✨ feat: add liveness and readiness checks

app.go

@@ -453,6 +453,8 @@ const (
 	DefaultReadBufferSize       = 4096
 	DefaultWriteBufferSize      = 4096
 	DefaultCompressedFileSuffix = ".fiber.gz"
+	DefaultLivenessEndpoint     = "/livez"
+	DefaultReadinessEndpoint    = "/readyz"
 )
 
 // HTTP methods enabled by default

docs/api/app.md

@@ -654,4 +654,4 @@ Hooks is a method to return [hooks](../guide/hooks.md) property.
 
 ```go title="Signature"
 func (app *App) Hooks() *Hooks
-```
+```

docs/api/middleware/probechecker.md

@@ -0,0 +1,75 @@
+---
+id: probecheker
+title: probecheker
+---
+
+Liveness and readiness probes middleware for [Fiber](https://github.com/gofiber/fiber) that provides two endpoints for checking the health and ready state of any HTTP application.
+
+The endpoint values default to `/livez` 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. 
+
+The HTTP status returned to the containerized environment are: 200 OK if the checker function returns true and 503 Service Unavailable if the checker function returns false.
+
+## Signatures
+
+```go
+func New() fiber.Handler
+```
+
+## Examples
+
+Import the middleware package that is part of the Fiber web framework
+
+```go
+import (
+  "github.com/gofiber/fiber/v2"
+  "github.com/gofiber/fiber/v2/middleware/probechecker"
+)
+```
+
+After you initiate your Fiber app, you can use the following possibilities:
+
+```go
+// Initializing with default config
+app.Use(probechecker.New())
+
+// Initialize with custom config
+app.Use(
+	probechecker.New(
+		IsLive: func (c *fiber.Ctx) bool {
+    	return true
+  	},
+  	IsLiveEndpoint: "/livez",
+  	IsReady: func (c *fiber.Ctx) bool {
+	    return serviceA.Ready() && serviceB.Ready() && ...
+	  }
+	  IsReadyEndpoint: "/readyz",
+	)
+)
+
+```
+
+## Config
+
+```go
+type Config struct {
+	// Config for liveness probe of the container engine being used
+	//
+	// Optional. Default: func(c *Ctx) bool { return true }
+	IsLive ProbeChecker
+
+	// HTTP endpoint of the liveness probe
+	//
+	// Optional. Default: /livez
+	IsLiveEndpoint string
+
+	// Config for readiness probe of the container engine being used
+	//
+	// Optional. Default: nil
+	IsReady ProbeChecker
+
+	// HTTP endpoint of the readiness probe
+	//
+	// Optional. Default: /readyz
+	IsReadyEndpoint string
+}
+```

middleware/probechecker/config.go

@@ -0,0 +1,63 @@
+package probechecker
+
+import "github.com/gofiber/fiber/v2"
+
+// Config is the config struct for the probechecker middleware
+type Config struct {
+	// Config for liveness probe of the container engine being used
+	//
+	// Optional. Default: func(c *Ctx) bool { return true }
+	IsLive ProbeChecker
+
+	// HTTP endpoint of the liveness probe
+	//
+	// Optional. Default: /livez
+	IsLiveEndpoint string
+
+	// Config for readiness probe of the container engine being used
+	//
+	// Optional. Default: nil
+	IsReady ProbeChecker
+
+	// HTTP endpoint of the readiness probe
+	//
+	// Optional. Default: /readyz
+	IsReadyEndpoint string
+}
+
+const (
+	DefaultLivenessEndpoint  = "/livez"
+	DefaultReadinessEndpoint = "/readyz"
+)
+
+func defaultLiveFunc(*fiber.Ctx) bool { return true }
+
+// ConfigDefault is the default config
+var ConfigDefault = Config{
+	IsLive:          defaultLiveFunc,
+	IsLiveEndpoint:  DefaultLivenessEndpoint,
+	IsReadyEndpoint: DefaultReadinessEndpoint,
+}
+
+// defaultConfig returns a default config for the probechecker middleware.
+func defaultConfig(config ...Config) Config {
+	if len(config) < 1 {
+		return ConfigDefault
+	}
+
+	cfg := config[0]
+
+	if cfg.IsLive == nil {
+		cfg.IsLive = defaultLiveFunc
+	}
+
+	if cfg.IsLiveEndpoint == "" {
+		cfg.IsLiveEndpoint = DefaultLivenessEndpoint
+	}
+
+	if cfg.IsReadyEndpoint == "" {
+		cfg.IsReadyEndpoint = DefaultReadinessEndpoint
+	}
+
+	return cfg
+}

middleware/probechecker/probechecker.go

@@ -0,0 +1,64 @@
+package probechecker
+
+import (
+	"fmt"
+
+	"github.com/gofiber/fiber/v2"
+)
+
+// ProbeChecker defines a function to check liveness or readiness of the application
+type ProbeChecker func(*fiber.Ctx) bool
+
+// ProbeCheckerHandler defines a function that returns a ProbeChecker
+type ProbeCheckerHandler func(ProbeChecker) fiber.Handler
+
+func probeCheckerHandler(checker ProbeChecker) fiber.Handler {
+	return func(c *fiber.Ctx) error {
+		if checker == nil {
+			return c.Next()
+		}
+
+		if checker(c) {
+			return c.SendStatus(fiber.StatusOK)
+		}
+
+		return c.SendStatus(fiber.StatusServiceUnavailable)
+	}
+}
+
+func checkRoute(path string, config *Config) string {
+	switch path {
+	case DefaultLivenessEndpoint, config.IsLiveEndpoint:
+		return "liveness"
+	case DefaultReadinessEndpoint, config.IsReadyEndpoint:
+		return "readiness"
+	default:
+		return ""
+	}
+}
+
+func New(config ...Config) fiber.Handler {
+	cfg := defaultConfig(config...)
+
+	checkers := map[string]fiber.Handler{
+		"liveness":  probeCheckerHandler(cfg.IsLive),
+		"readiness": probeCheckerHandler(cfg.IsReady),
+	}
+
+	return func(c *fiber.Ctx) error {
+		route := c.Route()
+		routeType := checkRoute(route.Path, &cfg)
+
+		if routeType != "" || route.Method != fiber.MethodGet {
+			handler, ok := checkers[routeType]
+
+			if !ok {
+				return fmt.Errorf("routeType of %s not found in checkers", routeType)
+			}
+
+			return handler(c)
+		}
+
+		return c.Next()
+	}
+}