Make S3 checksum settings configurable via JSON config (#81)

Author: serdarozerr

README.md

@@ -163,4 +163,4 @@ These commit IDs represent the last migration checkpoint from each provider's or
 - azurebs -> 18667d2a0b5237c38d053238906b4500cfb82ce8
 - dav   -> c64e57857539d0173d46e79093c2e998ec71ab63
 - gcs   -> d4ab2040f37415a559942feb7e264c6b28950f77
-- s3    -> 39c1e2a988e3ec0026038cba041d0c2f1fb7dc93
+- s3    -> 9b75c9e3598fcd87924789ddf0035e5597a3df63

s3/README.md

@@ -30,7 +30,10 @@ The S3 client requires a JSON configuration file with the following structure:
   "upload_part_size":             <int64> (optional - default: 5242880),   # 5 MB
   "multipart_copy_threshold":     <int64> (optional - default: 5368709120), # 5 GB - files larger than this use multipart copy
   "multipart_copy_part_size":     <int64> (optional - default: 104857600), # 100 MB - must be at least 5 MB
-  "single_upload_threshold":      <int64> (optional - default: 0)          # bytes; files <= this use a single PutObject call, larger files use multipart upload. 0 means always use multipart. Max 5 GB for AWS S3. GCS ignores this and always uses single upload.
+  "single_upload_threshold":      <int64> (optional - default: 0),         # bytes; files <= this use a single PutObject call, larger files use multipart upload. 0 means always use multipart. Max 5 GB for AWS S3. GCS ignores this and always uses single upload.
+  "request_checksum_calculation_enabled":          <bool> (optional - default: true),
+  "response_checksum_calculation_enabled":         <bool> (optional - default: true),
+  "uploader_request_checksum_calculation_enabled": <bool> (optional - default: true)
 }
 ```
 

s3/config/config.go

@@ -27,9 +27,9 @@ type S3Cli struct {
 	HostStyle                                 bool   `json:"host_style"`
 	SwiftAuthAccount                          string `json:"swift_auth_account"`
 	SwiftTempURLKey                           string `json:"swift_temp_url_key"`
-	RequestChecksumCalculationEnabled         bool
-	ResponseChecksumCalculationEnabled        bool
-	UploaderRequestChecksumCalculationEnabled bool
+	RequestChecksumCalculationEnabled         bool   `json:"request_checksum_calculation_enabled"`
+	ResponseChecksumCalculationEnabled        bool   `json:"response_checksum_calculation_enabled"`
+	UploaderRequestChecksumCalculationEnabled bool   `json:"uploader_request_checksum_calculation_enabled"`
 	// Optional knobs to tune transfer performance.
 	// If zero, the client will apply sensible defaults (handled by the S3 client layer).
 	// Part size values are provided in bytes.