How to use grok if some pattern is not want to match?

[RameshNagargoje]

I have one input field in which contain boardName and I don’t want to match regex as ".*tester.*" . How we can write grok filter to do not match boardname which contain "tester" name.

input json is
first input
{
boardname : "sys-tester-log1",
logSnippet:" fdsffdsfdsfdsd",
location : "rack1"
}
second input
{
boardname : "tcpdump-tester-log1",
logSnippet:" fdsffdsfdsfdsd",
location : "rack1"
}

thirt input json

{
boardname : "tcpdump-client-log1",
logSnippet:" fdsffdsfdsfdsd",
location : "rack1"
}
I want grok filter to check boardName and I don’t want to dump json in ES if boardName contains tester name

[Jenni]

Assuming there is more content in the input field and the boardName is separated from the rest of the input by ';', you would match it like this:

;(?<boardName>(?(?!tester).)+);

[RameshNagargoje]

@Jenni post is edited please check.

[Jenni]

Then you don't even need grok, do you?

if([boardname] =~ /^.*tester.*$/) {
  drop{}
}

[RameshNagargoje]

thanks @Jenni it solved my problem