fix(storage): accept emulator env var without scheme

storage/storage.go

@@ -101,7 +101,6 @@ type Client struct {
 // Clients should be reused instead of created as needed. The methods of Client
 // are safe for concurrent use by multiple goroutines.
 func NewClient(ctx context.Context, opts ...option.ClientOption) (*Client, error) {
-	var host, readHost, scheme string
 
 	// In general, it is recommended to use raw.NewService instead of htransport.NewClient
 	// since raw.NewService configures the correct default endpoints when initializing the
@@ -110,23 +109,35 @@ func NewClient(ctx context.Context, opts ...option.ClientOption) (*Client, error
 	// here so it can be re-used by both reader.go and raw.NewService. This means we need to
 	// manually configure the default endpoint options on the http client. Furthermore, we
 	// need to account for STORAGE_EMULATOR_HOST override when setting the default endpoints.
-	if host = os.Getenv("STORAGE_EMULATOR_HOST"); host == "" {
-		scheme = "https"
-		readHost = "storage.googleapis.com"
-
+	if host := os.Getenv("STORAGE_EMULATOR_HOST"); host == "" {
 		// Prepend default options to avoid overriding options passed by the user.
 		opts = append([]option.ClientOption{option.WithScopes(ScopeFullControl), option.WithUserAgent(userAgent)}, opts...)
 
 		opts = append(opts, internaloption.WithDefaultEndpoint("https://storage.googleapis.com/storage/v1/"))
 		opts = append(opts, internaloption.WithDefaultMTLSEndpoint("https://storage.mtls.googleapis.com/storage/v1/"))
 	} else {
-		scheme = "http"
-		readHost = host
+		var hostURL *url.URL
 
+		if strings.Contains(host, "://") {
+			h, err := url.Parse(host)
+			if err != nil {
+				return nil, err
+			}
+			hostURL = h
+		} else {
+			// Add scheme for user if not supplied in STORAGE_EMULATOR_HOST
+			// URL is only parsed correctly if it has a scheme, so we build it ourselves
+			hostURL = &url.URL{Scheme: "http", Host: host}
+		}
+
+		hostURL.Path = "storage/v1/"
+		endpoint := hostURL.String()
+
+		// Prepend the emulator host as default endpoint for the user
 		opts = append([]option.ClientOption{option.WithoutAuthentication()}, opts...)
 
-		opts = append(opts, internaloption.WithDefaultEndpoint(host))
-		opts = append(opts, internaloption.WithDefaultMTLSEndpoint(host))
+		opts = append(opts, internaloption.WithDefaultEndpoint(endpoint))
+		opts = append(opts, internaloption.WithDefaultMTLSEndpoint(endpoint))
 	}
 
 	// htransport selects the correct endpoint among WithEndpoint (user override), WithDefaultEndpoint, and WithDefaultMTLSEndpoint.
@@ -144,16 +155,12 @@ func NewClient(ctx context.Context, opts ...option.ClientOption) (*Client, error
 	if err != nil {
 		return nil, fmt.Errorf("supplied endpoint %q is not valid: %v", ep, err)
 	}
-	readHost = u.Host
-	if u.Scheme != "" {
-		scheme = u.Scheme
-	}
 
 	return &Client{
 		hc:       hc,
 		raw:      rawService,
-		scheme:   scheme,
-		readHost: readHost,
+		scheme:   u.Scheme,
+		readHost: u.Host,
 	}, nil
 }
 

storage/storage_test.go

@@ -1287,10 +1287,26 @@ func TestWithEndpoint(t *testing.T) {
 			desc:                "Emulator host specified, no specified endpoint",
 			CustomEndpoint:      "",
 			StorageEmulatorHost: "http://emu.com",
-			WantRawBasePath:     "http://emu.com",
+			WantRawBasePath:     "http://emu.com/storage/v1/",
 			WantReadHost:        "emu.com",
 			WantScheme:          "http",
 		},
+		{
+			desc:                "Emulator host specified without scheme",
+			CustomEndpoint:      "",
+			StorageEmulatorHost: "emu.com",
+			WantRawBasePath:     "http://emu.com/storage/v1/",
+			WantReadHost:        "emu.com",
+			WantScheme:          "http",
+		},
+		{
+			desc:                "Emulator host specified as host:port",
+			CustomEndpoint:      "",
+			StorageEmulatorHost: "localhost:9000",
+			WantRawBasePath:     "http://localhost:9000/storage/v1/",
+			WantReadHost:        "localhost:9000",
+			WantScheme:          "http",
+		},
 		{
 			desc:                "Endpoint overrides emulator host when both are specified - https",
 			CustomEndpoint:      "https://fake.gcs.com:8080/storage/v1",
@@ -1315,9 +1331,6 @@ func TestWithEndpoint(t *testing.T) {
 		if err != nil {
 			t.Fatalf("error creating client: %v", err)
 		}
-		if err != nil {
-			t.Fatalf("error creating client: %v", err)
-		}
 
 		if c.raw.BasePath != tc.WantRawBasePath {
 			t.Errorf("%s: raw.BasePath not set correctly\n\tgot %v, want %v", tc.desc, c.raw.BasePath, tc.WantRawBasePath)