sneak
2a7af1b1be
check / check (push) Waiting to run
TestService_Get_ReturnsByItsDeadline failed on a busy host because its request, past its deadline, still waited for its miss count to be written, a database write with no deadline; in pixad that write waits for the one database connection every request shares. The hit, miss, upstream fetch and transform counts are now each written in a goroutine of their own, which the request waits for only until its deadline; a count not written by then is written after it returns. Shutdown waits for those writes within ShutdownTimeout and reports any left unfinished. The test phase also runs go test with -parallel 4: on a busy host, as many tests at once as there are CPUs wait so long to be scheduled that a timed request can fail. Model: opus-5-5
117 lines
3.3 KiB
Go
117 lines
3.3 KiB
Go
package imgcache
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import (
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"context"
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"errors"
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"testing"
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"time"
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)
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// holdDatabase takes the one connection of the test service's database, so
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// that every other query waits for it, and returns the func that frees it.
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func holdDatabase(t *testing.T, svc *Service) func() {
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t.Helper()
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conn, err := svc.cache.db.Conn(t.Context())
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if err != nil {
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t.Fatalf("failed to take the database connection: %v", err)
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}
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release := func() { _ = conn.Close() }
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t.Cleanup(release)
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return release
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}
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// TestService_Get_ReturnsByItsDeadlineWhileTheDatabaseIsBusy holds the
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// database's one connection while a request whose fetch is held reaches its
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// deadline. The request must still return by its deadline with the
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// deadline's error, and its miss must be counted once the connection is free.
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func TestService_Get_ReturnsByItsDeadlineWhileTheDatabaseIsBusy(t *testing.T) {
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t.Parallel()
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svc, fixtures, fetcher := setupHeldFetchService(t)
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const timeout = 200 * time.Millisecond
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ctx, cancel := context.WithTimeout(t.Context(), timeout)
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defer cancel()
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results := startGet(ctx, svc, photoVariant(fixtures, 85, FitCover))
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// The request has made its database reads by the time it fetches.
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<-fetcher.started
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releaseDatabase := holdDatabase(t, svc)
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select {
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case got := <-results:
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deadline, _ := ctx.Deadline()
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t.Logf("Get() returned %v after its deadline, error = %v",
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time.Since(deadline), got.err)
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if !errors.Is(got.err, context.DeadlineExceeded) {
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t.Errorf("Get() error = %v, want %v", got.err, context.DeadlineExceeded)
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}
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case <-time.After(timeout + time.Second):
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t.Fatal("request did not return by its deadline while the database was busy")
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}
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releaseDatabase()
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waitCtx, cancelWait := context.WithTimeout(t.Context(), 5*time.Second)
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defer cancelWait()
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if !svc.WaitForCountWrites(waitCtx) {
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t.Fatal("the miss was not counted once the database was free")
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}
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want := cacheStatsCounters{missCount: 1}
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if got := readCacheStatsCounters(t, svc.cache); got != want {
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t.Errorf("counters = %+v, want %+v", got, want)
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}
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}
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// TestService_WaitForCountWrites holds the database's one connection while a
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// request past its deadline counts a miss. WaitForCountWrites must report the
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// count unwritten when its context ends, and written once the connection is
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// free.
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func TestService_WaitForCountWrites(t *testing.T) {
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t.Parallel()
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svc, _, _ := setupHeldFetchService(t)
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releaseDatabase := holdDatabase(t, svc)
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ended, cancel := context.WithDeadline(t.Context(), time.Now())
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defer cancel()
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svc.writeCount(ended, func(ctx context.Context) {
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svc.cache.IncrementStats(ctx, false, 0)
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})
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shortCtx, cancelShort := context.WithTimeout(t.Context(), 100*time.Millisecond)
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defer cancelShort()
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written := svc.WaitForCountWrites(shortCtx)
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t.Logf("WaitForCountWrites() while the database was busy = %t", written)
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if written {
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t.Fatal("WaitForCountWrites() = true while the database was busy")
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}
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releaseDatabase()
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waitCtx, cancelWait := context.WithTimeout(t.Context(), 5*time.Second)
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defer cancelWait()
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if !svc.WaitForCountWrites(waitCtx) {
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t.Fatal("WaitForCountWrites() = false once the database was free")
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}
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want := cacheStatsCounters{missCount: 1}
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if got := readCacheStatsCounters(t, svc.cache); got != want {
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t.Errorf("counters = %+v, want %+v", got, want)
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}
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}
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