Add custom ping http code when Traefik is terminating

docs/content/operations/ping.md

@@ -81,3 +81,28 @@ ping:
 ```bash tab="CLI"
 --ping.manualrouting=true
 ```
+
+### `terminatingStatusCode`
+
+_Optional, Default=503_
+
+During the period in which Traefik is gracefully shutting down, the ping handler
+returns a 503 status code by default. If Traefik is behind e.g. a load-balancer
+doing health checks (such as the Kubernetes LivenessProbe), another code might
+be expected as the signal for graceful termination. In which case, the
+terminatingStatusCode can be used to set the code returned by the ping
+handler during termination.
+
+```toml tab="File (TOML)"
+[ping]
+  terminatingStatusCode = 204
+```
+
+```yaml tab="File (YAML)"
+ping:
+  terminatingStatusCode: 204
+```
+
+```bash tab="CLI"
+--ping.terminatingStatusCode=204
+```

docs/content/reference/static-configuration/cli-ref.md

@@ -279,6 +279,9 @@ EntryPoint (Default: ```traefik```)
 `--ping.manualrouting`:  
 Manual routing (Default: ```false```)
 
+`--ping.terminatingstatuscode`:  
+Terminating status code (Default: ```503```)
+
 `--providers.consul`:  
 Enable Consul backend with default settings. (Default: ```false```)
 

docs/content/reference/static-configuration/env-ref.md

@@ -279,6 +279,9 @@ EntryPoint (Default: ```traefik```)
 `TRAEFIK_PING_MANUALROUTING`:  
 Manual routing (Default: ```false```)
 
+`TRAEFIK_PING_TERMINATINGSTATUSCODE`:  
+Terminating status code (Default: ```503```)
+
 `TRAEFIK_PROVIDERS_CONSUL`:  
 Enable Consul backend with default settings. (Default: ```false```)
 

integration/fixtures/custom_ping_termination_status_code.toml

@@ -0,0 +1,16 @@
+[global]
+  checkNewVersion = false
+  sendAnonymousUsage = false
+
+[log]
+  level = "DEBUG"
+
+[entryPoints]
+
+  [entryPoints.traefik]
+    address = ":8001"
+    [entryPoints.traefik.transport.lifeCycle]
+      requestAcceptGraceTimeout = "10s"
+
+[ping]
+    terminatingStatusCode = 204

integration/simple_test.go

@@ -161,6 +161,35 @@ func (s *SimpleSuite) TestRequestAcceptGraceTimeout(c *check.C) {
 	}
 }
 
+func (s *SimpleSuite) TestCustomPingTerminationStatusCode(c *check.C) {
+	file := s.adaptFile(c, "fixtures/custom_ping_termination_status_code.toml", struct{}{})
+	defer os.Remove(file)
+	cmd, display := s.traefikCmd(withConfigFile(file))
+	defer display(c)
+
+	err := cmd.Start()
+	c.Assert(err, checker.IsNil)
+	defer cmd.Process.Kill()
+
+	// Wait for Traefik to turn ready.
+	err = try.GetRequest("http://127.0.0.1:8001/", 2*time.Second, try.StatusCodeIs(http.StatusNotFound))
+	c.Assert(err, checker.IsNil)
+
+	// Check that /ping endpoint is responding with 200.
+	err = try.GetRequest("http://127.0.0.1:8001/ping", 3*time.Second, try.StatusCodeIs(http.StatusOK))
+	c.Assert(err, checker.IsNil)
+
+	// Send SIGTERM to Traefik.
+	proc, err := os.FindProcess(cmd.Process.Pid)
+	c.Assert(err, checker.IsNil)
+	err = proc.Signal(syscall.SIGTERM)
+	c.Assert(err, checker.IsNil)
+
+	// ping endpoint should now return a Service Unavailable.
+	err = try.GetRequest("http://127.0.0.1:8001/ping", 2*time.Second, try.StatusCodeIs(http.StatusNoContent))
+	c.Assert(err, checker.IsNil)
+}
+
 func (s *SimpleSuite) TestStatsWithMultipleEntryPoint(c *check.C) {
 	c.Skip("Stats is missing")
 	s.createComposeProject(c, "stats")

pkg/ping/ping.go

@@ -10,12 +10,14 @@ import (
 type Handler struct {
 	EntryPoint            string `description:"EntryPoint" export:"true" json:"entryPoint,omitempty" toml:"entryPoint,omitempty" yaml:"entryPoint,omitempty"`
 	ManualRouting         bool   `description:"Manual routing" json:"manualRouting,omitempty" toml:"manualRouting,omitempty" yaml:"manualRouting,omitempty"`
+	TerminatingStatusCode int    `description:"Terminating status code" json:"terminatingStatusCode,omitempty" toml:"terminatingStatusCode,omitempty" yaml:"terminatingStatusCode,omitempty"`
 	terminating           bool
 }
 
 // SetDefaults sets the default values.
 func (h *Handler) SetDefaults() {
 	h.EntryPoint = "traefik"
+	h.TerminatingStatusCode = http.StatusServiceUnavailable
 }
 
 // WithContext causes the ping endpoint to serve non 200 responses.
@@ -29,7 +31,7 @@ func (h *Handler) WithContext(ctx context.Context) {
 func (h *Handler) ServeHTTP(response http.ResponseWriter, request *http.Request) {
 	statusCode := http.StatusOK
 	if h.terminating {
-		statusCode = http.StatusServiceUnavailable
+		statusCode = h.TerminatingStatusCode
 	}
 	response.WriteHeader(statusCode)
 	fmt.Fprint(response, http.StatusText(statusCode))