feat(health): HEALTH_SUCCESS_WAIT_DURATION

Dockerfile

@@ -141,6 +141,7 @@ ENV VPN_SERVICE_PROVIDER=pia \
     # Health
     HEALTH_SERVER_ADDRESS=127.0.0.1:9999 \
     HEALTH_TARGET_ADDRESS=cloudflare.com:443 \
+    HEALTH_SUCCESS_WAIT_DURATION=5s \
     HEALTH_VPN_DURATION_INITIAL=6s \
     HEALTH_VPN_DURATION_ADDITION=5s \
     # DNS over TLS

internal/configuration/settings/health.go

@@ -20,13 +20,19 @@ type Health struct {
 	// duration of the HTTP server. It defaults to 100 milliseconds.
 	ReadHeaderTimeout time.Duration
 	// ReadTimeout is the HTTP read timeout duration of the
-	//  HTTP server. It defaults to 500 milliseconds.
+	// HTTP server. It defaults to 500 milliseconds.
 	ReadTimeout time.Duration
 	// TargetAddress is the address (host or host:port)
 	// to TCP dial to periodically for the health check.
 	// It cannot be the empty string in the internal state.
 	TargetAddress string
-	VPN           HealthyWait
+	// SuccessWait is the duration to wait to re-run the
+	// healthcheck after a successful healthcheck.
+	// It defaults to 5 seconds and cannot be zero in
+	// the internal state.
+	SuccessWait time.Duration
+	// VPN has health settings specific to the VPN loop.
+	VPN HealthyWait
 }
 
 func (h Health) Validate() (err error) {
@@ -51,6 +57,7 @@ func (h *Health) copy() (copied Health) {
 		ReadHeaderTimeout: h.ReadHeaderTimeout,
 		ReadTimeout:       h.ReadTimeout,
 		TargetAddress:     h.TargetAddress,
+		SuccessWait:       h.SuccessWait,
 		VPN:               h.VPN.copy(),
 	}
 }
@@ -62,6 +69,7 @@ func (h *Health) MergeWith(other Health) {
 	h.ReadHeaderTimeout = helpers.MergeWithDuration(h.ReadHeaderTimeout, other.ReadHeaderTimeout)
 	h.ReadTimeout = helpers.MergeWithDuration(h.ReadTimeout, other.ReadTimeout)
 	h.TargetAddress = helpers.MergeWithString(h.TargetAddress, other.TargetAddress)
+	h.SuccessWait = helpers.MergeWithDuration(h.SuccessWait, other.SuccessWait)
 	h.VPN.mergeWith(other.VPN)
 }
 
@@ -73,6 +81,7 @@ func (h *Health) OverrideWith(other Health) {
 	h.ReadHeaderTimeout = helpers.OverrideWithDuration(h.ReadHeaderTimeout, other.ReadHeaderTimeout)
 	h.ReadTimeout = helpers.OverrideWithDuration(h.ReadTimeout, other.ReadTimeout)
 	h.TargetAddress = helpers.OverrideWithString(h.TargetAddress, other.TargetAddress)
+	h.SuccessWait = helpers.OverrideWithDuration(h.SuccessWait, other.SuccessWait)
 	h.VPN.overrideWith(other.VPN)
 }
 
@@ -83,6 +92,8 @@ func (h *Health) SetDefaults() {
 	const defaultReadTimeout = 500 * time.Millisecond
 	h.ReadTimeout = helpers.DefaultDuration(h.ReadTimeout, defaultReadTimeout)
 	h.TargetAddress = helpers.DefaultString(h.TargetAddress, "cloudflare.com:443")
+	const defaultSuccessWait = 5 * time.Second
+	h.SuccessWait = helpers.DefaultDuration(h.SuccessWait, defaultSuccessWait)
 	h.VPN.setDefaults()
 }
 
@@ -94,6 +105,7 @@ func (h Health) toLinesNode() (node *gotree.Node) {
 	node = gotree.New("Health settings:")
 	node.Appendf("Server listening address: %s", h.ServerAddress)
 	node.Appendf("Target address: %s", h.TargetAddress)
+	node.Appendf("Duration to wait after success: %s", h.SuccessWait)
 	node.Appendf("Read header timeout: %s", h.ReadHeaderTimeout)
 	node.Appendf("Read timeout: %s", h.ReadTimeout)
 	node.AppendNode(h.VPN.toLinesNode("VPN"))

internal/configuration/settings/settings_test.go

@@ -66,6 +66,7 @@ func Test_Settings_String(t *testing.T) {
 ├── Health settings:
 |   ├── Server listening address: 127.0.0.1:9999
 |   ├── Target address: cloudflare.com:443
+|   ├── Duration to wait after success: 5s
 |   ├── Read header timeout: 100ms
 |   ├── Read timeout: 500ms
 |   └── VPN wait durations:

internal/configuration/sources/env/health.go

@@ -11,6 +11,13 @@ func (s *Source) ReadHealth() (health settings.Health, err error) {
 	health.ServerAddress = getCleanedEnv("HEALTH_SERVER_ADDRESS")
 	_, health.TargetAddress = s.getEnvWithRetro("HEALTH_TARGET_ADDRESS", "HEALTH_ADDRESS_TO_PING")
 
+	successWaitPtr, err := envToDurationPtr("HEALTH_SUCCESS_WAIT_DURATION")
+	if err != nil {
+		return health, fmt.Errorf("environment variable HEALTH_SUCCESS_WAIT_DURATION: %w", err)
+	} else if successWaitPtr != nil {
+		health.SuccessWait = *successWaitPtr
+	}
+
 	health.VPN.Initial, err = s.readDurationWithRetro(
 		"HEALTH_VPN_DURATION_INITIAL",
 		"HEALTH_OPENVPN_DURATION_INITIAL")

internal/healthcheck/health.go

@@ -49,9 +49,8 @@ func (s *Server) runHealthcheckLoop(ctx context.Context, done chan<- struct{}) {
 			continue
 		}
 
-		// Success, check again in 5 seconds
+		// Success, check again after the success wait duration
-		const period = 5 * time.Second
+		timer := time.NewTimer(s.config.SuccessWait)
-		timer := time.NewTimer(period)
 		select {
 		case <-ctx.Done():
 			if !timer.Stop() {