Merge pull request #77 from ivanilves/ivancito-strikes-back

Moar cleaning!

README.md

@@ -31,8 +31,11 @@ You could use `lstags`, if you ...
 ## How do I use it myself?
 I run `lstags` inside a Cron Job on my Kubernetes worker nodes to poll my own Docker registry for a new [stable] images.
 ```
-lstags --pull -u myuser -p mypass registry.ivanilves.local/tools/sicario~/v1\\.[0-9]+$/
+lstags --pull registry.ivanilves.local/tools/sicario~/v1\\.[0-9]+$/
 ```
+**NB!** In case you use private registry with authentication, make sure your Docker client knows how to authenticate against it!
+`lstags` will reuse credentials saved by Docker client in its `config.json` file, one usually found at `~/.docker/config.json`
+
 ... and following cronjob runs on my CI server to ensure I always have latest Ubuntu 14.04 and 16.04 images to play with:
 ```
 lstags --pull ubuntu~/^1[46]\\.04$/

auth/auth.go

@@ -11,7 +11,7 @@ import (
 )
 
 // WebSchema defines how do we connect to remote web servers
-var WebSchema = "https://"
+const WebSchema = "https://"
 
 // TokenResponse is an abstraction for aggregated token-related information we get from authentication services
 type TokenResponse interface {

docker/client/client.go

@@ -62,7 +62,7 @@ func buildImageListOptions(repo string) (types.ImageListOptions, error) {
 
 // Pull pulls Docker image specified
 func (dc *DockerClient) Pull(ref string) error {
-	registryAuth, _ := dc.cnf.GetRegistryAuth(
+	registryAuth := dc.cnf.GetRegistryAuth(
 		docker.GetRegistry(ref),
 	)
 
@@ -83,7 +83,7 @@ func (dc *DockerClient) Pull(ref string) error {
 
 // Push pushes Docker image specified
 func (dc *DockerClient) Push(ref string) error {
-	registryAuth, _ := dc.cnf.GetRegistryAuth(
+	registryAuth := dc.cnf.GetRegistryAuth(
 		docker.GetRegistry(ref),
 	)
 

docker/config/config.go

@@ -8,12 +8,6 @@ import (
 	"strings"
 )
 
-// DefaultUsername is the username we use if none is defined in config
-var DefaultUsername string
-
-// DefaultPassword is the password we use if none is defined in config
-var DefaultPassword string
-
 // DefaultDockerJSON is the defalt path for Docker JSON config file
 var DefaultDockerJSON = "~/.docker/config.json"
 
@@ -29,33 +23,30 @@ type Auth struct {
 	B64Auth string `json:"auth"`
 }
 
-// AreDefaultCredentialsDefined tells if default username & password are defined
-func AreDefaultCredentialsDefined() bool {
-	return DefaultUsername != "" || DefaultPassword != ""
-}
-
 // IsEmpty return true if structure has no relevant data inside
 func (c *Config) IsEmpty() bool {
 	return len(c.Auths) == 0
 }
 
 // GetCredentials gets per-registry credentials from loaded Docker config
 func (c *Config) GetCredentials(registry string) (string, string, bool) {
-	_, defined := c.usernames[registry]
-	if !defined {
-		return DefaultUsername, DefaultUsername, false
+	if _, defined := c.usernames[registry]; !defined {
+		return "", "", false
 	}
 
 	return c.usernames[registry], c.passwords[registry], true
 }
 
 // GetRegistryAuth gets per-registry base64 authentication string
-func (c *Config) GetRegistryAuth(registry string) (string, bool) {
+func (c *Config) GetRegistryAuth(registry string) string {
 	username, password, defined := c.GetCredentials(registry)
+	if !defined {
+		return ""
+	}
 
-	jsonString := fmt.Sprintf("{ \"username\": \"%s\", \"password\": \"%s\" }", username, password)
+	jsonString := fmt.Sprintf(`{ "username": "%s", "password": "%s" }`, username, password)
 
-	return base64.StdEncoding.EncodeToString([]byte(jsonString)), defined
+	return base64.StdEncoding.EncodeToString([]byte(jsonString))
 }
 
 // Load loads a Config object from Docker JSON configuration file specified

docker/config/config_test.go

@@ -8,27 +8,6 @@ const configFile = "../../fixtures/docker/config.json"
 const irrelevantConfigFile = "../../fixtures/docker/config.json.irrelevant"
 const invalidConfigFile = "../../fixtures/docker/config.json.invalid"
 
-func TestAreDefaultCredentialsDefined(t *testing.T) {
-	if AreDefaultCredentialsDefined() {
-		t.Fatalf(
-			"By default no credentials should be defined, but they are: username '%s', password '%s'",
-			DefaultUsername,
-			DefaultPassword,
-		)
-	}
-
-	DefaultUsername = "user"
-	DefaultPassword = "pass"
-
-	if !AreDefaultCredentialsDefined() {
-		t.Fatalf(
-			"Credentials should be defined now, but we get contrary: username '%s', password '%s'",
-			DefaultUsername,
-			DefaultPassword,
-		)
-	}
-}
-
 func TestLoad(t *testing.T) {
 	examples := map[string]string{
 		"registry.company.io":     "user1:pass1",