1 files changed, 47 insertions, 16 deletions

diff --git a/vendor/github.com/prometheus/client_golang/prometheus/promhttp/http.go b/vendor/github.com/prometheus/client_golang/prometheus/promhttp/http.go
index cea5a90..b0ee467 100644
--- a/vendor/github.com/prometheus/client_golang/prometheus/promhttp/http.go
+++ b/vendor/github.com/prometheus/client_golang/prometheus/promhttp/http.go
@@ -144,7 +144,12 @@ func HandlerFor(reg prometheus.Gatherer, opts HandlerOpts) http.Handler {
                         }
                 }
 
-                contentType := expfmt.Negotiate(req.Header)
+                var contentType expfmt.Format
+                if opts.EnableOpenMetrics {
+                        contentType = expfmt.NegotiateIncludingOpenMetrics(req.Header)
+                } else {
+                        contentType = expfmt.Negotiate(req.Header)
+                }
                 header := rsp.Header()
                 header.Set(contentTypeHeader, string(contentType))
 
@@ -163,22 +168,38 @@ func HandlerFor(reg prometheus.Gatherer, opts HandlerOpts) http.Handler {
                 enc := expfmt.NewEncoder(w, contentType)
 
                 var lastErr error
+
+                // handleError handles the error according to opts.ErrorHandling
+                // and returns true if we have to abort after the handling.
+                handleError := func(err error) bool {
+                        if err == nil {
+                                return false
+                        }
+                        lastErr = err
+                        if opts.ErrorLog != nil {
+                                opts.ErrorLog.Println("error encoding and sending metric family:", err)
+                        }
+                        errCnt.WithLabelValues("encoding").Inc()
+                        switch opts.ErrorHandling {
+                        case PanicOnError:
+                                panic(err)
+                        case HTTPErrorOnError:
+                                httpError(rsp, err)
+                                return true
+                        }
+                        // Do nothing in all other cases, including ContinueOnError.
+                        return false
+                }
+
                 for _, mf := range mfs {
-                        if err := enc.Encode(mf); err != nil {
-                                lastErr = err
-                                if opts.ErrorLog != nil {
-                                        opts.ErrorLog.Println("error encoding and sending metric family:", err)
-                                }
-                                errCnt.WithLabelValues("encoding").Inc()
-                                switch opts.ErrorHandling {
-                                case PanicOnError:
-                                        panic(err)
-                                case ContinueOnError:
-                                        // Handled later.
-                                case HTTPErrorOnError:
-                                        httpError(rsp, err)
-                                        return
-                                }
+                        if handleError(enc.Encode(mf)) {
+                                return
+                        }
+                }
+                if closer, ok := enc.(expfmt.Closer); ok {
+                        // This in particular takes care of the final "# EOF\n" line for OpenMetrics.
+                        if handleError(closer.Close()) {
+                                return
                         }
                 }
 
@@ -318,6 +339,16 @@ type HandlerOpts struct {
         // away). Until the implementation is improved, it is recommended to
         // implement a separate timeout in potentially slow Collectors.
         Timeout time.Duration
+        // If true, the experimental OpenMetrics encoding is added to the
+        // possible options during content negotiation. Note that Prometheus
+        // 2.5.0+ will negotiate OpenMetrics as first priority. OpenMetrics is
+        // the only way to transmit exemplars. However, the move to OpenMetrics
+        // is not completely transparent. Most notably, the values of "quantile"
+        // labels of Summaries and "le" labels of Histograms are formatted with
+        // a trailing ".0" if they would otherwise look like integer numbers
+        // (which changes the identity of the resulting series on the Prometheus
+        // server).
+        EnableOpenMetrics bool
 }
 
 // gzipAccepted returns whether the client will accept gzip-encoded content.