ADd consul support , multiple monitors, config file

controller/consul.go

@@ -0,0 +1,115 @@
+package controller
+
+import (
+	"encoding/json"
+	"fmt"
+	"github.com/golang/glog"
+	"net/http"
+	"os"
+	"strings"
+)
+
+const (
+	consulNodeEnv  = "CONSUL_NODE"
+	matchTag       = "enable_gocast"
+	nodeUrl        = "/catalog/node"
+	healthCheckurl = "/health/checks"
+)
+
+type ConsulMon struct {
+	addr string
+	node string
+}
+
+type ConsulServiceData struct {
+	Services map[string]struct {
+		ID      string
+		Service string
+		Tags    []string
+	}
+}
+
+func contains(inp []string, elem string) bool {
+	for _, a := range inp {
+		if a == elem {
+			return true
+		}
+	}
+	return false
+}
+
+func NewConsulMon(addr string) (*ConsulMon, error) {
+	node := os.Getenv(consulNodeEnv)
+	if node == "" {
+		return nil, fmt.Errorf("%s env variable not set", consulNodeEnv)
+	}
+	return &ConsulMon{addr: addr, node: node}, nil
+}
+
+func (c *ConsulMon) queryServices() ([]*App, error) {
+	var apps []*App
+	addr := c.addr + fmt.Sprintf("%s/%s", nodeUrl, c.node)
+	resp, err := http.Get(addr)
+	if err != nil {
+		return apps, err
+	}
+	defer resp.Body.Close()
+	var consulData ConsulServiceData
+	if err := json.NewDecoder(resp.Body).Decode(&consulData); err != nil {
+		return apps, fmt.Errorf("Unable to decode consul data: %v", err)
+	}
+	for _, service := range consulData.Services {
+		if !contains(service.Tags, matchTag) {
+			continue
+		}
+		var (
+			vip      string
+			monitors []string
+		)
+		for _, tag := range service.Tags {
+			// try to find the requires tags. Only vip is mandatory
+			parts := strings.Split(tag, "=")
+			if len(parts) != 2 {
+				continue
+			}
+			switch parts[0] {
+			case "vip":
+				vip = parts[1]
+			case "monitor":
+				monitors = append(monitors, parts[1])
+			}
+		}
+		if vip == "" {
+			glog.Errorf("No vip Tag found in matched service :%s", service.Service)
+			continue
+		}
+		app, err := NewApp(service.Service, vip, monitors)
+		if err != nil {
+			glog.Errorf("Unable to add consul app: %v", err)
+			continue
+		}
+		apps = append(apps, app)
+
+	}
+	return apps, nil
+}
+
+func (c *ConsulMon) healthCheck(service string) (bool, error) {
+	addr := c.addr + fmt.Sprintf("%s/%s", healthCheckurl, service)
+	resp, err := http.Get(addr)
+	if err != nil {
+		return false, err
+	}
+	defer resp.Body.Close()
+	var data []interface{}
+	if err := json.NewDecoder(resp.Body).Decode(&data); err != nil {
+		return false, err
+	}
+	for _, nodeInfo := range data {
+		n := nodeInfo.(map[string]interface{})
+		if n["Node"] == c.node && n["Status"].(string) == "passing" {
+			return true, nil
+		}
+	}
+	return false, fmt.Errorf("No healcheck info found for node %s in consul", c.node)
+}