open-consul/agent/consul/leader_peering.go

252 lines
8.2 KiB
Go

package consul
import (
"container/ring"
"context"
"crypto/tls"
"crypto/x509"
"fmt"
"net"
"github.com/hashicorp/consul/agent/rpc/peering"
"github.com/hashicorp/go-hclog"
"github.com/hashicorp/go-memdb"
"github.com/hashicorp/go-multierror"
"github.com/hashicorp/go-uuid"
"google.golang.org/grpc"
"google.golang.org/grpc/credentials"
"github.com/hashicorp/consul/agent/pool"
"github.com/hashicorp/consul/agent/structs"
"github.com/hashicorp/consul/proto/pbpeering"
)
func (s *Server) startPeeringStreamSync(ctx context.Context) {
s.leaderRoutineManager.Start(ctx, peeringStreamsRoutineName, s.runPeeringSync)
}
func (s *Server) runPeeringSync(ctx context.Context) error {
logger := s.logger.Named("peering-syncer")
cancelFns := make(map[string]context.CancelFunc)
retryLoopBackoff(ctx, func() error {
if err := s.syncPeeringsAndBlock(ctx, logger, cancelFns); err != nil {
return err
}
return nil
}, func(err error) {
s.logger.Error("error syncing peering streams from state store", "error", err)
})
return nil
}
func (s *Server) stopPeeringStreamSync() {
// will be a no-op when not started
s.leaderRoutineManager.Stop(peeringStreamsRoutineName)
}
// syncPeeringsAndBlock is a long-running goroutine that is responsible for watching
// changes to peerings in the state store and managing streams to those peers.
func (s *Server) syncPeeringsAndBlock(ctx context.Context, logger hclog.Logger, cancelFns map[string]context.CancelFunc) error {
state := s.fsm.State()
// Pull the state store contents and set up to block for changes.
ws := memdb.NewWatchSet()
ws.Add(state.AbandonCh())
ws.Add(ctx.Done())
_, peers, err := state.PeeringList(ws, *structs.NodeEnterpriseMetaInPartition(structs.WildcardSpecifier))
if err != nil {
return err
}
// TODO(peering) Adjust this debug info.
// Generate a UUID to trace different passes through this function.
seq, err := uuid.GenerateUUID()
if err != nil {
s.logger.Debug("failed to generate sequence uuid while syncing peerings")
}
logger.Trace("syncing new list of peers", "num_peers", len(peers), "sequence_id", seq)
// Stored tracks the unique set of peers that should be dialed.
// It is used to reconcile the list of active streams.
stored := make(map[string]struct{})
var merr *multierror.Error
// Create connections and streams to peers in the state store that do not have an active stream.
for _, peer := range peers {
logger.Trace("evaluating stored peer", "peer", peer.Name, "should_dial", peer.ShouldDial(), "sequence_id", seq)
if !peer.ShouldDial() {
continue
}
// TODO(peering) Account for deleted peers that are still in the state store
stored[peer.ID] = struct{}{}
status, found := s.peeringService.StreamStatus(peer.ID)
// TODO(peering): If there is new peering data and a connected stream, should we tear down the stream?
// If the data in the updated token is bad, the user wouldn't know until the old servers/certs become invalid.
// Alternatively we could do a basic Ping from the initiate peering endpoint to avoid dealing with that here.
if found && status.Connected {
// Nothing to do when we already have an active stream to the peer.
continue
}
logger.Trace("ensuring stream to peer", "peer_id", peer.ID, "sequence_id", seq)
if cancel, ok := cancelFns[peer.ID]; ok {
// If the peer is known but we're not connected, clean up the retry-er and start over.
// There may be new data in the state store that would enable us to get out of an error state.
logger.Trace("cancelling context to re-establish stream", "peer_id", peer.ID, "sequence_id", seq)
cancel()
}
if err := s.establishStream(ctx, logger, peer, cancelFns); err != nil {
// TODO(peering): These errors should be reported in the peer status, otherwise they're only in the logs.
// Lockable status isn't available here though. Could report it via the peering.Service?
logger.Error("error establishing peering stream", "peer_id", peer.ID, "error", err)
merr = multierror.Append(merr, err)
// Continue on errors to avoid one bad peering from blocking the establishment and cleanup of others.
continue
}
}
logger.Trace("checking connected streams", "streams", s.peeringService.ConnectedStreams(), "sequence_id", seq)
// Clean up active streams of peerings that were deleted from the state store.
// TODO(peering): This is going to trigger shutting down peerings we generated a token for. Is that OK?
for stream, doneCh := range s.peeringService.ConnectedStreams() {
if _, ok := stored[stream]; ok {
// Active stream is in the state store, nothing to do.
continue
}
select {
case <-doneCh:
// channel is closed, do nothing to avoid a panic
default:
logger.Trace("tearing down stream for deleted peer", "peer_id", stream, "sequence_id", seq)
close(doneCh)
}
}
logger.Trace("blocking for changes", "sequence_id", seq)
// Block for any changes to the state store.
ws.WatchCtx(ctx)
logger.Trace("unblocked", "sequence_id", seq)
return merr.ErrorOrNil()
}
func (s *Server) establishStream(ctx context.Context, logger hclog.Logger, peer *pbpeering.Peering, cancelFns map[string]context.CancelFunc) error {
tlsOption := grpc.WithInsecure()
if len(peer.PeerCAPems) > 0 {
var haveCerts bool
pool := x509.NewCertPool()
for _, pem := range peer.PeerCAPems {
if !pool.AppendCertsFromPEM([]byte(pem)) {
return fmt.Errorf("failed to parse PEM %s", pem)
}
if len(pem) > 0 {
haveCerts = true
}
}
if !haveCerts {
return fmt.Errorf("failed to build cert pool from peer CA pems")
}
cfg := tls.Config{
ServerName: peer.PeerServerName,
RootCAs: pool,
}
tlsOption = grpc.WithTransportCredentials(credentials.NewTLS(&cfg))
}
// Create a ring buffer to cycle through peer addresses in the retry loop below.
buffer := ring.New(len(peer.PeerServerAddresses))
for _, addr := range peer.PeerServerAddresses {
buffer.Value = addr
buffer = buffer.Next()
}
logger.Trace("establishing stream to peer", "peer_id", peer.ID)
retryCtx, cancel := context.WithCancel(ctx)
cancelFns[peer.ID] = cancel
// Establish a stream-specific retry so that retrying stream/conn errors isn't dependent on state store changes.
go retryLoopBackoff(retryCtx, func() error {
// Try a new address on each iteration by advancing the ring buffer on errors.
defer func() {
buffer = buffer.Next()
}()
addr, ok := buffer.Value.(string)
if !ok {
return fmt.Errorf("peer server address type %T is not a string", buffer.Value)
}
logger.Trace("dialing peer", "peer_id", peer.ID, "addr", addr)
conn, err := grpc.DialContext(retryCtx, addr,
grpc.WithContextDialer(newPeerDialer(addr)),
grpc.WithBlock(),
tlsOption,
)
if err != nil {
return fmt.Errorf("failed to dial: %w", err)
}
defer conn.Close()
client := pbpeering.NewPeeringServiceClient(conn)
stream, err := client.StreamResources(retryCtx)
if err != nil {
return err
}
err = s.peeringService.HandleStream(peering.HandleStreamRequest{
LocalID: peer.ID,
RemoteID: peer.PeerID,
PeerName: peer.Name,
Partition: peer.Partition,
Stream: stream,
})
if err == nil {
// This will cancel the retry-er context, letting us break out of this loop when we want to shut down the stream.
cancel()
}
return err
}, func(err error) {
// TODO(peering): These errors should be reported in the peer status, otherwise they're only in the logs.
// Lockable status isn't available here though. Could report it via the peering.Service?
logger.Error("error managing peering stream", "peer_id", peer.ID, "error", err)
})
return nil
}
func newPeerDialer(peerAddr string) func(context.Context, string) (net.Conn, error) {
return func(ctx context.Context, addr string) (net.Conn, error) {
d := net.Dialer{}
conn, err := d.DialContext(ctx, "tcp", peerAddr)
if err != nil {
return nil, err
}
// TODO(peering): This is going to need to be revisited. This type uses the TLS settings configured on the agent, but
// for peering we never want mutual TLS because the client peer doesn't share its CA cert.
_, err = conn.Write([]byte{byte(pool.RPCGRPC)})
if err != nil {
conn.Close()
return nil, err
}
return conn, nil
}
}