Add OTLP payload byte-size chunking to Agent365Exporter

[fpfp100]

Summary

• Adds heuristic span size estimator (estimateSpanBytes) and byte-size chunking (chunkBySize) to split export batches into sub-batches under 900 KB (configurable via maxPayloadBytes on Agent365ExporterOptions)
• Refactors exportGroup to map+truncate spans, chunk by estimated size, then POST each chunk with all-or-nothing retry semantics
• Existing per-span truncation (250 KB cap) is unchanged; this complements it at the batch level to prevent 1 MB server-side rejection (403/502/500)

Test plan

Unit tests

• 12 new unit tests for estimator, chunking, and truncation verification
• All 40 existing exporter tests pass
• Full suite: 1262 tests across 62 suites, 0 failures

Span comparison: Base SDK vs A365 Distro

Compare spans between the base OTel SDK and the A365 distro to verify correctness and export fidelity.

Configurations under test:

Setting	Base SDK	A365 Distro (span correctness)	A365 Distro (export correctness)
A365 distro initialized	No	Yes	Yes
isObservabilityExporterEnabled	N/A	true	true
A365 remote export	N/A	Disabled	Enabled
Exporter	ConsoleSpanExporter	Agent365Exporter (no remote)	Agent365Exporter (remote)

1. Span correctness (A365 enabled, export disabled)

Verify that spans produced by the A365 distro are correct and consistent with base SDK behavior when remote export is off.

Manual instrumentation (scope classes)

• Create spans via InvokeAgentScope, InferenceScope, ExecuteToolScope with A365 distro initialized
• Verify span attributes (gen_ai.operation.name, gen_ai.system, custom attributes) match what the base SDK tracer would produce
• Verify parent-child span relationships are preserved (InvokeAgent → Inference → ExecuteTool)
• Verify BaggageBuilder context propagation (tenant ID, agent ID, correlation ID) is copied to span attributes by the SpanProcessor without altering the underlying span structure
• Verify span timing (start/end), status codes, and events are identical to base SDK output

Auto-instrumentation (SpanProcessor enrichment)

• Create spans via the raw OTel tracer API (not scope classes) with the A365 SpanProcessor registered
• Verify SpanProcessor.onStart copies baggage entries to span attributes for genAI operations only
• Verify non-genAI spans pass through the SpanProcessor without modification — attributes, timing, and status identical to base SDK
• Verify span count: same number of spans recorded in both configurations
• Verify trace/span IDs: format and propagation consistent between base and distro

2. Export correctness (A365 enabled, export enabled)

Verify that spans are exported faithfully through the Agent365Exporter pipeline including chunking and truncation.

Manual instrumentation

• Create spans via scope classes and verify the exported OTLP payload contains all expected spans with correct attributes
• Verify per-span truncation (250 KB cap) is applied without data loss on non-oversized spans
• Verify byte-size chunking splits batches correctly — no spans dropped, duplicated, or reordered across chunks
• Verify each chunk POST contains valid OTLP structure with correct resource and scope metadata

Auto-instrumentation

• Create spans via raw OTel tracer API and verify SpanProcessor-enriched attributes appear in the exported payload
• Verify genAI spans include baggage-derived attributes in export; non-genAI spans are filtered out by the exporter
• Verify retry semantics: failed chunk export retries the full chunk, not individual spans

Comparison checklist

• A365 distro adds baggage-derived attributes but does not remove or alter base span attributes
• Exported span count matches recorded span count (for genAI spans)
• No data loss from chunking/truncation — all spans under size limits are exported intact

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Adds batch-level OTLP payload size control to the Agent365 span exporter by estimating per-span serialized size and splitting export batches into multiple HTTP POST requests under a configurable byte limit (default 900 KB), complementing the existing per-span truncation cap.

Changes:

• Introduces estimateSpanBytes / estimateValueBytes and generic chunkBySize utilities for heuristic byte-size estimation and chunking.
• Refactors Agent365Exporter.exportGroup to map+truncate spans, chunk them, and POST each chunk sequentially.
• Adds unit tests validating estimator behavior, chunking invariants, and truncation behavior; exports new utilities from package index.

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
tests/observability/core/payload-chunking.test.ts	Adds unit tests for span size estimation, chunking, and truncation verification.
packages/agents-a365-observability/src/tracing/exporter/utils.ts	Adds heuristic byte-size estimator and chunking helper used for request-size control.
packages/agents-a365-observability/src/tracing/exporter/Agent365ExporterOptions.ts	Adds maxPayloadBytes option (default 900,000 bytes).
packages/agents-a365-observability/src/tracing/exporter/Agent365Exporter.ts	Refactors group export to chunk spans by estimated size and POST per chunk.
packages/agents-a365-observability/src/index.ts	Exposes the new exporter utility functions from the package entrypoint.

[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 6 comments.