allow multiple docker providers, added file provider support

src/go-proxy/config.go

@@ -0,0 +1,74 @@
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/fsnotify/fsnotify"
+	"github.com/golang/glog"
+	"gopkg.in/yaml.v3"
+)
+
+type Config struct {
+	Providers map[string]*Provider `yaml:",flow"`
+}
+
+var config *Config
+
+func ReadConfig() (*Config, error) {
+	config := Config{}
+	data, err := os.ReadFile(configPath)
+
+	if err != nil {
+		return nil, fmt.Errorf("unable to read config file: %v", err)
+	}
+
+	err = yaml.Unmarshal(data, &config)
+
+	if err != nil {
+		return nil, fmt.Errorf("unable to parse config file: %v", err)
+	}
+
+	for name, p := range config.Providers {
+		p.name = name
+	}
+
+	return &config, nil
+}
+
+func ListenConfigChanges() {
+	watcher, err := fsnotify.NewWatcher()
+	if err != nil {
+		glog.Errorf("[Config] unable to create file watcher: %v", err)
+	}
+	defer watcher.Close()
+
+	if err = watcher.Add(configPath); err != nil {
+		glog.Errorf("[Config] unable to watch file: %v", err)
+		return
+	}
+
+	for {
+		select {
+		case event, ok := <-watcher.Events:
+			if !ok {
+				return
+			}
+			switch {
+			case event.Has(fsnotify.Write):
+				glog.Infof("[Config] file change detected")
+				for _, p := range config.Providers {
+					p.StopAllRoutes()
+				}
+				config, err = ReadConfig()
+				if err != nil {
+					glog.Fatalf("[Config] unable to read config: %v", err)
+				}
+			case event.Has(fsnotify.Remove), event.Has(fsnotify.Rename):
+				glog.Fatalf("[Config] file renamed / deleted")
+			}
+		case err := <-watcher.Errors:
+			glog.Errorf("[Config] File watcher error: %s", err)
+		}
+	}
+}