From de6d2c524430287c699aaa898c1325da6afea539 Mon Sep 17 00:00:00 2001 From: Niall Sheridan Date: Wed, 20 Jun 2018 22:39:07 +0100 Subject: Update dependencies --- vendor/go.opencensus.io/plugin/ochttp/server.go | 217 ++++++++++++++++++++++++ 1 file changed, 217 insertions(+) create mode 100644 vendor/go.opencensus.io/plugin/ochttp/server.go (limited to 'vendor/go.opencensus.io/plugin/ochttp/server.go') diff --git a/vendor/go.opencensus.io/plugin/ochttp/server.go b/vendor/go.opencensus.io/plugin/ochttp/server.go new file mode 100644 index 0000000..4b3c855 --- /dev/null +++ b/vendor/go.opencensus.io/plugin/ochttp/server.go @@ -0,0 +1,217 @@ +// Copyright 2018, OpenCensus 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 ochttp + +import ( + "bufio" + "context" + "errors" + "net" + "net/http" + "strconv" + "sync" + "time" + + "go.opencensus.io/stats" + "go.opencensus.io/tag" + "go.opencensus.io/trace" + "go.opencensus.io/trace/propagation" +) + +// Handler is a http.Handler that is aware of the incoming request's span. +// +// The extracted span can be accessed from the incoming request's +// context. +// +// span := trace.FromContext(r.Context()) +// +// The server span will be automatically ended at the end of ServeHTTP. +// +// Incoming propagation mechanism is determined by the given HTTP propagators. +type Handler struct { + // Propagation defines how traces are propagated. If unspecified, + // B3 propagation will be used. + Propagation propagation.HTTPFormat + + // Handler is the handler used to handle the incoming request. + Handler http.Handler + + // StartOptions are applied to the span started by this Handler around each + // request. + // + // StartOptions.SpanKind will always be set to trace.SpanKindServer + // for spans started by this transport. + StartOptions trace.StartOptions + + // IsPublicEndpoint should be set to true for publicly accessible HTTP(S) + // servers. If true, any trace metadata set on the incoming request will + // be added as a linked trace instead of being added as a parent of the + // current trace. + IsPublicEndpoint bool +} + +func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) { + var traceEnd, statsEnd func() + r, traceEnd = h.startTrace(w, r) + defer traceEnd() + w, statsEnd = h.startStats(w, r) + defer statsEnd() + handler := h.Handler + if handler == nil { + handler = http.DefaultServeMux + } + handler.ServeHTTP(w, r) +} + +func (h *Handler) startTrace(w http.ResponseWriter, r *http.Request) (*http.Request, func()) { + name := spanNameFromURL(r.URL) + ctx := r.Context() + var span *trace.Span + sc, ok := h.extractSpanContext(r) + if ok && !h.IsPublicEndpoint { + ctx, span = trace.StartSpanWithRemoteParent(ctx, name, sc, + trace.WithSampler(h.StartOptions.Sampler), + trace.WithSpanKind(trace.SpanKindServer)) + } else { + ctx, span = trace.StartSpan(ctx, name, + trace.WithSampler(h.StartOptions.Sampler), + trace.WithSpanKind(trace.SpanKindServer), + ) + if ok { + span.AddLink(trace.Link{ + TraceID: sc.TraceID, + SpanID: sc.SpanID, + Type: trace.LinkTypeChild, + Attributes: nil, + }) + } + } + span.AddAttributes(requestAttrs(r)...) + return r.WithContext(ctx), span.End +} + +func (h *Handler) extractSpanContext(r *http.Request) (trace.SpanContext, bool) { + if h.Propagation == nil { + return defaultFormat.SpanContextFromRequest(r) + } + return h.Propagation.SpanContextFromRequest(r) +} + +func (h *Handler) startStats(w http.ResponseWriter, r *http.Request) (http.ResponseWriter, func()) { + ctx, _ := tag.New(r.Context(), + tag.Upsert(Host, r.URL.Host), + tag.Upsert(Path, r.URL.Path), + tag.Upsert(Method, r.Method)) + track := &trackingResponseWriter{ + start: time.Now(), + ctx: ctx, + writer: w, + } + if r.Body == nil { + // TODO: Handle cases where ContentLength is not set. + track.reqSize = -1 + } else if r.ContentLength > 0 { + track.reqSize = r.ContentLength + } + stats.Record(ctx, ServerRequestCount.M(1)) + return track, track.end +} + +type trackingResponseWriter struct { + ctx context.Context + reqSize int64 + respSize int64 + start time.Time + statusCode int + statusLine string + endOnce sync.Once + writer http.ResponseWriter +} + +// Compile time assertions for widely used net/http interfaces +var _ http.CloseNotifier = (*trackingResponseWriter)(nil) +var _ http.Flusher = (*trackingResponseWriter)(nil) +var _ http.Hijacker = (*trackingResponseWriter)(nil) +var _ http.Pusher = (*trackingResponseWriter)(nil) +var _ http.ResponseWriter = (*trackingResponseWriter)(nil) + +var errHijackerUnimplemented = errors.New("ResponseWriter does not implement http.Hijacker") + +func (t *trackingResponseWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) { + hj, ok := t.writer.(http.Hijacker) + if !ok { + return nil, nil, errHijackerUnimplemented + } + return hj.Hijack() +} + +func (t *trackingResponseWriter) CloseNotify() <-chan bool { + cn, ok := t.writer.(http.CloseNotifier) + if !ok { + return nil + } + return cn.CloseNotify() +} + +func (t *trackingResponseWriter) Push(target string, opts *http.PushOptions) error { + pusher, ok := t.writer.(http.Pusher) + if !ok { + return http.ErrNotSupported + } + return pusher.Push(target, opts) +} + +func (t *trackingResponseWriter) end() { + t.endOnce.Do(func() { + if t.statusCode == 0 { + t.statusCode = 200 + } + + span := trace.FromContext(t.ctx) + span.SetStatus(TraceStatus(t.statusCode, t.statusLine)) + + m := []stats.Measurement{ + ServerLatency.M(float64(time.Since(t.start)) / float64(time.Millisecond)), + ServerResponseBytes.M(t.respSize), + } + if t.reqSize >= 0 { + m = append(m, ServerRequestBytes.M(t.reqSize)) + } + ctx, _ := tag.New(t.ctx, tag.Upsert(StatusCode, strconv.Itoa(t.statusCode))) + stats.Record(ctx, m...) + }) +} + +func (t *trackingResponseWriter) Header() http.Header { + return t.writer.Header() +} + +func (t *trackingResponseWriter) Write(data []byte) (int, error) { + n, err := t.writer.Write(data) + t.respSize += int64(n) + return n, err +} + +func (t *trackingResponseWriter) WriteHeader(statusCode int) { + t.writer.WriteHeader(statusCode) + t.statusCode = statusCode + t.statusLine = http.StatusText(t.statusCode) +} + +func (t *trackingResponseWriter) Flush() { + if flusher, ok := t.writer.(http.Flusher); ok { + flusher.Flush() + } +} -- cgit v1.2.3