aws/defaults: Export Shared Config/Creds filename helpers (#1308)

Exports the shared credentials and shared config filename helper functions to make it easier to get the filename of the credentials and config file.

Corrects a bug in the shared credentials and config HOME path that would return an invalid filename on windows if the HOME environment variable was defined.

Replaces #1293

CHANGELOG_PENDING.md

@@ -1,5 +1,9 @@
 ### SDK Features
 
 ### SDK Enhancements
+* `aws/defaults`: Exports shared credentials and config default filenames used by the SDK. [#1308](https://github.com/aws/aws-sdk-go/pull/1308)
+  * Adds SharedCredentialsFilename and SharedConfigFilename functions to defaults package.
 
 ### SDK Bugs
+* `aws/credentials`: Fixes shared credential provider's default filename on Windows. [#1308](https://github.com/aws/aws-sdk-go/pull/1308)
+  * The shared credentials provider would attempt to use the wrong filename on Windows if the `HOME` environment variable was defined.

aws/credentials/shared_credentials_provider.go

@@ -3,20 +3,18 @@ package credentials
 import (
 	"fmt"
 	"os"
-	"path/filepath"
 
 	"github.com/go-ini/ini"
 
 	"github.com/aws/aws-sdk-go/aws/awserr"
+	"github.com/aws/aws-sdk-go/internal/shareddefaults"
 )
 
 // SharedCredsProviderName provides a name of SharedCreds provider
 const SharedCredsProviderName = "SharedCredentialsProvider"
 
 var (
 	// ErrSharedCredentialsHomeNotFound is emitted when the user directory cannot be found.
-	//
-	// @readonly
 	ErrSharedCredentialsHomeNotFound = awserr.New("UserHomeNotFound", "user home directory not found.", nil)
 )
 
@@ -117,22 +115,23 @@ func loadProfile(filename, profile string) (Value, error) {
 //
 // Will return an error if the user's home directory path cannot be found.
 func (p *SharedCredentialsProvider) filename() (string, error) {
-	if p.Filename == "" {
-		if p.Filename = os.Getenv("AWS_SHARED_CREDENTIALS_FILE"); p.Filename != "" {
-			return p.Filename, nil
-		}
-
-		homeDir := os.Getenv("HOME") // *nix
-		if homeDir == "" {           // Windows
-			homeDir = os.Getenv("USERPROFILE")
-		}
-		if homeDir == "" {
-			return "", ErrSharedCredentialsHomeNotFound
-		}
-
-		p.Filename = filepath.Join(homeDir, ".aws", "credentials")
+	if len(p.Filename) != 0 {
+		return p.Filename, nil
+	}
+
+	if p.Filename = os.Getenv("AWS_SHARED_CREDENTIALS_FILE"); len(p.Filename) != 0 {
+		return p.Filename, nil
 	}
 
+	if home := shareddefaults.UserHomeDir(); len(home) == 0 {
+		// Backwards compatibility of home directly not found error being returned.
+		// This error is too verbose, failure when opening the file would of been
+		// a better error to return.
+		return "", ErrSharedCredentialsHomeNotFound
+	}
+
+	p.Filename = shareddefaults.SharedConfigFilename()
+
 	return p.Filename, nil
 }
 

aws/defaults/shared_config.go

@@ -0,0 +1,27 @@
+package defaults
+
+import (
+	"github.com/aws/aws-sdk-go/internal/shareddefaults"
+)
+
+// SharedCredentialsFilename returns the SDK's default file path
+// for the shared credentials file.
+//
+// Builds the shared config file path based on the OS's platform.
+//
+//   - Linux/Unix: $HOME/.aws/credentials
+//   - Windows: %USERPROFILE%\.aws\credentials
+func SharedCredentialsFilename() string {
+	return shareddefaults.SharedCredentialsFilename()
+}
+
+// SharedConfigFilename returns the SDK's default file path for
+// the shared config file.
+//
+// Builds the shared config file path based on the OS's platform.
+//
+//   - Linux/Unix: $HOME/.aws/config
+//   - Windows: %USERPROFILE%\.aws\config
+func SharedConfigFilename() string {
+	return shareddefaults.SharedConfigFilename()
+}

aws/session/custom_ca_bundle_test.go

@@ -42,7 +42,7 @@ func TestMain(m *testing.M) {
 
 func TestNewSession_WithCustomCABundle_Env(t *testing.T) {
 	oldEnv := initSessionTestEnv()
-	defer popEnv(oldEnv)
+	defer awstesting.PopEnv(oldEnv)
 
 	endpoint, err := awstesting.CreateTLSServer(TLSBundleCertFile, TLSBundleKeyFile, nil)
 	if err != nil {
@@ -76,7 +76,7 @@ func TestNewSession_WithCustomCABundle_Env(t *testing.T) {
 
 func TestNewSession_WithCustomCABundle_EnvNotExists(t *testing.T) {
 	oldEnv := initSessionTestEnv()
-	defer popEnv(oldEnv)
+	defer awstesting.PopEnv(oldEnv)
 
 	os.Setenv("AWS_CA_BUNDLE", "file-not-exists")
 
@@ -94,7 +94,7 @@ func TestNewSession_WithCustomCABundle_EnvNotExists(t *testing.T) {
 
 func TestNewSession_WithCustomCABundle_Option(t *testing.T) {
 	oldEnv := initSessionTestEnv()
-	defer popEnv(oldEnv)
+	defer awstesting.PopEnv(oldEnv)
 
 	endpoint, err := awstesting.CreateTLSServer(TLSBundleCertFile, TLSBundleKeyFile, nil)
 	if err != nil {
@@ -129,7 +129,7 @@ func TestNewSession_WithCustomCABundle_Option(t *testing.T) {
 
 func TestNewSession_WithCustomCABundle_OptionPriority(t *testing.T) {
 	oldEnv := initSessionTestEnv()
-	defer popEnv(oldEnv)
+	defer awstesting.PopEnv(oldEnv)
 
 	endpoint, err := awstesting.CreateTLSServer(TLSBundleCertFile, TLSBundleKeyFile, nil)
 	if err != nil {
@@ -172,7 +172,7 @@ func (m *mockRoundTripper) RoundTrip(r *http.Request) (*http.Response, error) {
 
 func TestNewSession_WithCustomCABundle_UnsupportedTransport(t *testing.T) {
 	oldEnv := initSessionTestEnv()
-	defer popEnv(oldEnv)
+	defer awstesting.PopEnv(oldEnv)
 
 	s, err := NewSessionWithOptions(Options{
 		Config: aws.Config{
@@ -199,7 +199,7 @@ func TestNewSession_WithCustomCABundle_UnsupportedTransport(t *testing.T) {
 
 func TestNewSession_WithCustomCABundle_TransportSet(t *testing.T) {
 	oldEnv := initSessionTestEnv()
-	defer popEnv(oldEnv)
+	defer awstesting.PopEnv(oldEnv)
 
 	endpoint, err := awstesting.CreateTLSServer(TLSBundleCertFile, TLSBundleKeyFile, nil)
 	if err != nil {

aws/session/env_config.go

@@ -2,7 +2,6 @@ package session
 
 import (
 	"os"
-	"path/filepath"
 	"strconv"
 
 	"github.com/aws/aws-sdk-go/aws/credentials"
@@ -116,6 +115,12 @@ var (
 		"AWS_PROFILE",
 		"AWS_DEFAULT_PROFILE", // Only read if AWS_SDK_LOAD_CONFIG is also set
 	}
+	sharedCredsFileEnvKey = []string{
+		"AWS_SHARED_CREDENTIALS_FILE",
+	}
+	sharedConfigFileEnvKey = []string{
+		"AWS_CONFIG_FILE",
+	}
 )
 
 // loadEnvConfig retrieves the SDK's environment configuration.
@@ -165,8 +170,8 @@ func envConfigLoad(enableSharedConfig bool) envConfig {
 	setFromEnvVal(&cfg.Region, regionKeys)
 	setFromEnvVal(&cfg.Profile, profileKeys)
 
-	cfg.SharedCredentialsFile = sharedCredentialsFilename()
-	cfg.SharedConfigFile = sharedConfigFilename()
+	setFromEnvVal(&cfg.SharedCredentialsFile, sharedCredsFileEnvKey)
+	setFromEnvVal(&cfg.SharedConfigFile, sharedConfigFileEnvKey)
 
 	cfg.CustomCABundle = os.Getenv("AWS_CA_BUNDLE")
 
@@ -181,28 +186,3 @@ func setFromEnvVal(dst *string, keys []string) {
 		}
 	}
 }
-
-func sharedCredentialsFilename() string {
-	if name := os.Getenv("AWS_SHARED_CREDENTIALS_FILE"); len(name) > 0 {
-		return name
-	}
-
-	return filepath.Join(userHomeDir(), ".aws", "credentials")
-}
-
-func sharedConfigFilename() string {
-	if name := os.Getenv("AWS_CONFIG_FILE"); len(name) > 0 {
-		return name
-	}
-
-	return filepath.Join(userHomeDir(), ".aws", "config")
-}
-
-func userHomeDir() string {
-	homeDir := os.Getenv("HOME") // *nix
-	if len(homeDir) == 0 {       // windows
-		homeDir = os.Getenv("USERPROFILE")
-	}
-
-	return homeDir
-}