box: make --box-commit-retries flag defaulting to 100 - Fixes #2054

Sometimes it takes many more commit retries than expected to commit a
multipart file, so split this number into its own config variable and
default it to 100 which should always be enough.

backend/box/box.go

@@ -88,13 +88,19 @@ func init() {
 			Help:     "Cutoff for switching to multipart upload.",
 			Default:  fs.SizeSuffix(defaultUploadCutoff),
 			Advanced: true,
+		}, {
+			Name:     "commit_retries",
+			Help:     "Max number of times to try committing a multipart file.",
+			Default:  100,
+			Advanced: true,
 		}},
 	})
 }
 
 // Options defines the configuration for this backend
 type Options struct {
-	UploadCutoff fs.SizeSuffix `config:"upload_cutoff"`
+	UploadCutoff  fs.SizeSuffix `config:"upload_cutoff"`
+	CommitRetries int           `config:"commit_retries"`
 }
 
 // Fs represents a remote box

backend/box/upload.go

@@ -96,7 +96,9 @@ func (o *Object) commitUpload(SessionID string, parts []api.Part, modTime time.T
 	request.Attributes.ContentCreatedAt = api.Time(modTime)
 	var body []byte
 	var resp *http.Response
-	maxTries := fs.Config.LowLevelRetries
+	// For discussion of this value see:
+	// https://github.com/ncw/rclone/issues/2054
+	maxTries := o.fs.opt.CommitRetries
 	const defaultDelay = 10
 	var tries int
 outer:

docs/content/box.md

@@ -227,6 +227,10 @@ system.
 Cutoff for switching to chunked upload - must be >= 50MB. The default
 is 50MB.
 
+#### --box-commit-retries int ####
+
+Max number of times to try committing a multipart file. (default 100)
+
 ### Limitations ###
 
 Note that Box is case insensitive so you can't have a file called