Added AuthConfig to login to multiple registry

cmd/drone-docker/main.go

@@ -208,6 +208,11 @@ func main() {
 			Usage:  "docker email",
 			EnvVar: "PLUGIN_EMAIL,DOCKER_EMAIL",
 		},
+		cli.StringFlag{
+			Name:   "docker.authconfig",
+			Usage:  "docker json authconfig content",
+			EnvVar: "PLUGIN_AUTHCONFIG,DOCKER_AUTHCONFIG",
+		},
 		cli.BoolTFlag{
 			Name:   "docker.purge",
 			Usage:  "docker should cleanup images",
@@ -240,10 +245,11 @@ func run(c *cli.Context) error {
 		Dryrun:  c.Bool("dry-run"),
 		Cleanup: c.BoolT("docker.purge"),
 		Login: docker.Login{
-			Registry: c.String("docker.registry"),
+			Registry:   c.String("docker.registry"),
-			Username: c.String("docker.username"),
+			Username:   c.String("docker.username"),
-			Password: c.String("docker.password"),
+			Password:   c.String("docker.password"),
-			Email:    c.String("docker.email"),
+			Email:      c.String("docker.email"),
+			AuthConfig: c.String("docker.authconfig"),
 		},
 		Build: docker.Build{
 			Remote:      c.String("remote.url"),

docker.go

@@ -28,10 +28,11 @@ type (
 
 	// Login defines Docker login parameters.
 	Login struct {
-		Registry string // Docker registry address
+		Registry   string // Docker registry address
-		Username string // Docker registry username
+		Username   string // Docker registry username
-		Password string // Docker registry password
+		Password   string // Docker registry password
-		Email    string // Docker registry email
+		Email      string // Docker registry email
+		AuthConfig string // Docker Auth Config
 	}
 
 	// Build defines Docker build parameters.
@@ -83,6 +84,35 @@ func (p Plugin) Exec() error {
 		time.Sleep(time.Second * 1)
 	}
 
+	// Create Auth Config File
+	if p.Login.AuthConfig != "" {
+		fmt.Println("AuthConfig provided.")
+		err_mkdir := os.MkdirAll("/root/.docker", 0600)
+		if err_mkdir != nil {
+			fmt.Println("Error creating root's docker auth config directory: ")
+			fmt.Println(err_mkdir)
+		}
+		cfile, err_create := os.Create("/root/.docker/config.json")
+		if err_create != nil {
+			fmt.Println("Error creating root's docker auth config file: ")
+			fmt.Println(err_create)
+			cfile.Close()
+		}
+		err_chmod := os.Chmod("/root/.docker/config.json", 0600)
+		if err_chmod != nil {
+			fmt.Println("Error setting permissions on root's docker auth config file: ")
+			fmt.Println(err_chmod)
+		}
+		_, err_str := cfile.WriteString(p.Login.AuthConfig)
+		if err_str != nil {
+			fmt.Println("Error filling root's docker auth config file: ")
+			fmt.Println(err_str)
+		} else {
+			cfile.Close()
+		}
+
+	}
+
 	// login to the Docker registry
 	if p.Login.Password != "" {
 		cmd := commandLogin(p.Login)