Adding upstream version 1.34.4.

Signed-off-by: Daniel Baumann <daniel@debian.org>

plugins/processors/reverse_dns/rdnscache_test.go

@@ -0,0 +1,142 @@
+package reverse_dns
+
+import (
+	"context"
+	"errors"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestSimpleReverseDNSLookup(t *testing.T) {
+	d := NewReverseDNSCache(60*time.Second, 1*time.Second, -1)
+	defer d.Stop()
+
+	d.Resolver = &localResolver{}
+	answer, err := d.Lookup("127.0.0.1")
+	require.NoError(t, err)
+	require.Equal(t, []string{"localhost"}, answer)
+	err = blockAllWorkers(t.Context(), d)
+	require.NoError(t, err)
+
+	// do another request with no workers available.
+	// it should read from cache instantly.
+	answer, err = d.Lookup("127.0.0.1")
+	require.NoError(t, err)
+	require.Equal(t, []string{"localhost"}, answer)
+
+	require.Len(t, d.cache, 1)
+	require.Len(t, d.expireList, 1)
+	d.cleanup()
+	require.Len(t, d.expireList, 1) // ttl hasn't hit yet.
+
+	stats := d.Stats()
+
+	require.EqualValues(t, 0, stats.CacheExpire)
+	require.EqualValues(t, 1, stats.CacheMiss)
+	require.EqualValues(t, 1, stats.CacheHit)
+	require.EqualValues(t, 1, stats.RequestsFilled)
+	require.EqualValues(t, 0, stats.RequestsAbandoned)
+}
+
+func TestParallelReverseDNSLookup(t *testing.T) {
+	d := NewReverseDNSCache(1*time.Second, 1*time.Second, -1)
+	defer d.Stop()
+
+	d.Resolver = &localResolver{}
+	var answer1, answer2 []string
+	var err1, err2 error
+	wg := &sync.WaitGroup{}
+	wg.Add(2)
+	go func() {
+		answer1, err1 = d.Lookup("127.0.0.1")
+		wg.Done()
+	}()
+	go func() {
+		answer2, err2 = d.Lookup("127.0.0.1")
+		wg.Done()
+	}()
+
+	wg.Wait()
+
+	require.NoError(t, err1)
+	require.NoError(t, err2)
+
+	t.Log(answer1)
+	t.Log(answer2)
+
+	require.Equal(t, []string{"localhost"}, answer1)
+	require.Equal(t, []string{"localhost"}, answer2)
+
+	require.Len(t, d.cache, 1)
+
+	stats := d.Stats()
+
+	require.EqualValues(t, 1, stats.CacheMiss)
+	require.EqualValues(t, 1, stats.CacheHit)
+}
+
+func TestUnavailableDNSServerRespectsTimeout(t *testing.T) {
+	d := NewReverseDNSCache(0, 1, -1)
+	defer d.Stop()
+
+	d.Resolver = &timeoutResolver{}
+
+	result, err := d.Lookup("192.153.33.3")
+	require.Error(t, err)
+	require.Equal(t, ErrTimeout, err)
+
+	require.Nil(t, result)
+}
+
+func TestCleanupHappens(t *testing.T) {
+	ttl := 100 * time.Millisecond
+	d := NewReverseDNSCache(ttl, 1*time.Second, -1)
+	defer d.Stop()
+
+	d.Resolver = &localResolver{}
+	_, err := d.Lookup("127.0.0.1")
+	require.NoError(t, err)
+
+	require.Len(t, d.cache, 1)
+
+	time.Sleep(ttl) // wait for cache entry to expire.
+	d.cleanup()
+	require.Empty(t, d.expireList)
+
+	stats := d.Stats()
+
+	require.EqualValues(t, 1, stats.CacheExpire)
+	require.EqualValues(t, 1, stats.CacheMiss)
+	require.EqualValues(t, 0, stats.CacheHit)
+}
+
+func TestLookupTimeout(t *testing.T) {
+	d := NewReverseDNSCache(10*time.Second, 10*time.Second, -1)
+	defer d.Stop()
+
+	d.Resolver = &timeoutResolver{}
+	_, err := d.Lookup("127.0.0.1")
+	require.Error(t, err)
+	require.EqualValues(t, 1, d.Stats().RequestsAbandoned)
+}
+
+type timeoutResolver struct{}
+
+func (*timeoutResolver) LookupAddr(context.Context, string) (names []string, err error) {
+	return nil, errors.New("timeout")
+}
+
+type localResolver struct{}
+
+func (*localResolver) LookupAddr(context.Context, string) (names []string, err error) {
+	return []string{"localhost"}, nil
+}
+
+// blockAllWorkers is a test function that eats up all the worker pool space to
+// make sure workers are done running and there's no room to acquire a new worker.
+func blockAllWorkers(testContext context.Context, d *ReverseDNSCache) error {
+	return d.sem.Acquire(testContext, int64(d.maxWorkers))
+}