mirror of https://github.com/dapr/kit.git
98 lines
2.7 KiB
Go
98 lines
2.7 KiB
Go
/*
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Copyright 2023 The Dapr 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 concurrency
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import (
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"context"
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"errors"
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"sync"
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"sync/atomic"
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)
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var ErrManagerAlreadyStarted = errors.New("runner manager already started")
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// Runner is a function that runs a task.
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type Runner func(ctx context.Context) error
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// RunnerManager is a manager for runners. It runs all runners in parallel and
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// waits for all runners to finish. If any runner returns, the RunnerManager
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// will stop all other runners and return any error.
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type RunnerManager struct {
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lock sync.Mutex
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runners []Runner
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running atomic.Bool
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}
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// NewRunnerManager creates a new RunnerManager.
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func NewRunnerManager(runners ...Runner) *RunnerManager {
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return &RunnerManager{
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runners: runners,
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}
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}
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// Add adds a new runner to the RunnerManager.
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func (r *RunnerManager) Add(runner ...Runner) error {
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if r.running.Load() {
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return ErrManagerAlreadyStarted
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}
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r.lock.Lock()
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defer r.lock.Unlock()
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r.runners = append(r.runners, runner...)
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return nil
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}
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// Run runs all runners in parallel and waits for all runners to finish. If any
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// runner returns, the RunnerManager will stop all other runners and return any
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// error.
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func (r *RunnerManager) Run(ctx context.Context) error {
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if !r.running.CompareAndSwap(false, true) {
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return ErrManagerAlreadyStarted
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}
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ctx, cancel := context.WithCancel(ctx)
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defer cancel()
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errCh := make(chan error)
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for _, runner := range r.runners {
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go func(runner Runner) {
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// Since the task returned, we need to cancel all other tasks.
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// This is a noop if the parent context is already cancelled, or another
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// task returned before this one.
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defer cancel()
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// Ignore context cancelled errors since errors from a runner manager
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// will likely determine the exit code of the program.
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// Context cancelled errors are also not really useful to the user in
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// this situation.
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rErr := runner(ctx)
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if rErr != nil && !errors.Is(rErr, context.Canceled) {
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errCh <- rErr
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return
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}
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errCh <- nil
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}(runner)
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}
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// Collect all errors
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errObjs := make([]error, 0)
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for i := 0; i < len(r.runners); i++ {
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err := <-errCh
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if err != nil {
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errObjs = append(errObjs, err)
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}
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}
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return errors.Join(errObjs...)
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}
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