Embed MetadaStore in scrape context (#10450)

This will allow downstream users to easily access metadata required.

Signed-off-by: Goutham Veeramachaneni <gouthamve@gmail.com>
This commit is contained in:
Goutham Veeramachaneni 2022-03-16 09:45:15 +01:00 committed by GitHub
parent c1387494dd
commit c4f8020dca
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@ -303,8 +303,11 @@ func newScrapePool(cfg *config.ScrapeConfig, app storage.Appendable, jitterSeed
}
opts.target.SetMetadataStore(cache)
// Store the cache in the context.
loopCtx := ContextWithMetricMetadataStore(ctx, cache)
return newScrapeLoop(
ctx,
loopCtx,
opts.scraper,
log.With(logger, "target", opts.target),
buffers,
@ -1801,3 +1804,21 @@ func reusableCache(r, l *config.ScrapeConfig) bool {
}
return reflect.DeepEqual(zeroConfig(r), zeroConfig(l))
}
// CtxKey is a dedicated type for keys of context-embedded values propagated
// with the scrape context.
type ctxKey int
// Valid CtxKey values.
const (
ctxKeyMetadata ctxKey = iota + 1
)
func ContextWithMetricMetadataStore(ctx context.Context, s MetricMetadataStore) context.Context {
return context.WithValue(ctx, ctxKeyMetadata, s)
}
func MetricMetadataStoreFromContext(ctx context.Context) (MetricMetadataStore, bool) {
s, ok := ctx.Value(ctxKeyMetadata).(MetricMetadataStore)
return s, ok
}