/
tailer.go
265 lines (225 loc) · 6.03 KB
/
tailer.go
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package ingester
import (
"encoding/binary"
"hash/fnv"
"sync"
"time"
util_log "github.com/cortexproject/cortex/pkg/util/log"
"github.com/go-kit/kit/log/level"
"github.com/prometheus/prometheus/pkg/labels"
"golang.org/x/net/context"
"github.com/credativ/vali/pkg/logproto"
"github.com/credativ/vali/pkg/logql"
"github.com/credativ/vali/pkg/logql/log"
"github.com/credativ/vali/pkg/util"
)
const bufferSizeForTailResponse = 5
type TailServer interface {
Send(*logproto.TailResponse) error
Context() context.Context
}
type tailer struct {
id uint32
orgID string
matchers []*labels.Matcher
pipeline logql.Pipeline
expr logql.Expr
pipelineMtx sync.Mutex
sendChan chan *logproto.Stream
// Signaling channel used to notify once the tailer gets closed
// and the loop and senders should stop
closeChan chan struct{}
closeOnce sync.Once
blockedAt *time.Time
blockedMtx sync.RWMutex
droppedStreams []*logproto.DroppedStream
conn TailServer
}
func newTailer(orgID, query string, conn TailServer) (*tailer, error) {
expr, err := logql.ParseLogSelector(query)
if err != nil {
return nil, err
}
pipeline, err := expr.Pipeline()
if err != nil {
return nil, err
}
matchers := expr.Matchers()
return &tailer{
orgID: orgID,
matchers: matchers,
pipeline: pipeline,
sendChan: make(chan *logproto.Stream, bufferSizeForTailResponse),
conn: conn,
droppedStreams: []*logproto.DroppedStream{},
id: generateUniqueID(orgID, query),
closeChan: make(chan struct{}),
expr: expr,
}, nil
}
func (t *tailer) loop() {
var stream *logproto.Stream
var err error
var ok bool
ticker := time.NewTicker(3 * time.Second)
defer ticker.Stop()
for {
select {
case <-ticker.C:
err := t.conn.Context().Err()
if err != nil {
t.close()
return
}
case <-t.closeChan:
return
case stream, ok = <-t.sendChan:
if !ok {
return
} else if stream == nil {
continue
}
// while sending new stream pop lined up dropped streams metadata for sending to querier
tailResponse := logproto.TailResponse{Stream: stream, DroppedStreams: t.popDroppedStreams()}
err = t.conn.Send(&tailResponse)
if err != nil {
// Don't log any error due to tail client closing the connection
if !util.IsConnCanceled(err) {
level.Error(util_log.WithContext(t.conn.Context(), util_log.Logger)).Log("msg", "Error writing to tail client", "err", err)
}
t.close()
return
}
}
}
}
func (t *tailer) send(stream logproto.Stream, lbs labels.Labels) {
if t.isClosed() {
return
}
// if we are already dropping streams due to blocked connection, drop new streams directly to save some effort
if blockedSince := t.blockedSince(); blockedSince != nil {
if blockedSince.Before(time.Now().Add(-time.Second * 15)) {
t.close()
return
}
t.dropStream(stream)
return
}
streams := t.processStream(stream, lbs)
if len(streams) == 0 {
return
}
for _, s := range streams {
select {
case t.sendChan <- s:
default:
t.dropStream(*s)
}
}
}
func (t *tailer) processStream(stream logproto.Stream, lbs labels.Labels) []*logproto.Stream {
// Optimization: skip filtering entirely, if no filter is set
if log.IsNoopPipeline(t.pipeline) {
return []*logproto.Stream{&stream}
}
// pipeline are not thread safe and tailer can process multiple stream at once.
t.pipelineMtx.Lock()
defer t.pipelineMtx.Unlock()
streams := map[uint64]*logproto.Stream{}
sp := t.pipeline.ForStream(lbs)
for _, e := range stream.Entries {
newLine, parsedLbs, ok := sp.ProcessString(e.Line)
if !ok {
continue
}
var stream *logproto.Stream
if stream, ok = streams[parsedLbs.Hash()]; !ok {
stream = &logproto.Stream{
Labels: parsedLbs.String(),
}
streams[parsedLbs.Hash()] = stream
}
stream.Entries = append(stream.Entries, logproto.Entry{
Timestamp: e.Timestamp,
Line: newLine,
})
}
streamsResult := make([]*logproto.Stream, 0, len(streams))
for _, stream := range streams {
streamsResult = append(streamsResult, stream)
}
return streamsResult
}
// isMatching returns true if lbs matches all matchers.
func isMatching(lbs labels.Labels, matchers []*labels.Matcher) bool {
for _, matcher := range matchers {
if !matcher.Matches(lbs.Get(matcher.Name)) {
return false
}
}
return true
}
func (t *tailer) isClosed() bool {
select {
case <-t.closeChan:
return true
default:
return false
}
}
func (t *tailer) close() {
t.closeOnce.Do(func() {
// Signal the close channel
close(t.closeChan)
// We intentionally do not close sendChan in order to avoid a panic on
// send to a just-closed channel. It's OK not to close a channel, since
// it will be eventually garbage collected as soon as no goroutine
// references it anymore, whether it has been closed or not.
})
}
func (t *tailer) blockedSince() *time.Time {
t.blockedMtx.RLock()
defer t.blockedMtx.RUnlock()
return t.blockedAt
}
func (t *tailer) dropStream(stream logproto.Stream) {
if len(stream.Entries) == 0 {
return
}
t.blockedMtx.Lock()
defer t.blockedMtx.Unlock()
if t.blockedAt == nil {
blockedAt := time.Now()
t.blockedAt = &blockedAt
}
t.droppedStreams = append(t.droppedStreams, &logproto.DroppedStream{
From: stream.Entries[0].Timestamp,
To: stream.Entries[len(stream.Entries)-1].Timestamp,
Labels: stream.Labels,
})
}
func (t *tailer) popDroppedStreams() []*logproto.DroppedStream {
t.blockedMtx.Lock()
defer t.blockedMtx.Unlock()
if t.blockedAt == nil {
return nil
}
droppedStreams := t.droppedStreams
t.droppedStreams = []*logproto.DroppedStream{}
t.blockedAt = nil
return droppedStreams
}
func (t *tailer) getID() uint32 {
return t.id
}
// An id is useful in managing tailer instances
func generateUniqueID(orgID, query string) uint32 {
uniqueID := fnv.New32()
_, _ = uniqueID.Write([]byte(orgID))
_, _ = uniqueID.Write([]byte(query))
timeNow := make([]byte, 8)
binary.LittleEndian.PutUint64(timeNow, uint64(time.Now().UnixNano()))
_, _ = uniqueID.Write(timeNow)
return uniqueID.Sum32()
}