fix(loki.source.file): Fix position tracking when component stops#5800
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Pull request overview
This PR updates the loki.source.file tailer shutdown behavior to avoid deadlocks when cancellation occurs while a log entry send is blocked, and adjusts component shutdown accordingly.
Changes:
- Make
tailer.readLinesabortable via context when a send to the receiver channel is blocked. - Replace the tailer “done channel” shutdown signaling with a
sync.WaitGroup-based approach. - Simplify
loki.source.filecomponent shutdown and add a regression test for cancel-while-send-blocked.
Reviewed changes
Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.
| File | Description |
|---|---|
| internal/component/loki/source/file/tailer.go | Makes blocked sends cancelable and changes shutdown coordination to use a WaitGroup. |
| internal/component/loki/source/file/tailer_test.go | Adds a regression test for cancellation during blocked sends. |
| internal/component/loki/source/file/file.go | Simplifies shutdown path now that tailers can exit cleanly without a drain routine. |
Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>
ptodev
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Mar 17, 2026
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Makes sense. I personally can't think of any downsides to this. I don't think we were making some tradeoff to get better performance or anything like that.
blewis12
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Mar 30, 2026
🤖 I have created a release *beep* *boop* --- ## [1.15.0](v1.14.0...v1.15.0) (2026-03-26) ### ⚠ BREAKING CHANGES * **otelcol:** Upgrade to OTel Collector v0.147.0 ([#5784](#5784)) * Renamed undocumented metrics that was previously prefixed with <component_id>_<metric_name> to loki_source_awsfirehose_<metric_name> ### Features 🌟 * **alloy-mixin:** Add filters, groupBy, and multi-select dashboard variables ([#5611](#5611)) ([3ef714e](3ef714e)) * **beyla.ebpf:** Add support for Prometheus native histograms ([#5812](#5812)) ([7d806fb](7d806fb)) * **beyla.ebpf:** Bump Beyla to v3.6 ([#5833](#5833)) ([cd878d5](cd878d5)) * **converters:** Support converting Promtail limits_config ([#5777](#5777)) ([9491385](9491385)) * **database_observability.mysql:** Add filtering of query samples and wait events by minimum duration ([#5678](#5678)) ([5a4d03b](5a4d03b)) * **database_observability.mysql:** Embed prometheus exporter within db-o11y component ([#5711](#5711)) ([88bffb0](88bffb0)) * **database_observability.postgres:** Add configurable limit to `pg_stat_statements` query ([#5639](#5639)) ([0de0a3f](0de0a3f)) * **database_observability.postgres:** Embed prometheus exporter within db-o11y component ([#5714](#5714)) ([9dc2e83](9dc2e83)) * **database_observability:** Add scaffolding for db-o11y integration tests ([#5575](#5575)) ([ca637d8](ca637d8)) * **database_observability:** Promote components to stable ([#5736](#5736)) ([21a9af6](21a9af6)) * Expose Functionality to Handle syslogs with Empty MSG Field ([#5687](#5687)) ([178b1e6](178b1e6)) * **helm:** Allow setting `revisionHistoryLimit` in the helm chart ([#5847](#5847)) ([9713ad4](9713ad4)) * **loki.process:** Support structured metadata as source type of stage.labels for loki.process ([#5055](#5055)) ([eda3152](eda3152)) * **loki.secretfilter:** Add sampling for secretfilter entries ([#5663](#5663)) ([9997802](9997802)) * **loki.source.gcplog:** Add alloy config for MaxOutstandingBytes and MaxOutstandingMessages ([#5760](#5760)) ([c2b9f0b](c2b9f0b)) * **loki.write:** Add loki pipeline latency metric ([#5702](#5702)) ([cc744a1](cc744a1)) * **mixin:** Update loki dashboard ([#5848](#5848)) ([b616d58](b616d58)) * **otelcol.receiver.datadog:** Expose intake proxy and trace_id_cache_size settings ([#5776](#5776)) ([0384ad4](0384ad4)) * **otelcol:** Upgrade to OTel Collector v0.147.0 ([#5784](#5784)) ([a9b5396](a9b5396)) * **prometheus.exporter.cloudwatch:** Use aws-sdk-go-v2 by default ([#5768](#5768)) ([a2f3489](a2f3489)) * **pyroscope.ebpf:** Add comm, pid labels and kernel frame options ([#5769](#5769)) ([4fa7068](4fa7068)) * **pyroscope.ebpf:** Expose OTel eBPF profiler internal metrics to Prometheus ([#5774](#5774)) ([e713392](e713392)) * **pyroscope:** Copy prometheus common/config HTTP client into promhttp2 package ([#5810](#5810)) ([0b31aaa](0b31aaa)) ### Bug Fixes 🐛 * **beyla:** Inject Beyla version into binary via ldflags ([#5735](#5735)) ([71c03ec](71c03ec)) * Correctly handle the deprecated topic field in otelcol.receiver.kafka configuration ([#5726](#5726)) ([538ac75](538ac75)) * **database_observability.mysql:** Ensure result sets are properly closed ([#5893](#5893)) ([f28f91c](f28f91c)) * **database_observability:** Ensure all collectors are properly stopped ([#5796](#5796)) ([6bfa2a7](6bfa2a7)) * **database_observability:** Ensure that `connection_info` metric is only emitted for a given DB instance when it is available ([#5707](#5707)) ([bf0c3dc](bf0c3dc)) * **database_observability:** Solve test flakiness in MySQL and Postgres sample collectors ([#5130](#5130)) ([a7590d1](a7590d1)) * **deps:** Update module github.com/buger/jsonparser to v1.1.2 [SECURITY] ([#5834](#5834)) ([b2fee8a](b2fee8a)) * **deps:** Update module github.com/buger/jsonparser to v1.1.2 [SECURITY] ([#5870](#5870)) ([698b4e7](698b4e7)) * **deps:** Update module google.golang.org/grpc to v1.79.3 [SECURITY] ([#5825](#5825)) ([5cfbcc4](5cfbcc4)) * **deps:** Update module google.golang.org/grpc to v1.79.3 [SECURITY] ([#5871](#5871)) ([259152d](259152d)) * **deps:** Update npm dependencies ([#5876](#5876)) ([f0f6a11](f0f6a11)) * **deps:** Update npm deps across repo to address CVE-2026-26996 and CVE-2026-22029 ([#5872](#5872)) ([df518dd](df518dd)) * **go:** Update build image to go v1.25.8 ([#5832](#5832)) ([f9b3043](f9b3043)) * **go:** Update go to 1.25.8 ([#5844](#5844)) ([534e7db](534e7db)) * Helm: alloy.extraPorts not working with service.type=NodePort [COPY] ([#5892](#5892)) ([162c6f7](162c6f7)) * **loki.enrich:** Use shared loki functions and fix locking ([#5821](#5821)) ([f916c72](f916c72)) * **loki.process:** Multiline no longer pass empty entry if start was flushed ([#5746](#5746)) ([7bdedf1](7bdedf1)) * **loki.process:** Protect against json that does not look like docker json format ([#5761](#5761)) ([0af6eaa](0af6eaa)) * **loki.secretfilter:** Fix bug where entries were being shadow dropped ([#5786](#5786)) ([90243f9](90243f9)) * **loki.source.file:** Fix position tracking when component stops ([#5800](#5800)) ([9762946](9762946)) * **loki.source.file:** Keep positions for compressed files when reading is finished ([#5723](#5723)) ([fb41d0a](fb41d0a)) * **loki.source.gcplog:** Update to pubsub v2 and fix shutdown semantics ([#5713](#5713)) ([e9d9b69](e9d9b69)) * **loki.source.heroku:** Fix shutdown semantics and consume logs in batches ([#5804](#5804)) ([deda452](deda452)) * **loki.write:** Remove noisy log ([#5837](#5837)) ([8e28f35](8e28f35)) * **loki:** Make drain forward entries with fallback timeout ([#5830](#5830)) ([cfbca90](cfbca90)) * **prometheus.scrape:** Update arguments and targets even if `scrape_native_histograms` and `extra_metrics` are updated ([#5787](#5787)) ([dc4cb0a](dc4cb0a)) * **pyroscope.ebpf:** Update opentelemetry-ebpf-profiler ([#5904](#5904)) ([dfaec47](dfaec47)) * Stop components in a deterministic order ([#5613](#5613)) ([00cd371](00cd371)) ### Chores * Use shared source structures for aws firehose ([#5739](#5739)) ([aef19dc](aef19dc)) --- This PR was generated with [Release Please](https://github.com/googleapis/release-please). See [documentation](https://github.com/googleapis/release-please#release-please). Co-authored-by: grafana-alloybot[bot] <167359181+grafana-alloybot[bot]@users.noreply.github.com>
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Pull Request Details
Usage of
source.Drainis an indicator that something else is not working correctly. This pr will fix the root cause i.e. a tailer being stuck on sending next entry to component handler.I added a test that on main will fail but with the fix works. With this we no longer need to drain channel and we only advance position if we managed to send entry to component.
Issue(s) fixed by this Pull Request
Notes to the Reviewer
PR Checklist