Override derived label value case #136
Open
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This applies to individual entries in the derived implementation Signed-off-by: Eric Hodel <drbrain@segment7.net>
When deriving label values for an enum the default case of the label matches the identifier case. This forced derived label values to use rust's case rules which may not match up with metrics exported from other programs, or metrics from other crates that export prometheus metrics. This change adds the ability to set the case of a derived value label to all-lowercase or all-uppercase for the entire struct in addition to for an individual label from the prior commit. Signed-off-by: Eric Hodel <drbrain@segment7.net>
Signed-off-by: Eric Hodel <drbrain@segment7.net>
drbrain
force-pushed
the
override-derived-label-value-case
branch
from
6af464b
to
ecaf155
Compare
mxinden
reviewed
May 9, 2023
Comment on lines
+109
to
+110
| /// For variants you can use `#[prometheus(lower)]` or `#[prometheus(upper)]` to set the case for | ||
| /// only that variant. |
There was a problem hiding this comment.
Do you have a concrete use-case where one would upper or lower case a specific variant only?
There was a problem hiding this comment.
I do not
it might be better to remove this and wait for a motivated individual to plumb serde in to label generation which could provide all manner of derive customization
There was a problem hiding this comment.
Do you want me to remove per-variant case changing?
| let body = match ast.clone().data { | ||
| syn::Data::Struct(_) => { | ||
| panic!("Can not derive EncodeLabel for struct.") | ||
| panic!("Can not derive EncodeLabelValue for struct.") |
Comment on lines
+229
to
+237
| "lower" => config.value_case = ValueCase::Lower, | ||
| "upper" => config.value_case = ValueCase::Upper, | ||
| invalid => { | ||
| return Err(syn::Error::new( | ||
| case.span(), | ||
| format!( | ||
| "value case may only be \"lower\" or \"upper\", not \"{invalid}\"" | ||
| ), | ||
| )) |
There was a problem hiding this comment.
To de-duplicate this code with the one above in line 146, how about implementing FromStr for ValueCase?
There was a problem hiding this comment.
It will take me some time, but I think I can do this
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
By default deriving label values for an enum:
Results in a label that matches the variant identifier's, here
"One".To allow compatibility with metrics emitted from other processes, or compatibility when switching crates, this PR allows overriding the default case for EncodeLabelValue for an entire enum or for individual enum entries.
Would have labels for values
EnumLabel::OneandEnumLabel::Twowould be"one"and"two"respectively.The case can be overridden for a single variant as well:
Would have labels for values
EnumLabel::OneandEnumLabel::Twowould be"one"and"Two"respectively.