74 lines
1.7 KiB
Go
74 lines
1.7 KiB
Go
/*
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Copyright 2016 The Kubernetes Authors All rights reserved.
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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 util
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import (
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"fmt"
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"io"
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"os"
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"time"
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)
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// Until endlessly loops the provided function until a message is received on the done channel.
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// The function will wait the duration provided in sleep between function calls. Errors will be sent on provider Writer.
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func Until(fn func() error, w io.Writer, name string, sleep time.Duration, done <-chan struct{}) {
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var exitErr error
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for {
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select {
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case <-done:
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return
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default:
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exitErr = fn()
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if exitErr == nil {
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fmt.Fprintf(w, Pad("%s: Exited with no errors.\n"), name)
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} else {
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fmt.Fprintf(w, Pad("%s: Exit with error: %v"), name, exitErr)
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}
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// wait provided duration before trying again
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time.Sleep(sleep)
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}
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}
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}
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func Pad(str string) string {
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return fmt.Sprint("\n%s\n", str)
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}
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// If the file represented by path exists and
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// readable, return true otherwise return false.
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func CanReadFile(path string) bool {
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f, err := os.Open(path)
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if err != nil {
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return false
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}
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defer f.Close()
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return true
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}
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func Retry(attempts int, callback func() error) (err error) {
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for i := 0; i < attempts; i++ {
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err = callback()
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if err == nil {
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return nil
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}
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}
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return err
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}
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