data sink: add incremental mode

weed/command/scaffold.go

@@ -356,6 +356,9 @@ directory = "/buckets"
 [sink.local]
 enabled = false
 directory = "/data"
+# all replicated files are under modified time as yyyy-mm-dd directories
+# so each date directory contains all new and updated files.
+is_incremental = false
 
 [sink.local_incremental]
 # all replicated files are under modified time as yyyy-mm-dd directories
@@ -373,6 +376,7 @@ directory = "/backup"
 replication = ""
 collection = ""
 ttlSec = 0
+is_incremental = false
 
 [sink.s3]
 # read credentials doc at https://docs.aws.amazon.com/sdk-for-go/v1/developer-guide/sessions.html
@@ -384,6 +388,7 @@ region = "us-east-2"
 bucket = "your_bucket_name"    # an existing bucket
 directory = "/"                # destination directory
 endpoint = ""
+is_incremental = false
 
 [sink.google_cloud_storage]
 # read credentials doc at https://cloud.google.com/docs/authentication/getting-started
@@ -391,6 +396,7 @@ enabled = false
 google_application_credentials = "/path/to/x.json" # path to json credential file
 bucket = "your_bucket_seaweedfs"    # an existing bucket
 directory = "/"                     # destination directory
+is_incremental = false
 
 [sink.azure]
 # experimental, let me know if it works
@@ -399,6 +405,7 @@ account_name = ""
 account_key  = ""
 container = "mycontainer"      # an existing container
 directory = "/"                # destination directory
+is_incremental = false
 
 [sink.backblaze]
 enabled = false
@@ -406,6 +413,7 @@ b2_account_id = ""
 b2_master_application_key  = ""
 bucket = "mybucket"            # an existing bucket
 directory = "/"                # destination directory
+is_incremental = false
 
 `