forked from grafana/loki
/
middleware.go
30 lines (24 loc) · 859 Bytes
/
middleware.go
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package queryrangebase
import (
"net/http"
"github.com/grafana/dskit/tenant"
"github.com/weaveworks/common/middleware"
)
const (
// ResultsCacheGenNumberHeaderName holds name of the header we want to set in http response
ResultsCacheGenNumberHeaderName = "Results-Cache-Gen-Number"
)
func CacheGenNumberHeaderSetterMiddleware(cacheGenNumbersLoader CacheGenNumberLoader) middleware.Interface {
return middleware.Func(func(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
userIDs, err := tenant.TenantIDs(r.Context())
if err != nil {
http.Error(w, err.Error(), http.StatusUnauthorized)
return
}
cacheGenNumber := cacheGenNumbersLoader.GetResultsCacheGenNumber(userIDs)
w.Header().Set(ResultsCacheGenNumberHeaderName, cacheGenNumber)
next.ServeHTTP(w, r)
})
})
}