/
gateway.go
262 lines (236 loc) · 6.25 KB
/
gateway.go
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package dblog
import (
"context"
"encoding/binary"
"errors"
"hash/crc32"
"net"
"regexp"
"sync"
"github.com/replicase/pgcapture/pkg/cursor"
"github.com/replicase/pgcapture/pkg/pb"
"github.com/replicase/pgcapture/pkg/pgcapture"
"github.com/replicase/pgcapture/pkg/source"
"github.com/sirupsen/logrus"
"google.golang.org/grpc"
"google.golang.org/grpc/peer"
)
type Gateway struct {
pb.UnimplementedDBLogGatewayServer
SourceResolver SourceResolver
DumpInfoPuller DumpInfoPuller
}
func (s *Gateway) Serve(ctx context.Context, ln net.Listener, opts ...grpc.ServerOption) error {
server := grpc.NewServer(opts...)
pb.RegisterDBLogGatewayServer(server, s)
if ch := ctx.Done(); ch != nil {
ctx, cancel := context.WithCancel(ctx)
defer cancel()
go func(ctx context.Context) {
<-ctx.Done()
server.GracefulStop()
}(ctx)
}
return server.Serve(ln)
}
func (s *Gateway) Capture(server pb.DBLogGateway_CaptureServer) error {
request, err := server.Recv()
if err != nil {
return err
}
init := request.GetInit()
if init == nil {
return ErrCaptureInitMessageRequired
}
filter, err := tableRegexFromInit(init)
if err != nil {
return err
}
src, err := s.SourceResolver.Source(server.Context(), init.Uri)
if err != nil {
return err
}
dumper, err := s.SourceResolver.Dumper(server.Context(), init.Uri)
if err != nil {
return err
}
defer dumper.Stop()
return s.capture(init, filter, server, src, dumper)
}
func (s *Gateway) acknowledge(server pb.DBLogGateway_CaptureServer, src source.RequeueSource, dumps *dumpMap) chan error {
done := make(chan error)
go func() {
for {
request, err := server.Recv()
if err != nil {
done <- err
close(done)
return
}
if ack := request.GetAck(); ack != nil {
if ack.Checkpoint.Lsn != 0 {
if ack.RequeueReason != "" {
src.Requeue(cursor.Checkpoint{
LSN: ack.Checkpoint.Lsn,
Seq: ack.Checkpoint.Seq,
Data: ack.Checkpoint.Data,
}, ack.RequeueReason)
} else {
src.Commit(cursor.Checkpoint{
LSN: ack.Checkpoint.Lsn,
Seq: ack.Checkpoint.Seq,
Data: ack.Checkpoint.Data,
})
}
} else {
// ack.Checkpoint.Lsn == 0 for dumps
// ack.Checkpoint.Seq is dump id
// len(ack.Checkpoint.Data) == 1 for last record of dump
if len(ack.Checkpoint.Data) == 1 {
dumps.ack(ack.Checkpoint.Seq, ack.RequeueReason)
} else if ack.RequeueReason != "" {
dumps.ack(ack.Checkpoint.Seq, ack.RequeueReason)
}
}
}
}
}()
return done
}
func (s *Gateway) capture(init *pb.CaptureInit, filter *regexp.Regexp, server pb.DBLogGateway_CaptureServer, src source.RequeueSource, dumper SourceDumper) error {
var addr string
if p, ok := peer.FromContext(server.Context()); ok {
addr = p.Addr.String()
}
logger := logrus.WithFields(logrus.Fields{"URI": init.Uri, "From": "Gateway", "Peer": addr})
changes, err := src.Capture(cursor.Checkpoint{})
if err != nil {
return err
}
once := sync.Once{}
cleanUp := func() {
logger.Infof("stoping pulsar source")
go func() {
for range changes {
// this loop should do nothing and only exit when the input channel is closed
}
}()
src.Stop()
logger.Infof("pulsar source stopped")
}
go func() {
<-server.Context().Done()
once.Do(cleanUp)
}()
defer func() {
once.Do(cleanUp)
}()
logger.Infof("start capturing")
ongoingDumps := &dumpMap{m: make(map[uint32]DumpInfo, 2)}
done := s.acknowledge(server, src, ongoingDumps)
dumps := s.DumpInfoPuller.Pull(server.Context(), init.Uri)
lsn := uint64(0)
for {
select {
case <-server.Context().Done():
return server.Context().Err()
case msg, more := <-changes:
if !more {
return nil
}
if change := msg.Message.GetChange(); change != nil && (filter == nil || filter.MatchString(change.Table)) {
if err := server.Send(&pb.CaptureMessage{Checkpoint: &pb.Checkpoint{
Lsn: msg.Checkpoint.LSN,
Seq: msg.Checkpoint.Seq,
Data: msg.Checkpoint.Data,
}, Change: change}); err != nil {
return err
}
} else {
src.Commit(cursor.Checkpoint{
LSN: msg.Checkpoint.LSN,
Seq: msg.Checkpoint.Seq,
Data: msg.Checkpoint.Data,
})
}
lsn = msg.Checkpoint.LSN
case info, more := <-dumps:
if !more {
return nil
}
var dump []*pb.Change
if filter == nil || filter.MatchString(info.Resp.Table) {
dump, err = dumper.LoadDump(lsn, info.Resp)
if err != nil {
logger.WithFields(logrus.Fields{"Dump": info.Resp.String()}).Errorf("dump error %v", err)
if !errors.Is(err, ErrMissingTable) {
info.Ack(err.Error())
continue
}
}
}
if len(dump) == 0 {
info.Ack("")
continue
}
logger.WithFields(logrus.Fields{"Dump": info.Resp.String(), "Len": len(dump)}).Info("dump loaded")
dumpID := ongoingDumps.store(info)
var isLast []byte
for i, change := range dump {
if i+1 == len(dump) {
isLast = []byte{1}
}
if err = server.Send(&pb.CaptureMessage{Checkpoint: &pb.Checkpoint{
Lsn: 0,
Seq: dumpID,
Data: isLast,
}, Change: change}); err != nil {
logger.WithFields(logrus.Fields{"Dump": info.Resp.String(), "Len": len(dump), "Idx": i}).Errorf("partial dump error: %v", err)
info.Ack(err.Error())
return err
}
}
case err := <-done:
return err
}
}
}
func tableRegexFromInit(init *pb.CaptureInit) (*regexp.Regexp, error) {
if init.Parameters == nil || init.Parameters.Fields == nil {
return nil, nil
}
if regex, ok := init.Parameters.Fields[pgcapture.TableRegexOption]; ok {
return regexp.Compile(regex.GetStringValue())
}
return nil, nil
}
var (
ErrCaptureInitMessageRequired = errors.New("the first request should be a CaptureInit message")
)
type dumpMap struct {
mu sync.Mutex
m map[uint32]DumpInfo
}
func (m *dumpMap) store(info DumpInfo) uint32 {
id := dumpID(info.Resp)
m.mu.Lock()
m.m[id] = info
m.mu.Unlock()
return id
}
func (m *dumpMap) ack(id uint32, reason string) {
m.mu.Lock()
if info, ok := m.m[id]; ok {
info.Ack(reason)
delete(m.m, id)
}
m.mu.Unlock()
}
func dumpID(info *pb.DumpInfoResponse) uint32 {
sum := crc32.NewIEEE()
sum.Write([]byte(info.Schema))
sum.Write([]byte(info.Table))
binary.Write(sum, binary.BigEndian, info.PageBegin)
binary.Write(sum, binary.BigEndian, info.PageEnd)
return sum.Sum32()
}