Configurable value replacement on match failure for RegexExtractionFn

[jon-wei]

Addresses issue #2064

This adds 3 new parameters to the RegexExtractionFn:

replaceMissingValues: Boolean, if a regex match fails, replace the dimval with a user specified value instead of returning the orignal dimval, default is false

replaceMissingValuesWith: String, replace dimval with this value when regex match fails if replaceMissingValues == true

injective: Boolean, currently unused, but same usage as "injective" property in the JavaScriptExtractionFn and LookupExtractionFn

[jon-wei]

@b-slim Reopened PR, referring to your earlier comment, what property did you think was unneeded?

[b-slim]

@jon-wei injective property is only used by classes extending FunctionalExtraction.

[b-slim]

use arrays to compare bytes

[jon-wei]

@b-slim added byte array value check for cache key

[jon-wei]

@b-slim I think "injective" is fine here, a regex->match extraction can be thought of as a a function.

JavascriptExtractionFn also supports the injective property and it doesn't extend FunctionalExtraction.

A hypothetical "injective" use case might be a dimension value with various formats that all contain some unique ID, where the regex is used to strip out parts of the dim val that don't provide any unique information beyond the ID substring.

[b-slim]

@jon-wei ok i got it now, thanks !

[vogievetsky]

Very excited about this PR!

[gianm]

extraneous import

[jon-wei]

@gianm removed unused import

[gianm]

code style

[jon-wei]

@gianm fixed code style

[gianm]

"Injective" doesn't seem to be used for anything right now- is it necessary? What should it be used for?

[jon-wei]

@b-slim @gianm Based on prevailing opinion, I'll remove the injective property from this PR; isInjective() isn't really being used by LookupExtractionFn or JavascriptExtractionFn either, presently.

[gianm]

👍 after travis

[fjy]

👍