code to update credential file (#3)

remove awscli dependency

cmd/login.go

@@ -106,13 +106,20 @@ var loginCmd = &cobra.Command{
 			fmt.Println(err)
 			os.Exit(1)
 		}
-		intAWS.SetCredentials(
+		err = intAWS.SetCredentials(
+			&intAWS.CredentialFileGetter{},
+			&intAWS.CredentialFileWriter{},
 			*result.Credentials.AccessKeyId,
 			*result.Credentials.SecretAccessKey,
 			*result.Credentials.SessionToken,
 			config.DefaultRegion,
 			profileName,
 		)
+		if err != nil {
+			fmt.Println(err)
+			os.Exit(1)
+		}
+
 		fmt.Printf("Successfully set credentials for: %s\n", profileName)
 	},
 }

internal/aws/credential-manager.go

@@ -1,47 +1,151 @@
 package aws
 
 import (
+	"bufio"
+	"errors"
 	"fmt"
-	"log"
-	"os/exec"
+	"io/ioutil"
+	"os"
+	"strings"
 )
 
-func SetCredentials(accessKey, secretAccessKey, sessionToken, region, profileName string) {
-	err := setProfileParameter("aws_access_key_id", accessKey, profileName)
+type CredentialFileGetterIface interface {
+	Get() (string, error)
+	Exists() (bool, error)
+	SetHomeDir(string)
+}
+type CredentialFileWriterIface interface {
+	Write(b []byte) error
+	SetHomeDir(string)
+}
+
+type CredentialFileGetter struct {
+	Homedir string
+}
+
+func (c *CredentialFileGetter) SetHomeDir(homedir string) {
+	c.Homedir = homedir
+}
+func (c *CredentialFileGetter) Get() (string, error) {
+	credentials, err := ioutil.ReadFile(c.Homedir + "/.aws/credentials")
 	if err != nil {
-		log.Fatalln("Error while writing credentials to file. ", err)
+		return "", fmt.Errorf("Could not read file: %s", err)
 	}
-	err = setProfileParameter("aws_secret_access_key", secretAccessKey, profileName)
-	if err != nil {
-		log.Fatalln("Error while writing credentials to file. ", err)
+
+	return string(credentials), nil
+}
+func (c *CredentialFileGetter) Exists() (bool, error) {
+	credentialsFileExists := false
+
+	if _, err := os.Stat(c.Homedir + "/.aws/credentials"); err == nil {
+		credentialsFileExists = true
+	} else if errors.Is(err, os.ErrNotExist) {
+		credentialsFileExists = false
+	} else {
+		return credentialsFileExists, fmt.Errorf("Could not determine if credential file exists: %s", err)
 	}
-	err = setProfileParameter("aws_session_token", sessionToken, profileName)
+	return credentialsFileExists, nil
+}
+
+type CredentialFileWriter struct {
+	Homedir string
+}
+
+func (c *CredentialFileWriter) Write(b []byte) error {
+	return os.WriteFile(c.Homedir+"/.aws/credentials", b, 0600)
+}
+func (c *CredentialFileWriter) SetHomeDir(homedir string) {
+	c.Homedir = homedir
+}
+
+func SetCredentials(credFileGetter CredentialFileGetterIface, credFileWriter CredentialFileWriterIface, accessKey, secretAccessKey, sessionToken, region, profileName string) error {
+	// set user homedir
+	homedir, err := os.UserHomeDir()
 	if err != nil {
-		log.Fatalln("Error while writing credentials to file. ", err)
+		return fmt.Errorf("could not get user's home directory: %s", err)
 	}
-	err = setProfileParameter("region", region, profileName)
+	credFileGetter.SetHomeDir(homedir)
+	credFileWriter.SetHomeDir(homedir)
+
+	// check whether file exists
+	exists, err := credFileGetter.Exists()
 	if err != nil {
-		log.Fatalln("Error while writing credentials to file. ", err)
+		return fmt.Errorf("Couldn't determine whether credential file exists: %s", err)
+	}
+
+	// if exists, update / write file
+	if exists {
+		credentials, err := credFileGetter.Get()
+		if err != nil {
+			return fmt.Errorf("Couldn't get credential file: %s", err)
+		}
+		if profileExists(credentials, profileName) {
+			err = updateCredential(credFileWriter, credentials, accessKey, secretAccessKey, sessionToken, region, profileName)
+			if err != nil {
+				return fmt.Errorf("updateCredential error: %s", err)
+			}
+		} else {
+			err = appendCredential(credFileWriter, credentials, accessKey, secretAccessKey, sessionToken, region, profileName)
+			if err != nil {
+				return fmt.Errorf("appendCredential error: %s", err)
+			}
+		}
+	} else { // write new file if credential file doesn't exist
+		err = writeCredentialAsNewFile(credFileWriter, accessKey, secretAccessKey, sessionToken, region, profileName)
+		if err != nil {
+			return fmt.Errorf("writeCredentialAsNewFile error: %s", err)
+		}
 	}
+
+	return nil
 }
 
-func setProfileParameter(parameter, value, profileName string) error {
-	command := []string{
-		"aws",
-		"configure",
-		"set",
-		parameter,
-		value,
-		"--profile",
-		profileName,
+func profileExists(credentials string, profileName string) bool {
+	scanner := bufio.NewScanner(strings.NewReader(credentials))
+	for scanner.Scan() {
+		if strings.Trim(scanner.Text(), " ") == "["+profileName+"]" {
+			return true
+		}
 	}
+	return false
+}
 
-	cmd := exec.Command(command[0], command[1], command[2], command[3], command[4], command[5], command[6])
-	_, err := cmd.Output()
+func updateCredential(writer CredentialFileWriterIface, credentials, accessKey, secretAccessKey, sessionToken, region, profileName string) error {
+	newCredentials := ""
+	found := false
+	scanner := bufio.NewScanner(strings.NewReader(credentials))
+	for scanner.Scan() {
+		line := scanner.Text()
+		if strings.Trim(line, " ") == "["+profileName+"]" {
+			found = true
+			newCredentials += formatCredential(accessKey, secretAccessKey, sessionToken, region, profileName)
+		}
 
-	if err != nil {
-		fmt.Println(err.Error())
-		return err
+		if !found {
+			newCredentials += line + "\n"
+		}
+
+		if found && line == "" {
+			found = false
+			newCredentials += "\n\n"
+		}
 	}
-	return nil
+	newCredentials = strings.TrimRight(newCredentials, "\n")
+	return writer.Write([]byte(newCredentials))
+}
+func appendCredential(writer CredentialFileWriterIface, credentials, accessKey, secretAccessKey, sessionToken, region, profileName string) error {
+	credentials = strings.TrimRight(credentials, "\n")
+	if credentials != "" {
+		credentials += "\n\n"
+	}
+	credentials += formatCredential(accessKey, secretAccessKey, sessionToken, region, profileName)
+	return writer.Write([]byte(credentials))
+}
+
+func writeCredentialAsNewFile(writer CredentialFileWriterIface, accessKey, secretAccessKey, sessionToken, region, profileName string) error {
+	return writer.Write([]byte(formatCredential(accessKey, secretAccessKey, sessionToken, region, profileName)))
+}
+
+func formatCredential(accessKey, secretAccessKey, sessionToken, region, profileName string) string {
+	return fmt.Sprintf("[%s]\naws_access_key_id = %s\naws_secret_access_key = %s\naws_session_token = %s", profileName, accessKey, secretAccessKey, sessionToken)
 }

internal/aws/credential-manager_test.go

@@ -0,0 +1,172 @@
+package aws
+
+import (
+	"testing"
+)
+
+type MockCredentialFileGetter struct {
+	CredentialOutput string
+	CredentialExists bool
+}
+type MockCredentialFileWriter struct {
+	Out []byte
+}
+
+func (c MockCredentialFileGetter) SetHomeDir(homedir string) {
+
+}
+func (c MockCredentialFileGetter) Get() (string, error) {
+	return c.CredentialOutput, nil
+}
+func (c MockCredentialFileGetter) Exists() (bool, error) {
+	return c.CredentialExists, nil
+}
+
+func (c MockCredentialFileWriter) SetHomeDir(homedir string) {
+
+}
+func (c *MockCredentialFileWriter) Write(b []byte) error {
+	c.Out = b
+	return nil
+}
+
+func TestSetCredentialsEmpty(t *testing.T) {
+	mockGetter := MockCredentialFileGetter{
+		CredentialOutput: "",
+		CredentialExists: true,
+	}
+	mockWriter := MockCredentialFileWriter{}
+	err := SetCredentials(
+		mockGetter,
+		&mockWriter,
+		"accessKey",
+		"secretKey",
+		"sessionToken",
+		"us-eas-1",
+		"myProfile",
+	)
+	if err != nil {
+		t.Errorf("error: %s", err)
+	}
+	if string(mockWriter.Out) != formatCredential("accessKey", "secretKey", "sessionToken", "us-eas-1", "myProfile") {
+		t.Errorf("Wrong output. Got: %s", mockWriter.Out)
+	}
+}
+
+func TestSetCredentialsNonExisting(t *testing.T) {
+	mockGetter := MockCredentialFileGetter{
+		CredentialOutput: "",
+		CredentialExists: false,
+	}
+	mockWriter := MockCredentialFileWriter{}
+	err := SetCredentials(
+		mockGetter,
+		&mockWriter,
+		"accessKey",
+		"secretKey",
+		"sessionToken",
+		"us-eas-1",
+		"myProfile",
+	)
+	if err != nil {
+		t.Errorf("error: %s", err)
+	}
+	if string(mockWriter.Out) != formatCredential("accessKey", "secretKey", "sessionToken", "us-eas-1", "myProfile") {
+		t.Errorf("Wrong output. Got: %s", mockWriter.Out)
+	}
+}
+func TestSetCredentialsExistingFile(t *testing.T) {
+	mockGetter := MockCredentialFileGetter{
+		CredentialOutput: formatCredential("accessKey1", "secretKey1", "sessionToken1", "us-east-2", "profile123"),
+		CredentialExists: true,
+	}
+	mockWriter := MockCredentialFileWriter{}
+	err := SetCredentials(
+		mockGetter,
+		&mockWriter,
+		"accessKey",
+		"secretKey",
+		"sessionToken",
+		"us-east-1",
+		"myProfile",
+	)
+	if err != nil {
+		t.Errorf("error: %s", err)
+	}
+	expected := formatCredential("accessKey1", "secretKey1", "sessionToken1", "us-east-2", "profile123") + "\n\n" + formatCredential("accessKey", "secretKey", "sessionToken", "us-east-1", "myProfile")
+	if string(mockWriter.Out) != expected {
+		t.Errorf("Wrong output. Got: %s", mockWriter.Out)
+	}
+}
+
+func TestSetCredentialsExistingFileReplace1(t *testing.T) {
+	mockGetter := MockCredentialFileGetter{
+		CredentialOutput: formatCredential("accessKey1", "secretKey1", "sessionToken1", "us-east-2", "profile123") + "\n\n" + formatCredential("accessKey2", "secretKey2", "sessionToken2", "us-east-2", "myProfile"),
+		CredentialExists: true,
+	}
+	mockWriter := MockCredentialFileWriter{}
+	err := SetCredentials(
+		mockGetter,
+		&mockWriter,
+		"accessKey",
+		"secretKey",
+		"sessionToken",
+		"us-east-1",
+		"myProfile",
+	)
+	if err != nil {
+		t.Errorf("error: %s", err)
+	}
+	expected := formatCredential("accessKey1", "secretKey1", "sessionToken1", "us-east-2", "profile123") + "\n\n" + formatCredential("accessKey", "secretKey", "sessionToken", "us-east-1", "myProfile")
+	if string(mockWriter.Out) != expected {
+		t.Errorf("Wrong output. Got: %s", mockWriter.Out)
+	}
+}
+
+func TestSetCredentialsExistingFileReplace2(t *testing.T) {
+	mockGetter := MockCredentialFileGetter{
+		CredentialOutput: formatCredential("accessKey2", "secretKey2", "sessionToken2", "us-east-2", "myProfile") + "\n\n" + formatCredential("accessKey1", "secretKey1", "sessionToken1", "us-east-2", "profile123"),
+		CredentialExists: true,
+	}
+	mockWriter := MockCredentialFileWriter{}
+	err := SetCredentials(
+		mockGetter,
+		&mockWriter,
+		"accessKey",
+		"secretKey",
+		"sessionToken",
+		"us-east-1",
+		"myProfile",
+	)
+	if err != nil {
+		t.Errorf("error: %s", err)
+	}
+	expected := formatCredential("accessKey", "secretKey", "sessionToken", "us-east-1", "myProfile") + "\n\n" + formatCredential("accessKey1", "secretKey1", "sessionToken1", "us-east-2", "profile123")
+	if string(mockWriter.Out) != expected {
+		t.Errorf("Wrong output. Got: %s\n\nExpected: %s", mockWriter.Out, expected)
+	}
+}
+
+func TestSetCredentialsExistingFileReplace3(t *testing.T) {
+	mockGetter := MockCredentialFileGetter{
+		CredentialOutput: formatCredential("accessKey1", "secretKey1", "sessionToken1", "us-east-2", "profile123") + "\n\n" + formatCredential("accessKey2", "secretKey2", "sessionToken2", "us-east-2", "myProfile") + "\n\n" + formatCredential("accessKey1", "secretKey1", "sessionToken1", "us-east-2", "profile1234"),
+		CredentialExists: true,
+	}
+	mockWriter := MockCredentialFileWriter{}
+	err := SetCredentials(
+		mockGetter,
+		&mockWriter,
+		"accessKey",
+		"secretKey",
+		"sessionToken",
+		"us-east-1",
+		"myProfile",
+	)
+	if err != nil {
+		t.Errorf("error: %s", err)
+	}
+	expected := formatCredential("accessKey1", "secretKey1", "sessionToken1", "us-east-2", "profile123") + "\n\n" + formatCredential("accessKey", "secretKey", "sessionToken", "us-east-1", "myProfile") + "\n\n" + formatCredential("accessKey1", "secretKey1", "sessionToken1", "us-east-2", "profile1234")
+	if string(mockWriter.Out) != expected {
+		t.Errorf("Wrong output. Got: %s\n\nExpected: %s", mockWriter.Out, expected)
+	}
+}