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

177 lines
4.2 KiB
Go

package peerstream
import (
"context"
"crypto/sha256"
"encoding/hex"
"fmt"
"strings"
"github.com/golang/protobuf/proto"
"github.com/hashicorp/go-hclog"
"github.com/hashicorp/consul/agent/cache"
"github.com/hashicorp/consul/agent/structs"
"github.com/hashicorp/consul/proto/pbservice"
)
// subscriptionState is a collection of working state tied to a peerID subscription.
type subscriptionState struct {
// peerName is immutable and is the LOCAL name for the peering
peerName string
// partition is immutable
partition string
// plain data
exportList *structs.ExportedServiceList
watchedServices map[structs.ServiceName]context.CancelFunc
connectServices map[structs.ServiceName]structs.ExportedDiscoveryChainInfo
// eventVersions is a duplicate event suppression system keyed by the "id"
// not the "correlationID"
eventVersions map[string]string
meshGateway *pbservice.IndexedCheckServiceNodes
// updateCh is an internal implementation detail for the machinery of the
// manager.
updateCh chan<- cache.UpdateEvent
// publicUpdateCh is the channel the manager uses to pass data back to the
// caller.
publicUpdateCh chan<- cache.UpdateEvent
}
func newSubscriptionState(peerName, partition string) *subscriptionState {
return &subscriptionState{
peerName: peerName,
partition: partition,
watchedServices: make(map[structs.ServiceName]context.CancelFunc),
connectServices: make(map[structs.ServiceName]structs.ExportedDiscoveryChainInfo),
eventVersions: make(map[string]string),
}
}
func (s *subscriptionState) sendPendingEvents(
ctx context.Context,
logger hclog.Logger,
pending *pendingPayload,
) {
for _, pendingEvt := range pending.Events {
cID := pendingEvt.CorrelationID
newVersion := pendingEvt.Version
oldVersion, ok := s.eventVersions[pendingEvt.ID]
if ok && newVersion == oldVersion {
logger.Trace("skipping send of duplicate public event", "correlationID", cID)
continue
}
logger.Trace("sending public event", "correlationID", cID)
s.eventVersions[pendingEvt.ID] = newVersion
evt := cache.UpdateEvent{
CorrelationID: cID,
Result: pendingEvt.Result,
}
select {
case s.publicUpdateCh <- evt:
case <-ctx.Done():
}
}
}
func (s *subscriptionState) cleanupEventVersions(logger hclog.Logger) {
for id := range s.eventVersions {
keep := false
switch {
case id == meshGatewayPayloadID:
keep = true
case id == caRootsPayloadID:
keep = true
case id == serverAddrsPayloadID:
keep = true
case strings.HasPrefix(id, servicePayloadIDPrefix):
name := strings.TrimPrefix(id, servicePayloadIDPrefix)
sn := structs.ServiceNameFromString(name)
if _, ok := s.watchedServices[sn]; ok {
keep = true
}
case strings.HasPrefix(id, discoveryChainPayloadIDPrefix):
name := strings.TrimPrefix(id, discoveryChainPayloadIDPrefix)
sn := structs.ServiceNameFromString(name)
if _, ok := s.connectServices[sn]; ok {
keep = true
}
}
if !keep {
logger.Trace("cleaning up unreferenced event id version", "id", id)
delete(s.eventVersions, id)
}
}
}
type pendingPayload struct {
Events []pendingEvent
}
type pendingEvent struct {
ID string
CorrelationID string
Result proto.Message
Version string
}
const (
serverAddrsPayloadID = "server-addrs"
caRootsPayloadID = "roots"
meshGatewayPayloadID = "mesh-gateway"
servicePayloadIDPrefix = "service:"
discoveryChainPayloadIDPrefix = "chain:"
)
func (p *pendingPayload) Add(id string, correlationID string, raw interface{}) error {
result, ok := raw.(proto.Message)
if !ok {
return fmt.Errorf("invalid type for %q event: %T", correlationID, raw)
}
version, err := hashProtobuf(result)
if err != nil {
return fmt.Errorf("error hashing %q event: %w", correlationID, err)
}
p.Events = append(p.Events, pendingEvent{
ID: id,
CorrelationID: correlationID,
Result: result,
Version: version,
})
return nil
}
func hashProtobuf(res proto.Message) (string, error) {
h := sha256.New()
buffer := proto.NewBuffer(nil)
buffer.SetDeterministic(true)
err := buffer.Marshal(res)
if err != nil {
return "", err
}
h.Write(buffer.Bytes())
buffer.Reset()
return hex.EncodeToString(h.Sum(nil)), nil
}