fiber/docs/api/middleware/healthcheck.md

id
healthcheck

Health Check

Liveness and readiness probes middleware for Fiber that provides two endpoints for checking the liveness and readiness state of HTTP applications.

Overview

• Liveness Probe: Checks if the server is up and running.

  • Default Endpoint: /livez
  • Behavior: By default returns true immediately when the server is operational.

• Readiness Probe: Assesses if the application is ready to handle requests.

  • Default Endpoint: /readyz
  • Behavior: By default returns true immediately when the server is operational.

• HTTP Status Codes:

  • 200 OK: Returned when the checker function evaluates to true.
  • 503 Service Unavailable: Returned when the checker function evaluates to false.

Signatures

func New(config Config) fiber.Handler

Examples

Import the middleware package that is part of the Fiber web framework

import (
    "github.com/gofiber/fiber/v3"
    "github.com/gofiber/fiber/v3/middleware/healthcheck"
)

After you initiate your Fiber app, you can use the following possibilities:

// Provide a minimal config
app.Use(healthcheck.New())

// Or extend your config for customization
app.Use(healthcheck.New(healthcheck.Config{
    LivenessProbe: func(c fiber.Ctx) bool {
        return true
    },
    LivenessEndpoint: "/live",
    ReadinessProbe: func(c fiber.Ctx) bool {
        return serviceA.Ready() && serviceB.Ready() && ...
    },
    ReadinessEndpoint: "/ready",
}))

Config

type Config struct {
	// Next defines a function to skip this middleware when returned true.
	//
	// Optional. Default: nil
	Next func(fiber.Ctx) bool

	// Function used for checking the liveness of the application. Returns true if the application
	// is running and false if it is not. The liveness probe is typically used to indicate if 
	// the application is in a state where it can handle requests (e.g., the server is up and running).
	//
	// Optional. Default: func(c fiber.Ctx) bool { return true }
	LivenessProbe HealthChecker

	// HTTP endpoint at which the liveness probe will be available.
	//
	// Optional. Default: "/livez"
	LivenessEndpoint string

	// Function used for checking the readiness of the application. Returns true if the application
	// is ready to process requests and false otherwise. The readiness probe typically checks if all necessary
	// services, databases, and other dependencies are available for the application to function correctly.
	//
	// Optional. Default: func(c fiber.Ctx) bool { return true }
	ReadinessProbe HealthChecker

	// HTTP endpoint at which the readiness probe will be available.
	// Optional. Default: "/readyz"
	ReadinessEndpoint string
}

Default Config

The default configuration used by this middleware is defined as follows:

func defaultLivenessProbe(fiber.Ctx) bool { return true }

func defaultReadinessProbe(fiber.Ctx) bool { return true }

var ConfigDefault = Config{
	LivenessProbe:     defaultLivenessProbe,
	ReadinessProbe:    defaultReadinessProbe,
	LivenessEndpoint:  "/livez",
	ReadinessEndpoint: "/readyz",
}