feat(metrics/family): 🍬 contains() checks if metrics exist
#245
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cratelyn
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this commit introduces a `len()` method to `Family<S, M, C>`, which returns the number of series within a metric family. see also prometheus#245, which allows callers to check if a family `contains()` a given label set. Signed-off-by: katelyn martin <me+cratelyn@katelyn.world>
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my understanding is that this could be added behind the |
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this commit introduces a `len()` method to `Family<S, M, C>`, which returns the number of series within a metric family. see also prometheus#245, which allows callers to check if a family `contains()` a given label set. ```shell $ cargo clippy --all-features --all-targets --tests Compiling prometheus-client v0.23.0 (/path/to/prometheus-client) warning: struct `Family` has a public `len` method, but no `is_empty` method --> src/metrics/family.rs:309:5 | 309 | pub fn len(&self) -> usize { | ^^^^^^^^^^^^^^^^^^^^^^^^^^ | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#len_without_is_empty = note: `#[warn(clippy::len_without_is_empty)]` on by default warning: `prometheus-client` (lib) generated 1 warning warning: `prometheus-client` (lib test) generated 1 warning (1 duplicate) Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.63s ``` Signed-off-by: katelyn martin <git@katelyn.world>
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Jan 22, 2026
| /// assert!(family.contains(&get), "a `method=\"GET\"`-labeled metric exists"); | ||
| /// assert!(!family.contains(&post), "a `method=\"POST\"`-labeled metric does NOT exist"); | ||
| /// ``` | ||
| #[cfg(any(test, feature = "test-util"))] |
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i've rebased this branch, and added the conditional test-util feature flag introduced in #242!
this commit introduces a small accessor to the `Family<S, M, C>` metric family type. this new `contains()` method allows callers to check whether or not a metric with the provided set of labels exists. if no metric has been created via e.g. `get_or_create()`, this method will return `false`. Signed-off-by: katelyn martin <git@katelyn.world>
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this commit introduces a `len()` method to `Family<S, M, C>`, which returns the number of series within a metric family. see also prometheus#245, which allows callers to check if a family `contains()` a given label set. ```shell $ cargo clippy --all-features --all-targets --tests Compiling prometheus-client v0.23.0 (/path/to/prometheus-client) warning: struct `Family` has a public `len` method, but no `is_empty` method --> src/metrics/family.rs:309:5 | 309 | pub fn len(&self) -> usize { | ^^^^^^^^^^^^^^^^^^^^^^^^^^ | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#len_without_is_empty = note: `#[warn(clippy::len_without_is_empty)]` on by default warning: `prometheus-client` (lib) generated 1 warning warning: `prometheus-client` (lib test) generated 1 warning (1 duplicate) Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.63s ``` Signed-off-by: katelyn martin <git@katelyn.world>
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Jan 22, 2026
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i've also added changelog notes summarizing this change.
mxinden
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Jan 23, 2026
Signed-off-by: Max Inden <mail@max-inden.de>
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this commit introduces a small accessor to the
Family<S, M, C>metric family type. this newcontains()method allows callers to check whether or not a metric with the provided set of labels exists.if no metric has been created via e.g.
get_or_create(), this method will returnfalse.