Invert default chunk upload logic

README.md

@@ -69,7 +69,7 @@ The configuration of the MultiApps CF plugin is done via env variables. The foll
 * `MULTIAPPS_UPLOAD_CHUNK_SIZE=<POSITIVE_INTEGER>` - By default, large MTARs are not uploaded as a single unit, but are split up into smaller chunks of 45 MBs that are uploaded separately. The goal is to prevent failed uploads due to [gorouter](https://github.com/cloudfoundry/gorouter)'s request timeout. In case the default chunk size is still too large, you can configure it via this environment variable. **The specified values are in megabytes.**
 :rotating_light: Note: The total number of chunks in which an MTAR is split cannot exceed 50, since the multiapps-controller could interpret bigger values as a denial-of-service attack. For this reason, the minimum value for this environment variable is computed based on the formula: `MIN = MTAR_SIZE / 50`
 For example, with a 100MB MTAR the minimum value for this environment variable would be 2, and for a 400MB MTAR it would be 8. Finally, the minimum value cannot grow over 50, so with a 4GB MTAR, the minimum value would be 50 and not 80.
-* `MULTIAPPS_UPLOAD_CHUNKS_IN_PARALLEL=<BOOLEAN>` - By default, MTAR chunks are uploaded sequentially so as not to produce too much network traffic. In case of a good internet connection, the option to upload them in parallel may improve upload performance.
+* `MULTIAPPS_UPLOAD_CHUNKS_SEQUENTIALLY=<BOOLEAN>` - By default, MTAR chunks are uploaded in parallel for better performance. In case of a bad internet connection, the option to upload them sequentially will lessen network load.
 
 # How to contribute
 * [Did you find a bug?](CONTRIBUTING.md#did-you-find-a-bug)

commands/file_uploader.go

@@ -25,7 +25,7 @@ type FileUploader struct {
 	mtaClient           mtaclient.MtaClientOperations
 	namespace           string
 	uploadChunkSizeInMB uint64
-	isParallel          bool
+	sequentialUpload    bool
 }
 
 type progressBarReader struct {
@@ -68,7 +68,7 @@ func NewFileUploader(mtaClient mtaclient.MtaClientOperations, namespace string,
 		mtaClient:           mtaClient,
 		namespace:           namespace,
 		uploadChunkSizeInMB: uploadChunkSizeInMB,
-		isParallel:          configuration.NewSnapshot().GetUploadChunksInParallel(),
+		sequentialUpload:    configuration.NewSnapshot().GetUploadChunksSequentially(),
 	}
 }
 
@@ -170,7 +170,7 @@ func (f *FileUploader) uploadInChunks(fileToUpload *os.File) ([]*models.FileMeta
 			}
 			uploadedFilesChannel <- file
 		}()
-		if !f.isParallel {
+		if f.sequentialUpload {
 			if err := waitForChannelData(uploadedFilesChannel, errorChannel, &uploadedFileParts); err != nil {
 				return nil, err
 			}

configuration/configuration.go

@@ -9,16 +9,16 @@ import (
 const unknownError = "An unknown error occurred during the parsing of the environment variable \"%s\". Please report this! Value type: %T"
 
 type Snapshot struct {
-	backendURL             properties.ConfigurableProperty
-	uploadChunkSizeInMB    properties.ConfigurableProperty
-	uploadChunksInParallel properties.ConfigurableProperty
+	backendURL               properties.ConfigurableProperty
+	uploadChunkSizeInMB      properties.ConfigurableProperty
+	uploadChunksSequentially properties.ConfigurableProperty
 }
 
 func NewSnapshot() Snapshot {
 	return Snapshot{
-		backendURL:             properties.BackendURL,
-		uploadChunkSizeInMB:    properties.UploadChunkSizeInMB,
-		uploadChunksInParallel: properties.UploadChunksInParallel,
+		backendURL:               properties.BackendURL,
+		uploadChunkSizeInMB:      properties.UploadChunkSizeInMB,
+		uploadChunksSequentially: properties.UploadChunksSequentially,
 	}
 }
 
@@ -30,8 +30,8 @@ func (c Snapshot) GetUploadChunkSizeInMB() uint64 {
 	return getUint64Property(c.uploadChunkSizeInMB)
 }
 
-func (c Snapshot) GetUploadChunksInParallel() bool {
-	return getBoolProperty(c.uploadChunksInParallel)
+func (c Snapshot) GetUploadChunksSequentially() bool {
+	return getBoolProperty(c.uploadChunksSequentially)
 }
 
 func getStringProperty(property properties.ConfigurableProperty) string {

configuration/properties/upload_chunks_in_parallel_property.go → configuration/properties/upload_chunks_sequentially_property.go

@@ -2,8 +2,8 @@ package properties
 
 import "strconv"
 
-var UploadChunksInParallel = ConfigurableProperty{
-	Name:                  "MULTIAPPS_UPLOAD_CHUNKS_IN_PARALLEL",
+var UploadChunksSequentially = ConfigurableProperty{
+	Name:                  "MULTIAPPS_UPLOAD_CHUNKS_SEQUENTIALLY",
 	Parser:                booleanParser{},
 	ParsingSuccessMessage: "Attention: You've specified %v for the environment variable %s.\n",
 	ParsingFailureMessage: "Invalid boolean value (%s) for environment variable %s. Using default value %v.\n",