aliasSub does not support perl-style regex

[Dieterbe]

Apparently Graphite supports a query like:

aliasSub(metrictank.stats.docker-env.default.api.request.*.latency.median.gauge32,'(?!-[0-9]*-)-[0-9]','')

But metrictank does not.

It returns an error error parsing regexp: invalid or unsupported Perl syntax: '(?!'...

[woodsaj]

PCRE cant be used safely with untrusted users. Regex queries can be used to cause denial of service attacks (basically consume all the resources on the node handling the regex).

Golang uses RE2.
https://github.com/google/re2/wiki/WhyRE2

RE2 is safe, and significantly more performant than other regex implementations.

[Dieterbe]

Note that as of #1778 this error is correctly classified as "bad request", and as such invokes the proxy to graphite (if enabled), and graphite handles it seamlessly, so the user doesn't have to notice anything.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.