Make -endpoint work consistently w/ -watch

See #18

Author: jwilder

docker-gen.go

@@ -252,9 +252,12 @@ func main() {
 			Config: []Config{config}}
 	}
 
-	endpoint := getEndpoint()
-	client, err := docker.NewClient(endpoint)
+	endpoint, err := getEndpoint()
+	if err != nil {
+		log.Fatalf("Bad endpoint: %s", err)
+	}
 
+	client, err := docker.NewClient(endpoint)
 	if err != nil {
 		log.Fatalf("Unable to parse %s: %s", endpoint, err)
 	}

docker_client.go

@@ -104,7 +104,10 @@ func splitDockerImage(img string) (string, string, string) {
 }
 
 func newConn() (*httputil.ClientConn, error) {
-	endpoint := getEndpoint()
+	endpoint, err := getEndpoint()
+	if err != nil {
+		return nil, err
+	}
 
 	proto, addr, err := parseHost(endpoint)
 	if err != nil {

utils.go

@@ -1,8 +1,11 @@
 package main
 
-import "os"
+import (
+	"errors"
+	"os"
+)
 
-func getEndpoint() string {
+func getEndpoint() (string, error) {
 	defaultEndpoint := "unix:///var/run/docker.sock"
 	if os.Getenv("DOCKER_HOST") != "" {
 		defaultEndpoint = os.Getenv("DOCKER_HOST")
@@ -12,6 +15,21 @@ func getEndpoint() string {
 		defaultEndpoint = endpoint
 	}
 
-	return defaultEndpoint
+	proto, host, err := parseHost(defaultEndpoint)
+	if err != nil {
+		return "", err
+	}
+
+	if proto == "unix" {
+		exist, err := exists(host)
+		if err != nil {
+			return "", err
+		}
+
+		if !exist {
+			return "", errors.New(host + " does not exists.")
+		}
+	}
 
+	return defaultEndpoint, nil
 }

utils_test.go

@@ -7,7 +7,10 @@ import (
 )
 
 func TestDefaultEndpoint(t *testing.T) {
-	endpoint := getEndpoint()
+	endpoint, err := getEndpoint()
+	if err != nil {
+		t.Fatal("%s", err)
+	}
 	if endpoint != "unix:///var/run/docker.sock" {
 		t.Fatal("Expected unix:///var/run/docker.sock")
 	}
@@ -19,7 +22,11 @@ func TestDockerHostEndpoint(t *testing.T) {
 		t.Fatalf("Unable to set DOCKER_HOST: %s", err)
 	}
 
-	endpoint := getEndpoint()
+	endpoint, err := getEndpoint()
+	if err != nil {
+		t.Fatal("%s", err)
+	}
+
 	if endpoint != "tcp://127.0.0.1:4243" {
 		t.Fatal("Expected tcp://127.0.0.1:4243")
 	}
@@ -39,8 +46,33 @@ func TestDockerFlagEndpoint(t *testing.T) {
 		t.Fatalf("Unable to set endpoint flag: %s", err)
 	}
 
-	endpoint := getEndpoint()
+	endpoint, err := getEndpoint()
+	if err != nil {
+		t.Fatal("%s", err)
+	}
 	if endpoint != "tcp://127.0.0.1:5555" {
 		t.Fatal("Expected tcp://127.0.0.1:5555")
 	}
 }
+
+func TestUnixNotExists(t *testing.T) {
+
+	endpoint = ""
+	err := os.Setenv("DOCKER_HOST", "unix:///does/not/exist")
+	if err != nil {
+		t.Fatalf("Unable to set DOCKER_HOST: %s", err)
+	}
+
+	_, err = getEndpoint()
+	if err == nil {
+		t.Fatal("endpoint should have failed")
+	}
+}
+
+func TestUnixBadFormat(t *testing.T) {
+	endpoint = "unix:/var/run/docker.sock"
+	_, err := getEndpoint()
+	if err == nil {
+		t.Fatal("endpoint should have failed")
+	}
+}