How can I drop an empty line in logstash - logstash

Question

In my logstash logs I have sometimes empty lines or lines with only spaces.
To drop the empty line I created a dropemptyline filter file
# drop empty lines
filter {
if [message] =~ /^\s*$/ {
drop { }
}
}
But the empty line filter is not working as expected, mainly because this particular filter is inside a chain other filters where there are filter coming afterwards afterwards.
00_input.conf
05_syslogfilter.conf
06_dropemptylines.conf
07_classifier.conf
So I think my particular filter would work if it was the only one but its not.
2015-02-11 15:02:12.347 WARN 1 --- [tp1812226644-23] o.eclipse.jetty.servlet.ServletHandler :
org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.springframework.dao.DataAccessResourceFailureException: Timed out after 10000 ms while waiting for a server that matches AnyServerSelector{}. Client view of cluster state is {type=Unknown, servers=[{address=mongo:27017, type=Unknown, state=Connecting, exception={com.mongodb.MongoException$Network: Exception opening the socket}, caused by {java.net.UnknownHostException: mongo: unknown error}}]; nested exception is com.mongodb.MongoTimeoutException: Timed out after 10000 ms while waiting for a server that matches AnyServerSelector{}. Client view of cluster state is {type=Unknown, servers=[{address=mongo:27017, type=Unknown, state=Connecting, exception={com.mongodb.MongoException$Network: Exception opening the socket}, caused by {java.net.UnknownHostException: mongo: unknown error}}]
My question is how can I drop out of all filters and go directly to output?

Answer 1

you can just ignore empty lines entirely using a grok filter,
%{GREEDYDATA:1st}(\n{1,})%{GREEDYDATA:2nd}
it will generate,
{
"1st": [
[
"2015-02-11 15:02:12.347 WARN 1 --- [tp1812226644-23] o.eclipse.jetty.servlet.ServletHandler : "
]
],
"2nd": [
[
"org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.springframework.dao.DataAccessResourceFailureException: Timed out after 10000 ms while waiting for a server that matches AnyServerSelector{}. Client view of cluster state is {type=Unknown, servers=[{address=mongo:27017, type=Unknown, state=Connecting, exception={com.mongodb.MongoException$Network: Exception opening the socket}, caused by {java.net.UnknownHostException: mongo: unknown error}}]; nested exception is com.mongodb.MongoTimeoutException: Timed out after 10000 ms while waiting for a server that matches AnyServerSelector{}. Client view of cluster state is {type=Unknown, servers=[{address=mongo:27017, type=Unknown, state=Connecting, exception={com.mongodb.MongoException$Network: Exception opening the socket}, caused by {java.net.UnknownHostException: mongo: unknown error}}]"
]
]
}
or more elegant way,
(?m)%{GREEDYDATA:log}
Output:
{
"log": [
[
"2015-02-11 15:02:12.347 WARN 1 --- [tp1812226644-23] o.eclipse.jetty.servlet.ServletHandler : \n\n\n\norg.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.springframework.dao.DataAccessResourceFailureException: Timed out after 10000 ms while waiting for a server that matches AnyServerSelector{}. Client view of cluster state is {type=Unknown, servers=[{address=mongo:27017, type=Unknown, state=Connecting, exception={com.mongodb.MongoException$Network: Exception opening the socket}, caused by {java.net.UnknownHostException: mongo: unknown error}}]; nested exception is com.mongodb.MongoTimeoutException: Timed out after 10000 ms while waiting for a server that matches AnyServerSelector{}. Client view of cluster state is {type=Unknown, servers=[{address=mongo:27017, type=Unknown, state=Connecting, exception={com.mongodb.MongoException$Network: Exception opening the socket}, caused by {java.net.UnknownHostException: mongo: unknown error}}]"
]
]
}