From e6bb45dcd5f65cec9ec9a5d286aeee305b6bd3e5 Mon Sep 17 00:00:00 2001
From: Jack Westwood <jack.westwood@couchbase.com>
Date: Fri, 24 Oct 2025 14:57:24 +0100
Subject: [PATCH] ING-1307: Initial implementation of watchRouting

---
 gateway/dataimpl/dataimpl.go                |   7 ++
 gateway/dataimpl/server_v1/routingserver.go | 107 ++++++++++++++++++++
 gateway/system/system.go                    |   2 +
 3 files changed, 116 insertions(+)
 create mode 100644 gateway/dataimpl/server_v1/routingserver.go

diff --git a/gateway/dataimpl/dataimpl.go b/gateway/dataimpl/dataimpl.go
index e93585e7..441de3eb 100644
--- a/gateway/dataimpl/dataimpl.go
+++ b/gateway/dataimpl/dataimpl.go
@@ -26,6 +26,7 @@ type Servers struct {
 	AdminQueryIndexV1Server  *server_v1.QueryIndexAdminServer
 	AdminSearchIndexV1Server *server_v1.SearchIndexAdminServer
 	TransactionsV1Server     *server_v1.TransactionsServer
+	RoutingServer            *server_v1.RoutingServer
 }
 
 func New(opts *NewOptions) *Servers {
@@ -87,5 +88,11 @@ func New(opts *NewOptions) *Servers {
 			v1ErrHandler,
 			v1AuthHandler,
 		),
+		RoutingServer: server_v1.NewRoutingServer(
+			opts.Logger.Named("routing"),
+			v1ErrHandler,
+			v1AuthHandler,
+			opts.CbClient,
+		),
 	}
 }
diff --git a/gateway/dataimpl/server_v1/routingserver.go b/gateway/dataimpl/server_v1/routingserver.go
new file mode 100644
index 00000000..badeaa94
--- /dev/null
+++ b/gateway/dataimpl/server_v1/routingserver.go
@@ -0,0 +1,107 @@
+package server_v1
+
+import (
+	"context"
+	"time"
+
+	"github.com/couchbase/gocbcorex"
+	"github.com/couchbase/gocbcorex/cbmgmtx"
+	"github.com/couchbase/gocbcorex/contrib/cbconfig"
+	"github.com/couchbase/stellar-gateway/contrib/goprotostellar/genproto/routing_v1"
+	"go.uber.org/zap"
+)
+
+type RoutingServer struct {
+	routing_v1.UnimplementedRoutingServiceServer
+
+	logger       *zap.Logger
+	errorHandler *ErrorHandler
+	authHandler  *AuthHandler
+	cbClient     *gocbcorex.BucketsTrackingAgentManager
+}
+
+func NewRoutingServer(
+	logger *zap.Logger,
+	errorHandler *ErrorHandler,
+	authHandler *AuthHandler,
+	cbClient *gocbcorex.BucketsTrackingAgentManager,
+) *RoutingServer {
+	return &RoutingServer{
+		logger:       logger,
+		errorHandler: errorHandler,
+		authHandler:  authHandler,
+		cbClient:     cbClient,
+	}
+}
+
+func (s *RoutingServer) WatchRouting(
+	in *routing_v1.WatchRoutingRequest,
+	out routing_v1.RoutingService_WatchRoutingServer,
+) error {
+	bucketAgent, _, errSt := s.authHandler.GetMemdOboAgent(out.Context(), *in.BucketName)
+	if errSt != nil {
+		return errSt.Err()
+	}
+
+	ticker := time.NewTicker(5 * time.Second)
+	var prevVBucketMap cbconfig.VBucketServerMapJson
+	for {
+		bucket, err := bucketAgent.GetBucket(context.Background(), &cbmgmtx.GetBucketOptions{BucketName: *in.BucketName})
+		if err != nil {
+			return err
+		}
+
+		if !prevVBucketMap.Equal(*bucket.RawConfig.VBucketServerMap) {
+			prevVBucketMap = *bucket.RawConfig.VBucketServerMap
+
+			var resp routing_v1.WatchRoutingResponse
+			var dataRoutingEps []*routing_v1.DataRoutingEndpoint
+			for i, addr := range bucket.RawConfig.VBucketServerMap.ServerList {
+				resp.Endpoints = append(resp.Endpoints, &routing_v1.RoutingEndpoint{
+					// TO DO -figure out what this ID is supposed to be
+					Id: "",
+					// TODO - get the server group from somewhere
+					ServerGroup: "",
+					Address:     addr,
+				})
+
+				localVBuckets := localVBuckets(i, bucket.RawConfig.VBucketServerMap.VBucketMap)
+
+				dataRoutingEps = append(dataRoutingEps, &routing_v1.DataRoutingEndpoint{
+					EndpointIdx:   uint32(i),
+					LocalVbuckets: localVBuckets,
+					// TODO - implement funcitonality to get group vBuckets
+					GroupVbuckets: []uint32{},
+				})
+			}
+			resp.DataRouting = &routing_v1.WatchRoutingResponse_VbucketDataRouting{
+				VbucketDataRouting: &routing_v1.VbucketDataRoutingStrategy{
+					Endpoints: dataRoutingEps,
+				},
+			}
+
+			err = out.Send(&resp)
+			if err != nil {
+				return err
+			}
+		}
+
+		select {
+		case <-out.Context().Done():
+			return nil
+		case <-ticker.C:
+		}
+	}
+}
+
+// At the moment this will just return the vBuckets that are local for the master
+// copy, need to consider what to do about other replicas
+func localVBuckets(serverIndex int, vbMap [][]int) []uint32 {
+	var vbIds []uint32
+	for i, vBucket := range vbMap {
+		if vBucket[0] == serverIndex {
+			vbIds = append(vbIds, uint32(i))
+		}
+	}
+	return vbIds
+}
diff --git a/gateway/system/system.go b/gateway/system/system.go
index 03729360..d7ea0226 100644
--- a/gateway/system/system.go
+++ b/gateway/system/system.go
@@ -30,6 +30,7 @@ import (
 	"github.com/couchbase/goprotostellar/genproto/kv_v1"
 	"github.com/couchbase/goprotostellar/genproto/query_v1"
 	"github.com/couchbase/goprotostellar/genproto/search_v1"
+	"github.com/couchbase/stellar-gateway/contrib/goprotostellar/genproto/routing_v1"
 	"github.com/couchbase/stellar-gateway/contrib/oapimetrics"
 	"github.com/couchbase/stellar-gateway/dataapiv1"
 	"github.com/couchbase/stellar-gateway/gateway/apiversion"
@@ -131,6 +132,7 @@ func NewSystem(opts *SystemOptions) (*System, error) {
 	admin_collection_v1.RegisterCollectionAdminServiceServer(dataSrv, dataImpl.AdminCollectionV1Server)
 	admin_query_v1.RegisterQueryAdminServiceServer(dataSrv, dataImpl.AdminQueryIndexV1Server)
 	admin_search_v1.RegisterSearchAdminServiceServer(dataSrv, dataImpl.AdminSearchIndexV1Server)
+	routing_v1.RegisterRoutingServiceServer(dataSrv, dataImpl.RoutingServer)
 
 	// health check
 	healthServer := health.NewServer()