diff --git a/Dockerfile b/Dockerfile
index 7c81fa1..93f4090 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM golang:1.19-alpine as builder
+FROM golang:1.22-alpine as builder
 ENV CGO_ENABLED=0
 ENV GOOS=linux
 
diff --git a/cmon_sd.go b/cmon_sd.go
index 042656b..c8eab56 100644
--- a/cmon_sd.go
+++ b/cmon_sd.go
@@ -15,58 +15,110 @@ package main
 
 import (
 	"encoding/json"
+	"errors"
 	"log"
+	"log/slog"
 	"net/http"
 	"os"
+	"slices"
+	"sort"
 	"strconv"
 
 	"flag"
 	"fmt"
+
 	"github.com/severalnines/cmon-proxy/cmon"
 	"github.com/severalnines/cmon-proxy/cmon/api"
 	"github.com/severalnines/cmon-proxy/config"
 )
 
-const namespace = "cmon"
-
-var cmonEndpoint string
-var cmonUsername string
-var cmonPassword string
-
 type ClusterTarget struct {
 	Target []string          `json:"targets,omitempty"`
 	Label  map[string]string `json:"labels,omitempty"`
 }
 
-func IndexHandler(w http.ResponseWriter, r *http.Request) {
+type Cmon interface {
+	Authenticate() error
+	ControllerID() string
+	GetAllClusterInfo(req *api.GetAllClusterInfoRequest) (*api.GetAllClusterInfoResponse, error)
+}
+
+type ErrorMessage struct {
+	Error string `json:"error"`
+}
+
+type Service struct {
+	cmonClient Cmon
+	log        *slog.Logger
+}
+
+func NewService() (*Service, error) {
+	cmonEndpoint := os.Getenv("CMON_ENDPOINT")
+	cmonUsername := os.Getenv("CMON_USERNAME")
+	cmonPassword := os.Getenv("CMON_PASSWORD")
+
+	if cmonEndpoint == "" {
+		cmonEndpoint = "https://127.0.0.1:9501"
+	}
+
+	if cmonUsername == "" {
+		return nil, errors.New("CMON_USERNAME is required")
+	}
+
+	if cmonPassword == "" {
+		return nil, errors.New("CMON_PASSWORD is required")
+	}
 
-	client := cmon.NewClient(&config.CmonInstance{
+	cmonClient := cmon.NewClient(&config.CmonInstance{
 		Url:      cmonEndpoint,
 		Username: cmonUsername,
 		Password: cmonPassword,
 	},
 		30)
 
-	err := client.Authenticate()
+	logger := slog.New(slog.NewJSONHandler(os.Stdout, nil))
+
+	err := cmonClient.Authenticate()
+	if err != nil {
+		return nil, err
+	}
+
+	return &Service{
+		cmonClient: cmonClient,
+		log:        logger,
+	}, nil
+}
+
+func (s *Service) errorResponse(w http.ResponseWriter, statusCode int, message string) {
+	m := ErrorMessage{Error: message}
+
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(statusCode)
+	json.NewEncoder(w).Encode(m)
+}
+
+func (s *Service) IndexHandler(w http.ResponseWriter, r *http.Request) {
+	err := s.cmonClient.Authenticate()
 	if err != nil {
-		res, err := client.Ping()
-		log.Println("Test: ", err, res)
+		s.log.Error("Error authenticating", err)
+		s.errorResponse(w, http.StatusUnauthorized, fmt.Sprintf("Error authenticating: %s", err.Error()))
 		return
 	}
 
-	res, err := client.GetAllClusterInfo(&api.GetAllClusterInfoRequest{
+	res, err := s.cmonClient.GetAllClusterInfo(&api.GetAllClusterInfoRequest{
 		WithHosts: true,
 	})
 
 	if err != nil {
-		log.Println("Test: ", err, res)
+		s.log.Error("Error getting cluster info", "error", err)
+		s.errorResponse(w, http.StatusInternalServerError, fmt.Sprintf("Error getting cluster info: %s", err.Error()))
+		return
 	}
 
 	clusterTarget := []ClusterTarget{}
 
 	// iterate through all clusters
 	for i, cluster := range res.Clusters {
-
 		temp := ClusterTarget{
 			Target: []string{},
 			Label: map[string]string{
@@ -74,74 +126,51 @@ func IndexHandler(w http.ResponseWriter, r *http.Request) {
 				"ClusterName":  cluster.ClusterName,
 				"cid":          strconv.FormatInt(int64(cluster.ClusterID), 10),
 				"ClusterType":  cluster.ClusterType,
-				"ControllerId": client.ControllerID(),
+				"ControllerId": s.cmonClient.ControllerID(),
 			},
 		}
 
 		// iterate through all hosts for given cluster
 		for _, host := range cluster.Hosts {
-
-			if host.Nodetype == "controller" {
-				continue
-			}
-
-			if host.Nodetype == "prometheus" {
-				continue
-			}
-
-			if host.Nodetype == "keepalived" {
+			switch host.Nodetype {
+			case "controller", "prometheus", "keepalived":
 				continue
 			}
 
-			//check host type and assign exporter port
+			// check host type and assign exporter port
 			// node_exporter and process_exporter applies to any node type
 			temp.Target = append(temp.Target, host.IP+":9100") // node exporter
 			temp.Target = append(temp.Target, host.IP+":9011") // process exporter
 
-			if host.Nodetype == "mysql" || host.Nodetype == "galera" {
-
-				temp.Target = append(temp.Target, host.IP+":9104") // mysql exporter
-			}
-
-			if host.Nodetype == "haproxy" {
-				temp.Target = append(temp.Target, host.IP+":9600") // haproxy exporter
-			}
-
-			if host.Nodetype == "mongo" {
-				if host.Role == "shardsvr" {
+			switch host.Nodetype {
+			case "mysql", "galera":
+				temp.Target = append(temp.Target, host.IP+":9104")
+			case "haproxy":
+				temp.Target = append(temp.Target, host.IP+":9600")
+			case "mongo":
+				switch host.Role {
+				case "shardsvr":
 					temp.Target = append(temp.Target, host.IP+":9216") // mongo exporter
-				}
-				if host.Role == "mongos" {
+				case "mongos":
 					temp.Target = append(temp.Target, host.IP+":9215") // mongos exporter
-				}
-
-				if host.Role == "mongocfg" {
+				case "mongocfg":
 					temp.Target = append(temp.Target, host.IP+":9214") // mongocfg exporter
 				}
+			case "mssql":
+				temp.Target = append(temp.Target, host.IP+":9399")
+			case "postgres":
+				temp.Target = append(temp.Target, host.IP+":9187")
+			case "redis":
+				temp.Target = append(temp.Target, host.IP+":9121")
+			case "proxysql":
+				temp.Target = append(temp.Target, host.IP+":42004")
+			case "pgbouncer":
+				temp.Target = append(temp.Target, host.IP+":9127")
 			}
-
-			if host.Nodetype == "mssql" {
-				temp.Target = append(temp.Target, host.IP+":9399") // mssql exporter
-			}
-
-			if host.Nodetype == "postgres" {
-				temp.Target = append(temp.Target, host.IP+":9187") // postgres exporter
-			}
-
-			if host.Nodetype == "redis" {
-				temp.Target = append(temp.Target, host.IP+":9121") // redis exporter
-			}
-
-			if host.Nodetype == "proxysql" {
-				temp.Target = append(temp.Target, host.IP+":42004") // proxysql exporter
-			}
-
-			if host.Nodetype == "pgbouncer" {
-				temp.Target = append(temp.Target, host.IP+":9127") // pgbouncer exporter
-			}
-
 		}
-		temp.Target = removeDuplicateStr(temp.Target)
+
+		sort.Strings(temp.Target)
+		temp.Target = slices.Compact(temp.Target)
 		clusterTarget = append(clusterTarget, temp)
 		i++
 	}
@@ -151,43 +180,25 @@ func IndexHandler(w http.ResponseWriter, r *http.Request) {
 	json.NewEncoder(w).Encode(clusterTarget)
 }
 
-func removeDuplicateStr(strSlice []string) []string {
-	allKeys := make(map[string]bool)
-	list := []string{}
-	for _, item := range strSlice {
-		if _, value := allKeys[item]; !value {
-			allKeys[item] = true
-			list = append(list, item)
-		}
-	}
-	return list
-}
+func (s *Service) Handler() http.Handler {
+	r := http.NewServeMux()
+	r.HandleFunc("/", s.IndexHandler)
 
-var port int
-
-func init() {
-	flag.IntVar(&port, "p", 8080, "Listen port.")
-	flag.Parse()
+	return r
 }
 
 func main() {
-	cmonEndpoint = os.Getenv("CMON_ENDPOINT")
-	cmonUsername = os.Getenv("CMON_USERNAME")
-	cmonPassword = os.Getenv("CMON_PASSWORD")
-
-	if cmonEndpoint == "" {
-		cmonEndpoint = "https://127.0.0.1:9501"
-	}
+	var port int
 
-	if cmonUsername == "" {
-		log.Fatalf("Env variable CMON_USERNAME is not set.")
-	}
+	flag.IntVar(&port, "p", 8080, "Listen port.")
+	flag.Parse()
 
-	if cmonPassword == "" {
-		log.Fatalf("Env variable CMON_PASSWORD is not set.")
+	service, err := NewService()
+	if err != nil {
+		log.Fatalf("Error creating the service: %v", err)
 	}
 
-	http.HandleFunc("/", IndexHandler)
+	mux := service.Handler()
 	listenAddress := fmt.Sprintf(":%d", port)
-	log.Fatal(http.ListenAndServe(listenAddress, nil))
+	log.Fatal(http.ListenAndServe(listenAddress, mux))
 }
diff --git a/cmon_sd_test.go b/cmon_sd_test.go
new file mode 100644
index 0000000..5fca07b
--- /dev/null
+++ b/cmon_sd_test.go
@@ -0,0 +1,177 @@
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"io"
+	"log/slog"
+	"net/http"
+	"net/http/httptest"
+	"reflect"
+	"testing"
+	"time"
+
+	"github.com/severalnines/cmon-proxy/cmon/api"
+)
+
+type CmonClientMock struct {
+	Fail bool
+}
+
+func (c CmonClientMock) Authenticate() error {
+	return nil
+}
+
+func (c CmonClientMock) ControllerID() string {
+	return "00000000-0000-0000-0000-000000000000"
+}
+
+func (c CmonClientMock) GetAllClusterInfo(req *api.GetAllClusterInfoRequest) (*api.GetAllClusterInfoResponse, error) {
+	if c.Fail {
+		return nil, errors.New("cmon client error")
+	}
+
+	return &api.GetAllClusterInfoResponse{
+		Clusters: []*api.Cluster{
+			{
+				ClusterID:   1,
+				ClusterName: "cluster1",
+				ClusterType: "postgresql_single",
+				Hosts: []*api.Host{
+					{
+						Nodetype: "mysql",
+						IP:       "127.0.0.1",
+					},
+					{
+						Nodetype: "mongo",
+						IP:       "127.0.0.1",
+						Role:     "mongos",
+					},
+				},
+			},
+		},
+	}, nil
+}
+
+func TestHandlerIndexHandlerFail(t *testing.T) {
+	cmonMock := CmonClientMock{
+		Fail: true,
+	}
+
+	b := bytes.NewBuffer(nil)
+	logger := slog.New(slog.NewJSONHandler(b, nil))
+
+	s := Service{
+		cmonClient: cmonMock,
+		log:        logger,
+	}
+
+	mux := s.Handler()
+	ts := httptest.NewServer(mux)
+
+	defer ts.Close()
+
+	resp, err := http.Get(ts.URL)
+	if err != nil {
+		t.Fatalf("GET failed: %v", err)
+	}
+
+	if resp.StatusCode != http.StatusInternalServerError {
+		t.Fatalf("GET failed: expected %d, got %d", http.StatusInternalServerError, resp.StatusCode)
+	}
+
+	if resp.Header.Get("Content-Type") != "application/json" {
+		t.Errorf("GET failed: expected %s, got %s", "application/json", resp.Header.Get("Content-Type"))
+	}
+
+	errMsg := ErrorMessage{}
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		t.Errorf("read body failed: %v", err)
+	}
+
+	err = json.Unmarshal(body, &errMsg)
+	if err != nil {
+		t.Errorf("unmarshal body failed: %v", err)
+	}
+
+	if errMsg.Error != "Error getting cluster info: cmon client error" {
+		t.Errorf("wrong error message should be 'Error getting cluster info: cmon client error', got %s", errMsg.Error)
+	}
+
+	type log struct {
+		Time  time.Time `json:"time"`
+		Level string    `json:"level"`
+		Msg   string    `json:"msg"`
+		Error string    `json:"error"`
+	}
+
+	l := log{}
+
+	err = json.Unmarshal(b.Bytes(), &l)
+	if err != nil {
+		t.Errorf("failed to unmarshal log: %v", err)
+	}
+
+	if l.Level != "ERROR" {
+		t.Errorf("expected 'ERROR', got '%s'", l.Level)
+	}
+
+	if l.Msg != "Error getting cluster info" {
+		t.Errorf("expected 'Error getting cluster info', got '%s'", l.Msg)
+	}
+
+	if l.Error != "cmon client error" {
+		t.Errorf("expected 'cmon client error', got '%s'", l.Error)
+	}
+}
+
+func TestHandlerIndexHandlerSuccess(t *testing.T) {
+	cmonMock := CmonClientMock{}
+	s := Service{
+		cmonClient: cmonMock,
+	}
+
+	mux := s.Handler()
+	ts := httptest.NewServer(mux)
+
+	defer ts.Close()
+
+	resp, err := http.Get(ts.URL)
+	if err != nil {
+		t.Fatalf("GET failed: %v", err)
+	}
+
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		t.Errorf("GET failed: expected status OK, got %v", resp.StatusCode)
+	}
+
+	if resp.Header.Get("Content-Type") != "application/json" {
+		t.Errorf("GET failed: expected Content-Type application/json, got %v", resp.Header.Get("Content-Type"))
+	}
+
+	var clusterTarget []ClusterTarget
+	err = json.NewDecoder(resp.Body).Decode(&clusterTarget)
+	if err != nil {
+		t.Errorf("GET failed: %v", err)
+	}
+
+	expectedClusterTarget := []ClusterTarget{}
+	expectedClusterTarget = append(expectedClusterTarget, ClusterTarget{
+		Target: []string{"127.0.0.1:9011", "127.0.0.1:9100", "127.0.0.1:9104", "127.0.0.1:9215"},
+		Label: map[string]string{
+			"ClusterID":    "1",
+			"ClusterName":  "cluster1",
+			"ClusterType":  "postgresql_single",
+			"ControllerId": "00000000-0000-0000-0000-000000000000",
+			"cid":          "1",
+		},
+	})
+
+	if !reflect.DeepEqual(clusterTarget, expectedClusterTarget) {
+		t.Errorf("GET failed: expected cluster target %v, got %v", expectedClusterTarget, clusterTarget)
+	}
+}
diff --git a/go.mod b/go.mod
index 3433bd4..c797c37 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,6 @@
 module github.com/severalnines/cmon_sd
 
-go 1.19
+go 1.22
 
 require github.com/severalnines/cmon-proxy v0.3.0
 
diff --git a/go.sum b/go.sum
index d775360..5b2968b 100644
--- a/go.sum
+++ b/go.sum
@@ -31,6 +31,7 @@ github.com/gin-gonic/gin v1.9.1/go.mod h1:hPrL7YrpYKXt5YId3A/Tnip5kqbEAP+KLuI3SU
 github.com/globalsign/mgo v0.0.0-20181015135952-eeefdecb41b8/go.mod h1:xkRDCp4j0OGD1HRkm4kmhM+pmpv3AKq5SU7GMg4oO/Q=
 github.com/go-playground/assert/v2 v2.0.1/go.mod h1:VDjEfimB/XKnb+ZQfWdccd7VUvScMdVu0Titje2rxJ4=
 github.com/go-playground/assert/v2 v2.2.0 h1:JvknZsQTYeFEAhQwI4qEt9cyV5ONwRHC+lYKSsYSR8s=
+github.com/go-playground/assert/v2 v2.2.0/go.mod h1:VDjEfimB/XKnb+ZQfWdccd7VUvScMdVu0Titje2rxJ4=
 github.com/go-playground/locales v0.12.1/go.mod h1:IUMDtCfWo/w/mtMfIE/IG2K+Ey3ygWanZIBtBW0W2TM=
 github.com/go-playground/locales v0.13.0/go.mod h1:taPMhCMXrRLJO55olJkUXHZBHCxTMfnGwq/HNwmWNS8=
 github.com/go-playground/locales v0.14.1 h1:EWaQ/wswjilfKLTECiXz7Rh+3BjFhfDFKv/oXslEjJA=
@@ -75,6 +76,7 @@ github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORN
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
+github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
 github.com/leodido/go-urn v1.1.0/go.mod h1:+cyI34gQWZcE1eQU7NVgKkkzdXDQHr1dBMtdAPozLkw=
 github.com/leodido/go-urn v1.2.0/go.mod h1:+8+nEpDfqqsY+g338gtMEUOtuK+4dEMhiQEgxpxOKII=
 github.com/leodido/go-urn v1.2.1/go.mod h1:zt4jvISO2HfUBqxjfIshjdMTYS56ZS/qv49ictyFfxY=
@@ -132,6 +134,7 @@ go.uber.org/atomic v1.7.0/go.mod h1:fEN4uk6kAWBTFdckzkM89CLk9XfWZrxpCo0nPH17wJc=
 go.uber.org/atomic v1.9.0/go.mod h1:fEN4uk6kAWBTFdckzkM89CLk9XfWZrxpCo0nPH17wJc=
 go.uber.org/goleak v1.1.10/go.mod h1:8a7PlsEVH3e/a/GLqe5IIrQx6GzcnRmZEufDUTk4A7A=
 go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
+go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=
 go.uber.org/multierr v1.1.0/go.mod h1:wR5kodmAFQ0UK8QlbwjlSNy0Z68gJhDJUG5sjR94q/0=
 go.uber.org/multierr v1.6.0/go.mod h1:cdWPpRnG4AhwMwsgIHip0KRBQjJy5kYEpYjJxpXp9iU=
 go.uber.org/multierr v1.7.0/go.mod h1:7EAYxJLBy9rStEaz58O2t4Uvip6FSURkq8/ppBp95ak=