fix(storage): handle 503 errors with retry loop

packages/storage/Sources/GoogleCloudStorage/StorageClient+Upload.swift

@@ -194,7 +194,7 @@ extension StorageClient {
       } catch {
         throw RequestError.io(error)
       }
-      if response.status == .serviceUnavailable {
+      if response.isError() {
         throw await response.decodeError()
       }
       let object = try await handleObjectResponse(response: response)
@@ -225,7 +225,7 @@ extension StorageClient {
     guard statusCode == 200,
       let location = startResponse.headers.first(name: "Location")
     else {
-      if statusCode == 503 {
+      if startResponse.isError() {
         throw await startResponse.decodeError()
       }
       let startData = try await startResponse.data()
@@ -257,7 +257,7 @@ extension StorageClient {
     } else if statusCode == 308 {
       let queryStatus = try parseResumableUploadQueryStatus(from: queryResponse.headers)
       return (.inprogress(UInt64(queryStatus.nextOffset)), queryStatus.crc32cSeed)
-    } else if statusCode == 503 {
+    } else if queryResponse.isError() {
       throw await queryResponse.decodeError()
     } else {
       let queryData = try await queryResponse.data()
@@ -341,7 +341,7 @@ extension StorageClient {
         )
       )
       return (.inprogress(UInt64(nextOffset)), crc32cSeed)
-    } else if statusCode == 503 {
+    } else if uploadResponse.isError() {
       throw await uploadResponse.decodeError()
     } else {
       let uploadData = try await uploadResponse.data()
@@ -827,13 +827,10 @@ extension StorageClient {
     async throws
     -> Object
   {
-    let statusCode = Int(response.status.code)
-    let data = try await response.data()
-    guard (200..<300).contains(statusCode) else {
-      let message = String(data: data, encoding: .utf8) ?? ""
-      throw UploadError.unexpectedServerResponse(
-        statusCode: statusCode, message: message)
+    if response.isError() {
+      throw await response.decodeError()
     }
+    let data = try await response.data()
     let decoder = GoogleCloudWkt._ProtoJSONDecoder()
     let v1Object = try decoder.decode(ObjectV1Response.self, from: data)
     return v1Object.toObject()

packages/storage/Tests/ChecksumTests.swift

@@ -100,12 +100,14 @@ import Testing
     let uploadOptions = UploadOptions().with { $0.validation = .crc32c }
     let task = client.upload(source, to: bucket, as: objectName, options: uploadOptions)
 
-    do {
-      _ = try await task.value
-      Issue.record("Expected upload to fail with unexpected server response")
-    } catch UploadError.unexpectedServerResponse(let statusCode, let message) {
-      #expect(statusCode == 400)
-      #expect(message == errorMessage)
+    let error = await expectError(RequestError.self) {
+      try await task.value
+    }
+    if case .http(let details) = error {
+      #expect(details.http_status_code == 400)
+      #expect(String(data: details.payload, encoding: .utf8) == errorMessage)
+    } else {
+      Issue.record("Expected .http RequestError, got \(String(describing: error))")
     }
   }
 
@@ -144,12 +146,14 @@ import Testing
     let uploadOptions = UploadOptions().with { $0.validation = .md5 }
     let task = client.upload(source, to: bucket, as: objectName, options: uploadOptions)
 
-    do {
-      _ = try await task.value
-      Issue.record("Expected upload to fail with unexpected server response")
-    } catch UploadError.unexpectedServerResponse(let statusCode, let message) {
-      #expect(statusCode == 400)
-      #expect(message == errorMessage)
+    let error = await expectError(RequestError.self) {
+      try await task.value
+    }
+    if case .http(let details) = error {
+      #expect(details.http_status_code == 400)
+      #expect(String(data: details.payload, encoding: .utf8) == errorMessage)
+    } else {
+      Issue.record("Expected .http RequestError, got \(String(describing: error))")
     }
   }
 

packages/storage/Tests/IntegrationTests/StorageClientIntegrationTests.swift

@@ -13,6 +13,7 @@
 // limitations under the License.
 
 import Foundation
+import GoogleCloudGax
 @testable import GoogleCloudStorage
 import Testing
 
@@ -482,11 +483,16 @@ import Testing
       do {
         _ = try await task.value
         Issue.record("Expected GCS to reject upload with bad checksum, but it succeeded")
-      } catch UploadError.unexpectedServerResponse(let statusCode, let message) {
-        #expect(statusCode == 400)
-        print("GCS correctly rejected bad checksum: \(message)")
+      } catch RequestError.service(let serviceError) {
+        #expect(serviceError.message.contains("doesn't match"))
+        print("GCS correctly rejected bad checksum: \(serviceError.message)")
+      } catch RequestError.http(let details) {
+        #expect(details.http_status_code == 400)
+        print(
+          "GCS correctly rejected bad checksum: \(String(data: details.payload, encoding: .utf8) ?? "")"
+        )
       } catch {
-        Issue.record("Expected UploadError.unexpectedServerResponse, but got \(error)")
+        Issue.record("Expected RequestError, but got \(error)")
       }
     }