✨ feat: add liveness and readiness checks

app.go

@@ -35,6 +35,9 @@ const Version = "2.46.0"
 // Handler defines a function to serve HTTP requests.
 type Handler = func(*Ctx) error
 
+// Probe Checker defines a function to check liveness or readiness of the application
+type ProbeChecker = func(*Ctx) bool
+
 // Map is a shortcut for map[string]interface{}, useful for JSON returns
 type Map map[string]interface{}
 
@@ -390,6 +393,26 @@ type Config struct {
 	//
 	// Optional. Default: DefaultMethods
 	RequestMethods []string
+
+	// Config for liveness probe of the container engine being used
+	//
+	// Optional. Default: func(c *Ctx) bool { return true }
+	IsLive ProbeChecker
+
+	// Config for liveness probe of the container engine being used
+	//
+	// Optional. Default: /liveness
+	IsLiveEndpoint string
+
+	// Config for readiness probe of the container engine being used
+	//
+	// Optional. Default: func(c *Ctx) bool { return true }
+	IsReady ProbeChecker
+
+	// Config for readiness probe of the container engine being used
+	//
+	// Optional. Default: /readiness
+	IsReadyEndpoint string
 }
 
 // Static defines configuration options when defining static assets.
@@ -453,8 +476,22 @@ const (
 	DefaultReadBufferSize       = 4096
 	DefaultWriteBufferSize      = 4096
 	DefaultCompressedFileSuffix = ".fiber.gz"
+	DefaultLivenessEndpoint     = "/healthz"
+	DefaultReadinessEndpoint    = "/readyz"
 )
 
+var DefaultHealthFunction = func(c *Ctx) bool { return true }
+
+var ProbeCheckerHandler = func(checker ProbeChecker) Handler {
+	return func(c *Ctx) error {
+		if checker(c) {
+			return c.SendStatus(StatusOK)
+		}
+
+		return c.SendStatus(StatusServiceUnavailable)
+	}
+}
+
 // HTTP methods enabled by default
 var DefaultMethods = []string{
 	MethodGet,
@@ -564,6 +601,15 @@ func New(config ...Config) *App {
 	if len(app.config.RequestMethods) == 0 {
 		app.config.RequestMethods = DefaultMethods
 	}
+	if app.config.IsLiveEndpoint == "" {
+		app.config.IsLiveEndpoint = DefaultLivenessEndpoint
+	}
+	if app.config.IsReadyEndpoint == "" {
+		app.config.IsReadyEndpoint = DefaultReadinessEndpoint
+	}
+	if app.config.IsLive == nil {
+		app.config.IsLive = DefaultHealthFunction
+	}
 
 	app.config.trustedProxiesMap = make(map[string]struct{}, len(app.config.TrustedProxies))
 	for _, ipAddress := range app.config.TrustedProxies {
@@ -580,6 +626,14 @@ func New(config ...Config) *App {
 	// Init app
 	app.init()
 
+	if app.config.IsReady != nil {
+		app.Get(app.config.IsReadyEndpoint, ProbeCheckerHandler(app.config.IsReady))
+		app.Options(app.config.IsReadyEndpoint, ProbeCheckerHandler(app.config.IsReady))
+	}
+
+	app.Get(app.config.IsLiveEndpoint, ProbeCheckerHandler(app.config.IsLive))
+	app.Options(app.config.IsLiveEndpoint, ProbeCheckerHandler(app.config.IsLive))
+
 	// Return app
 	return app
 }

app_test.go

@@ -1862,3 +1862,47 @@ func Test_Middleware_Route_Naming_With_Use(t *testing.T) {
 		}
 	}
 }
+
+func Test_Default_Liveness_Probe(t *testing.T) {
+	app := New()
+
+	resp, err := app.Test(httptest.NewRequest(MethodGet, "/healthz", nil))
+
+	utils.AssertEqual(t, nil, err)
+	utils.AssertEqual(t, 200, resp.StatusCode)
+}
+
+func Test_Custom_Liveness_Probe(t *testing.T) {
+	app := New(Config{
+		IsLive:         func(c *Ctx) bool { return true },
+		IsLiveEndpoint: "/live",
+	})
+
+	resp, err := app.Test(httptest.NewRequest(MethodGet, "/live", nil))
+
+	utils.AssertEqual(t, nil, err)
+	utils.AssertEqual(t, 200, resp.StatusCode)
+}
+
+func Test_Default_Readiness_Probe(t *testing.T) {
+	app := New(Config{
+		IsReady: func(c *Ctx) bool { return true },
+	})
+
+	resp, err := app.Test(httptest.NewRequest(MethodGet, "/readyz", nil))
+
+	utils.AssertEqual(t, nil, err)
+	utils.AssertEqual(t, 200, resp.StatusCode)
+}
+
+func Test_Custom_Readiness_Probe(t *testing.T) {
+	app := New(Config{
+		IsReady:         func(c *Ctx) bool { return true },
+		IsReadyEndpoint: "/ready",
+	})
+
+	resp, err := app.Test(httptest.NewRequest(MethodGet, "/ready", nil))
+
+	utils.AssertEqual(t, nil, err)
+	utils.AssertEqual(t, 200, resp.StatusCode)
+}

docs/api/app.md

@@ -655,3 +655,26 @@ Hooks is a method to return [hooks](../guide/hooks.md) property.
 ```go title="Signature"
 func (app *App) Hooks() *Hooks
 ```
+
+## Liveness And Readiness Checks
+
+Fiber comes with an out of the box way of implementing your liveness and readiness checking, when creating a new app, you can pass your own handlers for liveness and readiness checks:
+
+```go title="Examples"
+// Create route with GET method for test:
+app := fiber.New(fiber.Config{
+  IsLive: func (c *fiber.Ctx) bool {
+    return true
+  },
+  IsLiveEndpoint: "/liveness",
+  IsReady: func (c *fiber.Ctx) bool {
+    return serviceA.Ready() && serviceB.Ready() && ...
+  }
+  IsReadyEndpoint: "/readiness",
+})
+
+// Listen on port :8080 
+app.Listen(":8080")
+```
+
+The endpoint values default to `/healthz` for liveness and `/readyz` for readiness. Both functions are optional, the liveness endpoint will return `true` right when the server is up and running but the readiness endpoint will not answer any requests if an `IsReady` function isn't provided.