go.chromium.org/luci@v0.0.0-20240309015107-7cdc2e660f33/common/sync/parallel/run.go (about)

     1  // Copyright 2016 The LUCI Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //      http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package parallel
    16  
    17  // Run executes a generator function, dispatching each generated task to the
    18  // Runner. Run returns immediately with an error channel that can be used to
    19  // reap the results of those tasks.
    20  //
    21  // The returned error channel must be consumed, or it can block additional
    22  // functions from being run from gen. A common consumption function is
    23  // errors.MultiErrorFromErrors, which will buffer all non-nil errors into an
    24  // errors.MultiError. Other functions to consider are Must and Ignore (in this
    25  // package).
    26  //
    27  // Note that there is no association between error channel's error order and
    28  // the generated task order. However, the channel will return exactly one error
    29  // result for each generated task.
    30  //
    31  // If workers is <= 0, it will be unbounded; otherwise, a pool of at most
    32  // workers sustained goroutines will be used to execute the task.
    33  func Run(workers int, gen func(chan<- func() error)) <-chan error {
    34  	r := Runner{
    35  		Maximum:   workers,
    36  		Sustained: workers,
    37  	}
    38  	return r.runThen(gen, r.Close)
    39  }