I don't want to call this a bug exactly, since it's technically documented behaviour within Hierynomus but it's not clear from the NiFi documentation itself and should probably be configurable behaviour.
When using the GetSmbFile processor to ingest files with "Keep Source File" set to "false", if any source file is marked "Read Only" then NiFi will not be able to delete the source file no matter what permissions the Nifi account has on the shared folder. Currently, the documentation for the GetSmbFile processor only indicates that "write" permission is needed. When the processor encounters a read-only file, it successfully ingests the file and generates a flowfile to the "success" relationship of the processor, but it also fails to delete the file and the processor raises an error within the Nifi UI and log files. Since the source file is not deleted, this typically results in Nifi generating a huge volume of duplicate flowfiles, along with a corresponding error message for each one. As far as I can tell, there is no way to make the built-in GetSmbFile processor to handle a read-only file. I was able to modify the existing processor to correctly delete a read-only file by clearing the read-only flag on a source file before share.rm(file) is called on the file, but I think it would make sense for that behaviour to be configurable on the processor, IE via a "force delete read-only files" property. I'm curious if this is a situation anybody else has run into and if there's an existing way to handle read-only files, or if handling read-only files explicitly makes sense as a new behaviour to add to the processor. -Evan Davies
