using Regex how do I capture the exception message only without stack trace

Question

I have this text:

System.FormatException: String '' was not recognized as a valid DateTime. at Application.Mappers.AutoMapperProfile.<>c.<.ctor>b__0_92(CartCampaignDto x, CartCampaign y) in /build/src/Application/Mappers/AutoMapperProfile.cs:line 60 at lambda_method543(Closure , Object , Cart , ResolutionContext ) --- End of inner exception stack trace --- at lambda_method543(Closure , Object , Cart , ResolutionContext ) --- End of inner exception stack trace ---

I'm trying to match only this part

System.FormatException: String '' was not recognized as a valid DateTime.

I tried

^(.*) at.*)

^(.+)(?=at ){1}(.*)

but it didn't work.

EDIT:

This is not in any programming language, this is to build a NewRelic dashboard where you can add a Regex to get some insights.

EDIT 2 NewRelic uses Google/R2 Regex

EDIT 3 I'm trying to build this query

SELECT uniqueCount(1) From Log where `@l` = 'Error' FACET capture(`@x`, r'(?P<anyvarname>^(.*?\.)\s*at\b)')

EDIT 4 Not sure why this doesn't work

Something like `^.*?\.(?=\s*at\b)`? See https://regex101.com/r/TzX2pe/1 — Wiktor Stribiżew, Aug 23 '22 at 14:07
What is the programming environment? What are exact pattern requirements? — Wiktor Stribiżew, Aug 23 '22 at 14:15
@WiktorStribiżew no specific one, just a search in a text. I updated my question to reflect that. — Nour, Aug 23 '22 at 14:26
@WiktorStribiżew my bad, it turned out it is a specific version of Regex called R2. While your suggestion work in Regex101.com, it doesn't work in NewRelic. — Nour, Aug 23 '22 at 14:37
See [RE2 regex demo](https://regex101.com/r/TzX2pe/2), it works there. There is no `R2` regex flavor. If it is a line in a multiline text, try `m` flag, `(?m)^(.*?\.)\s*at\b` — Wiktor Stribiżew, Aug 23 '22 at 14:44
Try it like this `(?P(.*?\.)\s*at\b).*` https://regex101.com/r/dovQWj/1 — The fourth bird, Aug 23 '22 at 15:50

score 1 · Answer 1 · answered Aug 23 '22 at 14:12

1

I think this will work for your:

^.+\.\s

Quickly breaking it in pieces:

^.+ -> matches, from the beggining of the line, any 1 or more characters
\.\s -> matches a dot followed by a whitespace.

answered Aug 23 '22 at 14:12

LeYAUable

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This works in a normal text, but it turned out that NewRelic uses Re2, so didn't work the same for some reason. – Nour Aug 23 '22 at 14:39
@Nour This pattern is RE2 compliant. – Wiktor Stribiżew Aug 23 '22 at 14:40
@LeYAUable I'm putting the same expression in a named group as required by NewRelic `r'(?P^(.*?\.)\s*at\b)` does that change anything? – Nour Aug 23 '22 at 15:05
I guess you then need to get the captured instead of just the capture of the entire regex. I don't have experience with NewRelic but Wiktor said that the pattern is compliant. – LeYAUable Aug 23 '22 at 15:12
typo above, should be "...get the captured group instead..." – LeYAUable Aug 23 '22 at 15:42

score 0 · Answer 2 · answered Aug 23 '22 at 17:15

You could write the pattern matching the whole line with a named capture group:

(?P<anyvarname>(.*?\.)\s*at\b).*

See these pages for more information about capture

using Regex how do I capture the exception message only without stack trace

2 Answers2