106 lines
2.6 KiB
Go
106 lines
2.6 KiB
Go
// Copyright 2015 clair authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// Package logic implements all the available API methods.
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// Every methods are documented in docs/API.md.
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package wrappers
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import (
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"errors"
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"fmt"
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"net/http"
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"sync"
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"time"
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"github.com/coreos/clair/api/jsonhttp"
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"github.com/julienschmidt/httprouter"
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)
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// ErrHandlerTimeout is returned on ResponseWriter Write calls
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// in handlers which have timed out.
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var ErrHandlerTimeout = errors.New("http: Handler timeout")
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type timeoutWriter struct {
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http.ResponseWriter
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mu sync.Mutex
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timedOut bool
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wroteHeader bool
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}
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func (tw *timeoutWriter) Header() http.Header {
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return tw.ResponseWriter.Header()
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}
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func (tw *timeoutWriter) Write(p []byte) (int, error) {
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tw.mu.Lock()
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defer tw.mu.Unlock()
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tw.wroteHeader = true // implicitly at least
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if tw.timedOut {
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return 0, ErrHandlerTimeout
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}
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return tw.ResponseWriter.Write(p)
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}
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func (tw *timeoutWriter) WriteHeader(status int) {
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tw.mu.Lock()
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defer tw.mu.Unlock()
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if tw.timedOut || tw.wroteHeader {
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return
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}
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tw.wroteHeader = true
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tw.ResponseWriter.WriteHeader(status)
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}
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// TimeOut wraps a http.HandlerFunc and ensure that a response is given under
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// the specified duration.
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//
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// If the handler takes longer than the time limit, the wrapper responds with
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// a Service Unavailable error, an error message and the handler response which
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// may come later is ignored.
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//
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// After a timeout, any write the handler to its ResponseWriter will return
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// ErrHandlerTimeout.
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//
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// If the duration is 0, the wrapper does nothing.
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func TimeOut(d time.Duration, fn httprouter.Handle) httprouter.Handle {
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if d == 0 {
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fmt.Println("nope timeout")
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return fn
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}
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return func(w http.ResponseWriter, r *http.Request, p httprouter.Params) {
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done := make(chan bool)
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tw := &timeoutWriter{ResponseWriter: w}
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go func() {
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fn(tw, r, p)
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done <- true
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}()
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select {
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case <-done:
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return
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case <-time.After(d):
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tw.mu.Lock()
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defer tw.mu.Unlock()
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if !tw.wroteHeader {
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jsonhttp.RenderError(tw.ResponseWriter, http.StatusServiceUnavailable, ErrHandlerTimeout)
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}
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tw.timedOut = true
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}
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}
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}
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