94 lines
2.1 KiB
Go
94 lines
2.1 KiB
Go
// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this
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// file, You can obtain one at http://mozilla.org/MPL/2.0/.
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package conditions
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import (
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"context"
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"errors"
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"fmt"
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"sync"
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"time"
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)
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// ErrSkipAssertion is used as a return value from AssertionFunc to indicate that this assertion
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// (and, by extension, condition, and check) is to be skipped.
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// It is not returned as an error by any Condition's Wait method
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// but recorded as description and returned by String method.
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var ErrSkipAssertion = errors.New("SKIP")
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// AssertionFunc is called every poll interval until it returns nil.
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type AssertionFunc func(ctx context.Context) error
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type pollingCondition struct {
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lastErrMu sync.Mutex
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lastErr error
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lastErrSet bool
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assertion AssertionFunc
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description string
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timeout, interval time.Duration
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}
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func (p *pollingCondition) String() string {
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lastErr := "..."
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p.lastErrMu.Lock()
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if p.lastErrSet {
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if p.lastErr != nil {
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lastErr = p.lastErr.Error()
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} else {
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lastErr = OK
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}
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}
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p.lastErrMu.Unlock()
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return fmt.Sprintf("%s: %s", p.description, lastErr)
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}
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func (p *pollingCondition) Wait(ctx context.Context) error {
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ticker := time.NewTicker(p.interval)
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defer ticker.Stop()
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timeoutCtx, timeoutCtxCancel := context.WithTimeout(ctx, p.timeout)
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defer timeoutCtxCancel()
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for {
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err := func() error {
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runCtx, runCtxCancel := context.WithTimeout(ctx, p.interval)
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defer runCtxCancel()
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err := p.assertion(runCtx)
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p.lastErrMu.Lock()
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p.lastErr = err
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p.lastErrSet = true
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p.lastErrMu.Unlock()
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return err
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}()
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if err == nil || err == ErrSkipAssertion {
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return nil
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}
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select {
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case <-timeoutCtx.Done():
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return timeoutCtx.Err()
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case <-ticker.C:
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}
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}
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}
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// PollingCondition converts AssertionFunc into Condition by calling it every interval until timeout
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// is reached.
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func PollingCondition(description string, assertion AssertionFunc, timeout, interval time.Duration) Condition {
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return &pollingCondition{
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assertion: assertion,
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description: description,
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timeout: timeout,
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interval: interval,
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}
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}
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