open-consul/agent/grpc-external/services/peerstream/stream_tracker.go

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package peerstream
import (
"fmt"
"sync"
"time"
"github.com/hashicorp/consul/agent/structs"
)
// Tracker contains a map of (PeerID -> MutableStatus).
// As streams are opened and closed we track details about their status.
type Tracker struct {
mu sync.RWMutex
streams map[string]*MutableStatus
// heartbeatTimeout is the max duration a connection is allowed to be
// disconnected before the stream health is reported as non-healthy
heartbeatTimeout time.Duration
// timeNow is a shim for testing.
timeNow func() time.Time
}
func NewTracker(heartbeatTimeout time.Duration) *Tracker {
if heartbeatTimeout == 0 {
heartbeatTimeout = defaultIncomingHeartbeatTimeout
}
return &Tracker{
streams: make(map[string]*MutableStatus),
timeNow: time.Now,
heartbeatTimeout: heartbeatTimeout,
}
}
// setClock is used for debugging purposes only.
func (t *Tracker) setClock(clock func() time.Time) {
if clock == nil {
t.timeNow = time.Now
} else {
t.timeNow = clock
}
}
// Register a stream for a given peer but do not mark it as connected.
func (t *Tracker) Register(id string) (*MutableStatus, error) {
t.mu.Lock()
defer t.mu.Unlock()
status, _, err := t.registerLocked(id, false)
return status, err
}
func (t *Tracker) registerLocked(id string, initAsConnected bool) (*MutableStatus, bool, error) {
status, ok := t.streams[id]
if !ok {
status = newMutableStatus(t.timeNow, initAsConnected)
t.streams[id] = status
return status, true, nil
}
return status, false, nil
}
// Connected registers a stream for a given peer, and marks it as connected.
// It also enforces that there is only one active stream for a peer.
func (t *Tracker) Connected(id string) (*MutableStatus, error) {
t.mu.Lock()
defer t.mu.Unlock()
return t.connectedLocked(id)
}
func (t *Tracker) connectedLocked(id string) (*MutableStatus, error) {
status, newlyRegistered, err := t.registerLocked(id, true)
if err != nil {
return nil, err
} else if newlyRegistered {
return status, nil
}
if status.IsConnected() {
return nil, fmt.Errorf("there is an active stream for the given PeerID %q", id)
}
status.TrackConnected()
return status, nil
}
// DisconnectedGracefully marks the peer id's stream status as disconnected gracefully.
func (t *Tracker) DisconnectedGracefully(id string) {
t.mu.Lock()
defer t.mu.Unlock()
if status, ok := t.streams[id]; ok {
status.TrackDisconnectedGracefully()
}
}
// DisconnectedDueToError marks the peer id's stream status as disconnected due to an error.
func (t *Tracker) DisconnectedDueToError(id string, error string) {
t.mu.Lock()
defer t.mu.Unlock()
if status, ok := t.streams[id]; ok {
status.TrackDisconnectedDueToError(error)
}
}
func (t *Tracker) StreamStatus(id string) (resp Status, found bool) {
t.mu.RLock()
defer t.mu.RUnlock()
s, ok := t.streams[id]
if !ok {
return Status{
NeverConnected: true,
}, false
}
return s.GetStatus(), true
}
func (t *Tracker) ConnectedStreams() map[string]chan struct{} {
t.mu.RLock()
defer t.mu.RUnlock()
resp := make(map[string]chan struct{})
for peer, status := range t.streams {
if status.IsConnected() {
resp[peer] = status.doneCh
}
}
return resp
}
func (t *Tracker) DeleteStatus(id string) {
t.mu.Lock()
defer t.mu.Unlock()
delete(t.streams, id)
}
// IsHealthy is a calculates the health of a peering status.
// We define a peering as unhealthy if its status has been in the following
// states for longer than the configured incomingHeartbeatTimeout.
// - If it is disconnected
// - If the last received Nack is newer than last received Ack
// - If the last received error is newer than last received success
//
// If none of these conditions apply, we call the peering healthy.
func (t *Tracker) IsHealthy(s Status) bool {
// If stream is in a disconnected state for longer than the configured
// heartbeat timeout, report as unhealthy.
if !s.DisconnectTime.IsZero() &&
t.timeNow().Sub(s.DisconnectTime) > t.heartbeatTimeout {
return false
}
// If last Nack is after last Ack, it means the peer is unable to
// handle our replication message.
if s.LastNack.After(s.LastAck) &&
t.timeNow().Sub(s.LastAck) > t.heartbeatTimeout {
return false
}
// If last recv error is newer than last recv success, we were unable
// to handle the peer's replication message.
if s.LastRecvError.After(s.LastRecvResourceSuccess) &&
t.timeNow().Sub(s.LastRecvError) > t.heartbeatTimeout {
return false
}
return true
}
type MutableStatus struct {
mu sync.RWMutex
// timeNow is a shim for testing.
timeNow func() time.Time
// doneCh allows for shutting down a stream gracefully by sending a termination message
// to the peer before the stream's context is cancelled.
doneCh chan struct{}
Status
}
// Status contains information about the replication stream to a peer cluster.
// TODO(peering): There's a lot of fields here...
type Status struct {
// Connected is true when there is an open stream for the peer.
Connected bool
// NeverConnected is true for peerings that have never connected, false otherwise.
NeverConnected bool
// DisconnectErrorMessage tracks the error that caused the stream to disconnect non-gracefully.
// If the stream is connected or it disconnected gracefully it will be empty.
DisconnectErrorMessage string
// If the status is not connected, DisconnectTime tracks when the stream was closed. Else it's zero.
DisconnectTime time.Time
// LastAck tracks the time we received the last ACK for a resource replicated TO the peer.
LastAck time.Time
// LastNack tracks the time we received the last NACK for a resource replicated to the peer.
LastNack time.Time
// LastNackMessage tracks the reported error message associated with the last NACK from a peer.
LastNackMessage string
// LastSendError tracks the time of the last error sending into the stream.
LastSendError time.Time
// LastSendErrorMessage tracks the last error message when sending into the stream.
LastSendErrorMessage string
// LastSendSuccess tracks the time we last successfully sent a resource TO the peer.
LastSendSuccess time.Time
// LastRecvHeartbeat tracks when we last received a heartbeat from our peer.
LastRecvHeartbeat time.Time
// LastRecvResourceSuccess tracks the time we last successfully stored a resource replicated FROM the peer.
LastRecvResourceSuccess time.Time
// LastRecvError tracks either:
// - The time we failed to store a resource replicated FROM the peer.
// - The time of the last error when receiving from the stream.
LastRecvError time.Time
// LastRecvErrorMessage tracks the last error message when receiving from the stream.
LastRecvErrorMessage string
// TODO(peering): consider keeping track of imported and exported services thru raft
// ImportedServices keeps track of which service names are imported for the peer
ImportedServices []string
// ExportedServices keeps track of which service names a peer asks to export
ExportedServices []string
}
func (s *Status) GetImportedServicesCount() uint64 {
return uint64(len(s.ImportedServices))
}
func (s *Status) GetExportedServicesCount() uint64 {
return uint64(len(s.ExportedServices))
}
func newMutableStatus(now func() time.Time, connected bool) *MutableStatus {
return &MutableStatus{
Status: Status{
Connected: connected,
NeverConnected: !connected,
},
timeNow: now,
doneCh: make(chan struct{}),
}
}
func (s *MutableStatus) Done() <-chan struct{} {
return s.doneCh
}
func (s *MutableStatus) TrackAck() {
s.mu.Lock()
s.LastAck = s.timeNow().UTC()
s.mu.Unlock()
}
func (s *MutableStatus) TrackSendError(error string) {
s.mu.Lock()
s.LastSendError = s.timeNow().UTC()
s.LastSendErrorMessage = error
s.mu.Unlock()
}
func (s *MutableStatus) TrackSendSuccess() {
s.mu.Lock()
s.LastSendSuccess = s.timeNow().UTC()
s.mu.Unlock()
}
// TrackRecvResourceSuccess tracks receiving a replicated resource.
func (s *MutableStatus) TrackRecvResourceSuccess() {
s.mu.Lock()
s.LastRecvResourceSuccess = s.timeNow().UTC()
s.mu.Unlock()
}
// TrackRecvHeartbeat tracks receiving a heartbeat from our peer.
func (s *MutableStatus) TrackRecvHeartbeat() {
s.mu.Lock()
s.LastRecvHeartbeat = s.timeNow().UTC()
s.mu.Unlock()
}
func (s *MutableStatus) TrackRecvError(error string) {
s.mu.Lock()
s.LastRecvError = s.timeNow().UTC()
s.LastRecvErrorMessage = error
s.mu.Unlock()
}
func (s *MutableStatus) TrackNack(msg string) {
s.mu.Lock()
s.LastNack = s.timeNow().UTC()
s.LastNackMessage = msg
s.mu.Unlock()
}
func (s *MutableStatus) TrackConnected() {
s.mu.Lock()
s.Connected = true
s.DisconnectTime = time.Time{}
s.DisconnectErrorMessage = ""
s.mu.Unlock()
}
// TrackDisconnectedGracefully tracks when the stream was disconnected in a way we expected.
// For example, we got a terminated message, or we terminated the stream ourselves.
func (s *MutableStatus) TrackDisconnectedGracefully() {
s.mu.Lock()
s.Connected = false
s.DisconnectTime = s.timeNow().UTC()
s.DisconnectErrorMessage = ""
s.mu.Unlock()
}
// TrackDisconnectedDueToError tracks when the stream was disconnected due to an error.
// For example the heartbeat timed out, or we couldn't send into the stream.
func (s *MutableStatus) TrackDisconnectedDueToError(error string) {
s.mu.Lock()
s.Connected = false
s.DisconnectTime = s.timeNow().UTC()
s.DisconnectErrorMessage = error
s.mu.Unlock()
}
func (s *MutableStatus) IsConnected() bool {
var resp bool
s.mu.RLock()
resp = s.Connected
s.mu.RUnlock()
return resp
}
func (s *MutableStatus) GetStatus() Status {
s.mu.RLock()
copy := s.Status
s.mu.RUnlock()
return copy
}
func (s *MutableStatus) SetImportedServices(serviceNames []structs.ServiceName) {
s.mu.Lock()
defer s.mu.Unlock()
s.ImportedServices = make([]string, len(serviceNames))
for i, sn := range serviceNames {
s.ImportedServices[i] = sn.Name
}
}
func (s *MutableStatus) GetImportedServicesCount() int {
s.mu.RLock()
defer s.mu.RUnlock()
return len(s.ImportedServices)
}
func (s *MutableStatus) SetExportedServices(serviceNames []structs.ServiceName) {
s.mu.Lock()
defer s.mu.Unlock()
s.ExportedServices = make([]string, len(serviceNames))
for i, sn := range serviceNames {
s.ExportedServices[i] = sn.Name
}
}
func (s *MutableStatus) GetExportedServicesCount() int {
s.mu.RLock()
defer s.mu.RUnlock()
return len(s.ExportedServices)
}