Feature request, support PCRE-style features, including lookaheads and backreferences in `nsq_to_file` to allow for wildcard archiving with exclusions

[danbf]

Right now nsq_to_file only supports RE2 style regex's in

nsq/apps/nsq_to_file/topic_discoverer.go

Line 99 in 51470ca

match, err := regexp.MatchString(t.opts.TopicPattern, topic)

through the use of the built-in golang regexp.MatchString. This prevents the use of wildcard archiving with exclusions which is a use case we have.

So a topic pattern like .* works but one like ^(?!not_so_important_events$)[a-z0-9_]+$ which would ignore the topic not_so_important_events doesn't work since it requires lookaheads which RE2 does not permit.
like: https://regex101.com/r/4S2pGx/1

Would you be up to accept a PR that added the https://github.com/philipprochazka/regexp2 library and used it for this regex in

nsq/apps/nsq_to_file/topic_discoverer.go

Line 99 in 51470ca

match, err := regexp.MatchString(t.opts.TopicPattern, topic)

@mreiferson thoughts?

[danbf]

running a workaround right now, building 1.3.0 from source and patching the

nsq/apps/nsq_to_file/topic_discoverer.go

Line 99 in 51470ca

match, err := regexp.MatchString(t.opts.TopicPattern, topic)

with #1519