Support OTLP export over "http/json" for traces, metrics, and logs by mcculls · Pull Request #12018 · DataDog/dd-trace-java

mcculls · 2026-07-21T10:52:22Z

What Does This Do

Support OTLP export over "http/json" for traces, metrics, and logs.

Adds JSON siblings of existing hand-rolled protobuf OTLP encoders (OtlpCommonJson, OtlpResourceJson, OtlpTraceJson/Collector, OtlpMetricsJson/Collector, OtlpLogsJson/Collector) and wires the previously unused/silently-disabled HTTP_JSON protocol into OtlpWriter, OtlpMetricsService, and OtlpLogsService.

Motivation

Adds support for OTLP over http/json to the existing http/protobuf and grpc support.

Contributor Checklist

Format the title according to the contribution guidelines
Assign the type: and (comp: or inst:) labels in addition to any other useful labels
Avoid using close, fix, or any linking keywords when referencing an issue
Use solves instead, and assign the PR milestone to the issue
Update the CODEOWNERS file on source file addition, migration, or deletion
Update public documentation with any new configuration flags or behaviors
Once approved, use merge queue to merge the PR

Jira ticket: [PROJ-IDENT]

dd-octo-sts · 2026-07-21T11:10:59Z

🟢 Java Benchmark SLOs — All performance SLOs passed

Suite	Status
Startup	🟢 pass

SLO thresholds are defined here based on automatically generated metrics. A warning is raised when results are within 5% of the threshold.

PR vs. master results

Scenario	Candidate	master	Δ (95% CI of mean)
startup:insecure-bank:iast:Agent	13.96 s	13.94 s	[-0.6%; +0.8%] (no difference)
startup:insecure-bank:tracing:Agent	12.86 s	13.05 s	[-2.2%; -0.8%] (maybe better)
startup:petclinic:appsec:Agent	16.93 s	16.72 s	[+0.4%; +2.1%] (maybe worse)
startup:petclinic:iast:Agent	16.95 s	16.92 s	[-0.6%; +1.0%] (no difference)
startup:petclinic:profiling:Agent	16.79 s	16.79 s	[-1.3%; +1.3%] (no difference)
startup:petclinic:sca:Agent	17.02 s	16.61 s	[+1.5%; +3.4%] (significantly worse)
startup:petclinic:tracing:Agent	16.16 s	16.07 s	[-0.3%; +1.4%] (no difference)

Commit: 12ec75df · CI Pipeline · Benchmarking Platform UI

Load and DaCapo benchmarks can be triggered manually in the GitLab pipeline. Results will appear in the Benchmarking Platform UI after completion.

mcculls · 2026-07-21T11:35:34Z

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Copilot

Pull request overview

This pull request adds first-class support for exporting OTLP signals over the http/json protocol across traces, metrics, and logs within dd-trace-core, aligning the agent’s OTLP export capabilities with the existing http/protobuf and grpc options.

Changes:

Added JSON OTLP encoders/collectors for traces, metrics, logs, plus shared JSON helpers.
Wired HTTP_JSON into OtlpWriter (traces) and into OtlpMetricsService / OtlpLogsService (metrics/logs).
Refactored shared OTLP constants/mappings (trace flags, span kind mapping, resource attributes, metrics temporality) to be reused across proto/JSON paths.

Reviewed changes

Copilot reviewed 35 out of 35 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
dd-trace-core/src/test/java/datadog/trace/core/otlp/trace/OtlpTraceProtoTest.java	Updates trace-flag constant reference to shared `OtlpTraceFlags`.
dd-trace-core/src/test/java/datadog/trace/core/otlp/trace/OtlpTraceJsonCollectorTest.java	Adds coverage for trace OTLP JSON encoding (hex ids, keys, kind, status).
dd-trace-core/src/test/java/datadog/trace/core/otlp/metrics/OtlpMetricsServiceTest.java	Verifies metrics service selects JSON collector + HTTP endpoint under `http/json`.
dd-trace-core/src/test/java/datadog/trace/core/otlp/metrics/OtlpMetricsJsonCollectorTest.java	Adds coverage for metrics OTLP JSON encoding (temporality, timestamps, histograms).
dd-trace-core/src/test/java/datadog/trace/core/otlp/logs/OtlpLogsServiceTest.java	Verifies logs service selects JSON collector + HTTP endpoint under `http/json`.
dd-trace-core/src/test/java/datadog/trace/core/otlp/logs/OtlpLogsProtoTest.java	Updates trace-flag constant reference to shared `OtlpTraceFlags`.
dd-trace-core/src/test/java/datadog/trace/core/otlp/logs/OtlpLogsJsonCollectorTest.java	Adds coverage for logs OTLP JSON encoding (ids, flags, timestamps, eventName).
dd-trace-core/src/test/java/datadog/trace/core/otlp/common/OtlpResourceJsonTest.java	Adds coverage for JSON resource fragment generation from `Config`.
dd-trace-core/src/test/java/datadog/trace/core/otlp/common/OtlpCommonJsonTest.java	Adds coverage for common JSON encoding primitives (ids, attributes, arrays).
dd-trace-core/src/test/java/datadog/trace/common/writer/OtlpWriterCombinedTest.java	Adds an end-to-end assertion that `HTTP_JSON` sends `Content-Type: application/json`.
dd-trace-core/src/main/java/datadog/trace/core/otlp/trace/OtlpTraceProto.java	Refactors span kind + trace flags to shared helpers/constants.
dd-trace-core/src/main/java/datadog/trace/core/otlp/trace/OtlpTraceJsonCollector.java	New trace JSON collector producing OTLP `trace.proto` JSON payloads.
dd-trace-core/src/main/java/datadog/trace/core/otlp/trace/OtlpTraceJson.java	New trace JSON writer for spans and span links in OTLP JSON shape.
dd-trace-core/src/main/java/datadog/trace/core/otlp/trace/OtlpSpanKind.java	New shared span-kind mapping for proto + JSON encoders.
dd-trace-core/src/main/java/datadog/trace/core/otlp/metrics/OtlpMetricsTemporality.java	Extracts temporality selection to a shared helper used by proto/JSON.
dd-trace-core/src/main/java/datadog/trace/core/otlp/metrics/OtlpMetricsService.java	Enables `HTTP_JSON` protocol and adds package-private accessors for testing.
dd-trace-core/src/main/java/datadog/trace/core/otlp/metrics/OtlpMetricsProto.java	Switches to shared temporality constants (logic moved out).
dd-trace-core/src/main/java/datadog/trace/core/otlp/metrics/OtlpMetricsJsonCollector.java	New metrics JSON collector producing OTLP `metrics.proto` JSON payloads.
dd-trace-core/src/main/java/datadog/trace/core/otlp/metrics/OtlpMetricsJson.java	New metrics JSON writer (metric headers + data point values).
dd-trace-core/src/main/java/datadog/trace/core/otlp/logs/OtlpLogsService.java	Enables `HTTP_JSON` protocol and adds package-private accessors for testing.
dd-trace-core/src/main/java/datadog/trace/core/otlp/logs/OtlpLogsProtoCollector.java	Removes duplicated protobuf content-type constant (centralized elsewhere).
dd-trace-core/src/main/java/datadog/trace/core/otlp/logs/OtlpLogsProto.java	Updates trace-flag constant reference to shared `OtlpTraceFlags`.
dd-trace-core/src/main/java/datadog/trace/core/otlp/logs/OtlpLogsJsonCollector.java	New logs JSON collector producing OTLP `logs.proto` JSON payloads.
dd-trace-core/src/main/java/datadog/trace/core/otlp/logs/OtlpLogsJson.java	New logs JSON writer for log-record JSON fields and flags.
dd-trace-core/src/main/java/datadog/trace/core/otlp/common/OtlpTraceFlags.java	New shared trace/logs flags constants to avoid duplication.
dd-trace-core/src/main/java/datadog/trace/core/otlp/common/OtlpResourceProto.java	Refactors resource attribute enumeration into shared helper.
dd-trace-core/src/main/java/datadog/trace/core/otlp/common/OtlpResourceJson.java	New resource JSON fragment generator for OTLP JSON payloads.
dd-trace-core/src/main/java/datadog/trace/core/otlp/common/OtlpResourceAttributes.java	New shared resource-attribute enumeration used by proto + JSON.
dd-trace-core/src/main/java/datadog/trace/core/otlp/common/OtlpProtoBuffer.java	Centralizes protobuf content type via `OtlpPayload`.
dd-trace-core/src/main/java/datadog/trace/core/otlp/common/OtlpPayload.java	Adds shared content-type constants for protobuf + JSON payloads.
dd-trace-core/src/main/java/datadog/trace/core/otlp/common/OtlpHttpSender.java	Exposes `url()` accessor (used by tests).
dd-trace-core/src/main/java/datadog/trace/core/otlp/common/OtlpCommonJson.java	New common OTLP JSON helpers (ids, scope/schema, attributes).
dd-trace-core/src/main/java/datadog/trace/core/otlp/common/LazyJsonArray.java	New helper for lazily-opened JSON arrays used by JSON collectors.
dd-trace-core/src/main/java/datadog/trace/common/writer/OtlpWriter.java	Chooses trace collector based on protocol (`HTTP_JSON` vs proto).
dd-trace-core/src/main/java/datadog/trace/common/writer/OtlpPayloadDispatcher.java	Removes implicit default proto collector; collector now injected explicitly.

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mcculls · 2026-07-21T12:03:41Z

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Pull request overview

Copilot reviewed 36 out of 36 changed files in this pull request and generated 2 comments.

chatgpt-codex-connector · 2026-07-21T12:10:40Z

Codex Review: Didn't find any major issues. 🎉

Reviewed commit: 414de6e9eb

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mcculls · 2026-07-21T14:46:28Z

@codex review

chatgpt-codex-connector · 2026-07-21T14:52:40Z

Codex Review: Didn't find any major issues. Bravo.

Reviewed commit: bcd2ba94ff

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Pull request overview

Copilot reviewed 38 out of 38 changed files in this pull request and generated 1 comment.

mhlidd

Small nits from Claude

Adds JSON siblings of existing hand-rolled protobuf OTLP encoders (OtlpCommonJson, OtlpResourceJson, OtlpTraceJson/Collector, OtlpMetricsJson/Collector, OtlpLogsJson/Collector) and wires the previously unused/silently-disabled HTTP_JSON protocol into OtlpWriter, OtlpMetricsService, and OtlpLogsService. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

mcculls · 2026-07-21T23:51:20Z

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Pull request overview

Copilot reviewed 42 out of 42 changed files in this pull request and generated no new comments.

chatgpt-codex-connector · 2026-07-21T23:58:45Z

Codex Review: Didn't find any major issues. What shall we delve into next?

Reviewed commit: 27286d6791

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mhlidd

LGTM

dd-octo-sts · 2026-07-22T21:17:04Z

/merge

gh-worker-devflow-routing-ef8351 · 2026-07-22T21:17:08Z

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⏳ Merge Commit: 4e13091
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dd-octo-sts · 2026-07-22T21:58:13Z

/merge

gh-worker-devflow-routing-ef8351 · 2026-07-22T21:58:17Z

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mcculls added type: feature Enhancements and improvements inst: opentelemetry OpenTelemetry instrumentation labels Jul 21, 2026

mcculls changed the title ~~Add OTLP/JSON export support for traces, metrics, and logs~~ Support OTLP export over "http/json" for traces, metrics, and logs Jul 21, 2026

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mcculls force-pushed the mcculls/otlp-json branch 2 times, most recently from 573483d to ae7ca71 Compare July 21, 2026 11:34

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Comment thread dd-trace-core/src/main/java/datadog/trace/core/otlp/metrics/OtlpMetricsJsonCollector.java

Comment thread dd-trace-core/src/main/java/datadog/trace/core/otlp/logs/OtlpLogsJsonCollector.java

mcculls force-pushed the mcculls/otlp-json branch from b8387d8 to bcd2ba9 Compare July 21, 2026 14:35

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Comment thread components/json/src/test/java/datadog/json/JsonWriterTest.java Outdated

mcculls force-pushed the mcculls/otlp-json branch from bcd2ba9 to 55d0509 Compare July 21, 2026 14:58

mcculls marked this pull request as ready for review July 21, 2026 14:59

mcculls requested review from a team as code owners July 21, 2026 14:59

mcculls requested review from PerfectSlayer and removed request for a team July 21, 2026 14:59

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mcculls force-pushed the mcculls/otlp-json branch from 55d0509 to 4447563 Compare July 21, 2026 15:38

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Comment thread dd-trace-core/src/main/java/datadog/trace/core/otlp/metrics/OtlpMetricsJsonCollector.java Outdated

Comment thread dd-trace-core/src/main/java/datadog/trace/core/otlp/trace/OtlpTraceJson.java

mcculls force-pushed the mcculls/otlp-json branch 2 times, most recently from 12ec75d to b08029a Compare July 21, 2026 23:44

mcculls force-pushed the mcculls/otlp-json branch from b08029a to 27286d6 Compare July 21, 2026 23:50

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mcculls added this pull request to the merge queue Jul 22, 2026

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What Does This Do

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🟢 Java Benchmark SLOs — All performance SLOs passed

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