make function ReadDockerConfigFile more flexible

rename the variable

make parameter more flexible

handle docker config file path

use a single set of paths

delete debug print

gofmt

delete the empty line

comment is not correct

move the comment to the correct place

keep original signature

godoc

pkg/credentialprovider/config.go

@@ -74,35 +74,24 @@ func GetPreferredDockercfgPath() string {
 	return preferredPath
 }
 
-func ReadDockerConfigFile() (cfg DockerConfig, err error) {
-	// Try happy path first - latest config file
-	dockerConfigJsonLocations := []string{GetPreferredDockercfgPath(), workingDirPath, homeJsonDirPath, rootJsonDirPath}
-	for _, configPath := range dockerConfigJsonLocations {
-		absDockerConfigFileLocation, err := filepath.Abs(filepath.Join(configPath, configJsonFileName))
-		if err != nil {
-			glog.Errorf("while trying to canonicalize %s: %v", configPath, err)
-			continue
-		}
-		glog.V(4).Infof("looking for .docker/config.json at %s", absDockerConfigFileLocation)
-		contents, err := ioutil.ReadFile(absDockerConfigFileLocation)
-		if os.IsNotExist(err) {
-			continue
-		}
-		if err != nil {
-			glog.V(4).Infof("while trying to read %s: %v", absDockerConfigFileLocation, err)
-			continue
-		}
-		cfg, err := readDockerConfigJsonFileFromBytes(contents)
-		if err == nil {
-			glog.V(4).Infof("found .docker/config.json at %s", absDockerConfigFileLocation)
-			return cfg, nil
-		}
-	}
-	glog.V(4).Infof("couldn't find valid .docker/config.json after checking in %v", dockerConfigJsonLocations)
+//DefaultDockercfgPaths returns default search paths of .dockercfg
+func DefaultDockercfgPaths() []string {
+	return []string{GetPreferredDockercfgPath(), workingDirPath, homeDirPath, rootDirPath}
+}
 
-	// Can't find latest config file so check for the old one
-	dockerConfigFileLocations := []string{GetPreferredDockercfgPath(), workingDirPath, homeDirPath, rootDirPath}
-	for _, configPath := range dockerConfigFileLocations {
+//DefaultDockerConfigJSONPaths returns default search paths of .docker/config.json
+func DefaultDockerConfigJSONPaths() []string {
+	return []string{GetPreferredDockercfgPath(), workingDirPath, homeJsonDirPath, rootJsonDirPath}
+}
+
+// ReadDockercfgFile attempts to read a legacy dockercfg file from the given paths.
+// if searchPaths is empty, the default paths are used.
+func ReadDockercfgFile(searchPaths []string) (cfg DockerConfig, err error) {
+	if len(searchPaths) == 0 {
+		searchPaths = DefaultDockercfgPaths()
+	}
+
+	for _, configPath := range searchPaths {
 		absDockerConfigFileLocation, err := filepath.Abs(filepath.Join(configPath, configFileName))
 		if err != nil {
 			glog.Errorf("while trying to canonicalize %s: %v", configPath, err)
@@ -123,7 +112,46 @@ func ReadDockerConfigFile() (cfg DockerConfig, err error) {
 			return cfg, nil
 		}
 	}
-	return nil, fmt.Errorf("couldn't find valid .dockercfg after checking in %v", dockerConfigFileLocations)
+	return nil, fmt.Errorf("couldn't find valid .dockercfg after checking in %v", searchPaths)
+}
+
+// ReadDockerConfigJSONFile attempts to read a docker config.json file from the given paths.
+// if searchPaths is empty, the default paths are used.
+func ReadDockerConfigJSONFile(searchPaths []string) (cfg DockerConfig, err error) {
+	if len(searchPaths) == 0 {
+		searchPaths = DefaultDockerConfigJSONPaths()
+	}
+
+	for _, configPath := range searchPaths {
+		absDockerConfigFileLocation, err := filepath.Abs(filepath.Join(configPath, configJsonFileName))
+		if err != nil {
+			glog.Errorf("while trying to canonicalize %s: %v", configPath, err)
+			continue
+		}
+		glog.V(4).Infof("looking for .docker/config.json at %s", absDockerConfigFileLocation)
+		contents, err := ioutil.ReadFile(absDockerConfigFileLocation)
+		if os.IsNotExist(err) {
+			continue
+		}
+		if err != nil {
+			glog.V(4).Infof("while trying to read %s: %v", absDockerConfigFileLocation, err)
+			continue
+		}
+		cfg, err := readDockerConfigJsonFileFromBytes(contents)
+		if err == nil {
+			glog.V(4).Infof("found .docker/config.json at %s", absDockerConfigFileLocation)
+			return cfg, nil
+		}
+	}
+	return nil, fmt.Errorf("couldn't find valid .docker/config.json after checking in %v", searchPaths)
+}
+
+func ReadDockerConfigFile() (cfg DockerConfig, err error) {
+	if cfg, err := ReadDockerConfigJSONFile(nil); err == nil {
+		return cfg, nil
+	}
+	// Can't find latest config file so check for the old one
+	return ReadDockercfgFile(nil)
 }
 
 // HttpError wraps a non-StatusOK error code as an error.

pkg/credentialprovider/config_test.go

@@ -18,10 +18,51 @@ package credentialprovider
 
 import (
 	"encoding/json"
+	"io/ioutil"
+	"os"
+	"path/filepath"
 	"reflect"
 	"testing"
 )
 
+func TestReadDockerConfigFile(t *testing.T) {
+	configJsonFileName := "config.json"
+	var fileInfo *os.File
+	preferredPaths := []string{}
+
+	//test dockerconfig json
+	inputDockerconfigJsonFile := "{ \"auths\": { \"http://foo.example.com\":{\"auth\":\"Zm9vOmJhcgo=\",\"email\":\"foo@example.com\"}}}"
+
+	preferredPath, err := ioutil.TempDir("", "test_foo_bar_dockerconfigjson_")
+	if err != nil {
+		t.Fatalf("Creating tmp dir fail: %v", err)
+		return
+	}
+	defer os.RemoveAll(preferredPath)
+	preferredPaths = append(preferredPaths, preferredPath)
+	absDockerConfigFileLocation, err := filepath.Abs(filepath.Join(preferredPath, configJsonFileName))
+	if err != nil {
+		t.Fatalf("While trying to canonicalize %s: %v", preferredPath, err)
+	}
+
+	if _, err := os.Stat(absDockerConfigFileLocation); os.IsNotExist(err) {
+		//create test cfg file
+		fileInfo, err = os.OpenFile(absDockerConfigFileLocation, os.O_CREATE|os.O_RDWR, 0664)
+		if err != nil {
+			t.Fatalf("While trying to create file %s: %v", absDockerConfigFileLocation, err)
+		}
+		defer fileInfo.Close()
+	}
+
+	fileInfo.WriteString(inputDockerconfigJsonFile)
+
+	orgPreferredPath := GetPreferredDockercfgPath()
+	SetPreferredDockercfgPath(preferredPath)
+	defer SetPreferredDockercfgPath(orgPreferredPath)
+	if _, err := ReadDockerConfigFile(); err != nil {
+		t.Errorf("Getting docker config file fail : %v preferredPath : %q", err, preferredPath)
+	}
+}
 func TestDockerConfigJsonJSONDecode(t *testing.T) {
 	input := []byte(`{"auths": {"http://foo.example.com":{"username": "foo", "password": "bar", "email": "foo@example.com"}, "http://bar.example.com":{"username": "bar", "password": "baz", "email": "bar@example.com"}}}`)