0c9949b6ec
Particulary helpful to decouple cri-tools from k/k. Signed-off-by: Sascha Grunert <sgrunert@redhat.com>
56 lines
1.3 KiB
Go
56 lines
1.3 KiB
Go
/*
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Copyright 2017 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 tail
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import (
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"io"
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"os"
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)
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const (
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// blockSize is the block size used in tail.
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blockSize = 1024
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)
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// ReadAtMost reads at most max bytes from the end of the file identified by path or
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// returns an error. It returns true if the file was longer than max. It will
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// allocate up to max bytes.
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func ReadAtMost(path string, max int64) ([]byte, bool, error) {
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f, err := os.Open(path)
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if err != nil {
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return nil, false, err
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}
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defer f.Close()
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fi, err := f.Stat()
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if err != nil {
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return nil, false, err
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}
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size := fi.Size()
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if size == 0 {
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return nil, false, nil
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}
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if size < max {
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max = size
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}
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offset, err := f.Seek(-max, io.SeekEnd)
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if err != nil {
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return nil, false, err
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}
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data, err := io.ReadAll(f)
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return data, offset > 0, err
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}
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