From ed8bc523fd0d1a66acf3fa449c453508035efdfc Mon Sep 17 00:00:00 2001
From: Kevin Lyda <kevin@ie.suberic.net>
Date: Sun, 12 Feb 2017 14:38:12 +0000
Subject: Initial pass at prometheus support. (#56)

---
 .../github.com/prometheus/common/expfmt/encode.go  | 88 ++++++++++++++++++++++
 1 file changed, 88 insertions(+)
 create mode 100644 vendor/github.com/prometheus/common/expfmt/encode.go

(limited to 'vendor/github.com/prometheus/common/expfmt/encode.go')

diff --git a/vendor/github.com/prometheus/common/expfmt/encode.go b/vendor/github.com/prometheus/common/expfmt/encode.go
new file mode 100644
index 0000000..11839ed
--- /dev/null
+++ b/vendor/github.com/prometheus/common/expfmt/encode.go
@@ -0,0 +1,88 @@
+// Copyright 2015 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package expfmt
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+
+	"github.com/golang/protobuf/proto"
+	"github.com/matttproud/golang_protobuf_extensions/pbutil"
+	"github.com/prometheus/common/internal/bitbucket.org/ww/goautoneg"
+
+	dto "github.com/prometheus/client_model/go"
+)
+
+// Encoder types encode metric families into an underlying wire protocol.
+type Encoder interface {
+	Encode(*dto.MetricFamily) error
+}
+
+type encoder func(*dto.MetricFamily) error
+
+func (e encoder) Encode(v *dto.MetricFamily) error {
+	return e(v)
+}
+
+// Negotiate returns the Content-Type based on the given Accept header.
+// If no appropriate accepted type is found, FmtText is returned.
+func Negotiate(h http.Header) Format {
+	for _, ac := range goautoneg.ParseAccept(h.Get(hdrAccept)) {
+		// Check for protocol buffer
+		if ac.Type+"/"+ac.SubType == ProtoType && ac.Params["proto"] == ProtoProtocol {
+			switch ac.Params["encoding"] {
+			case "delimited":
+				return FmtProtoDelim
+			case "text":
+				return FmtProtoText
+			case "compact-text":
+				return FmtProtoCompact
+			}
+		}
+		// Check for text format.
+		ver := ac.Params["version"]
+		if ac.Type == "text" && ac.SubType == "plain" && (ver == TextVersion || ver == "") {
+			return FmtText
+		}
+	}
+	return FmtText
+}
+
+// NewEncoder returns a new encoder based on content type negotiation.
+func NewEncoder(w io.Writer, format Format) Encoder {
+	switch format {
+	case FmtProtoDelim:
+		return encoder(func(v *dto.MetricFamily) error {
+			_, err := pbutil.WriteDelimited(w, v)
+			return err
+		})
+	case FmtProtoCompact:
+		return encoder(func(v *dto.MetricFamily) error {
+			_, err := fmt.Fprintln(w, v.String())
+			return err
+		})
+	case FmtProtoText:
+		return encoder(func(v *dto.MetricFamily) error {
+			_, err := fmt.Fprintln(w, proto.MarshalTextString(v))
+			return err
+		})
+	case FmtText:
+		return encoder(func(v *dto.MetricFamily) error {
+			_, err := MetricFamilyToText(w, v)
+			return err
+		})
+	}
+	panic("expfmt.NewEncoder: unknown format")
+}
-- 
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