Transforms not working on JSON events from Universal Forwader

[tmeader]

So, I've got (unfortunately multi-line) JSON files being sent from a host to our indexers via Universal Forwarder. By using the "sourcetype=_json" in the Universal Forwarder's inputs.conf stanza, messages are making it to the indexers just fine.

However, I'm trying to rename the sourcetype (as well as do, what should be, some simple extractions) based on the incoming logs' "source" on the indexer side. This isn't working at all... trying to figure out why. Based on the source visible in the Splunk when looking at the events, these should be matching.

inputs.conf
--
[monitor:///opt/cloud-custodian-container/.../resources.json]
sourcetype = _json
crcSalt = <SOURCE>
index = cloud_custodian

props.conf (on indexers)
--
[source::.../cloud-custodian-container/.../resources.json]
TRANSFORMS-cc_change_sourcetype = cc_change_sourcetype
TRANSFORMS-cc_indexed_fields = cc_indexed_fields

transforms.conf (on indexers)
--
[cc_change_sourcetype]
REGEX = \/cloud-custodian-container\/\d{12}\/[\w\-]+\/
FORMAT = sourcetype::cloud_custodian
SOURCE_KEY = MetaData:Source
DEST_KEY = MetaData:Sourcetype

[cc_indexed_fields]
REGEX = \/cloud-custodian-container\/(\d{12})\/([\w\-]+)\/
FORMAT = aws_account_id::$1 region::$2
SOURCE_KEY = MetaData:Source
WRITE_META = true

[manjunathmeti]

Configure props and transforms configurations on universal forwarder.

[tmeader]

I understand that I could turn on "force_local_processing" potentially, but this should be unnecessary given this (seemingly) simple setup. Also, the EC2 instance being used to host the Universal Forwarder is intentionally trying to be kept as small sized as possible. Introducing any further overhead to the Universal Forwarder side when not required is undesirable.

[manjunathmeti]

Since you are using default sourcetype _json which is already set up with INDEXED_EXTRACTIONS=json attribute in Universal Forwarder's etc/system/default/props.conf, parsing happens in universal forwarder only. 

More info here on parsing phase:  https://docs.splunk.com/Documentation/Splunk/8.1.1/Admin/Configurationparametersandthedatapipeline#S...

https://wiki.splunk.com/images/6/63/Splunk_EventProcessing_v20_1_UF_Indexer.pdf

Instead of using transforms.conf, you can use props.conf to override automated source type matching and explicitly assign a single source type to all data coming from a specific source on universal forwarder.

[source::.../cloud-custodian-container/*/*/resources.json]
sourcetype=cloud_custodian