Parse hex numbers

[giacomolicari]

This PR adds the ability for the scraper to convert hex numbers into float64.

Concrete example, if we have a JSON like:

{"jsonrpc":"2.0","result":"0x1d55359","id":83}

where the key result is an hex representation of an integer, and we want that hex data to be correctly interpreted into a number, we would get it parsed from 0x1d55359 to 30757721.

Also add a Dockerfile that builds the project.

[joaovitor-cx]

Hi @giacomolicari,
Can you merge or rebase your branch with master?
I tested this pr locally with an hex number and it worked.

Maybe circleci pass merging master in this pr.

BTW thanks for the change.

[joaovitor-cx]

@giacomolicari the tests are failing in ci because of fmt...

gofmt -s -w .

solves that...

Can you please update this pr with that?

[guillheu]

I'd really like this feature as well, hoping for the fix to get pushed soon...

[Pacman99]

I have a version of this PR thats been rebased on latest master with formatting over at https://github.com/Pacman99/json_exporter/tree/hex-parser. Happy to open a new PR if there is a chance of this feature being merged - commits on that branch are still credited to original author