Pass the correct context to staleness Appender (#10588)

OTel Collector prints the following error when a target disappears:

```
2022-04-13T14:20:24.932-0400	warn	scrape/scrape.go:1408	Stale append failed	{"kind": "receiver", "name": "prometheus", "scrape_pool": "beep-boop", "target": "http://localhost:9090/metrics", "error": "transaction aborted"}
```

This `transaction aborted` error is returned by the custom appender that is
used by the collector when the context of the appender is cancelled:
b7bf11174e/receiver/prometheusreceiver/internal/otlp_transaction.go (L81-L82)

We call `endOfRunStaleness` after `sl.stop()` which cancels `sl.ctx`.
The other `.Appender()` calls use `parentCtx` for the same reason.

This hasn't come up so far because Prometheus' Appender implementation just
ignores the context passed.

Signed-off-by: Goutham Veeramachaneni <gouthamve@gmail.com>
This commit is contained in:
Goutham Veeramachaneni 2022-04-14 10:03:07 -04:00 committed by GitHub
parent 580e852f10
commit ec3d02019e
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1 changed files with 3 additions and 2 deletions

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@ -1379,7 +1379,8 @@ func (sl *scrapeLoop) endOfRunStaleness(last time.Time, ticker *time.Ticker, int
// Call sl.append again with an empty scrape to trigger stale markers.
// If the target has since been recreated and scraped, the
// stale markers will be out of order and ignored.
app := sl.appender(sl.ctx)
// sl.context would have been cancelled, hence using sl.parentCtx.
app := sl.appender(sl.parentCtx)
var err error
defer func() {
if err != nil {
@ -1393,7 +1394,7 @@ func (sl *scrapeLoop) endOfRunStaleness(last time.Time, ticker *time.Ticker, int
}()
if _, _, _, err = sl.append(app, []byte{}, "", staleTime); err != nil {
app.Rollback()
app = sl.appender(sl.ctx)
app = sl.appender(sl.parentCtx)
level.Warn(sl.l).Log("msg", "Stale append failed", "err", err)
}
if err = sl.reportStale(app, staleTime); err != nil {