go 56 lines · 7 steps

Liveness vs readiness health checks in Gin

A Gin handler that separates 'is the process alive' from 'can it actually serve traffic' by pinging its dependencies.

Explained by highlit
Gin Intermediate health-checks dependency-injection context-timeout kubernetes-probes
1package handlers
2 
3import (
4 "context"
5 "net/http"
6 "time"
7 
8 "github.com/gin-gonic/gin"
9 "github.com/redis/go-redis/v9"
10 "gorm.io/gorm"
11)
12 
13type HealthHandler struct {
14 DB *gorm.DB
15 Redis *redis.Client
16}
17 
18func RegisterHealthRoutes(r *gin.Engine, h *HealthHandler) {
19 group := r.Group("/health")
20 {
21 group.GET("/live", h.Liveness)
22 group.GET("/ready", h.Readiness)
23 }
24}
25 
26func (h *HealthHandler) Liveness(c *gin.Context) {
27 c.JSON(http.StatusOK, gin.H{"status": "ok"})
28}
29 
30func (h *HealthHandler) Readiness(c *gin.Context) {
31 ctx, cancel := context.WithTimeout(c.Request.Context(), 2*time.Second)
32 defer cancel()
33 
34 checks := gin.H{"database": "ok", "redis": "ok"}
35 ready := true
36 
37 if sqlDB, err := h.DB.DB(); err != nil || sqlDB.PingContext(ctx) != nil {
38 checks["database"] = "unavailable"
39 ready = false
40 }
41 
42 if err := h.Redis.Ping(ctx).Err(); err != nil {
43 checks["redis"] = "unavailable"
44 ready = false
45 }
46 
47 status := http.StatusOK
48 if !ready {
49 status = http.StatusServiceUnavailable
50 }
51 
52 c.JSON(status, gin.H{
53 "ready": ready,
54 "checks": checks,
55 })
56}
01 / 01
STEP 01

Walkthrough

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Three takeaways
  1. 1Liveness answers whether the process is running while readiness answers whether it can serve requests, and they deserve separate endpoints.
  2. 2Bounding dependency checks with a context timeout stops a hung database or cache from making the probe itself hang.
  3. 3Returning 503 when any dependency is down lets orchestrators route traffic away instead of failing user requests.

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