Adds a command to generate credential process configuration (#10)

* Adds a command to generate credential process configuration

* handle error

cmd/credential_process.go

@@ -5,14 +5,25 @@ import (
 	"fmt"
 	"time"
 
+	"github.com/netflix/weep/util"
+	ini "gopkg.in/ini.v1"
+
 	"github.com/netflix/weep/consoleme"
 	log "github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
 )
 
 func init() {
 	CredentialProcessCmd.PersistentFlags().BoolVarP(&noIpRestrict, "no-ip", "n", false, "remove IP restrictions")
+	GenerateCredentialProcessCmd.PersistentFlags().StringVarP(&destinationConfig, "output", "o", getDefaultAwsConfigFile(), "output file for AWS config")
 	rootCmd.AddCommand(CredentialProcessCmd)
+	rootCmd.AddCommand(GenerateCredentialProcessCmd)
+}
+
+var GenerateCredentialProcessCmd = &cobra.Command{
+	Use:   "generate_credential_process_config",
+	Short: "Writes all of your eligible roles as profiles in your AWS Config to source credentials from Weep",
+	RunE:  runGenerateCredentialProcessConfig,
 }
 
 var CredentialProcessCmd = &cobra.Command{
@@ -22,6 +33,52 @@ var CredentialProcessCmd = &cobra.Command{
 	RunE:  runCredentialProcess,
 }
 
+func writeConfigFile(roles []string) error {
+	var configINI *ini.File
+	var err error
+
+	// Disable pretty format, but still put spaces around `=`
+	ini.PrettyFormat = false
+	ini.PrettyEqual = true
+
+	if util.FileExists(destination) {
+		configINI, err = ini.Load(destination)
+		if err != nil {
+			return err
+		}
+	} else {
+		configINI = ini.Empty()
+	}
+
+	for _, r := range roles {
+		profileName := fmt.Sprintf("profile %s", r)
+		command := fmt.Sprintf("weep credential_process %s", r)
+		configINI.Section(profileName).Key("credential_process").SetValue(command)
+	}
+	err = configINI.SaveTo(destinationConfig)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func runGenerateCredentialProcessConfig(cmd *cobra.Command, args []string) error {
+	client, err := consoleme.GetClient()
+	if err != nil {
+		return err
+	}
+	roles, err := client.Roles()
+	if err != nil {
+		return err
+	}
+	err = writeConfigFile(roles)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
 func runCredentialProcess(cmd *cobra.Command, args []string) error {
 	role = args[0]
 	client, err := consoleme.GetClient()

cmd/file.go

@@ -53,6 +53,15 @@ func getDefaultCredentialsFile() string {
 	return path.Join(home, ".aws", "credentials")
 }
 
+func getDefaultAwsConfigFile() string {
+	home, err := homedir.Dir()
+	if err != nil {
+		fmt.Printf("couldn't get default directory!")
+		os.Exit(1)
+	}
+	return path.Join(home, ".aws", "config")
+}
+
 func writeCredentialsFile(credentials consoleme.AwsCredentials) error {
 	var credentialsINI *ini.File
 	var err error

cmd/vars.go

@@ -4,6 +4,7 @@ var (
 	role               string
 	profileName        string
 	destination        string
+	destinationConfig  string
 	noIpRestrict       bool
 	metadataRegion     string
 	metadataListenAddr string