go-rel/gin-example

package handler

import (
    "context"
    "sync"

    "github.com/gin-gonic/gin"
    "go.uber.org/zap"
)

// Pinger interface.
type Pinger interface {
    Ping(ctx context.Context) error
}

type ping struct {
    Service string `json:"service"`
    Status  string `json:"status"`
}

// Healthz handler.
type Healthz struct {
    pingers map[string]Pinger
}

// Show handle GET /
func (h Healthz) Show(c *gin.Context) {
    var (
        wg     sync.WaitGroup
        status = 200
        pings  = make([]ping, len(h.pingers))
    )

    wg.Add(len(h.pingers))

    i := 0
    for service, pinger := range h.pingers {
        go func(i int, service string, pinger Pinger) {
            defer wg.Done()

            pings[i].Service = service
            if err := pinger.Ping(c); err != nil {
                logger.Error("ping error", zap.Error(err))

                status = 503
                pings[i].Status = err.Error()
            } else {
                pings[i].Status = "UP"
            }
        }(i, service, pinger)
        i++
    }
    wg.Wait()

    render(c, pings, status)
}

// Add a pinger.
func (h *Healthz) Add(name string, ping Pinger) {
    h.pingers[name] = ping
}

// Mount handlers to router group.
func (h *Healthz) Mount(router *gin.RouterGroup) {
    router.GET("/", h.Show)
}

// NewHealthz handler.
func NewHealthz() Healthz {
    h := Healthz{
        pingers: make(map[string]Pinger),
    }

    return h
}