consolidate attributes insertion in otel-metrics

[nikhilsinhaparseable]

remove metrics_ and exemplar_ prefixes in otel-metrics

When key collision happens i.e. attributes at two different hierarchies in the incoming event have same attribute, the later overrides the previous attribute entry in the ingested event.

We will add this behaviour to the documentation.

Summary by CodeRabbit

• Refactor
  • Streamlined internal attribute handling logic to improve code maintainability and consistency.

Note: This release contains no user-visible changes. Updates are internal to system architecture only.

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[coderabbitai]

Walkthrough

The change consolidates attribute insertion logic in OpenTelemetry metrics handling by replacing two specific helper functions (insert_metric_attributes and insert_exemplar_attributes) with a single generic insert_attributes function, removing automatic key prefixing and reducing code duplication.

Changes

Cohort / File(s)	Summary
OpenTelemetry Metrics Refactoring src/otel/metrics.rs	Removes insert_metric_attributes and insert_exemplar_attributes helper functions; replaces all call sites with generic insert_attributes function; removes KeyValue import; JSON attribute keys no longer auto-prefixed with metric/exemplar identifiers

Possibly related PRs

• fix: stringify otel attributes of array types #1298: Modifies OpenTelemetry attribute handling in src/otel directory with related insert_attributes usage patterns.
• update: field names of attributes in each metric type #1456: Directly related—introduces the metric_/exemplar_ prefixed helpers that this PR removes in favor of unified insert_attributes consolidation.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Poem

🐰 Hops through metrics with delight,
One helper function shines so bright,
Prefixes gone, the code runs lean,
Cleanest attributes ever seen! ✨

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The description addresses the core change but lacks required sections from the template: missing detailed goal statement, solution rationale, key changes explanation, and the testing/documentation checklist.	Add the required template sections including explicit description of the goal, rationale for the chosen approach, comprehensive list of key changes, and complete the testing and documentation checklist items.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title 'consolidate attributes insertion in otel-metrics' directly aligns with the main change of replacing specific attribute insertion functions with a generic insert_attributes helper.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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✨ Finishing touches

• 📝 Generate docstrings

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📜 Recent review details

Configuration used: Repository UI

Review profile: CHILL

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📥 Commits

Reviewing files that changed from the base of the PR and between ac1e6e0 and 8d19593.

📒 Files selected for processing (1)

• src/otel/metrics.rs

🧰 Additional context used

🧠 Learnings (1)

📚 Learning: 2025-08-25T01:31:41.786Z

Learnt from: nikhilsinhaparseable
Repo: parseablehq/parseable PR: 1415
File: src/metadata.rs:63-68
Timestamp: 2025-08-25T01:31:41.786Z
Learning: The TOTAL_EVENTS_INGESTED_DATE, TOTAL_EVENTS_INGESTED_SIZE_DATE, and TOTAL_EVENTS_STORAGE_SIZE_DATE metrics in src/metadata.rs and src/storage/object_storage.rs are designed to track total events across all streams, not per-stream. They use labels [origin, parsed_date] to aggregate by format and date, while per-stream metrics use [stream_name, origin, parsed_date] labels.

Applied to files:

• src/otel/metrics.rs

🧬 Code graph analysis (1)

src/otel/metrics.rs (1)

src/otel/otel_utils.rs (1)

• insert_attributes (185-190)

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🔇 Additional comments (3)

src/otel/metrics.rs (3)

73-114: Good: exemplar attributes are inserted before exemplar system fields (system fields win on collisions).
This ordering makes collisions like an attribute named exemplar_trace_id deterministic (the computed trace id wins).

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120-170: Collision semantics changed: datapoint attrs can now be overwritten by exemplar attrs/fields (and vice-versa) depending on insertion order.
Given the prefix removal, please ensure the “last write wins” behavior here is the intended documented precedence (especially if multiple exemplars exist, since later exemplars also overwrite earlier ones during the flatten+merge loop).

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448-587: The proposed reordering reverses a recently-committed intentional design decision. Commit 8d19593 explicitly establishes that attributes should override system fields at the same hierarchy level ("later overrides previous"). The current code order—system fields first, then insert_attributes()—correctly implements this intent and was scheduled for documentation.

If you intend to change this precedence strategy, that's a separate architectural decision beyond this PR. The current implementation is correct relative to the documented intent.

Regarding cross-level precedence (resource > scope > metric > datapoint): This remains an open design question. The code currently implements "resource wins" (later merge overrides). Please clarify the intended semantics and ensure test coverage reflects it.

Likely an incorrect or invalid review comment.

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