telegraf/plugins/inputs/zipkin/handler.go

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package zipkin
import (
"compress/gzip"
"fmt"
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"io/ioutil"
"mime"
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"net/http"
"strings"
"github.com/gorilla/mux"
"github.com/influxdata/telegraf/plugins/inputs/zipkin/codec"
"github.com/influxdata/telegraf/plugins/inputs/zipkin/codec/jsonV1"
"github.com/influxdata/telegraf/plugins/inputs/zipkin/codec/thrift"
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)
// SpanHandler is an implementation of a Handler which accepts zipkin thrift
// span data and sends it to the recorder
type SpanHandler struct {
Path string
recorder Recorder
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}
// NewSpanHandler returns a new server instance given path to handle
func NewSpanHandler(path string) *SpanHandler {
return &SpanHandler{
Path: path,
}
}
func cors(next http.HandlerFunc) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
if origin := r.Header.Get("Origin"); origin != "" {
w.Header().Set(`Access-Control-Allow-Origin`, origin)
w.Header().Set(`Access-Control-Allow-Methods`, strings.Join([]string{
`OPTIONS`,
`POST`,
}, ", "))
w.Header().Set(`Access-Control-Allow-Headers`, strings.Join([]string{
`Accept`,
`Accept-Encoding`,
`Content-Length`,
`Content-Type`,
}, ", "))
w.Header().Set(`Access-Control-Expose-Headers`, strings.Join([]string{
`Date`,
}, ", "))
}
if r.Method == "OPTIONS" {
return
}
next.ServeHTTP(w, r)
}
}
// Register implements the Service interface. Register accepts zipkin thrift data
// POSTed to the path of the mux router
func (s *SpanHandler) Register(router *mux.Router, recorder Recorder) error {
handler := cors(http.HandlerFunc(s.Spans))
router.Handle(s.Path, handler).Methods("POST", "OPTIONS")
s.recorder = recorder
return nil
}
// Spans handles zipkin thrift spans
func (s *SpanHandler) Spans(w http.ResponseWriter, r *http.Request) {
defer r.Body.Close()
body := r.Body
var err error
// Handle gzip decoding of the body
if r.Header.Get("Content-Encoding") == "gzip" {
body, err = gzip.NewReader(r.Body)
if err != nil {
s.recorder.Error(err)
w.WriteHeader(http.StatusInternalServerError)
return
}
defer body.Close()
}
decoder, err := ContentDecoder(r)
if err != nil {
s.recorder.Error(err)
w.WriteHeader(http.StatusUnsupportedMediaType)
}
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octets, err := ioutil.ReadAll(body)
if err != nil {
s.recorder.Error(err)
w.WriteHeader(http.StatusInternalServerError)
return
}
spans, err := decoder.Decode(octets)
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if err != nil {
s.recorder.Error(err)
w.WriteHeader(http.StatusBadRequest)
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return
}
trace, err := codec.NewTrace(spans)
if err != nil {
s.recorder.Error(err)
w.WriteHeader(http.StatusBadRequest)
return
}
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if err = s.recorder.Record(trace); err != nil {
s.recorder.Error(err)
w.WriteHeader(http.StatusInternalServerError)
return
}
w.WriteHeader(http.StatusNoContent)
}
// ContentDecoer returns a Decoder that is able to produce Traces from bytes.
// Failure should yield an HTTP 415 (`http.StatusUnsupportedMediaType`)
// If a Content-Type is not set, zipkin assumes application/json
func ContentDecoder(r *http.Request) (codec.Decoder, error) {
contentType := r.Header.Get("Content-Type")
if contentType == "" {
return &jsonV1.JSON{}, nil
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}
for _, v := range strings.Split(contentType, ",") {
t, _, err := mime.ParseMediaType(v)
if err != nil {
break
}
if t == "application/json" {
return &jsonV1.JSON{}, nil
} else if t == "application/x-thrift" {
return &thrift.Thrift{}, nil
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}
}
return nil, fmt.Errorf("Unknown Content-Type: %s", contentType)
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}