Get sub from azure CLI when not provided (#3519)

thanks @cpuguy83!

Gopkg.toml

@@ -104,3 +104,7 @@
 [prune]
   go-tests = true
   unused-packages = true
+
+[[constraint]]
+  name = "gopkg.in/ini.v1"
+  version = "1.38.1"

cmd/root.go

@@ -2,14 +2,17 @@ package cmd
 
 import (
 	"os"
+	"path/filepath"
 
 	"github.com/Azure/acs-engine/pkg/armhelpers"
+	"github.com/Azure/acs-engine/pkg/helpers"
 	"github.com/Azure/go-autorest/autorest/azure"
 	"github.com/pkg/errors"
 	uuid "github.com/satori/go.uuid"
 	log "github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
 	flag "github.com/spf13/pflag"
+	ini "gopkg.in/ini.v1"
 )
 
 const (
@@ -91,7 +94,12 @@ func (authArgs *authArgs) validateAuthArgs() error {
 	}
 
 	if authArgs.SubscriptionID.String() == "00000000-0000-0000-0000-000000000000" {
-		return errors.New("--subscription-id is required (and must be a valid UUID)")
+		subID, err := getSubFromAzDir(filepath.Join(helpers.GetHomeDir(), ".azure"))
+		if err != nil || subID.String() == "00000000-0000-0000-0000-000000000000" {
+			return errors.New("--subscription-id is required (and must be a valid UUID)")
+		}
+		log.Infoln("No subscription provided, using selected subscription from azure CLI:", subID.String())
+		authArgs.SubscriptionID = subID
 	}
 
 	_, err := azure.EnvironmentFromName(authArgs.RawAzureEnvironment)
@@ -101,6 +109,45 @@ func (authArgs *authArgs) validateAuthArgs() error {
 	return nil
 }
 
+func getSubFromAzDir(root string) (uuid.UUID, error) {
+	subConfig, err := ini.Load(filepath.Join(root, "clouds.config"))
+	if err != nil {
+		return uuid.UUID{}, errors.Wrap(err, "error decoding cloud subscription config")
+	}
+
+	cloudConfig, err := ini.Load(filepath.Join(root, "config"))
+	if err != nil {
+		return uuid.UUID{}, errors.Wrap(err, "error decoding cloud config")
+	}
+
+	cloud := getSelectedCloudFromAzConfig(cloudConfig)
+	return getCloudSubFromAzConfig(cloud, subConfig)
+}
+
+func getSelectedCloudFromAzConfig(f *ini.File) string {
+	selectedCloud := "AzureCloud"
+	if cloud, err := f.GetSection("cloud"); err == nil {
+		if name, err := cloud.GetKey("name"); err == nil {
+			if s := name.String(); s != "" {
+				selectedCloud = s
+			}
+		}
+	}
+	return selectedCloud
+}
+
+func getCloudSubFromAzConfig(cloud string, f *ini.File) (uuid.UUID, error) {
+	cfg, err := f.GetSection(cloud)
+	if err != nil {
+		return uuid.UUID{}, errors.New("could not find user defined subscription id")
+	}
+	sub, err := cfg.GetKey("subscription")
+	if err != nil {
+		return uuid.UUID{}, errors.Wrap(err, "error reading subscription id from cloud config")
+	}
+	return uuid.FromString(sub.String())
+}
+
 func (authArgs *authArgs) getClient() (*armhelpers.AzureClient, error) {
 	var client *armhelpers.AzureClient
 	env, err := azure.EnvironmentFromName(authArgs.RawAzureEnvironment)

cmd/root_test.go

@@ -3,7 +3,9 @@ package cmd
 import (
 	"testing"
 
+	uuid "github.com/satori/go.uuid"
 	"github.com/spf13/cobra"
+	ini "gopkg.in/ini.v1"
 )
 
 func TestNewRootCmd(t *testing.T) {
@@ -19,3 +21,88 @@ func TestNewRootCmd(t *testing.T) {
 		}
 	}
 }
+
+func TestGetSelectedCloudFromAzConfig(t *testing.T) {
+	for _, test := range []struct {
+		desc   string
+		data   []byte
+		expect string
+	}{
+		{"nil file", nil, "AzureCloud"},
+		{"empty file", []byte{}, "AzureCloud"},
+		{"no cloud section", []byte(`
+		[key]
+		foo = bar
+		`), "AzureCloud"},
+		{"cloud section empty", []byte(`
+		[cloud]
+		[foo]
+		foo = bar
+		`), "AzureCloud"},
+		{"AzureCloud selected", []byte(`
+		[cloud]
+		name = AzureCloud
+		`), "AzureCloud"},
+		{"custom cloud", []byte(`
+		[cloud]
+		name = myCloud
+		`), "myCloud"},
+	} {
+		t.Run(test.desc, func(t *testing.T) {
+			f, err := ini.Load(test.data)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			cloud := getSelectedCloudFromAzConfig(f)
+			if cloud != test.expect {
+				t.Fatalf("exepcted %q, got %q", test.expect, cloud)
+			}
+		})
+	}
+}
+
+func TestGetCloudSubFromAzConfig(t *testing.T) {
+	goodUUID, err := uuid.FromString("ccabad21-ea42-4ea1-affc-17ae73f9df66")
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, test := range []struct {
+		desc   string
+		data   []byte
+		expect uuid.UUID
+		err    bool
+	}{
+		{"empty file", []byte{}, uuid.UUID{}, true},
+		{"no entry for cloud", []byte(`
+		[SomeCloud]
+		subscription = 00000000-0000-0000-0000-000000000000
+		`), uuid.UUID{}, true},
+		{"invalid UUID", []byte(`
+		[AzureCloud]
+		subscription = not-a-good-value
+		`), uuid.UUID{}, true},
+		{"real UUID", []byte(`
+		[AzureCloud]
+		subscription = ` + goodUUID.String() + `
+		`), goodUUID, false},
+	} {
+		t.Run(test.desc, func(t *testing.T) {
+			f, err := ini.Load(test.data)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			uuid, err := getCloudSubFromAzConfig("AzureCloud", f)
+			if test.err != (err != nil) {
+				t.Fatalf("expected err=%v, got: %v", test.err, err)
+			}
+			if test.err {
+				return
+			}
+			if uuid.String() != test.expect.String() {
+				t.Fatalf("expected %s, got %s", test.expect, uuid)
+			}
+		})
+	}
+}

pkg/helpers/helpers.go

@@ -6,6 +6,8 @@ import (
 	"crypto/rsa"
 	"encoding/json"
 	"io"
+	"os"
+	"runtime"
 	"strings"
 
 	"github.com/Azure/acs-engine/pkg/i18n"
@@ -118,3 +120,15 @@ func AcceleratedNetworkingSupported(sku string) bool {
 	}
 	return true
 }
+
+// GetHomeDir attempts to get the home dir from env
+func GetHomeDir() string {
+	if runtime.GOOS == "windows" {
+		home := os.Getenv("HOMEDRIVE") + os.Getenv("HOMEPATH")
+		if home == "" {
+			home = os.Getenv("USERPROFILE")
+		}
+		return home
+	}
+	return os.Getenv("HOME")
+}