Lack of consistency in retrieval of observed values

[iustin]

Hi,

Looking at the library, it looks like:

• Counter and Gauge allow retrieving the current value.
• Family half-allows it - there's get_or_create, but that has the side-effect of creating the value if non-existent.
• Histogram and Info don't allow it at all.

Now, in production, there's not much use, but in tests, I'd rather be able to test the values directly rather than encode and parse back the text format. Would you mind a pull request allowing clean retrieval of:

• Info string
• Histogram count and sum?

Thanks!

[mxinden]

Family half-allows it - there's get_or_create, but that has the side-effect of creating the value if non-existent.

Note that there is Family::get now: #234

Histogram count and sum?

See discussion in #242

[iustin]

Thanks, then I'll subscribe to the histogram count and sum pull request.

There's still the question of retrieving info strings, unless I'm mistaken?

[mxinden]

There's still the question of retrieving info strings, unless I'm mistaken?

I assume you don't want to retrieve the value of an Info metric, since that will always be 1.

Existence of a Info metric label combination in e.g. a Family you can test via Family::get:

https://docs.rs/prometheus-client/latest/prometheus_client/metrics/family/struct.Family.html#method.get

[iustin]

Excellent, thanks for the explanation. Then I'll close this in favour of watching the remaining pull request.