Add ResponseCode to CircuitBreaker

docs/content/middlewares/http/circuitbreaker.md

@@ -85,6 +85,7 @@ At specified intervals (`checkPeriod`), the circuit breaker evaluates `expressio
 ### Open
 
 While open, the fallback mechanism takes over the normal service calls for a duration of `FallbackDuration`.
+The fallback mechanism returns a `HTTP 503` (or `ResponseCode`) to the client.
 After this duration, it enters the recovering state.
 
 ### Recovering
@@ -179,3 +180,9 @@ The duration for which the circuit breaker will wait before trying to recover (f
 _Optional, Default="10s"_
 
 The duration for which the circuit breaker will try to recover (as soon as it is in recovering state).
+
+### `ResponseCode`
+
+_Optional, Default="503"_
+
+The status code that the circuit breaker will return while it is in the open state.

docs/content/reference/dynamic-configuration/docker-labels.yml

@@ -16,6 +16,7 @@
 - "traefik.http.middlewares.middleware05.circuitbreaker.expression=foobar"
 - "traefik.http.middlewares.middleware05.circuitbreaker.fallbackduration=42s"
 - "traefik.http.middlewares.middleware05.circuitbreaker.recoveryduration=42s"
+- "traefik.http.middlewares.middleware05.circuitbreaker.responsecode=42"
 - "traefik.http.middlewares.middleware06.compress=true"
 - "traefik.http.middlewares.middleware06.compress.excludedcontenttypes=foobar, foobar"
 - "traefik.http.middlewares.middleware06.compress.includedcontenttypes=foobar, foobar"

docs/content/reference/dynamic-configuration/file.toml

@@ -137,6 +137,7 @@
         checkPeriod = "42s"
         fallbackDuration = "42s"
         recoveryDuration = "42s"
+        responseCode = 42
     [http.middlewares.Middleware06]
       [http.middlewares.Middleware06.compress]
         excludedContentTypes = ["foobar", "foobar"]

docs/content/reference/dynamic-configuration/file.yaml

@@ -142,6 +142,7 @@ http:
         checkPeriod: 42s
         fallbackDuration: 42s
         recoveryDuration: 42s
+        responseCode: 42
     Middleware06:
       compress:
         excludedContentTypes:

docs/content/reference/dynamic-configuration/kv-ref.md

@@ -20,6 +20,7 @@ THIS FILE MUST NOT BE EDITED BY HAND
 | `traefik/http/middlewares/Middleware05/circuitBreaker/expression` | `foobar` |
 | `traefik/http/middlewares/Middleware05/circuitBreaker/fallbackDuration` | `42s` |
 | `traefik/http/middlewares/Middleware05/circuitBreaker/recoveryDuration` | `42s` |
+| `traefik/http/middlewares/Middleware05/circuitBreaker/responseCode` | `42` |
 | `traefik/http/middlewares/Middleware06/compress/excludedContentTypes/0` | `foobar` |
 | `traefik/http/middlewares/Middleware06/compress/excludedContentTypes/1` | `foobar` |
 | `traefik/http/middlewares/Middleware06/compress/includedContentTypes/0` | `foobar` |

pkg/config/dynamic/middlewares.go

@@ -1,6 +1,7 @@
 package dynamic
 
 import (
+	"net/http"
 	"time"
 
 	ptypes "github.com/traefik/paerser/types"
@@ -141,6 +142,8 @@ type CircuitBreaker struct {
 	FallbackDuration ptypes.Duration `json:"fallbackDuration,omitempty" toml:"fallbackDuration,omitempty" yaml:"fallbackDuration,omitempty" export:"true"`
 	// RecoveryDuration is the duration for which the circuit breaker will try to recover (as soon as it is in recovering state).
 	RecoveryDuration ptypes.Duration `json:"recoveryDuration,omitempty" toml:"recoveryDuration,omitempty" yaml:"recoveryDuration,omitempty" export:"true"`
+	// ResponseCode is the status code that the circuit breaker will return while it is in the open state.
+	ResponseCode int `json:"responseCode,omitempty" toml:"responseCode,omitempty" yaml:"responseCode,omitempty" export:"true"`
 }
 
 // SetDefaults sets the default values on a RateLimit.
@@ -148,6 +151,7 @@ func (c *CircuitBreaker) SetDefaults() {
 	c.CheckPeriod = ptypes.Duration(100 * time.Millisecond)
 	c.FallbackDuration = ptypes.Duration(10 * time.Second)
 	c.RecoveryDuration = ptypes.Duration(10 * time.Second)
+	c.ResponseCode = http.StatusServiceUnavailable
 }
 
 // +k8s:deepcopy-gen=true

pkg/config/label/label_test.go

@@ -30,6 +30,7 @@ func TestDecodeConfiguration(t *testing.T) {
 		"traefik.HTTP.Middlewares.Middleware4.circuitbreaker.checkperiod":                          "1s",
 		"traefik.HTTP.Middlewares.Middleware4.circuitbreaker.fallbackduration":                     "1s",
 		"traefik.HTTP.Middlewares.Middleware4.circuitbreaker.recoveryduration":                     "1s",
+		"traefik.HTTP.Middlewares.Middleware4.circuitbreaker.responsecode":                         "403",
 		"traefik.http.middlewares.Middleware5.digestauth.headerfield":                              "foobar",
 		"traefik.http.middlewares.Middleware5.digestauth.realm":                                    "foobar",
 		"traefik.http.middlewares.Middleware5.digestauth.removeheader":                             "true",
@@ -496,6 +497,7 @@ func TestDecodeConfiguration(t *testing.T) {
 						CheckPeriod:      ptypes.Duration(time.Second),
 						FallbackDuration: ptypes.Duration(time.Second),
 						RecoveryDuration: ptypes.Duration(time.Second),
+						ResponseCode:     403,
 					},
 				},
 				"Middleware5": {
@@ -996,6 +998,7 @@ func TestEncodeConfiguration(t *testing.T) {
 						CheckPeriod:      ptypes.Duration(time.Second),
 						FallbackDuration: ptypes.Duration(time.Second),
 						RecoveryDuration: ptypes.Duration(time.Second),
+						ResponseCode:     404,
 					},
 				},
 				"Middleware5": {
@@ -1206,6 +1209,7 @@ func TestEncodeConfiguration(t *testing.T) {
 		"traefik.HTTP.Middlewares.Middleware4.CircuitBreaker.CheckPeriod":                          "1000000000",
 		"traefik.HTTP.Middlewares.Middleware4.CircuitBreaker.FallbackDuration":                     "1000000000",
 		"traefik.HTTP.Middlewares.Middleware4.CircuitBreaker.RecoveryDuration":                     "1000000000",
+		"traefik.HTTP.Middlewares.Middleware4.CircuitBreaker.ResponseCode":                         "404",
 		"traefik.HTTP.Middlewares.Middleware5.DigestAuth.HeaderField":                              "foobar",
 		"traefik.HTTP.Middlewares.Middleware5.DigestAuth.Realm":                                    "foobar",
 		"traefik.HTTP.Middlewares.Middleware5.DigestAuth.RemoveHeader":                             "true",

pkg/middlewares/circuitbreaker/circuit_breaker.go

@@ -30,12 +30,14 @@ func New(ctx context.Context, next http.Handler, confCircuitBreaker dynamic.Circ
 	logger.Debug().Msg("Creating middleware")
 	logger.Debug().Msgf("Setting up with expression: %s", expression)
 
+	responseCode := confCircuitBreaker.ResponseCode
+
 	cbOpts := []cbreaker.Option{
 		cbreaker.Fallback(http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
 			tracing.SetStatusErrorf(req.Context(), "blocked by circuit-breaker (%q)", expression)
-			rw.WriteHeader(http.StatusServiceUnavailable)
+			rw.WriteHeader(responseCode)
 
-			if _, err := rw.Write([]byte(http.StatusText(http.StatusServiceUnavailable))); err != nil {
+			if _, err := rw.Write([]byte(http.StatusText(responseCode))); err != nil {
 				log.Ctx(req.Context()).Error().Err(err).Send()
 			}
 		})),

pkg/provider/kv/kv_test.go

@@ -171,6 +171,7 @@ func Test_buildConfiguration(t *testing.T) {
 		"traefik/http/middlewares/Middleware04/circuitBreaker/checkPeriod":                           "1s",
 		"traefik/http/middlewares/Middleware04/circuitBreaker/fallbackDuration":                      "1s",
 		"traefik/http/middlewares/Middleware04/circuitBreaker/recoveryDuration":                      "1s",
+		"traefik/http/middlewares/Middleware04/circuitBreaker/responseCode":                          "404",
 		"traefik/http/middlewares/Middleware07/errors/status/0":                                      "foobar",
 		"traefik/http/middlewares/Middleware07/errors/status/1":                                      "foobar",
 		"traefik/http/middlewares/Middleware07/errors/service":                                       "foobar",
@@ -392,6 +393,7 @@ func Test_buildConfiguration(t *testing.T) {
 						CheckPeriod:      ptypes.Duration(time.Second),
 						FallbackDuration: ptypes.Duration(time.Second),
 						RecoveryDuration: ptypes.Duration(time.Second),
+						ResponseCode:     404,
 					},
 				},
 				"Middleware05": {