consul/agent/grpc-external/services/peerstream/subscription_blocking.go

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package peerstream
import (
"context"
"errors"
"fmt"
"time"
"github.com/hashicorp/go-memdb"
"github.com/hashicorp/consul/agent/cache"
"github.com/hashicorp/consul/agent/structs"
"github.com/hashicorp/consul/lib/retry"
Protobuf Refactoring for Multi-Module Cleanliness (#16302) Protobuf Refactoring for Multi-Module Cleanliness This commit includes the following: Moves all packages that were within proto/ to proto/private Rewrites imports to account for the packages being moved Adds in buf.work.yaml to enable buf workspaces Names the proto-public buf module so that we can override the Go package imports within proto/buf.yaml Bumps the buf version dependency to 1.14.0 (I was trying out the version to see if it would get around an issue - it didn't but it also doesn't break things and it seemed best to keep up with the toolchain changes) Why: In the future we will need to consume other protobuf dependencies such as the Google HTTP annotations for openapi generation or grpc-gateway usage. There were some recent changes to have our own ratelimiting annotations. The two combined were not working when I was trying to use them together (attempting to rebase another branch) Buf workspaces should be the solution to the problem Buf workspaces means that each module will have generated Go code that embeds proto file names relative to the proto dir and not the top level repo root. This resulted in proto file name conflicts in the Go global protobuf type registry. The solution to that was to add in a private/ directory into the path within the proto/ directory. That then required rewriting all the imports. Is this safe? AFAICT yes The gRPC wire protocol doesn't seem to care about the proto file names (although the Go grpc code does tack on the proto file name as Metadata in the ServiceDesc) Other than imports, there were no changes to any generated code as a result of this.
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"github.com/hashicorp/consul/proto/private/pbservice"
)
// This file contains direct state store functions that need additional
// management to have them emit events. Ideally these would go through
// streaming machinery instead to be cheaper.
func (m *subscriptionManager) notifyExportedServicesForPeerID(ctx context.Context, state *subscriptionState, peerID string) {
// Wait until this is subscribed-to.
select {
case <-m.serviceSubReady:
case <-ctx.Done():
return
}
// syncSubscriptionsAndBlock ensures that the subscriptions to the subscription backend
// match the list of services exported to the peer.
m.syncViaBlockingQuery(ctx, "exported-services", func(ctx context.Context, store StateStore, ws memdb.WatchSet) (interface{}, error) {
// Get exported services for peer id
_, list, err := store.ExportedServicesForPeer(ws, peerID, m.config.Datacenter)
if err != nil {
return nil, fmt.Errorf("failed to watch exported services for peer %q: %w", peerID, err)
}
return list, nil
}, subExportedServiceList, state.updateCh)
}
// TODO: add a new streaming subscription type to list-by-kind-and-partition since we're getting evictions
func (m *subscriptionManager) notifyMeshGatewaysForPartition(ctx context.Context, state *subscriptionState, partition string) {
// Wait until this is subscribed-to.
select {
case <-m.serviceSubReady:
case <-ctx.Done():
return
}
m.syncViaBlockingQuery(ctx, "mesh-gateways", func(ctx context.Context, store StateStore, ws memdb.WatchSet) (interface{}, error) {
// Fetch our current list of all mesh gateways.
entMeta := structs.DefaultEnterpriseMetaInPartition(partition)
idx, nodes, err := store.ServiceDump(ws, structs.ServiceKindMeshGateway, true, entMeta, structs.DefaultPeerKeyword)
if err != nil {
return nil, fmt.Errorf("failed to watch mesh gateways services for partition %q: %w", partition, err)
}
if idx == 0 {
idx = 1
}
// convert back to a protobuf flavor
result := &pbservice.IndexedCheckServiceNodes{
Index: idx,
Nodes: make([]*pbservice.CheckServiceNode, len(nodes)),
}
for i, csn := range nodes {
result.Nodes[i] = pbservice.NewCheckServiceNodeFromStructs(&csn)
}
return result, nil
}, subMeshGateway+partition, state.updateCh)
}
func (m *subscriptionManager) syncViaBlockingQuery(
ctx context.Context,
queryType string,
queryFn func(ctx context.Context, store StateStore, ws memdb.WatchSet) (interface{}, error),
correlationID string,
updateCh chan<- cache.UpdateEvent,
) {
waiter := &retry.Waiter{
MinFailures: 1,
Factor: 500 * time.Millisecond,
MaxWait: 60 * time.Second,
Jitter: retry.NewJitter(100),
}
logger := m.logger
if queryType != "" {
logger = m.logger.With("queryType", queryType)
}
store := m.getStore()
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for ctx.Err() == nil {
ws := memdb.NewWatchSet()
ws.Add(store.AbandonCh())
ws.Add(ctx.Done())
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if result, err := queryFn(ctx, store, ws); err != nil {
// Return immediately if the context was cancelled.
if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
return
}
logger.Error("failed to sync from query", "error", err)
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waiter.Wait(ctx)
} else {
select {
case <-ctx.Done():
return
case updateCh <- cache.UpdateEvent{CorrelationID: correlationID, Result: result}:
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waiter.Reset()
}
// Block for any changes to the state store.
ws.WatchCtx(ctx)
}
}
}