add process start time header to client_golang prometheus (#1278)

* add process start time header to client_golang prometheus

Signed-off-by: Han Kang <hankang@google.com>

* Apply suggestions from code review

Co-authored-by: Bartlomiej Plotka <bwplotka@gmail.com>
Signed-off-by: Han Kang <hankang@google.com>

* fix up changes due to incorporation of feedback

* fix lint issues

---------

Signed-off-by: Han Kang <hankang@google.com>
Co-authored-by: Bartlomiej Plotka <bwplotka@gmail.com>
This commit is contained in:
Han Kang 2023-05-26 04:58:36 -07:00 committed by GitHub
parent 8b1a836e7d
commit b8cb86a865
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 16 additions and 3 deletions

View File

@ -37,6 +37,7 @@ import (
"fmt"
"io"
"net/http"
"strconv"
"strings"
"sync"
"time"
@ -47,9 +48,10 @@ import (
)
const (
contentTypeHeader = "Content-Type"
contentEncodingHeader = "Content-Encoding"
acceptEncodingHeader = "Accept-Encoding"
contentTypeHeader = "Content-Type"
contentEncodingHeader = "Content-Encoding"
acceptEncodingHeader = "Accept-Encoding"
processStartTimeHeader = "Process-Start-Time-Unix"
)
var gzipPool = sync.Pool{
@ -121,6 +123,9 @@ func HandlerForTransactional(reg prometheus.TransactionalGatherer, opts HandlerO
}
h := http.HandlerFunc(func(rsp http.ResponseWriter, req *http.Request) {
if !opts.ProcessStartTime.IsZero() {
rsp.Header().Set(processStartTimeHeader, strconv.FormatInt(opts.ProcessStartTime.Unix(), 10))
}
if inFlightSem != nil {
select {
case inFlightSem <- struct{}{}: // All good, carry on.
@ -366,6 +371,14 @@ type HandlerOpts struct {
// (which changes the identity of the resulting series on the Prometheus
// server).
EnableOpenMetrics bool
// ProcessStartTime allows setting process start timevalue that will be exposed
// with "Process-Start-Time-Unix" response header along with the metrics
// payload. This allow callers to have efficient transformations to cumulative
// counters (e.g. OpenTelemetry) or generally _created timestamp estimation per
// scrape target.
// NOTE: This feature is experimental and not covered by OpenMetrics or Prometheus
// exposition format.
ProcessStartTime time.Time
}
// gzipAccepted returns whether the client will accept gzip-encoded content.