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author | Corey Hulen <corey@hulen.com> | 2016-11-22 11:05:54 -0800 |
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committer | Harrison Healey <harrisonmhealey@gmail.com> | 2016-11-22 14:05:54 -0500 |
commit | 7961599b2e41c71720a42b3bfde641f7529f05fe (patch) | |
tree | 3c039e1d3790a954ba65fe551c7b348331bce994 /vendor/github.com/prometheus/client_golang/prometheus/http.go | |
parent | e033dcce8e57ed6b6684227adf9b29347e4718b3 (diff) | |
download | chat-7961599b2e41c71720a42b3bfde641f7529f05fe.tar.gz chat-7961599b2e41c71720a42b3bfde641f7529f05fe.tar.bz2 chat-7961599b2e41c71720a42b3bfde641f7529f05fe.zip |
PLT-4357 adding performance monitoring (#4622)
* WIP
* WIP
* Adding metrics collection
* updating vendor packages
* Adding metrics to config
* Adding admin console page for perf monitoring
* Updating glide
* switching to tylerb/graceful
Diffstat (limited to 'vendor/github.com/prometheus/client_golang/prometheus/http.go')
-rw-r--r-- | vendor/github.com/prometheus/client_golang/prometheus/http.go | 490 |
1 files changed, 490 insertions, 0 deletions
diff --git a/vendor/github.com/prometheus/client_golang/prometheus/http.go b/vendor/github.com/prometheus/client_golang/prometheus/http.go new file mode 100644 index 000000000..67ee5ac79 --- /dev/null +++ b/vendor/github.com/prometheus/client_golang/prometheus/http.go @@ -0,0 +1,490 @@ +// Copyright 2014 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 prometheus + +import ( + "bufio" + "bytes" + "compress/gzip" + "fmt" + "io" + "net" + "net/http" + "strconv" + "strings" + "sync" + "time" + + "github.com/prometheus/common/expfmt" +) + +// TODO(beorn7): Remove this whole file. It is a partial mirror of +// promhttp/http.go (to avoid circular import chains) where everything HTTP +// related should live. The functions here are just for avoiding +// breakage. Everything is deprecated. + +const ( + contentTypeHeader = "Content-Type" + contentLengthHeader = "Content-Length" + contentEncodingHeader = "Content-Encoding" + acceptEncodingHeader = "Accept-Encoding" +) + +var bufPool sync.Pool + +func getBuf() *bytes.Buffer { + buf := bufPool.Get() + if buf == nil { + return &bytes.Buffer{} + } + return buf.(*bytes.Buffer) +} + +func giveBuf(buf *bytes.Buffer) { + buf.Reset() + bufPool.Put(buf) +} + +// Handler returns an HTTP handler for the DefaultGatherer. It is +// already instrumented with InstrumentHandler (using "prometheus" as handler +// name). +// +// Deprecated: Please note the issues described in the doc comment of +// InstrumentHandler. You might want to consider using promhttp.Handler instead +// (which is non instrumented). +func Handler() http.Handler { + return InstrumentHandler("prometheus", UninstrumentedHandler()) +} + +// UninstrumentedHandler returns an HTTP handler for the DefaultGatherer. +// +// Deprecated: Use promhttp.Handler instead. See there for further documentation. +func UninstrumentedHandler() http.Handler { + return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) { + mfs, err := DefaultGatherer.Gather() + if err != nil { + http.Error(w, "An error has occurred during metrics collection:\n\n"+err.Error(), http.StatusInternalServerError) + return + } + + contentType := expfmt.Negotiate(req.Header) + buf := getBuf() + defer giveBuf(buf) + writer, encoding := decorateWriter(req, buf) + enc := expfmt.NewEncoder(writer, contentType) + var lastErr error + for _, mf := range mfs { + if err := enc.Encode(mf); err != nil { + lastErr = err + http.Error(w, "An error has occurred during metrics encoding:\n\n"+err.Error(), http.StatusInternalServerError) + return + } + } + if closer, ok := writer.(io.Closer); ok { + closer.Close() + } + if lastErr != nil && buf.Len() == 0 { + http.Error(w, "No metrics encoded, last error:\n\n"+err.Error(), http.StatusInternalServerError) + return + } + header := w.Header() + header.Set(contentTypeHeader, string(contentType)) + header.Set(contentLengthHeader, fmt.Sprint(buf.Len())) + if encoding != "" { + header.Set(contentEncodingHeader, encoding) + } + w.Write(buf.Bytes()) + }) +} + +// 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). +func decorateWriter(request *http.Request, writer io.Writer) (io.Writer, string) { + header := request.Header.Get(acceptEncodingHeader) + parts := strings.Split(header, ",") + for _, part := range parts { + part := strings.TrimSpace(part) + if part == "gzip" || strings.HasPrefix(part, "gzip;") { + return gzip.NewWriter(writer), "gzip" + } + } + return writer, "" +} + +var instLabels = []string{"method", "code"} + +type nower interface { + Now() time.Time +} + +type nowFunc func() time.Time + +func (n nowFunc) Now() time.Time { + return n() +} + +var now nower = nowFunc(func() time.Time { + return time.Now() +}) + +func nowSeries(t ...time.Time) nower { + return nowFunc(func() time.Time { + defer func() { + t = t[1:] + }() + + return t[0] + }) +} + +// InstrumentHandler wraps the given HTTP handler for instrumentation. It +// registers four metric collectors (if not already done) and reports HTTP +// metrics to the (newly or already) registered collectors: http_requests_total +// (CounterVec), http_request_duration_microseconds (Summary), +// http_request_size_bytes (Summary), http_response_size_bytes (Summary). Each +// has a constant label named "handler" with the provided handlerName as +// value. http_requests_total is a metric vector partitioned by HTTP method +// (label name "method") and HTTP status code (label name "code"). +// +// Deprecated: InstrumentHandler has several issues: +// +// - It uses Summaries rather than Histograms. Summaries are not useful if +// aggregation across multiple instances is required. +// +// - It uses microseconds as unit, which is deprecated and should be replaced by +// seconds. +// +// - The size of the request is calculated in a separate goroutine. Since this +// calculator requires access to the request header, it creates a race with +// any writes to the header performed during request handling. +// httputil.ReverseProxy is a prominent example for a handler +// performing such writes. +// +// Upcoming versions of this package will provide ways of instrumenting HTTP +// handlers that are more flexible and have fewer issues. Please prefer direct +// instrumentation in the meantime. +func InstrumentHandler(handlerName string, handler http.Handler) http.HandlerFunc { + return InstrumentHandlerFunc(handlerName, handler.ServeHTTP) +} + +// InstrumentHandlerFunc wraps the given function for instrumentation. It +// otherwise works in the same way as InstrumentHandler (and shares the same +// issues). +// +// Deprecated: InstrumentHandlerFunc is deprecated for the same reasons as +// InstrumentHandler is. +func InstrumentHandlerFunc(handlerName string, handlerFunc func(http.ResponseWriter, *http.Request)) http.HandlerFunc { + return InstrumentHandlerFuncWithOpts( + SummaryOpts{ + Subsystem: "http", + ConstLabels: Labels{"handler": handlerName}, + }, + handlerFunc, + ) +} + +// InstrumentHandlerWithOpts works like InstrumentHandler (and shares the same +// issues) but provides more flexibility (at the cost of a more complex call +// syntax). As InstrumentHandler, this function registers four metric +// collectors, but it uses the provided SummaryOpts to create them. However, the +// fields "Name" and "Help" in the SummaryOpts are ignored. "Name" is replaced +// by "requests_total", "request_duration_microseconds", "request_size_bytes", +// and "response_size_bytes", respectively. "Help" is replaced by an appropriate +// help string. The names of the variable labels of the http_requests_total +// CounterVec are "method" (get, post, etc.), and "code" (HTTP status code). +// +// If InstrumentHandlerWithOpts is called as follows, it mimics exactly the +// behavior of InstrumentHandler: +// +// prometheus.InstrumentHandlerWithOpts( +// prometheus.SummaryOpts{ +// Subsystem: "http", +// ConstLabels: prometheus.Labels{"handler": handlerName}, +// }, +// handler, +// ) +// +// Technical detail: "requests_total" is a CounterVec, not a SummaryVec, so it +// cannot use SummaryOpts. Instead, a CounterOpts struct is created internally, +// and all its fields are set to the equally named fields in the provided +// SummaryOpts. +// +// Deprecated: InstrumentHandlerWithOpts is deprecated for the same reasons as +// InstrumentHandler is. +func InstrumentHandlerWithOpts(opts SummaryOpts, handler http.Handler) http.HandlerFunc { + return InstrumentHandlerFuncWithOpts(opts, handler.ServeHTTP) +} + +// InstrumentHandlerFuncWithOpts works like InstrumentHandlerFunc (and shares +// the same issues) but provides more flexibility (at the cost of a more complex +// call syntax). See InstrumentHandlerWithOpts for details how the provided +// SummaryOpts are used. +// +// Deprecated: InstrumentHandlerFuncWithOpts is deprecated for the same reasons +// as InstrumentHandler is. +func InstrumentHandlerFuncWithOpts(opts SummaryOpts, handlerFunc func(http.ResponseWriter, *http.Request)) http.HandlerFunc { + reqCnt := NewCounterVec( + CounterOpts{ + Namespace: opts.Namespace, + Subsystem: opts.Subsystem, + Name: "requests_total", + Help: "Total number of HTTP requests made.", + ConstLabels: opts.ConstLabels, + }, + instLabels, + ) + + opts.Name = "request_duration_microseconds" + opts.Help = "The HTTP request latencies in microseconds." + reqDur := NewSummary(opts) + + opts.Name = "request_size_bytes" + opts.Help = "The HTTP request sizes in bytes." + reqSz := NewSummary(opts) + + opts.Name = "response_size_bytes" + opts.Help = "The HTTP response sizes in bytes." + resSz := NewSummary(opts) + + regReqCnt := MustRegisterOrGet(reqCnt).(*CounterVec) + regReqDur := MustRegisterOrGet(reqDur).(Summary) + regReqSz := MustRegisterOrGet(reqSz).(Summary) + regResSz := MustRegisterOrGet(resSz).(Summary) + + return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { + now := time.Now() + + delegate := &responseWriterDelegator{ResponseWriter: w} + out := make(chan int) + urlLen := 0 + if r.URL != nil { + urlLen = len(r.URL.String()) + } + go computeApproximateRequestSize(r, out, urlLen) + + _, cn := w.(http.CloseNotifier) + _, fl := w.(http.Flusher) + _, hj := w.(http.Hijacker) + _, rf := w.(io.ReaderFrom) + var rw http.ResponseWriter + if cn && fl && hj && rf { + rw = &fancyResponseWriterDelegator{delegate} + } else { + rw = delegate + } + handlerFunc(rw, r) + + elapsed := float64(time.Since(now)) / float64(time.Microsecond) + + method := sanitizeMethod(r.Method) + code := sanitizeCode(delegate.status) + regReqCnt.WithLabelValues(method, code).Inc() + regReqDur.Observe(elapsed) + regResSz.Observe(float64(delegate.written)) + regReqSz.Observe(float64(<-out)) + }) +} + +func computeApproximateRequestSize(r *http.Request, out chan int, s int) { + s += len(r.Method) + s += len(r.Proto) + for name, values := range r.Header { + s += len(name) + for _, value := range values { + s += len(value) + } + } + s += len(r.Host) + + // N.B. r.Form and r.MultipartForm are assumed to be included in r.URL. + + if r.ContentLength != -1 { + s += int(r.ContentLength) + } + out <- s +} + +type responseWriterDelegator struct { + http.ResponseWriter + + handler, method string + status int + written int64 + wroteHeader bool +} + +func (r *responseWriterDelegator) WriteHeader(code int) { + r.status = code + r.wroteHeader = true + r.ResponseWriter.WriteHeader(code) +} + +func (r *responseWriterDelegator) Write(b []byte) (int, error) { + if !r.wroteHeader { + r.WriteHeader(http.StatusOK) + } + n, err := r.ResponseWriter.Write(b) + r.written += int64(n) + return n, err +} + +type fancyResponseWriterDelegator struct { + *responseWriterDelegator +} + +func (f *fancyResponseWriterDelegator) CloseNotify() <-chan bool { + return f.ResponseWriter.(http.CloseNotifier).CloseNotify() +} + +func (f *fancyResponseWriterDelegator) Flush() { + f.ResponseWriter.(http.Flusher).Flush() +} + +func (f *fancyResponseWriterDelegator) Hijack() (net.Conn, *bufio.ReadWriter, error) { + return f.ResponseWriter.(http.Hijacker).Hijack() +} + +func (f *fancyResponseWriterDelegator) ReadFrom(r io.Reader) (int64, error) { + if !f.wroteHeader { + f.WriteHeader(http.StatusOK) + } + n, err := f.ResponseWriter.(io.ReaderFrom).ReadFrom(r) + f.written += n + return n, err +} + +func sanitizeMethod(m string) string { + switch m { + case "GET", "get": + return "get" + case "PUT", "put": + return "put" + case "HEAD", "head": + return "head" + case "POST", "post": + return "post" + case "DELETE", "delete": + return "delete" + case "CONNECT", "connect": + return "connect" + case "OPTIONS", "options": + return "options" + case "NOTIFY", "notify": + return "notify" + default: + return strings.ToLower(m) + } +} + +func sanitizeCode(s int) string { + switch s { + case 100: + return "100" + case 101: + return "101" + + case 200: + return "200" + case 201: + return "201" + case 202: + return "202" + case 203: + return "203" + case 204: + return "204" + case 205: + return "205" + case 206: + return "206" + + case 300: + return "300" + case 301: + return "301" + case 302: + return "302" + case 304: + return "304" + case 305: + return "305" + case 307: + return "307" + + case 400: + return "400" + case 401: + return "401" + case 402: + return "402" + case 403: + return "403" + case 404: + return "404" + case 405: + return "405" + case 406: + return "406" + case 407: + return "407" + case 408: + return "408" + case 409: + return "409" + case 410: + return "410" + case 411: + return "411" + case 412: + return "412" + case 413: + return "413" + case 414: + return "414" + case 415: + return "415" + case 416: + return "416" + case 417: + return "417" + case 418: + return "418" + + case 500: + return "500" + case 501: + return "501" + case 502: + return "502" + case 503: + return "503" + case 504: + return "504" + case 505: + return "505" + + case 428: + return "428" + case 429: + return "429" + case 431: + return "431" + case 511: + return "511" + + default: + return strconv.Itoa(s) + } +} |