feat: make interval between synchronizations configurable (#123)

controller/controller.go

@@ -37,6 +37,8 @@ type Controller struct {
 
 	Source   source.Source
 	Provider provider.Provider
+	// The interval between individual synchronizations
+	Interval time.Duration
 }
 
 // RunOnce runs a single iteration of a reconciliation loop.
@@ -70,7 +72,7 @@ func (c *Controller) Run(stopChan <-chan struct{}) {
 		}
 
 		select {
-		case <-time.After(time.Minute):
+		case <-time.After(c.Interval):
 		case <-stopChan:
 			log.Infoln("terminating main controller loop")
 			return

main.go

@@ -96,6 +96,7 @@ func main() {
 		Zone:     cfg.Zone,
 		Source:   sources,
 		Provider: p,
+		Interval: cfg.Interval,
 	}
 
 	if cfg.Once {

pkg/apis/externaldns/types.go

@@ -17,6 +17,8 @@ limitations under the License.
 package externaldns
 
 import (
+	"time"
+
 	"github.com/spf13/pflag"
 
 	"k8s.io/client-go/pkg/api/v1"
@@ -37,6 +39,7 @@ type Config struct {
 	Provider      string
 	GoogleProject string
 	HealthPort    string
+	Interval      time.Duration
 	Once          bool
 	DryRun        bool
 	Debug         bool
@@ -61,6 +64,7 @@ func (cfg *Config) ParseFlags(args []string) error {
 	flags.StringVar(&cfg.GoogleProject, "google-project", "", "gcloud project to target")
 	flags.StringVar(&cfg.HealthPort, "health-port", defaultHealthPort, "health port to listen on")
 	flags.StringVar(&cfg.LogFormat, "log-format", defaultLogFormat, "log format output. options: [\"text\", \"json\"]")
+	flags.DurationVar(&cfg.Interval, "interval", time.Minute, "interval between synchronizations")
 	flags.BoolVar(&cfg.Once, "once", false, "run once and exit")
 	flags.BoolVar(&cfg.DryRun, "dry-run", true, "dry-run mode")
 	flags.BoolVar(&cfg.Debug, "debug", false, "debug mode")

pkg/apis/externaldns/types_test.go

@@ -19,6 +19,7 @@ package externaldns
 import (
 	"reflect"
 	"testing"
+	"time"
 )
 
 func TestParseFlags(t *testing.T) {
@@ -40,6 +41,8 @@ func TestParseFlags(t *testing.T) {
 				Provider:      "",
 				GoogleProject: "",
 				HealthPort:    defaultHealthPort,
+				Interval:      time.Minute,
+				Once:          false,
 				DryRun:        true,
 				Debug:         false,
 				LogFormat:     defaultLogFormat,
@@ -58,6 +61,8 @@ func TestParseFlags(t *testing.T) {
 				Provider:      "",
 				GoogleProject: "",
 				HealthPort:    defaultHealthPort,
+				Interval:      time.Minute,
+				Once:          false,
 				DryRun:        true,
 				Debug:         false,
 				LogFormat:     defaultLogFormat,
@@ -76,6 +81,8 @@ func TestParseFlags(t *testing.T) {
 				Provider:      "",
 				GoogleProject: "",
 				HealthPort:    defaultHealthPort,
+				Interval:      time.Minute,
+				Once:          false,
 				DryRun:        true,
 				Debug:         false,
 				LogFormat:     defaultLogFormat,
@@ -99,6 +106,8 @@ func TestParseFlags(t *testing.T) {
 				Provider:      "",
 				GoogleProject: "",
 				HealthPort:    defaultHealthPort,
+				Interval:      time.Minute,
+				Once:          false,
 				DryRun:        true,
 				Debug:         false,
 				LogFormat:     "json",
@@ -116,7 +125,9 @@ func TestParseFlags(t *testing.T) {
 				"--provider", "provider",
 				"--google-project", "project",
 				"--health-port", "1234",
-				"--dry-run", "true",
+				"--interval", "10m",
+				"--once",
+				"--dry-run=false",
 				"--debug",
 				"--version"}},
 			expected: &Config{
@@ -128,7 +139,9 @@ func TestParseFlags(t *testing.T) {
 				Provider:      "provider",
 				GoogleProject: "project",
 				HealthPort:    "1234",
-				DryRun:        true,
+				Interval:      10 * time.Minute,
+				Once:          true,
+				DryRun:        false,
 				Debug:         true,
 				LogFormat:     "yaml",
 				Version:       true,