[Feature] pika-exporter: let one exporter monitor the whole cluster (O…

…penAtomFoundation#1929) (OpenAtomFoundation#1953)

* let one exporter monitor the whole cluster by codis

* Automatically reload after cluster node changes.

tools/pika_exporter/discovery/codis_dashboard.go

@@ -0,0 +1,29 @@
+package discovery
+
+type CodisServerAction struct {
+	Action string `json:"action"`
+}
+
+type CodisServerInfo struct {
+	Server             string            `json:"server"`
+	Datacenter         string            `json:"datacenter"`
+	ServerAction       CodisServerAction `json:"action"`
+	ServerReplicaGroup bool              `json:"replica_group"`
+}
+
+type CodisModelInfo struct {
+	Id      int               `json:"id"`
+	Servers []CodisServerInfo `json:"servers"`
+}
+
+type CodisGroupInfo struct {
+	Models []CodisModelInfo `json:"models"`
+}
+
+type CodisStatsInfo struct {
+	Group CodisGroupInfo `json:"group"`
+}
+
+type CodisTopomInfo struct {
+	Stats CodisStatsInfo `json:"stats"`
+}

tools/pika_exporter/discovery/discovery.go

@@ -2,6 +2,8 @@ package discovery
 
 import (
 	"encoding/csv"
+	"encoding/json"
+	"net/http"
 	"os"
 	"strings"
 
@@ -20,6 +22,7 @@ type Instance struct {
 
 type Discovery interface {
 	GetInstances() []Instance
+	CheckUpdate(chan int, string)
 }
 
 type cmdArgsDiscovery struct {
@@ -55,6 +58,8 @@ func (d *cmdArgsDiscovery) GetInstances() []Instance {
 	return d.instances
 }
 
+func (d *cmdArgsDiscovery) CheckUpdate(chan int, string) {}
+
 type fileDiscovery struct {
 	instances []Instance
 }
@@ -101,3 +106,96 @@ func NewFileDiscovery(fileName string) (*fileDiscovery, error) {
 func (d *fileDiscovery) GetInstances() []Instance {
 	return d.instances
 }
+
+func (d *fileDiscovery) CheckUpdate(chan int, string) {}
+
+type codisDiscovery struct {
+	instances []Instance
+}
+
+func NewCodisDiscovery(url, password, alias string) (*codisDiscovery, error) {
+	resp, err := http.Get(url)
+	if err != nil {
+		log.Warnln("Get codis topom failed:", err)
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	var result CodisTopomInfo
+	err = json.NewDecoder(resp.Body).Decode(&result)
+	if err != nil {
+		log.Warnln("Response body decode failed:", err)
+		return &codisDiscovery{}, err
+	}
+
+	var addrs []string
+	for _, model := range result.Stats.Group.Models {
+		for _, server := range model.Servers {
+			if server.Server != "" {
+				addrs = append(addrs, server.Server)
+			}
+		}
+	}
+
+	passwords := strings.Split(password, defaultSeparator)
+	for len(passwords) < len(addrs) {
+		passwords = append(passwords, passwords[0])
+	}
+
+	aliases := strings.Split(alias, defaultSeparator)
+	for len(aliases) < len(addrs) {
+		aliases = append(aliases, aliases[0])
+	}
+
+	instances := make([]Instance, len(addrs))
+	for i := range addrs {
+		instances[i] = Instance{
+			Addr:     addrs[i],
+			Password: passwords[i],
+			Alias:    aliases[i],
+		}
+	}
+	return &codisDiscovery{instances: instances}, nil
+}
+
+func (d *codisDiscovery) GetInstances() []Instance {
+	return d.instances
+}
+
+func (d *codisDiscovery) CheckUpdate(updatechan chan int, codisaddr string) {
+	newdis, err := NewCodisDiscovery(codisaddr, "", "")
+	if err != nil {
+		log.Fatalln(" failed. err:", err)
+	}
+	diff := d.comparedis(newdis)
+	if !diff {
+		updatechan <- 1
+	}
+}
+
+func (d *codisDiscovery) comparedis(new_instance *codisDiscovery) bool {
+	var addrs []string
+	var diff bool = false
+	for _, instance := range new_instance.instances {
+		addrs = append(addrs, instance.Addr)
+	}
+	for _, instance := range d.instances {
+		if !contains(instance.Addr, addrs) {
+			diff = true
+			return false
+		}
+	}
+	if !diff && len(new_instance.instances) == len(d.instances) {
+		return true
+	}
+	return false
+}
+
+func contains(addr string, addrs []string) bool {
+	for _, a := range addrs {
+		if a == addr {
+			return true
+		}
+	}
+	return false
+}

tools/pika_exporter/discovery/discovery_test.go

@@ -0,0 +1,60 @@
+package discovery
+
+import (
+	"encoding/json"
+	"io/ioutil"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestNewCodisDiscovery(t *testing.T) {
+	jsonFile := "mockCodisTopom.json"
+	jsonData, err := ioutil.ReadFile(jsonFile)
+	if err != nil {
+		t.Fatalf("failed to read test data: %v", err)
+	}
+
+	var result CodisTopomInfo
+	err = json.Unmarshal(jsonData, &result)
+	if err != nil {
+		t.Fatalf("failed to parse test data: %v", err)
+	}
+
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(result)
+	}))
+	defer ts.Close()
+
+	url := ts.URL
+	password := "password1,password2"
+	alias := ""
+
+	discovery, err := NewCodisDiscovery(url, password, alias)
+	if err != nil {
+		t.Errorf("unexpected error: %v", err)
+	}
+
+	expectedAddrs := []string{
+		"1.1.1.6:1100",
+		"1.1.1.7:1100",
+	}
+	expectedPasswords := []string{
+		"password1",
+		"password2",
+	}
+
+	if len(discovery.instances) != len(expectedAddrs) {
+		t.Errorf("expected %d instances but got %d", len(expectedAddrs), len(discovery.instances))
+	}
+
+	for i := range expectedAddrs {
+		if discovery.instances[i].Addr != expectedAddrs[i] {
+			t.Errorf("instance %d address: expected %s but got %s", i, expectedAddrs[i], discovery.instances[i].Addr)
+		}
+		if discovery.instances[i].Password != expectedPasswords[i] {
+			t.Errorf("instance %d password: expected %s but got %s", i, expectedPasswords[i], discovery.instances[i].Password)
+		}
+	}
+}