Introducing go-sundheit code examples

custom-dns-check-example.go

import (
  "context"
  "fmt"
  "net"
  "time"

  "github.com/AppsFlyer/go-sundheit/checks"
  "github.com/pkg/errors"
)

func NewDNSCheck(host string, timeout time.Duration, minRequiredResults int) checks.Check {
  resolver := net.DefaultResolver

  return &checks.CustomCheck{
     CheckName: "resolve." + host,
     CheckFunc: func() (details interface{}, err error) {
        ctx, cancel := context.WithTimeout(context.TODO(), timeout)
        defer cancel()

        addrs, err := resolver.LookupHost(ctx, host)
        resolvedCount := len(addrs)
        details = fmt.Sprintf("[%d] results were resolved", resolvedCount)
        if err != nil {
           return
        }
        if resolvedCount < minRequiredResults {
           err = errors.Errorf("[%s] lookup returned %d results, but requires at least %d", host, resolvedCount, minRequiredResults)
        }

        return
     },
  }
}

health-api-compact-response.py

$ curl -i http://localhost:8080/admin/health.json?type=short
HTTP/1.1 200 OK
Content-Type: application/json
Date: Wed, 17 Jul 2019 12:54:18 GMT
Content-Length: 35

{
	"resolve.example.com": "PASS"
}

health-api-response.py

$ curl -i http://localhost:8080/admin/health.json
HTTP/1.1 200 OK
Content-Type: application/json
Date: Wed, 17 Jul 2019 12:54:20 GMT
Content-Length: 208

{
	"resolve.example.com": {
		"message": "[2] results were resolved",
		"timestamp": "2019-07-17T15:54:18.225468956+03:00",
		"duration": 1689142,
		"contiguousFailures": 0,
		"timeOfFirstFailure": null
	}
}

health-as-ping.go

http.HandleFunc("/health", func(w http.ResponseWriter, request *http.Request) {
  w.WriteHeader(200)
})
log.Fatal(http.ListenAndServe(":8080", nil))

register-health-checks-example.go

import (
  "time"

  health "github.com/AppsFlyer/go-sundheit"
  "github.com/AppsFlyer/go-sundheit/checks"

)

func registerHealthChecks() {
  // create a new health instance
  var h = health.New()
  // Schedule a host resolution check for `example.com`, requiring at least one results, and running every 10 sec
  h.RegisterCheck(&health.Config{
     Check:           checks.NewResolveCheck("example.com", 200*time.Millisecond, 1),
     ExecutionPeriod: 10 * time.Second,
  })

  // schedule more checks...
}