micrometer-metrics/micrometer

Add `Tags.of` method taking array of `Pair`

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#4960 opened on Apr 11, 2024

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 (6 comments) (0 reactions) (0 assignees)Java (4,220 stars) (935 forks)batch import
enhancementhelp wantedkotlinmodule: micrometer-core

Description

Please describe the feature request.

I would like to be able to provide metric tags as array of Pair objects

Rationale

Currently I have two ways to pass tags:

meterRegistry.counter(path, "foo", foo, "bar", bar).increment()                           // 1
meterRegistry.counter(path, Tags.of(Tag.of("foo", foo), Tag.of("bar", bar))).increment()  // 2

First method may lead to runtime errors if someone forgets to provide key or value resulting in uneven number of tag arguments. Second method is too verbose.

I would like to be able to write in Kotlin:

meterRegistry.counter(path, Tags.of("foo" to foo, "bar" to bar)).increment()

Note: to operator in Kotlin creates a Pair object so this is equivalent to:

meterRegistry.counter(path, Tags.of(Pair("foo", foo), Pair("bar", bar))).increment()

Nice to have: additional methods in MeterRegistry class allowing to avoid dealing with Tags class - probably a breaking change?

meterRegistry.counter(path, "foo" to foo, "bar" to bar).increment()

Additionally it would be nice if Micrometer allowed passing values of any type and converting them to String automatically, e.g.:

meterRegistry.counter(path, Tags.of("foo" to 10)).increment()

Contributor guide

Tech stack
javakotlin
Domain
backendapiobservability
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
familiarity with Java/Kotlinunderstanding of micrometer Tag API
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
75
Research direction
The issue requests adding a `Tags.of` method that accepts an array of `Pair` objects to reduce verbosity when creating tags, especially in Kotlin. The main change is adding an overload to the existing `Tags.of` method in the `Tags` class (likely in `micrometer core/src/main/java/io/micrometer/core/instrument/Tags.java`). Additionally, consider adding convenience methods in `MeterRegistry` that accept pairs. Review the discussion in the comments for concerns about breaking changes and auto conversion of non String values. Look at existing `Tags.of` implementations and `MeterRegistry` counter overloads to understand the pattern.