org/api/support/bundler, these two options
+	// control the max delay/count for batching the data points into one
+	// stackdriver request.
+	ReportingInterval    time.Duration `env:"STACKDRIVER_REPORTING_INTERVAL, default=2m"`
+	BundleDelayThreshold time.Duration `env:"STACKDRIVER_BUNDLE_DELAY_THRESHOLD, default=2s"`
+	BundleCountThreshold uint          `env:"STACKDRIVER_BUNDLE_COUNT_THRESHOLD, default=50"`
 }

pkg/observability/stackdriver.go

@@ -18,7 +18,6 @@ package observability
 import (
 	"context"
 	"fmt"
-	"time"
 
 	"github.com/google/exposure-notifications-server/pkg/logging"
 
@@ -27,11 +26,7 @@ import (
 	"go.opencensus.io/trace"
 )
 
-var (
-	_ Exporter = (*stackdriverExporter)(nil)
-
-	SDExportFrequency = time.Minute * 2
-)
+var _ Exporter = (*stackdriverExporter)(nil)
 
 type stackdriverExporter struct {
 	exporter *stackdriver.Exporter
@@ -53,7 +48,9 @@ func NewStackdriver(ctx context.Context, config *StackdriverConfig) (Exporter, e
 	exporter, err := stackdriver.NewExporter(stackdriver.Options{
 		Context:                 ctx,
 		ProjectID:               projectID,
-		ReportingInterval:       SDExportFrequency,
+		ReportingInterval:       config.ReportingInterval,
+		BundleDelayThreshold:    config.BundleDelayThreshold,
+		BundleCountThreshold:    int(config.BundleCountThreshold),
 		MonitoredResource:       monitoredResource,
 		DefaultMonitoringLabels: &stackdriver.Labels{},
 		OnError: func(err error) {
@@ -83,7 +80,6 @@ func (e *stackdriverExporter) StartExporter() error {
 	trace.RegisterExporter(e.exporter)
 
 	view.RegisterExporter(e.exporter)
-	view.SetReportingPeriod(SDExportFrequency)
 
 	return nil
 }