Change the parameters to the GCS drivers to allow CircleCI testing.

Remove the requirement of file system access to run GCS unit tests.  Deconstruct
the input parameters to take the private key and email which can be specified on
the build system via environment variables.

Signed-off-by: Richard Scothern <richard.scothern@gmail.com>

docs/storage/driver/gcs/gcs.go

@@ -32,7 +32,7 @@ import (
 	"golang.org/x/net/context"
 	"golang.org/x/oauth2"
 	"golang.org/x/oauth2/google"
-
+	"golang.org/x/oauth2/jwt"
 	"google.golang.org/api/googleapi"
 	storageapi "google.golang.org/api/storage/v1"
 	"google.golang.org/cloud"
@@ -47,10 +47,13 @@ import (
 const driverName = "gcs"
 const dummyProjectID = "<unknown>"
 
-//DriverParameters A struct that encapsulates all of the driver parameters after all values have been set
+// driverParameters is a struct that encapsulates all of the driver parameters after all values have been set
 type driverParameters struct {
 	bucket        string
-	keyfile       string
+	config        *jwt.Config
+	email         string
+	privateKey    []byte
+	client        *http.Client
 	rootDirectory string
 }
 
@@ -80,25 +83,43 @@ type driver struct {
 // Required parameters:
 // - bucket
 func FromParameters(parameters map[string]interface{}) (storagedriver.StorageDriver, error) {
-
 	bucket, ok := parameters["bucket"]
 	if !ok || fmt.Sprint(bucket) == "" {
 		return nil, fmt.Errorf("No bucket parameter provided")
 	}
 
-	keyfile, ok := parameters["keyfile"]
-	if !ok {
-		keyfile = ""
-	}
-
 	rootDirectory, ok := parameters["rootdirectory"]
 	if !ok {
 		rootDirectory = ""
 	}
+
+	var ts oauth2.TokenSource
+	jwtConf := new(jwt.Config)
+	if keyfile, ok := parameters["keyfile"]; ok {
+		jsonKey, err := ioutil.ReadFile(fmt.Sprint(keyfile))
+		if err != nil {
+			return nil, err
+		}
+		jwtConf, err = google.JWTConfigFromJSON(jsonKey, storage.ScopeFullControl)
+		if err != nil {
+			return nil, err
+		}
+		ts = jwtConf.TokenSource(context.Background())
+	} else {
+		var err error
+		ts, err = google.DefaultTokenSource(context.Background(), storage.ScopeFullControl)
+		if err != nil {
+			return nil, err
+		}
+
+	}
+
 	params := driverParameters{
-		fmt.Sprint(bucket),
-		fmt.Sprint(keyfile),
-		fmt.Sprint(rootDirectory),
+		bucket:        fmt.Sprint(bucket),
+		rootDirectory: fmt.Sprint(rootDirectory),
+		email:         jwtConf.Email,
+		privateKey:    jwtConf.PrivateKey,
+		client:        oauth2.NewClient(context.Background(), ts),
 	}
 
 	return New(params)
@@ -106,8 +127,6 @@ func FromParameters(parameters map[string]interface{}) (storagedriver.StorageDri
 
 // New constructs a new driver
 func New(params driverParameters) (storagedriver.StorageDriver, error) {
-	var ts oauth2.TokenSource
-	var err error
 	rootDirectory := strings.Trim(params.rootDirectory, "/")
 	if rootDirectory != "" {
 		rootDirectory += "/"
@@ -115,33 +134,11 @@ func New(params driverParameters) (storagedriver.StorageDriver, error) {
 	d := &driver{
 		bucket:        params.bucket,
 		rootDirectory: rootDirectory,
+		email:         params.email,
+		privateKey:    params.privateKey,
+		client:        params.client,
 	}
-	if params.keyfile == "" {
-		ts, err = google.DefaultTokenSource(context.Background(), storage.ScopeFullControl)
-		if err != nil {
-			return nil, err
-		}
-	} else {
-		jsonKey, err := ioutil.ReadFile(params.keyfile)
-		if err != nil {
-			return nil, err
-		}
-		conf, err := google.JWTConfigFromJSON(
-			jsonKey,
-			storage.ScopeFullControl,
-		)
-		if err != nil {
-			return nil, err
-		}
-		ts = conf.TokenSource(context.Background())
-		d.email = conf.Email
-		d.privateKey = conf.PrivateKey
-	}
-	client := oauth2.NewClient(context.Background(), ts)
-	d.client = client
-	if err != nil {
-		return nil, err
-	}
+
 	return &base.Base{
 		StorageDriver: d,
 	}, nil

docs/storage/driver/gcs/gcs_test.go

@@ -3,17 +3,18 @@
 package gcs
 
 import (
-	"fmt"
 	"io/ioutil"
 	"os"
 	"testing"
 
-	"google.golang.org/api/googleapi"
-
+	"fmt"
 	ctx "github.com/docker/distribution/context"
 	storagedriver "github.com/docker/distribution/registry/storage/driver"
 	"github.com/docker/distribution/registry/storage/driver/testsuites"
-
+	"golang.org/x/oauth2"
+	"golang.org/x/oauth2/google"
+	"google.golang.org/api/googleapi"
+	"google.golang.org/cloud/storage"
 	"gopkg.in/check.v1"
 )
 
@@ -25,34 +26,54 @@ var skipGCS func() string
 
 func init() {
 	bucket := os.Getenv("REGISTRY_STORAGE_GCS_BUCKET")
-	keyfile := os.Getenv("REGISTRY_STORAGE_GCS_KEYFILE")
 	credentials := os.Getenv("GOOGLE_APPLICATION_CREDENTIALS")
 
+	// Skip GCS storage driver tests if environment variable parameters are not provided
+	skipGCS = func() string {
+		if bucket == "" || credentials == "" {
+			return "The following environment variables must be set to enable these tests: REGISTRY_STORAGE_GCS_BUCKET, REGISTRY_STORAGE_GCS_CREDS"
+		}
+		return ""
+	}
+
+	if skipGCS() != "" {
+		return
+	}
+
 	root, err := ioutil.TempDir("", "driver-")
 	if err != nil {
 		panic(err)
 	}
 	defer os.Remove(root)
 
-	gcsDriverConstructor = func(rootDirectory string) (storagedriver.StorageDriver, error) {
+	_, err = os.Stat(credentials)
+	if err == nil {
+		jsonKey, err := ioutil.ReadFile(credentials)
+		if err != nil {
+			panic(fmt.Sprintf("Unable to read credentials from file : %s", err))
+		}
+		credentials = string(jsonKey)
+	}
 
+	// Assume that the file contents are within the environment variable since it exists
+	// but does not contain a valid file path
+	jwtConfig, err := google.JWTConfigFromJSON([]byte(credentials), storage.ScopeFullControl)
+	if err != nil {
+		panic(fmt.Sprintf("Error reading JWT config : %s", err))
+	}
+
+	gcsDriverConstructor = func(rootDirectory string) (storagedriver.StorageDriver, error) {
 		parameters := driverParameters{
-			bucket,
-			keyfile,
-			rootDirectory,
+			bucket:        bucket,
+			rootDirectory: root,
+			email:         jwtConfig.Email,
+			privateKey:    []byte(jwtConfig.PrivateKey),
+			client:        oauth2.NewClient(ctx.Background(), jwtConfig.TokenSource(ctx.Background())),
 		}
 
 		return New(parameters)
 	}
 
-	// Skip GCS storage driver tests if environment variable parameters are not provided
-	skipGCS = func() string {
-		if bucket == "" || (credentials == "" && keyfile == "") {
-			return "Must set REGISTRY_STORAGE_GCS_BUCKET and (GOOGLE_APPLICATION_CREDENTIALS or REGISTRY_STORAGE_GCS_KEYFILE) to run GCS tests"
-		}
-		return ""
-	}
-
 	testsuites.RegisterSuite(func() (storagedriver.StorageDriver, error) {
 		return gcsDriverConstructor(root)
 	}, skipGCS)