Refactor make config independent (cristianoliveira#86)

* refactor: Change config to be independent

* fix: Update config using channel signals

* refactor: Group methods by meaning

main.go

@@ -55,8 +55,7 @@ func command() func() {
 	command.StringVar(&config.Domain, "domain", ".dev", "Set a custom domain for services")
 	command.Parse(os.Args[2:])
 
-	var err error
-	config.Services, err = proxy.LoadServices(config.ConfigFile)
+	err := config.LoadServices()
 	if err != nil {
 		log.Fatalf("Could not load services: %v\n", err)
 		return nil
@@ -112,11 +111,10 @@ func command() func() {
 		command.StringVar(&config.ConfigFile, "config", "./.ergo", "Set the services file")
 		command.Parse(os.Args[4:])
 
-		services, err := proxy.LoadServices(config.ConfigFile)
+		err := config.LoadServices()
 		if err != nil {
-			log.Printf("Could not load services: %v\n", err)
+			log.Fatalf("Could not load services: %v\n", err)
 		}
-		config.Services = services
 
 		return execute(commands.AddServiceCommand{Service: service}, config)
 

proxy/config.go

@@ -7,15 +7,11 @@ import (
 	"log"
 	"os"
 	"regexp"
+	"sync"
 	"time"
 )
 
-var (
-	modTime time.Time
-	size    int64
-)
-
-var configChan = make(chan []Service, 1)
+const pollIntervall = 500
 
 //Service holds the details of the service (Name and URL)
 type Service struct {
@@ -25,6 +21,10 @@ type Service struct {
 
 //Config holds the configuration for the proxy.
 type Config struct {
+	mutex      *sync.Mutex
+	lastChange time.Time
+	size       int64
+
 	Port       string
 	Domain     string
 	URLPattern string
@@ -37,12 +37,7 @@ type Config struct {
 func (c *Config) GetService(host string) *Service {
 	domainPattern := regexp.MustCompile(`(\w*\:\/\/)?(.+)` + c.Domain)
 	parts := domainPattern.FindAllString(host, -1)
-	//we must lock the access as the configuration can be dynamically loaded
-	select {
-	case srv := <-configChan:
-		c.Services = srv
-	default:
-	}
+
 	for _, s := range c.Services {
 		if len(parts) > 0 && s.Name+c.Domain == parts[0] {
 			return &s
@@ -77,29 +72,81 @@ func NewService(name, url string) Service {
 
 //LoadServices loads the services from filepath, returns an error
 //if the configuration could not be parsed
-func LoadServices(filepath string) ([]Service, error) {
+func (c *Config) LoadServices() error {
+	services, err := LoadServicesFromConfig(c.ConfigFile)
+	if err != nil {
+		return err
+	}
 
-	info, err := os.Stat(filepath)
+	c.getMutex().Lock()
+	defer c.getMutex().Unlock()
+	c.Services = services
 
-	if err != nil {
-		return nil, err
+	return nil
+}
+
+func (c *Config) getMutex() *sync.Mutex {
+	if c.mutex == nil {
+		c.mutex = &sync.Mutex{}
 	}
 
-	size = info.Size()
-	modTime = info.ModTime()
+	return c.mutex
+}
 
-	file, e := os.Open(filepath)
+// ListenServices updates the services for each message in a given channel
+func (c *Config) ListenServices(servicesSignal <-chan []Service) {
+	for {
+		select {
+		case services := <-servicesSignal:
+			c.getMutex().Lock()
+			c.Services = services
+			c.mutex.Unlock()
+		}
+	}
+}
 
-	if e != nil {
-		return nil, fmt.Errorf("file error: %v", e)
+// WatchConfigFile listen for file changes and sends signal for updates
+func (c *Config) WatchConfigFile(servicesChan chan []Service) {
+	ticker := time.NewTicker(pollIntervall * time.Millisecond)
+	quit = make(chan struct{})
+
+	for {
+		select {
+		case <-ticker.C:
+			info, err := os.Stat(c.ConfigFile)
+			if err != nil {
+				log.Printf("Error reading config file: %s\r\n", err.Error())
+				continue
+			}
+
+			if info.ModTime().Before(c.lastChange) || info.Size() != c.size {
+				services, err := LoadServicesFromConfig(c.ConfigFile)
+				if err != nil {
+					log.Printf("Error reading the modified config file: %s\r\n", err.Error())
+					continue
+				}
+
+				c.size = info.Size()
+				c.lastChange = info.ModTime()
+				servicesChan <- services
+			}
+
+		case <-quit:
+			ticker.Stop()
+			return
+		}
 	}
+}
 
+// LoadServicesFromConfig reads the given path and parse it into services
+func LoadServicesFromConfig(filepath string) ([]Service, error) {
+	file, err := os.Open(filepath)
+	if err != nil {
+		return nil, fmt.Errorf("file error: %v", err)
+	}
 	defer file.Close()
 
-	log.Println("Just received ", filepath)
-
 	services := []Service{}
-
 	scanner := bufio.NewScanner(file)
 	for scanner.Scan() {
 		line := scanner.Text()
@@ -137,7 +184,6 @@ func AddService(filepath string, service Service) error {
 // RemoveService removes a service from the filepath
 func RemoveService(filepath string, service Service) error {
 	file, err := ioutil.ReadFile(filepath)
-
 	if err != nil {
 		log.Printf("File error: %v\n", err)
 		return err

proxy/config_test.go

@@ -8,13 +8,12 @@ import (
 
 func TestWhenHasErgoFile(t *testing.T) {
 	config := NewConfig()
-	services, err := LoadServices("../.ergo")
+	config.ConfigFile = "../.ergo"
+	err := config.LoadServices()
 	if err != nil {
 		t.Fatal("could not load requied configuration file for tests")
 	}
 
-	config.Services = services
-
 	t.Run("It loads the services redirections", func(t *testing.T) {
 		expected := 6
 		result := len(config.Services)
@@ -152,8 +151,8 @@ func TestWhenHasErgoFile(t *testing.T) {
 		defer ioutil.WriteFile("../.ergo", fileContent, 0755)
 
 		service := NewService("service-without-url", "")
-		AddService("../.ergo", service)
-		_, err = LoadServices("../.ergo")
+		AddService(config.ConfigFile, service)
+		err = config.LoadServices()
 		if err == nil {
 			tt.Error("Expected LoadServices to fail")
 		}

proxy/proxy.go

@@ -2,11 +2,9 @@ package proxy
 
 import (
 	"fmt"
-	"log"
 	"net/http"
 	"net/http/httputil"
 	"net/url"
-	"os"
 	"strings"
 	"time"
 )
@@ -15,8 +13,6 @@ import (
 //when the configuration watcher should stop
 var quit chan struct{}
 
-const pollIntervall = 500
-
 func singleJoiningSlash(a, b string) string {
 	aslash := strings.HasSuffix(a, "/")
 	bslash := strings.HasPrefix(b, "/")
@@ -42,43 +38,6 @@ func formatRequest(r *http.Request) string {
 	return strings.Join(request, "\n")
 }
 
-func pollConfigChange(config *Config) {
-	ticker := time.NewTicker(pollIntervall * time.Millisecond)
-
-	quit = make(chan struct{})
-
-	go func() {
-		for {
-			select {
-			case <-ticker.C:
-				info, err := os.Stat(config.ConfigFile)
-				if err != nil {
-					log.Printf("Error reading config file: %s\r\n", err.Error())
-					continue
-				}
-
-				if info.ModTime().Before(modTime) || info.Size() != size {
-					services, err := LoadServices(config.ConfigFile)
-					if err != nil {
-						log.Printf("Error reading the modified config file: %s\r\n", err.Error())
-						continue
-					}
-					//clear the data if there is any
-					select {
-					case <-configChan:
-					default:
-					}
-					configChan <- services
-				}
-
-			case <-quit:
-				ticker.Stop()
-				return
-			}
-		}
-	}()
-}
-
 //NewErgoProxy returns the new reverse proxy.
 func NewErgoProxy(config *Config) *httputil.ReverseProxy {
 	director := func(req *http.Request) {
@@ -146,6 +105,12 @@ func list(config *Config) func(w http.ResponseWriter, r *http.Request) {
 	}
 }
 
+func pollConfigChange(config *Config) {
+	servicesSignal := make(chan []Service)
+	go config.ListenServices(servicesSignal)
+	go config.WatchConfigFile(servicesSignal)
+}
+
 //ServeProxy listens & serves the HTTP proxy.
 func ServeProxy(config *Config) error {
 

proxy/proxy_test.go

@@ -18,11 +18,12 @@ import (
 
 func TestWhenHasCollectionFile(t *testing.T) {
 	config := NewConfig()
-	services, err := LoadServices("../.ergo")
+	config.ConfigFile = "../.ergo"
+	err := config.LoadServices()
 	if err != nil {
 		t.Fatal("could not load requied configuration file for tests")
 	}
-	config.Services = services
+
 	proxy := NewErgoProxy(config)
 
 	t.Run("it redirects foo.dev to localhost 3000", func(t *testing.T) {
@@ -184,8 +185,6 @@ func TestPollConfigChangeWithInvalidConfigFile(t *testing.T) {
 
 	pollConfigChange(&config)
 
-	stop := struct{}{}
-
 	time.Sleep(2 * time.Second)
 	logbuf := new(bytes.Buffer)
 
@@ -199,8 +198,6 @@ func TestPollConfigChangeWithInvalidConfigFile(t *testing.T) {
 
 	time.Sleep(2 * time.Second)
 
-	quit <- stop
-
 	if len(logbuf.String()) == 0 {
 		t.Fatalf("Expected to get a read from the log. Got none")
 	} else if !strings.Contains(logbuf.String(), "Error reading the modified config file") {
@@ -226,36 +223,34 @@ func TestPollConfigChangeWithValidConfigFile(t *testing.T) {
 
 	config := Config{}
 	config.ConfigFile = tmpfile.Name()
+	config.LoadServices()
 
 	pollConfigChange(&config)
 
-	stop := struct{}{}
-
 	time.Sleep(2 * time.Second)
 
-	err = ioutil.WriteFile(tmpfile.Name(), []byte("test.dev http://localhost:9900"), 0644)
-
+	configFile, err := os.OpenFile(config.ConfigFile, os.O_APPEND|os.O_WRONLY, 0600)
 	if err != nil {
+		t.Fatalf("Error while opening the config file %s", err.Error())
+	}
+
+	defer configFile.Close()
+
+	if _, err = configFile.WriteString("\ntest.dev http://localhost:9900"); err != nil {
 		t.Fatalf("Expected no error while rewriting the temporary config file. Got %s", err.Error())
 	}
 
 	time.Sleep(2 * time.Second)
 
 	var srv []Service
 
-	select {
-	case srv = <-configChan:
-		if len(srv) != 1 {
-			t.Fatalf("Expected to get 1 service Got %d", len(srv))
-		}
-		if srv[0].URL != "http://localhost:9900" || srv[0].Name != "test.dev" {
-			t.Fatalf("Expected to get 1 service with the URL http://localhost:9900 and the name test.dev. Got the URL: %s and the name: %s", srv[0].URL, srv[0].Name)
-		}
-	default:
-		quit <- stop
-		t.Fatalf("Expected to get the changed services. Got nothing")
+	if len(config.Services) != 2 {
+		t.Fatalf("Expected to get 2 service Got %d", len(srv))
+	}
+
+	if config.Services[1].URL != "http://localhost:9900" || config.Services[1].Name != "test.dev" {
+		t.Fatalf("Expected to get 1 service with the URL http://localhost:9900 and the name test.dev. Got the URL: %s and the name: %s", config.Services[1].URL, config.Services[1].Name)
 	}
-	quit <- stop
 }
 
 //structure to mock a http ResponseWriter
@@ -356,7 +351,8 @@ func TestListFunction(t *testing.T) {
 	config.ConfigFile = tmpfile.Name()
 	config.Domain = "dev"
 	config.Port = "2000"
-	config.Services, err = LoadServices(tmpfile.Name())
+	config.ConfigFile = tmpfile.Name()
+	err = config.LoadServices()
 	if err != nil {
 		t.Fatalf("Expected no error while loading services from temp file. Got %s", err.Error())
 	}