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[3.0] Extensions pre-release fixes (dist bundles test/examples; statsd DNS on probe thread; stddev overflow) #889
Description
Activity
Addressed by #909 (merged 2026-07-19 into
develop). All four items verified ondevelop:- dist allow-list —
btrace-dist/build.gradle:518-525now bundles an explicitreleaseExtensionProjectslist (contracts, gpu-bridge, llm-trace, metrics, rag-quality, statsd, utils);btrace-ext-testand theexamples/*extensions are no longer picked up. Covered byBTraceJarPackagingTest. - statsd DNS/socket per call —
StatsdImplresolves the address and opens a singleDatagramSocketininitialize(), caches them in an immutableEndpoint, and closes on detach. No lookup or allocation on the probe thread. - stddev overflow —
StatsMetricImplaccumulates squares in aDoubleAdder((double) value * value), so ns-scale latencies no longer overflow. - stale API version —
BTraceExtensionPlugin.groovy:796emitsBTrace-API-Version: 3.0+.
Small residual, not worth holding this issue open:
docs/architecture/ExtensionManifestFormat.mdstill shows2.3+in its example manifest (lines 39, 76, 161) and should be refreshed to3.0+. The descriptor-format reconciliation mentioned in the trailing note was also out of scope for #909; opening a separate issue if it is still wanted.- dist allow-list —
Summary
Pre-release fixes for
btrace-extensions/*— one packaging defect and two correctness/safety bugs, plus a stale manifest version. Grouped from the module review.Items
btrace-ext-testand bothexamples/*extensions (whose own READMEs say "not maintained as part of core BTrace") ship in the releasedextensions/dir.btrace-dist/build.gradle:516-532. Fix: add an explicit allow-list of extensions to bundle.StatsdImpl.increment()opens a freshDatagramSocketand does a blockingInetAddress.getByName()DNS lookup on the probe (application) thread on every call.StatsdImpl.java:32-50. Fix: resolve once and reuse a cached socket/address.StatsMetricImplaccumulates sum-of-squares in along(value*value), which overflows for realistic ns-latency inputs and silently corruptsstddev.StatsMetricImpl.java:54,94. Fix: usedoubleaccumulation (or a numerically stable online-variance algorithm).BTrace-API-Version: 2.3+. The gradle plugin hard-codes2.3+into every extension manifest while the loader default is3.0+(ExtensionMetadata.java:141). 3.0 satisfies2.3+so there is no functional gate today, but it is misleading and should track the current namespace/version. (Related to the gradle-plugin descriptor issue.)Also worth reconciling: three descriptor-format variants coexist across the extensions (DSL + legacy
@ExtensionDescriptorpackage-info +@ServiceDescriptor; DSL +@ServiceDescriptor; DSL-only), and the legacy package-infos hard-codeversion="1.0"that mismatches the manifest.Owner: extensions / build team.