mirror of
https://github.com/ceph/ceph-csi.git
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134 lines
3.6 KiB
Go
134 lines
3.6 KiB
Go
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/*
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Copyright 2020 The Kubernetes Authors.
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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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http://www.apache.org/licenses/LICENSE-2.0
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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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*/
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package filters
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import (
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"fmt"
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"net/http"
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"sync"
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"unicode/utf8"
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"k8s.io/apimachinery/pkg/util/net"
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utilruntime "k8s.io/apimachinery/pkg/util/runtime"
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"k8s.io/apiserver/pkg/warning"
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)
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// WithWarningRecorder attaches a deduplicating k8s.io/apiserver/pkg/warning#WarningRecorder to the request context.
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func WithWarningRecorder(handler http.Handler) http.Handler {
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return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
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recorder := &recorder{writer: w}
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req = req.WithContext(warning.WithWarningRecorder(req.Context(), recorder))
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handler.ServeHTTP(w, req)
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})
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}
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var (
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truncateAtTotalRunes = 4 * 1024
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truncateItemRunes = 256
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)
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type recordedWarning struct {
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agent string
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text string
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}
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type recorder struct {
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// lock guards calls to AddWarning from multiple threads
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lock sync.Mutex
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// recorded tracks whether AddWarning was already called with a given text
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recorded map[string]bool
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// ordered tracks warnings added so they can be replayed and truncated if needed
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ordered []recordedWarning
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// written tracks how many runes of text have been added as warning headers
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written int
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// truncating tracks if we have already exceeded truncateAtTotalRunes and are now truncating warning messages as we add them
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truncating bool
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// writer is the response writer to add warning headers to
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writer http.ResponseWriter
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}
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func (r *recorder) AddWarning(agent, text string) {
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if len(text) == 0 {
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return
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}
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r.lock.Lock()
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defer r.lock.Unlock()
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// if we've already exceeded our limit and are already truncating, return early
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if r.written >= truncateAtTotalRunes && r.truncating {
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return
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}
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// init if needed
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if r.recorded == nil {
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r.recorded = map[string]bool{}
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}
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// dedupe if already warned
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if r.recorded[text] {
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return
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}
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r.recorded[text] = true
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r.ordered = append(r.ordered, recordedWarning{agent: agent, text: text})
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// truncate on a rune boundary, if needed
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textRuneLength := utf8.RuneCountInString(text)
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if r.truncating && textRuneLength > truncateItemRunes {
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text = string([]rune(text)[:truncateItemRunes])
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textRuneLength = truncateItemRunes
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}
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// compute the header
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header, err := net.NewWarningHeader(299, agent, text)
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if err != nil {
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return
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}
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// if this fits within our limit, or we're already truncating, write and return
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if r.written+textRuneLength <= truncateAtTotalRunes || r.truncating {
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r.written += textRuneLength
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r.writer.Header().Add("Warning", header)
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return
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}
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// otherwise, enable truncation, reset, and replay the existing items as truncated warnings
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r.truncating = true
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r.written = 0
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r.writer.Header().Del("Warning")
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utilruntime.HandleError(fmt.Errorf("exceeded max warning header size, truncating"))
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for _, w := range r.ordered {
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agent := w.agent
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text := w.text
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textRuneLength := utf8.RuneCountInString(text)
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if textRuneLength > truncateItemRunes {
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text = string([]rune(text)[:truncateItemRunes])
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textRuneLength = truncateItemRunes
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}
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if header, err := net.NewWarningHeader(299, agent, text); err == nil {
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r.written += textRuneLength
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r.writer.Header().Add("Warning", header)
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}
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}
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}
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