fix(pkg/healthz): add readiness & liveness probes

Author: Aaron Schlesinger

pkg/healthsrv/healthz_handler.go

@@ -0,0 +1,49 @@
+package healthsrv
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"time"
+
+	s3 "github.com/aws/aws-sdk-go/service/s3"
+)
+
+type healthZRespBucket struct {
+	Name         string    `json:"name"`
+	CreationDate time.Time `json:"creation_date"`
+}
+
+func convertBucket(b *s3.Bucket) healthZRespBucket {
+	return healthZRespBucket{
+		Name:         *b.Name,
+		CreationDate: *b.CreationDate,
+	}
+}
+
+type healthZResp struct {
+	Buckets []healthZRespBucket `json:"buckets"`
+}
+
+func healthZHandler(s3Client *s3.S3) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		lbOut, err := s3Client.ListBuckets(s3.ListBucketsInput{})
+		if err != nil {
+			str := fmt.Sprintf("Error listing buckets (%s)", err)
+			log.Printf(str)
+			http.Error(w, str, http.StatusInternalServerError)
+			return
+		}
+		var rsp healthZResp
+		for _, buck := range lbOut.Buckets {
+			rsp.Buckets = append(rsp.Buckets, convertBucket(buck))
+		}
+		if err := json.NewEncoder(w).Encode(rsp); err != nil {
+			str := fmt.Sprintf("Error encoding JSON (%s)", err)
+			http.Error(w, str, http.StatusInternalServerError)
+			return
+		}
+		// TODO: check k8s API
+		// TODO: check server is running
+	})
+}

pkg/healthsrv/server.go

@@ -0,0 +1,22 @@
+package healthsrv
+
+import (
+	"fmt"
+	"net/http"
+
+	s3 "github.com/aws/aws-sdk-go/service/s3"
+)
+
+const (
+	DefaultHost = "0.0.0.0"
+	DefaultPort = 8082
+)
+
+// Start starts the healthcheck server on $host:$port and blocks. It only returns if the server fails, with the indicative error
+func Start(host string, port int, s3Client *s3.S3) error {
+	mux := http.NewServeMux()
+	mux.Handle("/healthz", healthZHandler(s3Client))
+
+	hostStr := fmt.Sprintf("%s:%d", host, port)
+	return http.ListenAndServe(hostStr, mux)
+}