Pull some config-related functions out to their own file.

config.go

@@ -0,0 +1,42 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	_ "strconv"
+	"strings"
+)
+
+// Configuration errors
+var ErrUndefined = errors.New("value not defined")
+
+type ConfigError struct {
+	Key	string
+	Value	interface{}
+	Err	error
+}
+
+func (e *ConfigError) Error() string {
+	return fmt.Sprintf("Error in configuration for %s: %s",
+		e.Key, e.Err.Error())
+}
+
+func (e *ConfigError) Unwrap() error { return e.Err }
+
+func undefinedError(key string) *ConfigError {
+	return &ConfigError{key, nil, ErrUndefined}
+}
+
+// Get the first host port from a service
+func (s ServiceConfig) GetHostPort() (string, error) {
+	if s.Ports == nil {
+		return "", undefinedError("ports")
+	}
+
+	ports := strings.Split(s.Ports[0], ":")
+	if len(ports) == 0 {
+		return "", undefinedError("ports")
+	}
+
+	return ports[0], nil
+}

main.go

@@ -138,13 +138,16 @@ func main() {
 
 			// If a proxy definition exists, append it
 			if s.Proxy != "" {
-				ports := strings.Split(s.Ports[0], ":")
-				if len(ports) == 0 {
-					fmt.Println("Error: No port defined for proxy to", s.Proxy)
+				port, err := s.GetHostPort()
+				if err != nil {
+					fmt.Println("Error in service", name)
+					fmt.Println(err.Error())
 					return
 				}
-				err = AddProxy(s.Proxy, ports[0])
+
+				err = AddProxy(s.Proxy, port)
 				if err != nil {
+					fmt.Println("Error adding proxy for service", name)
 					fmt.Println(err.Error())
 					return
 				}