prometheus/storage/remote/queue_manager_test.go
Callum Styan 6f69e31398 Tail the TSDB WAL for remote_write
This change switches the remote_write API to use the TSDB WAL.  This should reduce memory usage and prevent sample loss when the remote end point is down.

We use the new LiveReader from TSDB to tail WAL segments.  Logic for finding the tracking segment is included in this PR.  The WAL is tailed once for each remote_write endpoint specified. Reading from the segment is based on a ticker rather than relying on fsnotify write events, which were found to be complicated and unreliable in early prototypes.

Enqueuing a sample for sending via remote_write can now block, to provide back pressure.  Queues are still required to acheive parallelism and batching.  We have updated the queue config based on new defaults for queue capacity and pending samples values - much smaller values are now possible.  The remote_write resharding code has been updated to prevent deadlocks, and extra tests have been added for these cases.

As part of this change, we attempt to guarantee that samples are not lost; however this initial version doesn't guarantee this across Prometheus restarts or non-retryable errors from the remote end (eg 400s).

This changes also includes the following optimisations:
- only marshal the proto request once, not once per retry
- maintain a single copy of the labels for given series to reduce GC pressure

Other minor tweaks:
- only reshard if we've also successfully sent recently
- add pending samples, latest sent timestamp, WAL events processed metrics

Co-authored-by: Chris Marchbanks <csmarchbanks.com> (initial prototype)
Co-authored-by: Tom Wilkie <tom.wilkie@gmail.com> (sharding changes)
Signed-off-by: Callum Styan <callumstyan@gmail.com>
2019-02-12 11:39:13 +00:00

350 lines
9.7 KiB
Go

// Copyright 2013 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package remote
import (
"context"
"fmt"
"reflect"
"sync"
"sync/atomic"
"testing"
"time"
"github.com/gogo/protobuf/proto"
"github.com/golang/snappy"
"github.com/stretchr/testify/require"
"github.com/prometheus/common/model"
"github.com/prometheus/prometheus/config"
"github.com/prometheus/prometheus/prompb"
"github.com/prometheus/prometheus/util/testutil"
"github.com/prometheus/tsdb"
"github.com/prometheus/tsdb/labels"
)
const defaultFlushDeadline = 1 * time.Minute
func TestSampleDelivery(t *testing.T) {
// Let's create an even number of send batches so we don't run into the
// batch timeout case.
n := config.DefaultQueueConfig.Capacity * 2
samples, series := createTimeseries(n)
c := NewTestStorageClient()
c.expectSamples(samples[:len(samples)/2], series)
cfg := config.DefaultQueueConfig
cfg.BatchSendDeadline = model.Duration(100 * time.Millisecond)
cfg.MaxShards = 1
var temp int64
m := NewQueueManager(nil, "", newEWMARate(ewmaWeight, shardUpdateDuration), &temp, cfg, nil, nil, c, defaultFlushDeadline, 0)
m.seriesLabels = refSeriesToLabelsProto(series)
// These should be received by the client.
m.Start()
m.Append(samples[:len(samples)/2])
defer m.Stop()
c.waitForExpectedSamples(t)
m.Append(samples[len(samples)/2:])
c.expectSamples(samples[len(samples)/2:], series)
c.waitForExpectedSamples(t)
}
func TestSampleDeliveryTimeout(t *testing.T) {
// Let's send one less sample than batch size, and wait the timeout duration
n := 9
samples, series := createTimeseries(n)
c := NewTestStorageClient()
cfg := config.DefaultQueueConfig
cfg.MaxShards = 1
cfg.BatchSendDeadline = model.Duration(100 * time.Millisecond)
var temp int64
m := NewQueueManager(nil, "", newEWMARate(ewmaWeight, shardUpdateDuration), &temp, cfg, nil, nil, c, defaultFlushDeadline, 0)
m.seriesLabels = refSeriesToLabelsProto(series)
m.Start()
defer m.Stop()
// Send the samples twice, waiting for the samples in the meantime.
c.expectSamples(samples, series)
m.Append(samples)
c.waitForExpectedSamples(t)
c.expectSamples(samples, series)
m.Append(samples)
c.waitForExpectedSamples(t)
}
func TestSampleDeliveryOrder(t *testing.T) {
ts := 10
n := config.DefaultQueueConfig.MaxSamplesPerSend * ts
samples := make([]tsdb.RefSample, 0, n)
series := make([]tsdb.RefSeries, 0, n)
for i := 0; i < n; i++ {
name := fmt.Sprintf("test_metric_%d", i%ts)
samples = append(samples, tsdb.RefSample{
Ref: uint64(i),
T: int64(i),
V: float64(i),
})
series = append(series, tsdb.RefSeries{
Ref: uint64(i),
Labels: labels.Labels{labels.Label{Name: "__name__", Value: name}},
})
}
c := NewTestStorageClient()
c.expectSamples(samples, series)
var temp int64
m := NewQueueManager(nil, "", newEWMARate(ewmaWeight, shardUpdateDuration), &temp, config.DefaultQueueConfig, nil, nil, c, defaultFlushDeadline, 0)
m.seriesLabels = refSeriesToLabelsProto(series)
m.Start()
defer m.Stop()
// These should be received by the client.
m.Append(samples)
c.waitForExpectedSamples(t)
}
func TestShutdown(t *testing.T) {
deadline := 5 * time.Second
c := NewTestBlockedStorageClient()
var temp int64
m := NewQueueManager(nil, "", newEWMARate(ewmaWeight, shardUpdateDuration), &temp, config.DefaultQueueConfig, nil, nil, c, deadline, 0)
samples, series := createTimeseries(2 * config.DefaultQueueConfig.MaxSamplesPerSend)
m.seriesLabels = refSeriesToLabelsProto(series)
m.Start()
// Append blocks to guarantee delivery, so we do it in the background.
go func() {
m.Append(samples)
}()
time.Sleep(1 * time.Second)
// Test to ensure that Stop doesn't block.
start := time.Now()
m.Stop()
// The samples will never be delivered, so duration should
// be at least equal to deadline, otherwise the flush deadline
// was not respected.
duration := time.Since(start)
if duration > time.Duration(deadline+(deadline/10)) {
t.Errorf("Took too long to shutdown: %s > %s", duration, deadline)
}
if duration < time.Duration(deadline) {
t.Errorf("Shutdown occurred before flush deadline: %s < %s", duration, deadline)
}
}
func TestSeriesReset(t *testing.T) {
c := NewTestBlockedStorageClient()
deadline := 5 * time.Second
var temp int64
numSegments := 4
numSeries := 25
m := NewQueueManager(nil, "", newEWMARate(ewmaWeight, shardUpdateDuration), &temp, config.DefaultQueueConfig, nil, nil, c, deadline, 0)
for i := 0; i < numSegments; i++ {
series := []tsdb.RefSeries{}
for j := 0; j < numSeries; j++ {
series = append(series, tsdb.RefSeries{Ref: uint64((i * 100) + j), Labels: labels.Labels{labels.Label{Name: "a", Value: "a"}}})
}
m.StoreSeries(series, i)
}
testutil.Equals(t, numSegments*numSeries, len(m.seriesLabels))
m.SeriesReset(2)
testutil.Equals(t, numSegments*numSeries/2, len(m.seriesLabels))
}
func TestReshard(t *testing.T) {
size := 10 // Make bigger to find more races.
n := config.DefaultQueueConfig.Capacity * size
samples, series := createTimeseries(n)
c := NewTestStorageClient()
c.expectSamples(samples, series)
cfg := config.DefaultQueueConfig
cfg.MaxShards = 1
var temp int64
m := NewQueueManager(nil, "", newEWMARate(ewmaWeight, shardUpdateDuration), &temp, cfg, nil, nil, c, defaultFlushDeadline, 0)
m.seriesLabels = refSeriesToLabelsProto(series)
m.Start()
defer m.Stop()
go func() {
for i := 0; i < len(samples); i += config.DefaultQueueConfig.Capacity {
sent := m.Append(samples[i : i+config.DefaultQueueConfig.Capacity])
require.True(t, sent)
time.Sleep(100 * time.Millisecond)
}
}()
for i := 1; i < len(samples)/config.DefaultQueueConfig.Capacity; i++ {
m.shards.stop()
m.shards.start(i)
time.Sleep(100 * time.Millisecond)
}
c.waitForExpectedSamples(t)
}
func createTimeseries(n int) ([]tsdb.RefSample, []tsdb.RefSeries) {
samples := make([]tsdb.RefSample, 0, n)
series := make([]tsdb.RefSeries, 0, n)
for i := 0; i < n; i++ {
name := fmt.Sprintf("test_metric_%d", i)
samples = append(samples, tsdb.RefSample{
Ref: uint64(i),
T: int64(i),
V: float64(i),
})
series = append(series, tsdb.RefSeries{
Ref: uint64(i),
Labels: labels.Labels{labels.Label{Name: "__name__", Value: name}},
})
}
return samples, series
}
func getSeriesNameFromRef(r tsdb.RefSeries) string {
for _, l := range r.Labels {
if l.Name == "__name__" {
return l.Value
}
}
return ""
}
func refSeriesToLabelsProto(series []tsdb.RefSeries) map[uint64][]prompb.Label {
result := make(map[uint64][]prompb.Label)
for _, s := range series {
for _, l := range s.Labels {
result[s.Ref] = append(result[s.Ref], prompb.Label{
Name: l.Name,
Value: l.Value,
})
}
}
return result
}
type TestStorageClient struct {
receivedSamples map[string][]prompb.Sample
expectedSamples map[string][]prompb.Sample
wg sync.WaitGroup
mtx sync.Mutex
}
func NewTestStorageClient() *TestStorageClient {
return &TestStorageClient{
receivedSamples: map[string][]prompb.Sample{},
expectedSamples: map[string][]prompb.Sample{},
}
}
func (c *TestStorageClient) expectSamples(ss []tsdb.RefSample, series []tsdb.RefSeries) {
c.mtx.Lock()
defer c.mtx.Unlock()
c.expectedSamples = map[string][]prompb.Sample{}
c.receivedSamples = map[string][]prompb.Sample{}
for _, s := range ss {
seriesName := getSeriesNameFromRef(series[s.Ref])
c.expectedSamples[seriesName] = append(c.expectedSamples[seriesName], prompb.Sample{
Timestamp: s.T,
Value: s.V,
})
}
c.wg.Add(len(ss))
}
func (c *TestStorageClient) waitForExpectedSamples(t *testing.T) {
c.wg.Wait()
c.mtx.Lock()
defer c.mtx.Unlock()
for ts, expectedSamples := range c.expectedSamples {
if !reflect.DeepEqual(expectedSamples, c.receivedSamples[ts]) {
t.Fatalf("%s: Expected %v, got %v", ts, expectedSamples, c.receivedSamples[ts])
}
}
}
func (c *TestStorageClient) Store(_ context.Context, req []byte) error {
c.mtx.Lock()
defer c.mtx.Unlock()
reqBuf, err := snappy.Decode(nil, req)
if err != nil {
return err
}
var reqProto prompb.WriteRequest
if err := proto.Unmarshal(reqBuf, &reqProto); err != nil {
return err
}
count := 0
for _, ts := range reqProto.Timeseries {
var seriesName string
labels := labelProtosToLabels(ts.Labels)
for _, label := range labels {
if label.Name == "__name__" {
seriesName = label.Value
}
}
for _, sample := range ts.Samples {
count++
c.receivedSamples[seriesName] = append(c.receivedSamples[seriesName], sample)
}
}
c.wg.Add(-count)
return nil
}
func (c *TestStorageClient) Name() string {
return "teststorageclient"
}
// TestBlockingStorageClient is a queue_manager StorageClient which will block
// on any calls to Store(), until the request's Context is cancelled, at which
// point the `numCalls` property will contain a count of how many times Store()
// was called.
type TestBlockingStorageClient struct {
numCalls uint64
}
func NewTestBlockedStorageClient() *TestBlockingStorageClient {
return &TestBlockingStorageClient{}
}
func (c *TestBlockingStorageClient) Store(ctx context.Context, _ []byte) error {
atomic.AddUint64(&c.numCalls, 1)
<-ctx.Done()
return nil
}
func (c *TestBlockingStorageClient) NumCalls() uint64 {
return atomic.LoadUint64(&c.numCalls)
}
func (c *TestBlockingStorageClient) Name() string {
return "testblockingstorageclient"
}