Internal - Use pre-computed transaction name from span attributes

[cleverchuk]

TLDR

Short-circuit buildTransactionName when a sw.transaction attribute already exists on the span, avoiding redundant name resolution. Consolidate TRANSACTION_NAME_KEY and LEGACY_TRANSACTION_NAME_KEY into SharedNames as typed AttributeKey<String> constants.

Motivation

InboundMeasurementMetricsGenerator.onEnding computes and sets the transaction name on the span via setAttribute. However, if the span is later read again (e.g., by metrics recording in onEnd), buildTransactionName re-executes the full resolution chain — custom dictionary lookup, naming scheme, handler name, http.route, URL pattern extraction — even though the answer is already sitting in the span's attributes. This is wasted work.

What changed

Early-return on pre-computed name: buildTransactionName now checks spanAttributes.get(TRANSACTION_NAME_KEY) first. If a non-null, non-empty value exists, it returns immediately. This makes the already-set sw.transaction attribute the highest-priority source in the resolution chain, ahead of custom dictionary names, naming schemes, and URL-based derivation.

Type promotion of shared constants: TRANSACTION_NAME_KEY was previously a plain String in SharedNames and each consumer independently wrapped it with AttributeKey.stringKey(...). It is now declared as AttributeKey<String> directly, eliminating the repeated wrapping. LEGACY_TRANSACTION_NAME_KEY ("TransactionName") was a private constant in InboundMeasurementMetricsGenerator and is now shared alongside it.

Resolution priority order (unchanged except for the new first step):

1. Pre-computed sw.transaction span attribute (new)
2. Custom transaction name dictionary (CustomTransactionNameDict)
3. Naming scheme (NamingScheme.createName)
4. Handler name (e.g., Spring MVC)
5. http.route
6. URL pattern extraction
7. Span name fallback

Tests

Three new tests cover the pre-computed name path:

• Returns pre-computed name when sw.transaction attribute is present
• Falls back to standard resolution when attribute value is empty
• Falls back to standard resolution when attribute is absent

Test services data

1. e-1712644058766987264
2. e-1712643928659124224
3. e-1742334541200846848
4. e-1777406072376840192

[Copilot]

Pull request overview

This PR optimizes transaction-name resolution in the shared extensions by short-circuiting TransactionNameManager.buildTransactionName(...) when the transaction name is already present on the span, and centralizes transaction-name attribute keys in SharedNames.

Changes:

• Add an early-return in TransactionNameManager.buildTransactionName(...) when sw.transaction is already set on the span.
• Promote TRANSACTION_NAME_KEY (and add LEGACY_TRANSACTION_NAME_KEY) into SharedNames as typed AttributeKey<String> constants, and update consumers/tests accordingly.
• Add unit tests covering the pre-computed transaction-name behavior.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
libs/shared/src/main/java/com/solarwinds/opentelemetry/extensions/TransactionNameManager.java	Early-return when sw.transaction is already present on the span attributes.
libs/shared/src/main/java/com/solarwinds/opentelemetry/extensions/SharedNames.java	Converts transaction name constants to AttributeKey<String> and adds legacy key constant.
libs/shared/src/main/java/com/solarwinds/opentelemetry/extensions/InboundMeasurementMetricsGenerator.java	Switches to shared AttributeKey constants for setting transaction-name attributes.
libs/shared/src/test/java/com/solarwinds/opentelemetry/extensions/InboundMeasurementMetricsGeneratorTest.java	Updates assertions to use the typed shared attribute key.
libs/shared/src/test/java/com/solarwinds/opentelemetry/extensions/TransactionNameManagerTest.java	New tests for pre-computed transaction name and fallback behavior.

[jerrytfleung]

LGTM