github.com/cockroachdb/cockroach@v20.2.0-alpha.1+incompatible/pkg/util/limit/limiter_test.go (about)

     1  // Copyright 2018 The Cockroach Authors.
     2  //
     3  // Use of this software is governed by the Business Source License
     4  // included in the file licenses/BSL.txt.
     5  //
     6  // As of the Change Date specified in that file, in accordance with
     7  // the Business Source License, use of this software will be governed
     8  // by the Apache License, Version 2.0, included in the file
     9  // licenses/APL.txt.
    10  
    11  package limit
    12  
    13  import (
    14  	"context"
    15  	"runtime"
    16  	"sync/atomic"
    17  	"testing"
    18  
    19  	"github.com/cockroachdb/cockroach/pkg/util/leaktest"
    20  	"github.com/cockroachdb/errors"
    21  	"golang.org/x/sync/errgroup"
    22  )
    23  
    24  func TestConcurrentRequestLimiter(t *testing.T) {
    25  	defer leaktest.AfterTest(t)()
    26  
    27  	l := MakeConcurrentRequestLimiter("test", 1)
    28  	var wg errgroup.Group
    29  
    30  	const threads = 20
    31  	const runs = 1000000
    32  	var count int64
    33  
    34  	ctx, cancel := context.WithCancel(context.Background())
    35  	defer cancel()
    36  
    37  	for thread := 0; thread < threads; thread++ {
    38  		wg.Go(func() error {
    39  			runtime.Gosched()
    40  			req := 0
    41  			for {
    42  				//t.Logf("waiting to make request %d... (%d / %d)", req+1, l.sem.GetCount(), l.sem.GetLimit())
    43  				if err := l.Begin(ctx); err != nil {
    44  					if errors.Is(err, ctx.Err()) {
    45  						break
    46  					} else {
    47  						return err
    48  					}
    49  				}
    50  				if x := atomic.AddInt64(&count, 1); x >= runs {
    51  					t.Logf("canceling ctx after %d runs", x)
    52  					cancel()
    53  				}
    54  				req++
    55  				l.Finish()
    56  			}
    57  			t.Logf("thread done after handling %d requests", req)
    58  			return nil
    59  		})
    60  	}
    61  	if err := wg.Wait(); err != nil {
    62  		t.Fatal(err)
    63  	}
    64  }