get prometheus info from api. code skelton

src/webapi/prom/prom.go

@@ -3,6 +3,7 @@ package prom
 import (
 	"net"
 	"net/http"
+	"strings"
 	"sync"
 	"time"
 
@@ -15,26 +16,71 @@ type ClusterType struct {
 }
 
 type ClustersType struct {
-	datas map[string]ClusterType
+	datas map[string]*ClusterType
 	mutex *sync.RWMutex
 }
 
-func (cs *ClustersType) Put(name string, cluster ClusterType) {
+func (cs *ClustersType) Put(name string, cluster *ClusterType) {
 	cs.mutex.Lock()
 	cs.datas[name] = cluster
 	cs.mutex.Unlock()
 }
 
-func (cs *ClustersType) Get(name string) (ClusterType, bool) {
+func (cs *ClustersType) Get(name string) (*ClusterType, bool) {
-	cs.mutex.RLock()
+	cf := strings.ToLower(strings.TrimSpace(config.C.ClustersFrom))
-	defer cs.mutex.RUnlock()
 
+	cs.mutex.RLock()
 	c, has := cs.datas[name]
-	return c, has
+	cs.mutex.RUnlock()
+	if has {
+		return c, true
+	}
+
+	if cf == "" || cf == "config" {
+		return nil, false
+	}
+
+	// read from api
+	if cf == "api" {
+		return cs.GetFromAPI(name)
+	}
+
+	return nil, false
+}
+
+func (cs *ClustersType) GetFromAPI(name string) (*ClusterType, bool) {
+	// get from api, parse body
+	// 1. not found? return nil, false
+	// 2. found? new ClusterType, put, return
+	opt := config.ClusterOptions{
+		Name:                "",
+		Prom:                "",
+		BasicAuthUser:       "",
+		BasicAuthPass:       "",
+		Timeout:             60000,
+		DialTimeout:         5000,
+		MaxIdleConnsPerHost: 32,
+	}
+
+	cluster := &ClusterType{
+		Opts: opt,
+		Transport: &http.Transport{
+			// TLSClientConfig: tlsConfig,
+			Proxy: http.ProxyFromEnvironment,
+			DialContext: (&net.Dialer{
+				Timeout: time.Duration(opt.DialTimeout) * time.Millisecond,
+			}).DialContext,
+			ResponseHeaderTimeout: time.Duration(opt.Timeout) * time.Millisecond,
+			MaxIdleConnsPerHost:   opt.MaxIdleConnsPerHost,
+		},
+	}
+
+	cs.Put(opt.Name, cluster)
+	return cluster, true
 }
 
 var Clusters = ClustersType{
-	datas: make(map[string]ClusterType),
+	datas: make(map[string]*ClusterType),
 	mutex: new(sync.RWMutex),
 }
 
@@ -46,7 +92,7 @@ func Init() error {
 	opts := config.C.Clusters
 
 	for i := 0; i < len(opts); i++ {
-		cluster := ClusterType{
+		cluster := &ClusterType{
 			Opts: opts[i],
 			Transport: &http.Transport{
 				// TLSClientConfig: tlsConfig,