82 lines
1.8 KiB
Go
82 lines
1.8 KiB
Go
package limiter
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import (
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"context"
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"sync"
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"sync/atomic"
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"testing"
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"time"
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"github.com/stretchr/testify/require"
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"github.com/hashicorp/consul/lib"
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)
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func init() { lib.SeedMathRand() }
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func TestSessionLimiter(t *testing.T) {
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lim := NewSessionLimiter()
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ctx, cancel := context.WithCancel(context.Background())
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t.Cleanup(cancel)
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go lim.Run(ctx)
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// doneCh is used to shut the goroutines down at the end of the test.
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doneCh := make(chan struct{})
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t.Cleanup(func() { close(doneCh) })
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// Start 10 sessions, and increment the counter when they are terminated.
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var (
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terminations uint32
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wg sync.WaitGroup
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)
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for i := 0; i < 10; i++ {
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wg.Add(1)
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go func() {
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sess, err := lim.BeginSession()
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require.NoError(t, err)
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defer sess.End()
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wg.Done()
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select {
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case <-sess.Terminated():
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atomic.AddUint32(&terminations, 1)
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case <-doneCh:
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}
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}()
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}
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// Wait for all the sessions to begin.
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wg.Wait()
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// Lowering max sessions to 5 should result in 5 sessions being terminated.
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lim.SetMaxSessions(5)
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require.Eventually(t, func() bool {
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return atomic.LoadUint32(&terminations) == 5
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}, 2*time.Second, 50*time.Millisecond)
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// Attempting to start a new session should fail immediately.
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_, err := lim.BeginSession()
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require.Equal(t, ErrCapacityReached, err)
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// Raising MaxSessions should make room for a new session.
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lim.SetMaxSessions(6)
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sess, err := lim.BeginSession()
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require.NoError(t, err)
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// ...but trying to start another new one should fail
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_, err = lim.BeginSession()
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require.Equal(t, ErrCapacityReached, err)
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// ...until another session ends.
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sess.End()
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_, err = lim.BeginSession()
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require.NoError(t, err)
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// Calling End twice is a no-op.
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sess.End()
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_, err = lim.BeginSession()
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require.Equal(t, ErrCapacityReached, err)
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}
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