Merge pull request #172 from prometheus/move-to-common

Move from client_golang/text to common/expfmt

prometheus/registry.go

@@ -33,12 +33,10 @@ import (
 	"strings"
 	"sync"
 
-	"bitbucket.org/ww/goautoneg"
 	"github.com/golang/protobuf/proto"
+	"github.com/prometheus/common/expfmt"
 
 	dto "github.com/prometheus/client_model/go"
-
-	"github.com/prometheus/client_golang/text"
 )
 
 var (
@@ -345,7 +343,7 @@ func (r *registry) Push(job, instance, pushURL, method string) error {
 	}
 	buf := r.getBuf()
 	defer r.giveBuf(buf)
-	if _, err := r.writePB(buf, text.WriteProtoDelimited); err != nil {
+	if err := r.writePB(expfmt.NewEncoder(buf, expfmt.FmtProtoDelim)); err != nil {
 		if r.panicOnCollectError {
 			panic(err)
 		}
@@ -368,11 +366,11 @@ func (r *registry) Push(job, instance, pushURL, method string) error {
 }
 
 func (r *registry) ServeHTTP(w http.ResponseWriter, req *http.Request) {
-	enc, contentType := chooseEncoder(req)
+	contentType := expfmt.Negotiate(req.Header)
 	buf := r.getBuf()
 	defer r.giveBuf(buf)
 	writer, encoding := decorateWriter(req, buf)
-	if _, err := r.writePB(writer, enc); err != nil {
+	if err := r.writePB(expfmt.NewEncoder(writer, contentType)); err != nil {
 		if r.panicOnCollectError {
 			panic(err)
 		}
@@ -383,7 +381,7 @@ func (r *registry) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 		closer.Close()
 	}
 	header := w.Header()
-	header.Set(contentTypeHeader, contentType)
+	header.Set(contentTypeHeader, string(contentType))
 	header.Set(contentLengthHeader, fmt.Sprint(buf.Len()))
 	if encoding != "" {
 		header.Set(contentEncodingHeader, encoding)
@@ -391,7 +389,7 @@ func (r *registry) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 	w.Write(buf.Bytes())
 }
 
-func (r *registry) writePB(w io.Writer, writeEncoded encoder) (int, error) {
+func (r *registry) writePB(encoder expfmt.Encoder) error {
 	var metricHashes map[uint64]struct{}
 	if r.collectChecksEnabled {
 		metricHashes = make(map[uint64]struct{})
@@ -443,7 +441,7 @@ func (r *registry) writePB(w io.Writer, writeEncoded encoder) (int, error) {
 			// TODO: Consider different means of error reporting so
 			// that a single erroneous metric could be skipped
 			// instead of blowing up the whole collection.
-			return 0, fmt.Errorf("error collecting metric %v: %s", desc, err)
+			return fmt.Errorf("error collecting metric %v: %s", desc, err)
 		}
 		switch {
 		case metricFamily.Type != nil:
@@ -459,11 +457,11 @@ func (r *registry) writePB(w io.Writer, writeEncoded encoder) (int, error) {
 		case dtoMetric.Histogram != nil:
 			metricFamily.Type = dto.MetricType_HISTOGRAM.Enum()
 		default:
-			return 0, fmt.Errorf("empty metric collected: %s", dtoMetric)
+			return fmt.Errorf("empty metric collected: %s", dtoMetric)
 		}
 		if r.collectChecksEnabled {
 			if err := r.checkConsistency(metricFamily, dtoMetric, desc, metricHashes); err != nil {
-				return 0, err
+				return err
 			}
 		}
 		metricFamily.Metric = append(metricFamily.Metric, dtoMetric)
@@ -477,7 +475,7 @@ func (r *registry) writePB(w io.Writer, writeEncoded encoder) (int, error) {
 				if r.collectChecksEnabled {
 					for _, m := range mf.Metric {
 						if err := r.checkConsistency(mf, m, nil, metricHashes); err != nil {
-							return 0, err
+							return err
 						}
 					}
 				}
@@ -486,7 +484,7 @@ func (r *registry) writePB(w io.Writer, writeEncoded encoder) (int, error) {
 			for _, m := range mf.Metric {
 				if r.collectChecksEnabled {
 					if err := r.checkConsistency(existingMF, m, nil, metricHashes); err != nil {
-						return 0, err
+						return err
 					}
 				}
 				existingMF.Metric = append(existingMF.Metric, m)
@@ -507,15 +505,12 @@ func (r *registry) writePB(w io.Writer, writeEncoded encoder) (int, error) {
 	}
 	sort.Strings(names)
 
-	var written int
 	for _, name := range names {
-		w, err := writeEncoded(w, metricFamiliesByName[name])
-		written += w
-		if err != nil {
-			return written, err
+		if err := encoder.Encode(metricFamiliesByName[name]); err != nil {
+			return err
 		}
 	}
-	return written, nil
+	return nil
 }
 
 func (r *registry) checkConsistency(metricFamily *dto.MetricFamily, dtoMetric *dto.Metric, desc *Desc, metricHashes map[uint64]struct{}) error {
@@ -685,34 +680,6 @@ func newDefaultRegistry() *registry {
 	return r
 }
 
-func chooseEncoder(req *http.Request) (encoder, string) {
-	accepts := goautoneg.ParseAccept(req.Header.Get(acceptHeader))
-	for _, accept := range accepts {
-		switch {
-		case accept.Type == "application" &&
-			accept.SubType == "vnd.google.protobuf" &&
-			accept.Params["proto"] == "io.prometheus.client.MetricFamily":
-			switch accept.Params["encoding"] {
-			case "delimited":
-				return text.WriteProtoDelimited, DelimitedTelemetryContentType
-			case "text":
-				return text.WriteProtoText, ProtoTextTelemetryContentType
-			case "compact-text":
-				return text.WriteProtoCompactText, ProtoCompactTextTelemetryContentType
-			default:
-				continue
-			}
-		case accept.Type == "text" &&
-			accept.SubType == "plain" &&
-			(accept.Params["version"] == "0.0.4" || accept.Params["version"] == ""):
-			return text.MetricFamilyToText, TextTelemetryContentType
-		default:
-			continue
-		}
-	}
-	return text.MetricFamilyToText, TextTelemetryContentType
-}
-
 // decorateWriter wraps a writer to handle gzip compression if requested.  It
 // returns the decorated writer and the appropriate "Content-Encoding" header
 // (which is empty if no compression is enabled).