As of METRON-652 <https://github.com/apache/incubator-metron/pull/415>, we
will have decoupled the indexing configuration from the enrichment
configuration. As an immediate follow-up to that, I'd like to provide the
ability to turn off and on writers via the configs. I'd like to get some
community feedback on how the functionality should work, if y'all are
amenable. :)
As of now, we have 3 possible writers which can be used in the indexing
topology:
- Solr
- Elasticsearch
- HDFS
HDFS is always used, elasticsearch or solr is used depending on how you
start the indexing topology.
A couple of proposals come to mind immediately:
*Index Filtering*
You would be able to specify a filter as defined by a stellar statement
(likely a reuse of the StellarFilter that exists in the Parsers) which
would allow you to indicate on a message-by-message basis whether or not to
write the message.
The semantics of this would be as follows:
- Default (i.e. unspecified) is to pass everything through (hence
backwards compatible with the current default config).
- Messages which have the associated stellar statement evaluate to true
for the writer type will be written, otherwise not.
Sample indexing config which would write out no messages to HDFS and write
out only messages containing a field called "field1":
{
"index" : "squid"
,"batchSize" : 100
,"filters" : {
"HDFS" : "false"
,"ES" : "exists(field1)"
}
}
*Index On/Off Switch*
A simpler solution would be to just provide a list of writers to write
messages. The semantics would be as follows:
- If the list is unspecified, then the default is to write all messages
for every writer in the indexing topology
- If the list is specified, then a writer will write all messages if and
only if it is named in the list.
Sample indexing config which turns off HDFS and keeps on Elasticsearch:
{
"index" : "squid"
,"batchSize" : 100
,"writers" : [ "ES" ]
}
Thanks in advance for the feedback! Also, if you have any other, better
ideas than the ones presented here, let me know too.
Best,
Casey
