94 lines
2.4 KiB
Go
94 lines
2.4 KiB
Go
package stream
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import (
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"context"
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fmt "fmt"
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"math/rand"
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"testing"
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time "time"
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"github.com/stretchr/testify/assert"
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)
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// A property-based test to ensure that under heavy concurrent use trivial
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// correctness properties are not violated (and that -race doesn't complain).
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func TestEventBufferFuzz(t *testing.T) {
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if testing.Short() {
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t.Skip("too slow for testing.Short")
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}
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if testing.Short() {
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t.Skip("too slow for short run")
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}
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nReaders := 1000
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nMessages := 1000
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b := newEventBuffer()
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// Start a write goroutine that will publish 10000 messages with sequential
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// indexes and some jitter in timing (to allow clients to "catch up" and block
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// waiting for updates).
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go func() {
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seed := time.Now().UnixNano()
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t.Logf("Using seed %d", seed)
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// z is a Zipfian distribution that gives us a number of milliseconds to
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// sleep which are mostly low - near zero but occasionally spike up to near
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// 100.
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z := rand.NewZipf(rand.New(rand.NewSource(seed)), 1.5, 1.5, 50)
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for i := 0; i < nMessages; i++ {
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// Event content is arbitrary and not valid for our use of buffers in
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// streaming - here we only care about the semantics of the buffer.
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e := Event{
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Index: uint64(i), // Indexes should be contiguous
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Topic: testTopic,
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}
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b.Append([]Event{e})
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// Sleep sometimes for a while to let some subscribers catch up
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wait := time.Duration(z.Uint64()) * time.Millisecond
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time.Sleep(wait)
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}
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}()
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// Run n subscribers following and verifying
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errCh := make(chan error, nReaders)
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// Load head here so all subscribers start from the same point or they might
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// not run until several appends have already happened.
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head := b.Head()
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for i := 0; i < nReaders; i++ {
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go func(i int) {
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expect := uint64(0)
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item := head
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var err error
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for {
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item, err = item.Next(context.Background(), nil)
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if err != nil {
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errCh <- fmt.Errorf("subscriber %05d failed getting next %d: %s", i,
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expect, err)
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return
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}
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if item.Events[0].Index != expect {
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errCh <- fmt.Errorf("subscriber %05d got bad event want=%d, got=%d", i,
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expect, item.Events[0].Index)
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return
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}
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expect++
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if expect == uint64(nMessages) {
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// Succeeded
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errCh <- nil
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return
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}
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}
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}(i)
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}
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// Wait for all readers to finish one way or other
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for i := 0; i < nReaders; i++ {
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err := <-errCh
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assert.NoError(t, err)
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}
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}
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