feat(instrumentation-runtime-node): add v8js.memory.heap.max metric from v8.getHeapStatistics()#3405
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Hronom wants to merge 1 commit intoopen-telemetry:mainfrom
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feat(instrumentation-runtime-node): add v8js.memory.heap.max metric from v8.getHeapStatistics()#3405Hronom wants to merge 1 commit intoopen-telemetry:mainfrom
Hronom wants to merge 1 commit intoopen-telemetry:mainfrom
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just a drive by feedback (since this is marked as draft): before you make it ready for review, can you update the semantic convention for it? similar to open-telemetry/semantic-conventions#3445 |
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Add v8js.memory.heap.max gauge metric representing the absolute maximum heap size (heap_size_limit) from v8.getHeapStatistics(). This value is the hard ceiling controlled by --max-old-space-size or V8 defaults. Related issue: open-telemetry#3476 Related instrumentation PR: open-telemetry/opentelemetry-js-contrib#3405
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Semantic conventions PR created: open-telemetry/semantic-conventions#3481 This adds the |
Author
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Fixed lint |
maryliag
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Mar 3, 2026
packages/instrumentation-runtime-node/src/metrics/heapSizeLimitCollector.ts
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New collector that calls v8.getHeapStatistics() and emits v8js.memory.heap.max metric representing the absolute maximum heap size (heap_size_limit). Related: open-telemetry/semantic-conventions#3476
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Fixed conflict |
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Please can someone review? |
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We're waiting on the upstream changes to the semantic conventions to be accepted, per this comment. |
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What
Adds a new
v8js.memory.heap.maxmetric to@opentelemetry/instrumentation-runtime-nodethat exposes the absolute maximum heap size (heap_size_limit) fromv8.getHeapStatistics().Why
The existing V8 heap metrics (
v8js.memory.heap.limit,v8js.memory.heap.used, etc.) are all sourced fromv8.getHeapSpaceStatistics(), which provides per-space data. However, the absolute heap ceiling (heap_size_limit) -- controlled by--max-old-space-sizeor V8 defaults -- is only available fromv8.getHeapStatistics()and is not currently exposed.This value is critical for:
heap_used / heap_size_limit)Note:
v8js.memory.heap.limit(which maps tospace_sizefromgetHeapSpaceStatistics()) represents pre-allocated space size per heap space, not the hard OOM ceiling.Changes
src/semconv.ts-- AddedMETRIC_V8JS_MEMORY_HEAP_MAXconstantsrc/metrics/heapSizeLimitCollector.ts-- New collector usingv8.getHeapStatistics()and observingheap_size_limitas a gauge (unit: By)src/instrumentation.ts-- RegisteredHeapSizeLimitCollectoralongside existing collectorstest/heap_size_limit.test.ts-- Tests verifying metric is emitted as gauge with positive value and no per-space attributeSemantic Conventions
This metric is proposed in open-telemetry/semantic-conventions#3476. This PR is a draft pending the semconv discussion.
Checklist
Pull Request opened by Augment Code with guidance from the PR author