ash
d7af699e84
When the disk (or memory) tier is at cap or the volume returns ENOSPC, ops currently look like random misses with no clear "we are dropping data." Count those events as capacity_pressure_events on /metrics and log tier plus reason so operators can tell capacity pressure from a cold cache, without changing the existing evictions counter. Link: #36
64 lines
1.9 KiB
Go
64 lines
1.9 KiB
Go
package metrics
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import (
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"bytes"
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"errors"
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"net/http/httptest"
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"testing"
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)
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func TestCapacityPressureEventsWriteTextAndReset(t *testing.T) {
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t.Parallel()
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m := NewMetrics()
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if got := m.GetStats().CapacityPressureEvents; got != 0 {
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t.Fatalf("initial CapacityPressureEvents=%d, want 0", got)
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}
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NoteSoftEviction(m, "memory", 0)
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if got := m.GetStats().CapacityPressureEvents; got != 0 {
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t.Fatalf("zero-byte eviction counted: %d", got)
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}
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NoteSoftEviction(m, "memory", 128)
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st := m.GetStats()
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if st.CapacityPressureEvents != 1 {
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t.Fatalf("after memory eviction, CapacityPressureEvents=%d, want 1", st.CapacityPressureEvents)
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}
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if st.Evictions != 1 {
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t.Fatalf("after memory eviction, Evictions=%d, want 1 (existing counter kept)", st.Evictions)
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}
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NoteSoftEviction(m, "disk", 64)
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NoteNoSpace(m, errors.New("no space left on device"))
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st = m.GetStats()
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if st.CapacityPressureEvents != 3 {
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t.Fatalf("after disk eviction + ENOSPC, CapacityPressureEvents=%d, want 3", st.CapacityPressureEvents)
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}
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if st.Evictions != 2 {
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t.Fatalf("ENOSPC must not increment evictions; Evictions=%d, want 2", st.Evictions)
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}
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rec := httptest.NewRecorder()
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WriteText(rec, st)
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body := rec.Body.Bytes()
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if !bytes.Contains(body, []byte("capacity_pressure_events 3")) {
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t.Errorf("WriteText missing capacity_pressure_events 3: %q", rec.Body.String())
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}
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if !bytes.Contains(body, []byte("evictions 2")) {
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t.Errorf("WriteText missing evictions 2: %q", rec.Body.String())
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}
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m.Reset()
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st = m.GetStats()
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if st.CapacityPressureEvents != 0 || st.Evictions != 0 {
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t.Errorf("after Reset, CapacityPressureEvents=%d Evictions=%d, want 0", st.CapacityPressureEvents, st.Evictions)
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}
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}
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func TestNoteSoftEvictionNilMetrics(t *testing.T) {
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t.Parallel()
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// Must not panic when metrics are not wired (unit tests / early init).
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NoteSoftEviction(nil, "memory", 10)
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NoteNoSpace(nil, errors.New("ENOSPC"))
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}
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