Reformat doc comment of InstrumentHandler

To help linters detect the Deprecated message.

Signed-off-by: beorn7 <beorn@soundcloud.com>
This commit is contained in:
beorn7 2018-09-14 13:24:05 +02:00
parent cec67c9ec8
commit b7b390014b
1 changed files with 8 additions and 15 deletions

View File

@ -149,21 +149,14 @@ var now nower = nowFunc(func() time.Time {
// (label name "method") and HTTP status code (label name "code").
//
// Deprecated: InstrumentHandler has several issues. Use the tooling provided in
// package promhttp instead. The issues are the following:
//
// - It uses Summaries rather than Histograms. Summaries are not useful if
// aggregation across multiple instances is required.
//
// - It uses microseconds as unit, which is deprecated and should be replaced by
// seconds.
//
// - The size of the request is calculated in a separate goroutine. Since this
// calculator requires access to the request header, it creates a race with
// any writes to the header performed during request handling.
// httputil.ReverseProxy is a prominent example for a handler
// performing such writes.
//
// - It has additional issues with HTTP/2, cf.
// package promhttp instead. The issues are the following: (1) It uses Summaries
// rather than Histograms. Summaries are not useful if aggregation across
// multiple instances is required. (2) It uses microseconds as unit, which is
// deprecated and should be replaced by seconds. (3) The size of the request is
// calculated in a separate goroutine. Since this calculator requires access to
// the request header, it creates a race with any writes to the header performed
// during request handling. httputil.ReverseProxy is a prominent example for a
// handler performing such writes. (4) It has additional issues with HTTP/2, cf.
// https://github.com/prometheus/client_golang/issues/272.
func InstrumentHandler(handlerName string, handler http.Handler) http.HandlerFunc {
return InstrumentHandlerFunc(handlerName, handler.ServeHTTP)