docs(lambda): correct ESM behaviour coverage (ScalingConfig, ProvisionedPollerConfig, FunctionResponseTypes)#750
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quetzalliwrites merged 1 commit intoJul 7, 2026
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…sionedPollerConfig, FunctionResponseTypes - ScalingConfig: SQS Standard/FIFO 🟠 → 🟡 (config accepted but poller count hard-coded / single-poller FIFO, not auto-scaled) - ProvisionedPollerConfig: SQS Standard/FIFO ➖ → 🟡 (MinimumPollers honored; MaximumPollers / FIFO ignored) - FunctionResponseTypes: MSK & Self-Managed ➖ → 🟠 (AWS supports ReportBatchItemFailures for Kafka; not implemented in LocalStack) - Add footnotes [^3]/[^4] explaining the partial SQS behaviour Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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nik-localstack
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Thanks for updating this 🚀
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btw, shouldn't go in the main branch since the feature is already released in the june release ? |
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most yes with a nit no:
Given that merging to main is blocked; I don't think that's urgent enough to opt for an exception here. |
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tyvm @joe4dev, awesome contribution! |
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Motivation
The Lambda ESM behavior coverage docs became outdated after AWS released new features (e.g., FunctionResponseTypes support for MSK/Kafka), and @nik-localstack shipped provisioned poller support for SQS
Summary
Corrects the Lambda Event Source Mapping Behaviour Coverage table (
aws/services/lambda→ Behaviour Coverage) based on a review of LocalStack's actual ESM implementation.MaximumConcurrencyMinimumPollershonored;MaximumPollershas no effectReportBatchItemFailuresfor Kafka; not yet implemented in LocalStackAdds footnotes
[^3]/[^4]explaining the partial SQS behaviour.Notes / open questions
➖ → 🟡): framed as LocalStack behavioural coverage (the code partially honorsMinimumPollers). If reviewers prefer strict AWS-parity framing (ProvisionedPollerConfig as Kafka-only, hence➖for SQS), this can be reverted.🟠(not➖): AWS supports it there, LocalStack doesn't implement it.Batch ≥ 6 MB(mini-batching isn't a true by-size implementation) andMaximumRecordAgeInSeconds(fix landing soon).Preview
https://d13ec91a.localstack-docs.pages.dev/aws/services/lambda/#behaviour-coverage
🤖 Generated with Claude Code