zrepl/daemon/logging/trace/trace_unique_concurrent_task_namer_test.go
Christian Schwarz 10a14a8c50 [#307] add package trace, integrate it with logging, and adopt it throughout zrepl
package trace:

- introduce the concept of tasks and spans, tracked as linked list within ctx
    - see package-level docs for an overview of the concepts
    - **main feature 1**: unique stack of task and span IDs
        - makes it easy to follow a series of log entries in concurrent code
    - **main feature 2**: ability to produce a chrome://tracing-compatible trace file
        - either via an env variable or a `zrepl pprof` subcommand
        - this is not a CPU profile, we already have go pprof for that
        - but it is very useful to visually inspect where the
          replication / snapshotter / pruner spends its time
          ( fixes #307 )

usage in package daemon/logging:

- goal: every log entry should have a trace field with the ID stack from package trace

- make `logging.GetLogger(ctx, Subsys)` the authoritative `logger.Logger` factory function
    - the context carries a linked list of injected fields which
      `logging.GetLogger` adds to the logger it returns
    - `logging.GetLogger` also uses package `trace` to get the
      task-and-span-stack and injects it into the returned logger's fields
2020-05-19 11:30:02 +02:00

59 lines
1.1 KiB
Go

package trace
import (
"fmt"
"sync"
"sync/atomic"
"testing"
"github.com/stretchr/testify/require"
"github.com/willf/bitset"
)
func TestBitsetFeaturesForUniqueConcurrentTaskNamer(t *testing.T) {
var b bitset.BitSet
require.Equal(t, uint(0), b.Len())
require.Equal(t, uint(0), b.Count())
b.Set(0)
require.Equal(t, uint(1), b.Len())
require.Equal(t, uint(1), b.Count())
b.Set(8)
require.Equal(t, uint(9), b.Len())
require.Equal(t, uint(2), b.Count())
b.Set(1)
require.Equal(t, uint(9), b.Len())
require.Equal(t, uint(3), b.Count())
}
func TestUniqueConcurrentTaskNamer(t *testing.T) {
namer := newUniqueTaskNamer()
var wg sync.WaitGroup
const N = 8128
const Q = 23
var fails uint32
var m sync.Map
wg.Add(N)
for i := 0; i < N; i++ {
go func(i int) {
defer wg.Done()
name := fmt.Sprintf("%d", i/Q)
uniqueName, done := namer.UniqueConcurrentTaskName(name)
act, _ := m.LoadOrStore(uniqueName, i)
if act.(int) != i {
atomic.AddUint32(&fails, 1)
}
m.Delete(uniqueName)
done()
}(i)
}
wg.Wait()
require.Equal(t, uint32(0), fails)
}