sigs.k8s.io/kueue@v0.6.2/pkg/util/parallelize/parallelize.go (about)

     1  /*
     2  Copyright 2024 The Kubernetes Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package parallelize
    18  
    19  import (
    20  	"context"
    21  
    22  	"k8s.io/client-go/util/workqueue"
    23  )
    24  
    25  const maxParallelism = 8
    26  
    27  // ErrorChannel supports non-blocking send and receive operation to capture error.
    28  // A maximum of one error is kept in the channel and the rest of the errors sent
    29  // are ignored, unless the existing error is received and the channel becomes empty
    30  // again.
    31  type ErrorChannel struct {
    32  	ch chan error
    33  }
    34  
    35  func NewErrorChannel() *ErrorChannel {
    36  	return &ErrorChannel{
    37  		ch: make(chan error, 1),
    38  	}
    39  }
    40  
    41  func (e *ErrorChannel) SendError(err error) {
    42  	if err == nil {
    43  		return
    44  	}
    45  	select {
    46  	case e.ch <- err:
    47  	default:
    48  	}
    49  }
    50  
    51  func (e *ErrorChannel) Receive() error {
    52  	select {
    53  	case err := <-e.ch:
    54  		return err
    55  	default:
    56  		return nil
    57  	}
    58  }
    59  
    60  func Until(ctx context.Context, pieces int, doWorkPiece func(i int) error) error {
    61  	errCh := NewErrorChannel()
    62  	workers := min(pieces, maxParallelism)
    63  	workqueue.ParallelizeUntil(ctx, workers, pieces, func(i int) {
    64  		errCh.SendError(doWorkPiece(i))
    65  	})
    66  	return errCh.Receive()
    67  }