85 lines
2.0 KiB
Go
85 lines
2.0 KiB
Go
package resource
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import (
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"sync"
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"time"
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)
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// Retry is a basic wrapper around StateChangeConf that will just retry
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// a function until it no longer returns an error.
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func Retry(timeout time.Duration, f RetryFunc) error {
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// These are used to pull the error out of the function; need a mutex to
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// avoid a data race.
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var resultErr error
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var resultErrMu sync.Mutex
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c := &StateChangeConf{
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Pending: []string{"retryableerror"},
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Target: []string{"success"},
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Timeout: timeout,
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MinTimeout: 500 * time.Millisecond,
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Refresh: func() (interface{}, string, error) {
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rerr := f()
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resultErrMu.Lock()
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defer resultErrMu.Unlock()
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if rerr == nil {
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resultErr = nil
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return 42, "success", nil
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}
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resultErr = rerr.Err
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if rerr.Retryable {
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return 42, "retryableerror", nil
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}
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return nil, "quit", rerr.Err
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},
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}
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_, waitErr := c.WaitForState()
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// Need to acquire the lock here to be able to avoid race using resultErr as
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// the return value
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resultErrMu.Lock()
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defer resultErrMu.Unlock()
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// resultErr may be nil because the wait timed out and resultErr was never
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// set; this is still an error
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if resultErr == nil {
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return waitErr
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}
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// resultErr takes precedence over waitErr if both are set because it is
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// more likely to be useful
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return resultErr
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}
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// RetryFunc is the function retried until it succeeds.
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type RetryFunc func() *RetryError
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// RetryError is the required return type of RetryFunc. It forces client code
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// to choose whether or not a given error is retryable.
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type RetryError struct {
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Err error
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Retryable bool
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}
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// RetryableError is a helper to create a RetryError that's retryable from a
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// given error.
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func RetryableError(err error) *RetryError {
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if err == nil {
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return nil
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}
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return &RetryError{Err: err, Retryable: true}
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}
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// NonRetryableError is a helper to create a RetryError that's _not)_ retryable
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// from a given error.
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func NonRetryableError(err error) *RetryError {
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if err == nil {
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return nil
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}
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return &RetryError{Err: err, Retryable: false}
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}
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