encode registry credentials in docker config format

CHANGELOG.md

@@ -1,6 +1,10 @@
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [1.4.0] - 2019-11-05
+### Added
+- function to encode registry credentials in docker config.json format
+
 ## [1.3.1] - 2019-11-01
 ### Fixed
 - check if last exit code greater than 0 in powershell

registry/auths/auth.go

@@ -16,13 +16,18 @@ import (
 	"github.com/drone/drone-go/drone"
 )
 
-// config represents the Docker client configuration,
-// typically located at ~/.docker/config.json
-type config struct {
-	Auths map[string]struct {
+type (
+	// config represents the Docker client configuration,
+	// typically located at ~/.docker/config.json
+	config struct {
+		Auths map[string]auth `json:"auths"`
+	}
+
+	// auth stores the registry authentication string.
+	auth struct {
 		Auth string `json:"auth"`
-	} `json:"auths"`
-}
+	}
+)
 
 // Parse parses the registry credential from the reader.
 func Parse(r io.Reader) ([]*drone.Registry, error) {
@@ -63,10 +68,10 @@ func ParseBytes(b []byte) ([]*drone.Registry, error) {
 	return Parse(bytes.NewReader(b))
 }
 
-// Encode returns the json marshaled, base64 encoded
+// Header returns the json marshaled, base64 encoded
 // credential string that can be passed to the docker
 // registry authentication header.
-func Encode(username, password string) string {
+func Header(username, password string) string {
 	v := struct {
 		Username string `json:"username,omitempty"`
 		Password string `json:"password,omitempty"`

registry/auths/auth_test.go

@@ -103,10 +103,10 @@ func TestDecodeInvalid(t *testing.T) {
 	}
 }
 
-func TestEncode(t *testing.T) {
+func TestHeader(t *testing.T) {
 	username := "octocat"
 	password := "correct-horse-battery-staple"
-	result := Encode(username, password)
+	result := Header(username, password)
 	got, err := base64.URLEncoding.DecodeString(result)
 	if err != nil {
 		t.Error(err)

registry/auths/encode.go

@@ -0,0 +1,29 @@
+// Copyright 2019 Drone.IO Inc. All rights reserved.
+// Use of this source code is governed by the Polyform License
+// that can be found in the LICENSE file.
+
+package auths
+
+import (
+	"bytes"
+	"encoding/json"
+
+	"github.com/drone/drone-go/drone"
+)
+
+// Encode encodes the registry credentials to using the
+// docker config json format and returns the resulting
+// data in string format.
+func Encode(registry ...*drone.Registry) string {
+	c := new(config)
+	c.Auths = map[string]auth{}
+	for _, r := range registry {
+		c.Auths[r.Address] = auth{
+			Auth: encode(r.Username, r.Password),
+		}
+	}
+	buf := new(bytes.Buffer)
+	enc := json.NewEncoder(buf)
+	enc.Encode(c)
+	return buf.String()
+}

registry/auths/encode_test.go

@@ -0,0 +1,28 @@
+// Copyright 2019 Drone.IO Inc. All rights reserved.
+// Use of this source code is governed by the Polyform License
+// that can be found in the LICENSE file.
+
+package auths
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/drone/drone-go/drone"
+)
+
+func TestEncode(t *testing.T) {
+	endpoint := "docker.io"
+	username := "octocat"
+	password := "correct-horse-battery-staple"
+	registry := &drone.Registry{
+		Username: username,
+		Password: password,
+		Address:  endpoint,
+	}
+	got := Encode(registry, registry, registry)
+	want := `{"auths":{"docker.io":{"auth":"b2N0b2NhdDpjb3JyZWN0LWhvcnNlLWJhdHRlcnktc3RhcGxl"}}}`
+	if strings.TrimSpace(got) != strings.TrimSpace(want) {
+		t.Errorf("Unexpected encoding: %q want %q", got, want)
+	}
+}