Fix -endpoint being ignored

Fixes #1

Author: jwilder

docker-gen.go

@@ -184,14 +184,18 @@ func generateFromEvents(client *docker.Client, configs ConfigFile) {
 	}
 }
 
-func main() {
+func initFlags() {
 	flag.BoolVar(&watch, "watch", false, "watch for container changes")
 	flag.BoolVar(&onlyExposed, "only-exposed", false, "only include containers with exposed ports")
 	flag.StringVar(&notifyCmd, "notify", "", "run command after template is regenerated")
 	flag.StringVar(&configFile, "config", "", "config file with template directives")
 	flag.IntVar(&interval, "interval", 0, "notify command interval (s)")
 	flag.StringVar(&endpoint, "endpoint", "", "docker api endpoint")
 	flag.Parse()
+}
+
+func main() {
+	initFlags()
 
 	if flag.NArg() < 1 && configFile == "" {
 		usage()
@@ -217,12 +221,7 @@ func main() {
 			Config: []Config{config}}
 	}
 
-	if endpoint == "" && os.Getenv("DOCKER_HOST") != "" {
-		endpoint = os.Getenv("DOCKER_HOST")
-	} else {
-		endpoint = "unix:///var/run/docker.sock"
-	}
-
+	endpoint := getEndpoint()
 	client, err := docker.NewClient(endpoint)
 
 	if err != nil {

docker_client.go

@@ -103,10 +103,7 @@ func splitDockerImage(img string) (string, string, string) {
 }
 
 func newConn() (*httputil.ClientConn, error) {
-	dockerHost := endpoint
-	if dockerHost == "" && os.Getenv("DOCKER_HOST") != "" {
-		dockerHost = os.Getenv("DOCKER_HOST")
-	}
+	endpoint := getEndpoint()
 
 	proto, addr, err := parseHost(endpoint)
 	if err != nil {

utils.go

@@ -0,0 +1,17 @@
+package main
+
+import "os"
+
+func getEndpoint() string {
+	defaultEndpoint := "unix:///var/run/docker.sock"
+	if os.Getenv("DOCKER_HOST") != "" {
+		defaultEndpoint = os.Getenv("DOCKER_HOST")
+	}
+
+	if endpoint != "" {
+		defaultEndpoint = endpoint
+	}
+
+	return defaultEndpoint
+
+}

utils_test.go

@@ -0,0 +1,46 @@
+package main
+
+import (
+	"flag"
+	"os"
+	"testing"
+)
+
+func TestDefaultEndpoint(t *testing.T) {
+	endpoint := getEndpoint()
+	if endpoint != "unix:///var/run/docker.sock" {
+		t.Fatal("Expected unix:///var/run/docker.sock")
+	}
+}
+
+func TestDockerHostEndpoint(t *testing.T) {
+	err := os.Setenv("DOCKER_HOST", "tcp://127.0.0.1:4243")
+	if err != nil {
+		t.Fatalf("Unable to set DOCKER_HOST: %s", err)
+	}
+
+	endpoint := getEndpoint()
+	if endpoint != "tcp://127.0.0.1:4243" {
+		t.Fatal("Expected tcp://127.0.0.1:4243")
+	}
+}
+
+func TestDockerFlagEndpoint(t *testing.T) {
+
+	initFlags()
+	err := os.Setenv("DOCKER_HOST", "tcp://127.0.0.1:4243")
+	if err != nil {
+		t.Fatalf("Unable to set DOCKER_HOST: %s", err)
+	}
+
+	// flag value should override DOCKER_HOST and default value
+	err = flag.Set("endpoint", "tcp://127.0.0.1:5555")
+	if err != nil {
+		t.Fatalf("Unable to set endpoint flag: %s", err)
+	}
+
+	endpoint := getEndpoint()
+	if endpoint != "tcp://127.0.0.1:5555" {
+		t.Fatal("Expected tcp://127.0.0.1:5555")
+	}
+}