fix(discov): prevent unbounded memory growth on duplicate etcd PUT events (#5580)

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/go.yml

@@ -40,7 +40,7 @@ jobs:
         run: go test -race -coverprofile=coverage.txt -covermode=atomic ./...
 
       - name: Codecov
-        uses: codecov/codecov-action@v5
+        uses: codecov/codecov-action@v6
         with:
           files: ./coverage.txt
           flags: unittests

core/discov/internal/registry.go

@@ -263,14 +263,24 @@ func (c *cluster) handleWatchEvents(ctx context.Context, key watchKey, events []
 	for _, ev := range events {
 		switch ev.Type {
 		case clientv3.EventTypePut:
+			evKey := string(ev.Kv.Key)
+			evVal := string(ev.Kv.Value)
 			c.lock.Lock()
-			watcher.values[string(ev.Kv.Key)] = string(ev.Kv.Value)
+			oldVal, exists := watcher.values[evKey]
+			watcher.values[evKey] = evVal
 			c.lock.Unlock()
+			if exists && oldVal == evVal {
+				// duplicate PUT with same value, skip to prevent unbounded growth
+				continue
+			}
+			if exists {
+				// key moved to a new value, notify delete of old entry first
+				for _, l := range listeners {
+					l.OnDelete(KV{Key: evKey, Val: oldVal})
+				}
+			}
 			for _, l := range listeners {
-				l.OnAdd(KV{
-					Key: string(ev.Kv.Key),
-					Val: string(ev.Kv.Value),
-				})
+				l.OnAdd(KV{Key: evKey, Val: evVal})
 			}
 		case clientv3.EventTypeDelete:
 			c.lock.Lock()
@@ -433,7 +443,7 @@ func (c *cluster) setupWatch(cli EtcdClient, key watchKey, rev int64) (context.C
 	}
 
 	ctx, cancel := context.WithCancel(cli.Ctx())
-	
+
 	c.lock.Lock()
 	if watcher, ok := c.watchers[key]; ok {
 		watcher.cancel = cancel

core/discov/internal/registry_test.go

@@ -517,7 +517,7 @@ func TestCluster_ConcurrentMonitor(t *testing.T) {
 		go func() {
 			defer wg.Done()
 			key := keys[idx%len(keys)]
-			
+
 			if idx%2 == 0 {
 				// Half the goroutines add listeners (write operation)
 				c.addListener(key, &mockListener{})
@@ -543,6 +543,50 @@ func TestCluster_ConcurrentMonitor(t *testing.T) {
 	close(c.done)
 }
 
+func TestCluster_handleWatchEvents_DuplicatePut(t *testing.T) {
+	ctrl := gomock.NewController(t)
+	defer ctrl.Finish()
+	listener := NewMockUpdateListener(ctrl)
+	// OnAdd must be called exactly once despite two PUT events with the same key+value.
+	listener.EXPECT().OnAdd(KV{Key: "hello", Val: "world"}).Times(1)
+
+	c := newCluster([]string{"any"})
+	key := watchKey{key: "any"}
+	c.watchers[key] = &watchValue{
+		listeners: []UpdateListener{listener},
+		values:    make(map[string]string),
+	}
+	events := []*clientv3.Event{
+		{Type: clientv3.EventTypePut, Kv: &mvccpb.KeyValue{Key: []byte("hello"), Value: []byte("world")}},
+		{Type: clientv3.EventTypePut, Kv: &mvccpb.KeyValue{Key: []byte("hello"), Value: []byte("world")}},
+	}
+	c.handleWatchEvents(context.Background(), key, events)
+}
+
+func TestCluster_handleWatchEvents_ValueChange(t *testing.T) {
+	ctrl := gomock.NewController(t)
+	defer ctrl.Finish()
+	listener := NewMockUpdateListener(ctrl)
+	gomock.InOrder(
+		listener.EXPECT().OnAdd(KV{Key: "hello", Val: "world1"}),
+		listener.EXPECT().OnDelete(KV{Key: "hello", Val: "world1"}),
+		listener.EXPECT().OnAdd(KV{Key: "hello", Val: "world2"}),
+	)
+
+	c := newCluster([]string{"any"})
+	key := watchKey{key: "any"}
+	c.watchers[key] = &watchValue{
+		listeners: []UpdateListener{listener},
+		values:    make(map[string]string),
+	}
+	c.handleWatchEvents(context.Background(), key, []*clientv3.Event{
+		{Type: clientv3.EventTypePut, Kv: &mvccpb.KeyValue{Key: []byte("hello"), Value: []byte("world1")}},
+	})
+	c.handleWatchEvents(context.Background(), key, []*clientv3.Event{
+		{Type: clientv3.EventTypePut, Kv: &mvccpb.KeyValue{Key: []byte("hello"), Value: []byte("world2")}},
+	})
+}
+
 type mockListener struct {
 }
 

core/discov/subscriber.go

@@ -141,12 +141,23 @@ func (c *container) addKv(key, value string) ([]string, bool) {
 	c.lock.Lock()
 	defer c.lock.Unlock()
 
+	oldVal, alreadyMapped := c.mapping[key]
+	if alreadyMapped && oldVal == value {
+		// duplicate PUT with same key+value, nothing to do
+		return nil, false
+	}
+
 	c.dirty.Set(true)
+	if alreadyMapped {
+		// key moved to a new value; remove stale entry to prevent leak
+		c.doRemoveKey(key)
+	}
+
 	keys := c.values[value]
 	previous := append([]string(nil), keys...)
 	early := len(keys) > 0
 	if c.exclusive && early {
-		for _, each := range keys {
+		for _, each := range previous {
 			c.doRemoveKey(each)
 		}
 	}

core/discov/subscriber_test.go

@@ -201,6 +201,81 @@ func TestContainer(t *testing.T) {
 	}
 }
 
+func TestContainer_DuplicateAdd(t *testing.T) {
+	c := newContainer(false)
+	// Simulate 100 duplicate PUT events for the same key+value.
+	for i := 0; i < 100; i++ {
+		c.OnAdd(internal.KV{Key: "etcd-key", Val: "host:1234"})
+	}
+	assert.ElementsMatch(t, []string{"host:1234"}, c.GetValues())
+	// Internal slice must not have grown beyond one entry.
+	c.lock.Lock()
+	assert.Len(t, c.values["host:1234"], 1)
+	c.lock.Unlock()
+}
+
+func TestContainer_KeyValueChange(t *testing.T) {
+	c := newContainer(false)
+	c.OnAdd(internal.KV{Key: "etcd-key", Val: "host:1234"})
+	assert.ElementsMatch(t, []string{"host:1234"}, c.GetValues())
+
+	// Key moves to a different server value.
+	c.OnAdd(internal.KV{Key: "etcd-key", Val: "host:5678"})
+	assert.ElementsMatch(t, []string{"host:5678"}, c.GetValues())
+
+	// Old server must be fully removed; a subsequent delete must leave nothing.
+	c.OnDelete(internal.KV{Key: "etcd-key", Val: "host:5678"})
+	assert.Empty(t, c.GetValues())
+}
+
+// TestContainer_ExclusiveMode verifies that adding successive keys for the same
+// value in exclusive mode leaves only the latest key and evicts all prior ones.
+func TestContainer_ExclusiveMode(t *testing.T) {
+	c := newContainer(true)
+	c.OnAdd(internal.KV{Key: "key1", Val: "server1"})
+	c.OnAdd(internal.KV{Key: "key2", Val: "server1"})
+	c.OnAdd(internal.KV{Key: "key3", Val: "server1"})
+
+	assert.ElementsMatch(t, []string{"server1"}, c.GetValues())
+	c.lock.Lock()
+	assert.Equal(t, []string{"key3"}, c.values["server1"], "only the latest key must remain")
+	assert.NotContains(t, c.mapping, "key1", "key1 must have been evicted")
+	assert.NotContains(t, c.mapping, "key2", "key2 must have been evicted")
+	assert.Equal(t, "server1", c.mapping["key3"])
+	c.lock.Unlock()
+}
+
+// TestContainer_ExclusiveMode_MultipleEvictions injects 3 keys for the same
+// value directly into internal state and then triggers the exclusive eviction
+// loop via OnAdd. This exercises the range-over-previous fix: iterating over
+// the live slice (range keys) would corrupt iteration when doRemoveKey
+// compacts the shared underlying array in-place, causing the second and third
+// keys to be skipped; ranging over the deep copy (range previous) is safe.
+func TestContainer_ExclusiveMode_MultipleEvictions(t *testing.T) {
+	c := newContainer(true)
+
+	// Bypass the exclusive invariant to simulate 3 pre-existing keys for the
+	// same value — the state that would expose the in-place aliasing bug.
+	c.lock.Lock()
+	c.values["server1"] = []string{"key1", "key2", "key3"}
+	c.mapping["key1"] = "server1"
+	c.mapping["key2"] = "server1"
+	c.mapping["key3"] = "server1"
+	c.lock.Unlock()
+
+	// Adding key4 must evict all three existing keys via the exclusive loop.
+	c.OnAdd(internal.KV{Key: "key4", Val: "server1"})
+
+	assert.ElementsMatch(t, []string{"server1"}, c.GetValues())
+	c.lock.Lock()
+	assert.Equal(t, []string{"key4"}, c.values["server1"], "all prior keys must be evicted")
+	assert.NotContains(t, c.mapping, "key1", "key1 must be evicted")
+	assert.NotContains(t, c.mapping, "key2", "key2 must be evicted")
+	assert.NotContains(t, c.mapping, "key3", "key3 must be evicted")
+	assert.Equal(t, "server1", c.mapping["key4"])
+	c.lock.Unlock()
+}
+
 func TestSubscriber(t *testing.T) {
 	sub := new(Subscriber)
 	Exclusive()(sub)

go.mod

@@ -11,19 +11,19 @@ require (
 	github.com/golang-jwt/jwt/v4 v4.5.2
 	github.com/golang/protobuf v1.5.4
 	github.com/google/uuid v1.6.0
-	github.com/grafana/pyroscope-go v1.2.8
+	github.com/grafana/pyroscope-go v1.3.0
 	github.com/jackc/pgx/v5 v5.8.0
 	github.com/jhump/protoreflect v1.18.0
 	github.com/modelcontextprotocol/go-sdk v1.4.0
 	github.com/pelletier/go-toml/v2 v2.3.0
 	github.com/prometheus/client_golang v1.23.2
-	github.com/redis/go-redis/v9 v9.18.0
+	github.com/redis/go-redis/v9 v9.19.0
 	github.com/spaolacci/murmur3 v1.1.0
 	github.com/stretchr/testify v1.11.1
 	github.com/titanous/json5 v1.0.0
 	go.etcd.io/etcd/api/v3 v3.5.21
 	go.etcd.io/etcd/client/v3 v3.5.21
-	go.mongodb.org/mongo-driver/v2 v2.5.0
+	go.mongodb.org/mongo-driver/v2 v2.6.0
 	go.opentelemetry.io/otel v1.40.0
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc v1.40.0
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp v1.40.0
@@ -38,7 +38,7 @@ require (
 	golang.org/x/sys v0.41.0
 	golang.org/x/time v0.14.0
 	google.golang.org/genproto/googleapis/api v0.0.0-20260128011058-8636f8732409
-	google.golang.org/grpc v1.79.3
+	google.golang.org/grpc v1.80.0
 	google.golang.org/protobuf v1.36.11
 	gopkg.in/cheggaaa/pb.v1 v1.0.28
 	gopkg.in/h2non/gock.v1 v1.1.2
@@ -58,7 +58,6 @@ require (
 	github.com/coreos/go-semver v0.3.1 // indirect
 	github.com/coreos/go-systemd/v22 v22.5.0 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
-	github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f // indirect
 	github.com/emicklei/go-restful/v3 v3.12.2 // indirect
 	github.com/envoyproxy/go-control-plane/envoy v1.36.0 // indirect
 	github.com/envoyproxy/protoc-gen-validate v1.3.0 // indirect
@@ -73,7 +72,7 @@ require (
 	github.com/google/gnostic-models v0.7.0 // indirect
 	github.com/google/go-cmp v0.7.0 // indirect
 	github.com/google/jsonschema-go v0.4.2 // indirect
-	github.com/grafana/pyroscope-go/godeltaprof v0.1.9 // indirect
+	github.com/grafana/pyroscope-go/godeltaprof v0.1.10 // indirect
 	github.com/grpc-ecosystem/grpc-gateway/v2 v2.27.7 // indirect
 	github.com/h2non/parth v0.0.0-20190131123155-b4df798d6542 // indirect
 	github.com/jackc/pgpassfile v1.0.0 // indirect
@@ -82,7 +81,7 @@ require (
 	github.com/jhump/protoreflect/v2 v2.0.0-beta.1 // indirect
 	github.com/josharian/intern v1.0.0 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
-	github.com/klauspost/compress v1.18.0 // indirect
+	github.com/klauspost/compress v1.18.6 // indirect
 	github.com/kylelemons/godebug v1.1.0 // indirect
 	github.com/mailru/easyjson v0.7.7 // indirect
 	github.com/mattn/go-colorable v0.1.13 // indirect

go.sum

@@ -28,8 +28,6 @@ github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ3
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f h1:lO4WD4F/rVNCu3HqELle0jiPLLBs70cWOduZpkS1E78=
-github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f/go.mod h1:cuUVRXasLTGF7a8hSLbxyZXjz+1KgoB3wDUb6vlszIc=
 github.com/emicklei/go-restful/v3 v3.12.2 h1:DhwDP0vY3k8ZzE0RunuJy8GhNpPL6zqLkDf9B/a0/xU=
 github.com/emicklei/go-restful/v3 v3.12.2/go.mod h1:6n3XBCmQQb25CM2LCACGz8ukIrRry+4bhvbpWn3mrbc=
 github.com/envoyproxy/go-control-plane/envoy v1.36.0 h1:yg/JjO5E7ubRyKX3m07GF3reDNEnfOboJ0QySbH736g=
@@ -82,10 +80,10 @@ github.com/google/pprof v0.0.0-20241029153458-d1b30febd7db h1:097atOisP2aRj7vFgY
 github.com/google/pprof v0.0.0-20241029153458-d1b30febd7db/go.mod h1:vavhavw2zAxS5dIdcRluK6cSGGPlZynqzFM8NdvU144=
 github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
 github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
-github.com/grafana/pyroscope-go v1.2.8 h1:UvCwIhlx9DeV7F6TW/z8q1Mi4PIm3vuUJ2ZlCEvmA4M=
-github.com/grafana/pyroscope-go v1.2.8/go.mod h1:SSi59eQ1/zmKoY/BKwa5rSFsJaq+242Bcrr4wPix1g8=
-github.com/grafana/pyroscope-go/godeltaprof v0.1.9 h1:c1Us8i6eSmkW+Ez05d3co8kasnuOY813tbMN8i/a3Og=
-github.com/grafana/pyroscope-go/godeltaprof v0.1.9/go.mod h1:2+l7K7twW49Ct4wFluZD3tZ6e0SjanjcUUBPVD/UuGU=
+github.com/grafana/pyroscope-go v1.3.0 h1:t3Jehad8vvqN4oRAB0LdmfQ5ZSUXQw3asoft+K4GAT8=
+github.com/grafana/pyroscope-go v1.3.0/go.mod h1:XA7I3usNx+UdjOZfQnl1WV8y924vsJo9KIVrKB+9jx4=
+github.com/grafana/pyroscope-go/godeltaprof v0.1.10 h1:dvhndEbyavTb59vFCd6PsrAG5qi69/qZZtegh/TJKSY=
+github.com/grafana/pyroscope-go/godeltaprof v0.1.10/go.mod h1:XnWRGg2XO5uxZdiz1rfeJH6w1eZ+YICCBVXNWOfH86g=
 github.com/grpc-ecosystem/grpc-gateway/v2 v2.27.7 h1:X+2YciYSxvMQK0UZ7sg45ZVabVZBeBuvMkmuI2V3Fak=
 github.com/grpc-ecosystem/grpc-gateway/v2 v2.27.7/go.mod h1:lW34nIZuQ8UDPdkon5fmfp2l3+ZkQ2me/+oecHYLOII=
 github.com/h2non/parth v0.0.0-20190131123155-b4df798d6542 h1:2VTzZjLZBgl62/EtslCrtky5vbi9dd7HrQPQIx6wqiw=
@@ -109,10 +107,10 @@ github.com/json-iterator/go v1.1.12/go.mod h1:e30LSqwooZae/UwlEbR2852Gd8hjQvJoHm
 github.com/kisielk/errcheck v1.5.0/go.mod h1:pFxgyoBC7bSaBwPgfKdkLd5X25qrDl4LWUI2bnpBCr8=
 github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
 github.com/kisielk/sqlstruct v0.0.0-20201105191214-5f3e10d3ab46/go.mod h1:yyMNCyc/Ib3bDTKd379tNMpB/7/H5TjM2Y9QJ5THLbE=
-github.com/klauspost/compress v1.18.0 h1:c/Cqfb0r+Yi+JtIEq73FWXVkRonBlf0CRNYc8Zttxdo=
-github.com/klauspost/compress v1.18.0/go.mod h1:2Pp+KzxcywXVXMr50+X0Q/Lsb43OQHYWRCY2AiWywWQ=
-github.com/klauspost/cpuid/v2 v2.0.9 h1:lgaqFMSdTdQYdZ04uHyN2d/eKdOMyi2YLSvlQIBFYa4=
-github.com/klauspost/cpuid/v2 v2.0.9/go.mod h1:FInQzS24/EEf25PyTYn52gqo7WaD8xa0213Md/qVLRg=
+github.com/klauspost/compress v1.18.6 h1:2jupLlAwFm95+YDR+NwD2MEfFO9d4z4Prjl1XXDjuao=
+github.com/klauspost/compress v1.18.6/go.mod h1:cwPg85FWrGar70rWktvGQj8/hthj3wpl0PGDogxkrSQ=
+github.com/klauspost/cpuid/v2 v2.2.10 h1:tBs3QSyvjDyFTq3uoc/9xFpCuOsJQFNPiAhYdw2skhE=
+github.com/klauspost/cpuid/v2 v2.2.10/go.mod h1:hqwkgyIinND0mEev00jJYCxPNVRVXFQeu1XKlok6oO0=
 github.com/kr/pretty v0.2.1/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfnI=
 github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
 github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
@@ -169,8 +167,8 @@ github.com/prometheus/common v0.66.1 h1:h5E0h5/Y8niHc5DlaLlWLArTQI7tMrsfQjHV+d9Z
 github.com/prometheus/common v0.66.1/go.mod h1:gcaUsgf3KfRSwHY4dIMXLPV0K/Wg1oZ8+SbZk/HH/dA=
 github.com/prometheus/procfs v0.16.1 h1:hZ15bTNuirocR6u0JZ6BAHHmwS1p8B4P6MRqxtzMyRg=
 github.com/prometheus/procfs v0.16.1/go.mod h1:teAbpZRB1iIAJYREa1LsoWUXykVXA1KlTmWl8x/U+Is=
-github.com/redis/go-redis/v9 v9.18.0 h1:pMkxYPkEbMPwRdenAzUNyFNrDgHx9U+DrBabWNfSRQs=
-github.com/redis/go-redis/v9 v9.18.0/go.mod h1:k3ufPphLU5YXwNTUcCRXGxUoF1fqxnhFQmscfkCoDA0=
+github.com/redis/go-redis/v9 v9.19.0 h1:XPVaaPSnG6RhYf7p+rmSa9zZfeVAnWsH5h3lxthOm/k=
+github.com/redis/go-redis/v9 v9.19.0/go.mod h1:v/M13XI1PVCDcm01VtPFOADfZtHf8YW3baQf57KlIkA=
 github.com/rivo/uniseg v0.2.0 h1:S1pD9weZBuJdFmowNwbpi7BJ8TNftyUImj/0WQi72jY=
 github.com/rivo/uniseg v0.2.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
 github.com/robertkrimen/otto v0.2.1 h1:FVP0PJ0AHIjC+N4pKCG9yCDz6LHNPCwi/GKID5pGGF0=
@@ -218,16 +216,16 @@ github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9dec
 github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
 github.com/yuin/gopher-lua v1.1.1 h1:kYKnWBjvbNP4XLT3+bPEwAXJx262OhaHDWDVOPjL46M=
 github.com/yuin/gopher-lua v1.1.1/go.mod h1:GBR0iDaNXjAgGg9zfCvksxSRnQx76gclCIb7kdAd1Pw=
-github.com/zeebo/xxh3 v1.0.2 h1:xZmwmqxHZA8AI603jOQ0tMqmBr9lPeFwGg6d+xy9DC0=
-github.com/zeebo/xxh3 v1.0.2/go.mod h1:5NWz9Sef7zIDm2JHfFlcQvNekmcEl9ekUZQQKCYaDcA=
+github.com/zeebo/xxh3 v1.1.0 h1:s7DLGDK45Dyfg7++yxI0khrfwq9661w9EN78eP/UZVs=
+github.com/zeebo/xxh3 v1.1.0/go.mod h1:IisAie1LELR4xhVinxWS5+zf1lA4p0MW4T+w+W07F5s=
 go.etcd.io/etcd/api/v3 v3.5.21 h1:A6O2/JDb3tvHhiIz3xf9nJ7REHvtEFJJ3veW3FbCnS8=
 go.etcd.io/etcd/api/v3 v3.5.21/go.mod h1:c3aH5wcvXv/9dqIw2Y810LDXJfhSYdHQ0vxmP3CCHVY=
 go.etcd.io/etcd/client/pkg/v3 v3.5.21 h1:lPBu71Y7osQmzlflM9OfeIV2JlmpBjqBNlLtcoBqUTc=
 go.etcd.io/etcd/client/pkg/v3 v3.5.21/go.mod h1:BgqT/IXPjK9NkeSDjbzwsHySX3yIle2+ndz28nVsjUs=
 go.etcd.io/etcd/client/v3 v3.5.21 h1:T6b1Ow6fNjOLOtM0xSoKNQt1ASPCLWrF9XMHcH9pEyY=
 go.etcd.io/etcd/client/v3 v3.5.21/go.mod h1:mFYy67IOqmbRf/kRUvsHixzo3iG+1OF2W2+jVIQRAnU=
-go.mongodb.org/mongo-driver/v2 v2.5.0 h1:yXUhImUjjAInNcpTcAlPHiT7bIXhshCTL3jVBkF3xaE=
-go.mongodb.org/mongo-driver/v2 v2.5.0/go.mod h1:yOI9kBsufol30iFsl1slpdq1I0eHPzybRWdyYUs8K/0=
+go.mongodb.org/mongo-driver/v2 v2.6.0 h1:b9sJOYrkmt4l8bY43ZenFBcPlhYIjaOfYHLtbB/5qi8=
+go.mongodb.org/mongo-driver/v2 v2.6.0/go.mod h1:yOI9kBsufol30iFsl1slpdq1I0eHPzybRWdyYUs8K/0=
 go.opentelemetry.io/auto/sdk v1.2.1 h1:jXsnJ4Lmnqd11kwkBV2LgLoFMZKizbCi5fNZ/ipaZ64=
 go.opentelemetry.io/auto/sdk v1.2.1/go.mod h1:KRTj+aOaElaLi+wW1kO/DZRXwkF4C5xPbEe3ZiIhN7Y=
 go.opentelemetry.io/otel v1.40.0 h1:oA5YeOcpRTXq6NN7frwmwFR0Cn3RhTVZvXsP4duvCms=
@@ -327,14 +325,14 @@ golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8T
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
-gonum.org/v1/gonum v0.16.0 h1:5+ul4Swaf3ESvrOnidPp4GZbzf0mxVQpDCYUQE7OJfk=
-gonum.org/v1/gonum v0.16.0/go.mod h1:fef3am4MQ93R2HHpKnLk4/Tbh/s0+wqD5nfa6Pnwy4E=
+gonum.org/v1/gonum v0.17.0 h1:VbpOemQlsSMrYmn7T2OUvQ4dqxQXU+ouZFQsZOx50z4=
+gonum.org/v1/gonum v0.17.0/go.mod h1:El3tOrEuMpv2UdMrbNlKEh9vd86bmQ6vqIcDwxEOc1E=
 google.golang.org/genproto/googleapis/api v0.0.0-20260128011058-8636f8732409 h1:merA0rdPeUV3YIIfHHcH4qBkiQAc1nfCKSI7lB4cV2M=
 google.golang.org/genproto/googleapis/api v0.0.0-20260128011058-8636f8732409/go.mod h1:fl8J1IvUjCilwZzQowmw2b7HQB2eAuYBabMXzWurF+I=
 google.golang.org/genproto/googleapis/rpc v0.0.0-20260128011058-8636f8732409 h1:H86B94AW+VfJWDqFeEbBPhEtHzJwJfTbgE2lZa54ZAQ=
 google.golang.org/genproto/googleapis/rpc v0.0.0-20260128011058-8636f8732409/go.mod h1:j9x/tPzZkyxcgEFkiKEEGxfvyumM01BEtsW8xzOahRQ=
-google.golang.org/grpc v1.79.3 h1:sybAEdRIEtvcD68Gx7dmnwjZKlyfuc61Dyo9pGXXkKE=
-google.golang.org/grpc v1.79.3/go.mod h1:KmT0Kjez+0dde/v2j9vzwoAScgEPx/Bw1CYChhHLrHQ=
+google.golang.org/grpc v1.80.0 h1:Xr6m2WmWZLETvUNvIUmeD5OAagMw3FiKmMlTdViWsHM=
+google.golang.org/grpc v1.80.0/go.mod h1:ho/dLnxwi3EDJA4Zghp7k2Ec1+c2jqup0bFkw07bwF4=
 google.golang.org/protobuf v1.36.11 h1:fV6ZwhNocDyBLK0dj+fg8ektcVegBBuEolpbTQyBNVE=
 google.golang.org/protobuf v1.36.11/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=

mcp/options.go

@@ -0,0 +1,33 @@
+package mcp
+
+import "net/http"
+
+// RequestMetadataExtractor extracts request metadata for downstream handlers.
+type RequestMetadataExtractor func(*http.Request) RequestMetadata
+
+// McpOption customizes MCP server construction.
+type McpOption interface {
+	apply(*serverOptions)
+}
+
+type mcpOptionFunc func(*serverOptions)
+
+func (f mcpOptionFunc) apply(opts *serverOptions) {
+	f(opts)
+}
+
+type serverOptions struct {
+	requestMetadataExtractor RequestMetadataExtractor
+}
+
+func defaultServerOptions() serverOptions {
+	return serverOptions{}
+}
+
+// WithRequestMetadataExtractor installs an extractor that runs for each incoming
+// MCP HTTP request, and stores the extracted metadata into handler context.
+func WithRequestMetadataExtractor(extractor RequestMetadataExtractor) McpOption {
+	return mcpOptionFunc(func(opts *serverOptions) {
+		opts.requestMetadataExtractor = extractor
+	})
+}

mcp/readme.md

@@ -15,6 +15,7 @@ This package provides a go-zero integration for the [Model Context Protocol (MCP
 - **CORS Support**: Configurable CORS settings for cross-origin requests
 - **Type-Safe Tool Handlers**: Generic tool handlers with automatic JSON schema generation
 - **Prompts and Resources**: Full support for MCP prompts and resources
+- **Request Metadata Bridge**: Optional request metadata extraction into handler context
 
 ## Quick Start
 
@@ -220,6 +221,35 @@ mcp:
   messageEndpoint: /message
 ```
 
+## Request Metadata Bridge
+
+For multi-tenant or request-context-aware tools, you can extract selected HTTP request metadata once at the transport boundary and read it from `context.Context` in handlers.
+
+```go
+server := mcp.NewMcpServerWithOptions(c,
+	mcp.WithRequestMetadataExtractor(mcp.DefaultRequestMetadataExtractor),
+)
+
+handler := func(ctx context.Context, req *mcp.CallToolRequest, args SomeArgs) (*mcp.CallToolResult, any, error) {
+	tenant, _ := mcp.HeaderFromContext(ctx, "X-Tenant-Id")
+	traceID, _ := mcp.QueryFromContext(ctx, "trace")
+	scope, _ := mcp.PathFromContext(ctx, "scope")
+
+	_ = tenant
+	_ = traceID
+	_ = scope
+
+	return &mcp.CallToolResult{}, nil, nil
+}
+```
+
+Available helpers:
+
+- `RequestMetadataFromContext(ctx)`
+- `HeaderFromContext(ctx, key)`
+- `QueryFromContext(ctx, key)`
+- `PathFromContext(ctx, key)`
+
 ## Configuration Options
 
 | Field | Type | Default | Description |

mcp/request_metadata.go

@@ -0,0 +1,150 @@
+package mcp
+
+import (
+	"context"
+	"net/http"
+
+	"github.com/zeromicro/go-zero/rest/pathvar"
+)
+
+// RequestMetadata carries selected request-scoped values into MCP handlers.
+type RequestMetadata struct {
+	Headers map[string][]string
+	Query   map[string][]string
+	Path    map[string]string
+}
+
+type requestMetadataCtxKey struct{}
+
+// RequestMetadataFromContext returns metadata extracted at the transport boundary.
+func RequestMetadataFromContext(ctx context.Context) (RequestMetadata, bool) {
+	metadata, ok := requestMetadataFromContext(ctx)
+	if !ok {
+		return RequestMetadata{}, false
+	}
+
+	return normalizeRequestMetadata(metadata), true
+}
+
+// HeaderFromContext returns the first header value for key.
+func HeaderFromContext(ctx context.Context, key string) (string, bool) {
+	metadata, ok := requestMetadataFromContext(ctx)
+	if !ok {
+		return "", false
+	}
+
+	vals := metadata.Headers[http.CanonicalHeaderKey(key)]
+	if len(vals) == 0 {
+		return "", false
+	}
+
+	return vals[0], true
+}
+
+// QueryFromContext returns the first query value for key.
+func QueryFromContext(ctx context.Context, key string) (string, bool) {
+	metadata, ok := requestMetadataFromContext(ctx)
+	if !ok {
+		return "", false
+	}
+
+	vals := metadata.Query[key]
+	if len(vals) == 0 {
+		return "", false
+	}
+
+	return vals[0], true
+}
+
+// PathFromContext returns the path variable value for key.
+func PathFromContext(ctx context.Context, key string) (string, bool) {
+	metadata, ok := requestMetadataFromContext(ctx)
+	if !ok {
+		return "", false
+	}
+
+	val, ok := metadata.Path[key]
+	if !ok {
+		return "", false
+	}
+
+	return val, true
+}
+
+func requestMetadataFromContext(ctx context.Context) (RequestMetadata, bool) {
+	metadata, ok := ctx.Value(requestMetadataCtxKey{}).(RequestMetadata)
+	if !ok {
+		return RequestMetadata{}, false
+	}
+
+	return metadata, true
+}
+
+// DefaultRequestMetadataExtractor extracts headers, query values, and path variables.
+func DefaultRequestMetadataExtractor(r *http.Request) RequestMetadata {
+	metadata := RequestMetadata{
+		Headers: make(map[string][]string, len(r.Header)),
+		Query:   make(map[string][]string),
+		Path:    clonePathVars(pathvar.Vars(r)),
+	}
+
+	for key, vals := range r.Header {
+		metadata.Headers[http.CanonicalHeaderKey(key)] = append([]string(nil), vals...)
+	}
+
+	if r.URL != nil {
+		for key, vals := range r.URL.Query() {
+			metadata.Query[key] = append([]string(nil), vals...)
+		}
+	}
+
+	return metadata
+}
+
+func normalizeRequestMetadata(metadata RequestMetadata) RequestMetadata {
+	return RequestMetadata{
+		Headers: cloneCanonicalHeaderValues(metadata.Headers),
+		Query:   cloneHeaderValues(metadata.Query),
+		Path:    clonePathVars(metadata.Path),
+	}
+}
+
+func cloneHeaderValues(values map[string][]string) map[string][]string {
+	if len(values) == 0 {
+		return nil
+	}
+
+	cloned := make(map[string][]string, len(values))
+	for key, vals := range values {
+		cloned[key] = append([]string(nil), vals...)
+	}
+
+	return cloned
+}
+
+func cloneCanonicalHeaderValues(values map[string][]string) map[string][]string {
+	if len(values) == 0 {
+		return nil
+	}
+
+	cloned := make(map[string][]string, len(values))
+	for key, vals := range values {
+		canonical := http.CanonicalHeaderKey(key)
+		cloned[canonical] = append(cloned[canonical], vals...)
+	}
+
+	return cloned
+}
+
+func clonePathVars(values map[string]string) map[string]string {
+	if len(values) == 0 {
+		return nil
+	}
+
+	cloned := make(map[string]string, len(values))
+	for key, val := range values {
+		cloned[key] = val
+	}
+
+	return cloned
+}

mcp/request_metadata_test.go

@@ -0,0 +1,185 @@
+package mcp
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/zeromicro/go-zero/rest/pathvar"
+)
+
+func TestDefaultRequestMetadataExtractor(t *testing.T) {
+	req := httptest.NewRequest(http.MethodGet, "/sse?tenant=t1&trace=abc", nil)
+	req.Header.Add("X-Tenant-Id", "tenant-from-header")
+	req = pathvar.WithVars(req, map[string]string{"tool": "sum"})
+
+	metadata := DefaultRequestMetadataExtractor(req)
+	header, ok := metadata.Headers["X-Tenant-Id"]
+	assert.True(t, ok)
+	assert.Equal(t, []string{"tenant-from-header"}, header)
+	assert.Equal(t, []string{"t1"}, metadata.Query["tenant"])
+	assert.Equal(t, "sum", metadata.Path["tool"])
+}
+
+func TestRequestMetadataContextHelpers(t *testing.T) {
+	ctx := context.WithValue(context.Background(), requestMetadataCtxKey{}, RequestMetadata{
+		Headers: map[string][]string{"X-Trace-Id": {"trace-1"}},
+		Query:   map[string][]string{"tenant": {"foo"}},
+		Path:    map[string]string{"scope": "prod"},
+	})
+
+	metadata, ok := RequestMetadataFromContext(ctx)
+	assert.True(t, ok)
+	assert.Equal(t, []string{"trace-1"}, metadata.Headers["X-Trace-Id"])
+
+	header, ok := HeaderFromContext(ctx, "x-trace-id")
+	assert.True(t, ok)
+	assert.Equal(t, "trace-1", header)
+
+	query, ok := QueryFromContext(ctx, "tenant")
+	assert.True(t, ok)
+	assert.Equal(t, "foo", query)
+
+	path, ok := PathFromContext(ctx, "scope")
+	assert.True(t, ok)
+	assert.Equal(t, "prod", path)
+}
+
+func TestRequestMetadataContextHelpersMissingKeys(t *testing.T) {
+	ctx := context.WithValue(context.Background(), requestMetadataCtxKey{}, RequestMetadata{
+		Headers: map[string][]string{"X-Trace-Id": {"trace-1"}},
+		Query:   map[string][]string{"tenant": {"foo"}},
+		Path:    map[string]string{"scope": "prod"},
+	})
+
+	_, ok := HeaderFromContext(ctx, "x-missing")
+	assert.False(t, ok)
+
+	_, ok = QueryFromContext(ctx, "missing")
+	assert.False(t, ok)
+
+	_, ok = PathFromContext(ctx, "missing")
+	assert.False(t, ok)
+}
+
+func TestRequestMetadataFromContextNotFound(t *testing.T) {
+	_, ok := RequestMetadataFromContext(context.Background())
+	assert.False(t, ok)
+
+	_, ok = HeaderFromContext(context.Background(), "x-test")
+	assert.False(t, ok)
+
+	_, ok = QueryFromContext(context.Background(), "tenant")
+	assert.False(t, ok)
+
+	_, ok = PathFromContext(context.Background(), "tenant")
+	assert.False(t, ok)
+}
+
+func TestWrapRequestMetadata(t *testing.T) {
+	s := &mcpServerImpl{
+		options: serverOptions{
+			requestMetadataExtractor: DefaultRequestMetadataExtractor,
+		},
+	}
+
+	called := false
+	handler := s.wrapRequestMetadata(http.HandlerFunc(func(_ http.ResponseWriter, r *http.Request) {
+		called = true
+		header, ok := HeaderFromContext(r.Context(), "x-tenant-id")
+		assert.True(t, ok)
+		assert.Equal(t, "tenant-1", header)
+
+		query, ok := QueryFromContext(r.Context(), "tenant")
+		assert.True(t, ok)
+		assert.Equal(t, "q-tenant", query)
+	}))
+
+	req := httptest.NewRequest(http.MethodGet, "/sse?tenant=q-tenant", nil)
+	req.Header.Set("X-Tenant-Id", "tenant-1")
+	rr := httptest.NewRecorder()
+	handler.ServeHTTP(rr, req)
+
+	assert.True(t, called)
+}
+
+func TestWrapRequestMetadataNoExtractor(t *testing.T) {
+	s := &mcpServerImpl{}
+
+	called := false
+	handler := s.wrapRequestMetadata(http.HandlerFunc(func(_ http.ResponseWriter, r *http.Request) {
+		called = true
+		_, ok := RequestMetadataFromContext(r.Context())
+		assert.False(t, ok)
+	}))
+
+	rr := httptest.NewRecorder()
+	handler.ServeHTTP(rr, httptest.NewRequest(http.MethodGet, "/sse", nil))
+
+	assert.True(t, called)
+}
+
+func TestWrapRequestMetadataCanonicalizesCustomHeaders(t *testing.T) {
+	s := &mcpServerImpl{
+		options: serverOptions{
+			requestMetadataExtractor: func(*http.Request) RequestMetadata {
+				return RequestMetadata{
+					Headers: map[string][]string{
+						"x-tenant-id": {"tenant-lower"},
+					},
+				}
+			},
+		},
+	}
+
+	called := false
+	handler := s.wrapRequestMetadata(http.HandlerFunc(func(_ http.ResponseWriter, r *http.Request) {
+		called = true
+		header, ok := HeaderFromContext(r.Context(), "X-Tenant-Id")
+		assert.True(t, ok)
+		assert.Equal(t, "tenant-lower", header)
+	}))
+
+	rr := httptest.NewRecorder()
+	handler.ServeHTTP(rr, httptest.NewRequest(http.MethodGet, "/sse", nil))
+
+	assert.True(t, called)
+}
+
+func TestRequestMetadataFromContextReturnsCopy(t *testing.T) {
+	ctx := context.WithValue(context.Background(), requestMetadataCtxKey{}, RequestMetadata{
+		Headers: map[string][]string{"X-Trace-Id": {"trace-1"}},
+	})
+
+	metadata, ok := RequestMetadataFromContext(ctx)
+	assert.True(t, ok)
+	metadata.Headers["X-Trace-Id"][0] = "mutated"
+	metadata.Headers["X-New"] = []string{"new"}
+
+	fresh, ok := RequestMetadataFromContext(ctx)
+	assert.True(t, ok)
+	assert.Equal(t, []string{"trace-1"}, fresh.Headers["X-Trace-Id"])
+	assert.Nil(t, fresh.Headers["X-New"])
+}
+
+func TestRequestMetadataFromContextWithEmptyAndCanonicalizedHeaders(t *testing.T) {
+	emptyCtx := context.WithValue(context.Background(), requestMetadataCtxKey{}, RequestMetadata{})
+	empty, ok := RequestMetadataFromContext(emptyCtx)
+	assert.True(t, ok)
+	assert.Nil(t, empty.Headers)
+	assert.Nil(t, empty.Query)
+	assert.Nil(t, empty.Path)
+
+	ctx := context.WithValue(context.Background(), requestMetadataCtxKey{}, RequestMetadata{
+		Headers: map[string][]string{
+			"x-tenant-id": {"a"},
+			"X-Tenant-Id": {"b"},
+		},
+	})
+
+	metadata, ok := RequestMetadataFromContext(ctx)
+	assert.True(t, ok)
+	assert.Equal(t, []string{"a", "b"}, metadata.Headers["X-Tenant-Id"])
+}

mcp/server.go

@@ -1,6 +1,7 @@
 package mcp
 
 import (
+	"context"
 	"net/http"
 
 	sdkmcp "github.com/modelcontextprotocol/go-sdk/mcp"
@@ -20,10 +21,23 @@ type mcpServerImpl struct {
 	conf       McpConf
 	httpServer *rest.Server
 	mcpServer  *sdkmcp.Server
+	options    serverOptions
 }
 
 // NewMcpServer creates a new MCP server using the official SDK
 func NewMcpServer(c McpConf) McpServer {
+	return NewMcpServerWithOptions(c)
+}
+
+// NewMcpServerWithOptions creates a new MCP server with optional customizations.
+func NewMcpServerWithOptions(c McpConf, opts ...McpOption) McpServer {
+	serverOpts := defaultServerOptions()
+	for _, opt := range opts {
+		if opt != nil {
+			opt.apply(&serverOpts)
+		}
+	}
+
 	// Create the underlying rest HTTP server
 	var httpServer *rest.Server
 	if len(c.Mcp.Cors) == 0 {
@@ -52,6 +66,7 @@ func NewMcpServer(c McpConf) McpServer {
 		conf:       c,
 		httpServer: httpServer,
 		mcpServer:  mcpServer,
+		options:    serverOpts,
 	}
 
 	// Choose transport based on configuration
@@ -85,7 +100,7 @@ func (s *mcpServerImpl) setupSSETransport() {
 		return s.mcpServer
 	}, nil)
 
-	s.registerRoutes(handler, s.conf.Mcp.SseEndpoint)
+	s.registerRoutes(s.wrapRequestMetadata(handler), s.conf.Mcp.SseEndpoint)
 }
 
 // setupStreamableTransport configures the server to use Streamable HTTP transport (2025-03-26 spec)
@@ -96,7 +111,7 @@ func (s *mcpServerImpl) setupStreamableTransport() {
 		return s.mcpServer
 	}, nil)
 
-	s.registerRoutes(handler, s.conf.Mcp.MessageEndpoint)
+	s.registerRoutes(s.wrapRequestMetadata(handler), s.conf.Mcp.MessageEndpoint)
 }
 
 func (s *mcpServerImpl) registerRoutes(handler http.Handler, endpoint string) {
@@ -113,3 +128,16 @@ func (s *mcpServerImpl) registerRoutes(handler http.Handler, endpoint string) {
 		Handler: handler.ServeHTTP,
 	}, rest.WithTimeout(s.conf.Mcp.MessageTimeout))
 }
+
+func (s *mcpServerImpl) wrapRequestMetadata(next http.Handler) http.Handler {
+	extractor := s.options.requestMetadataExtractor
+	if extractor == nil {
+		return next
+	}
+
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		metadata := normalizeRequestMetadata(extractor(r))
+		ctx := context.WithValue(r.Context(), requestMetadataCtxKey{}, metadata)
+		next.ServeHTTP(w, r.WithContext(ctx))
+	})
+}

mcp/server_test.go

@@ -3,11 +3,14 @@ package mcp
 import (
 	"bytes"
 	"context"
+	"fmt"
+	"net"
 	"net/http"
 	"net/http/httptest"
 	"testing"
 	"time"
 
+	sdkmcp "github.com/modelcontextprotocol/go-sdk/mcp"
 	"github.com/stretchr/testify/assert"
 	"github.com/zeromicro/go-zero/core/conf"
 )
@@ -391,3 +394,148 @@ func TestAddToolWithCustomServer(t *testing.T) {
 		return nil, nil, nil
 	})
 }
+
+func TestRequestMetadataIntegrationSSEToolCall(t *testing.T) {
+	port := getFreePort(t)
+
+	c := McpConf{}
+	c.Host = "127.0.0.1"
+	c.Port = port
+	c.Mcp.Name = "metadata-integration-test"
+	c.Mcp.UseStreamable = false
+	c.Mcp.SseEndpoint = "/sse/:scope"
+	c.Mcp.MessageTimeout = 2 * time.Second
+	c.Mcp.SseTimeout = 2 * time.Second
+
+	server := NewMcpServerWithOptions(c, WithRequestMetadataExtractor(DefaultRequestMetadataExtractor))
+
+	tool := &Tool{
+		Name:        "inspect_metadata",
+		Description: "Inspect metadata in handler context",
+	}
+
+	type Args struct{}
+
+	AddTool(server, tool, func(ctx context.Context, req *CallToolRequest, args Args) (*CallToolResult, any, error) {
+		header, ok := HeaderFromContext(ctx, "x-tenant-id")
+		if !ok || header != "tenant-header" {
+			return nil, nil, fmt.Errorf("unexpected header from context: %q", header)
+		}
+
+		query, ok := QueryFromContext(ctx, "tenant")
+		if !ok || query != "tenant-query" {
+			return nil, nil, fmt.Errorf("unexpected query from context: %q", query)
+		}
+
+		scope, ok := PathFromContext(ctx, "scope")
+		if !ok || scope != "prod" {
+			return nil, nil, fmt.Errorf("unexpected path from context: %q", scope)
+		}
+
+		return &CallToolResult{
+			Content: []Content{&TextContent{Text: "metadata-ok"}},
+		}, nil, nil
+	})
+
+	go server.Start()
+	t.Cleanup(server.Stop)
+
+	baseURL := fmt.Sprintf("http://127.0.0.1:%d/sse/prod?tenant=tenant-query", port)
+	waitForServerReady(t, baseURL, 2*time.Second)
+
+	client := sdkmcp.NewClient(&sdkmcp.Implementation{
+		Name:    "metadata-client",
+		Version: "1.0.0",
+	}, nil)
+
+	httpClient := &http.Client{
+		Timeout: 2 * time.Second,
+		Transport: metadataHeaderRoundTripper{
+			next: http.DefaultTransport,
+		},
+	}
+
+	transport := &sdkmcp.SSEClientTransport{
+		Endpoint:   baseURL,
+		HTTPClient: httpClient,
+	}
+
+	session, err := client.Connect(context.Background(), transport, nil)
+	if !assert.NoError(t, err) {
+		return
+	}
+	t.Cleanup(func() {
+		_ = session.Close()
+	})
+
+	res, err := session.CallTool(context.Background(), &sdkmcp.CallToolParams{
+		Name:      "inspect_metadata",
+		Arguments: map[string]any{},
+	})
+	if !assert.NoError(t, err) {
+		return
+	}
+
+	if !assert.NotNil(t, res) {
+		return
+	}
+	assert.False(t, res.IsError)
+}
+
+type metadataHeaderRoundTripper struct {
+	next http.RoundTripper
+}
+
+func (r metadataHeaderRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
+	next := r.next
+	if next == nil {
+		next = http.DefaultTransport
+	}
+
+	clone := req.Clone(req.Context())
+	clone.Header.Set("X-Tenant-Id", "tenant-header")
+	return next.RoundTrip(clone)
+}
+
+func getFreePort(t *testing.T) int {
+	t.Helper()
+
+	listener, err := net.Listen("tcp", "127.0.0.1:0")
+	if !assert.NoError(t, err) {
+		return 0
+	}
+	defer listener.Close()
+
+	addr, ok := listener.Addr().(*net.TCPAddr)
+	if !assert.True(t, ok) {
+		return 0
+	}
+
+	return addr.Port
+}
+
+func waitForServerReady(t *testing.T, endpoint string, timeout time.Duration) {
+	t.Helper()
+
+	client := &http.Client{Timeout: 200 * time.Millisecond}
+	deadline := time.Now().Add(timeout)
+	for time.Now().Before(deadline) {
+		req, err := http.NewRequest(http.MethodGet, endpoint, nil)
+		if err != nil {
+			t.Fatalf("failed to build readiness request: %v", err)
+		}
+		req.Header.Set("Accept", "text/event-stream")
+
+		resp, err := client.Do(req)
+		if err == nil {
+			_ = resp.Body.Close()
+			if resp.StatusCode > 0 {
+				return
+			}
+		}
+
+		time.Sleep(20 * time.Millisecond)
+	}
+
+	t.Fatalf("server did not become ready for %s within %s", endpoint, timeout)
+}

tools/goctl/go.mod

@@ -7,8 +7,8 @@ require (
 	github.com/emicklei/proto v1.14.3
 	github.com/fatih/structtag v1.2.0
 	github.com/go-openapi/spec v0.21.1-0.20250328170532-a3928469592e
-	github.com/go-sql-driver/mysql v1.9.3
-	github.com/gookit/color v1.6.0
+	github.com/go-sql-driver/mysql v1.10.0
+	github.com/gookit/color v1.6.1
 	github.com/iancoleman/strcase v0.3.0
 	github.com/spf13/cobra v1.10.2
 	github.com/spf13/pflag v1.0.10
@@ -18,13 +18,13 @@ require (
 	github.com/zeromicro/ddl-parser v1.0.5
 	github.com/zeromicro/go-zero v1.10.1
 	golang.org/x/text v0.34.0
-	google.golang.org/grpc v1.79.3
+	google.golang.org/grpc v1.80.0
 	google.golang.org/protobuf v1.36.11
 	gopkg.in/yaml.v2 v2.4.0
 )
 
 require (
-	filippo.io/edwards25519 v1.1.0 // indirect
+	filippo.io/edwards25519 v1.2.0 // indirect
 	github.com/alicebob/miniredis/v2 v2.37.0 // indirect
 	github.com/antlr/antlr4/runtime/Go/antlr v0.0.0-20210521184019-c5ad59b459ec // indirect
 	github.com/beorn7/perks v1.0.1 // indirect

tools/goctl/go.sum

@@ -1,5 +1,5 @@
-filippo.io/edwards25519 v1.1.0 h1:FNf4tywRC1HmFuKW5xopWpigGjJKiJSV0Cqo0cJWDaA=
-filippo.io/edwards25519 v1.1.0/go.mod h1:BxyFTGdWcka3PhytdK4V28tE5sGfRvvvRV7EaN4VDT4=
+filippo.io/edwards25519 v1.2.0 h1:crnVqOiS4jqYleHd9vaKZ+HKtHfllngJIiOpNpoJsjo=
+filippo.io/edwards25519 v1.2.0/go.mod h1:xzAOLCNug/yB62zG1bQ8uziwrIqIuxhctzJT18Q77mc=
 github.com/DATA-DOG/go-sqlmock v1.5.2 h1:OcvFkGmslmlZibjAjaHm3L//6LiuBgolP7OputlJIzU=
 github.com/DATA-DOG/go-sqlmock v1.5.2/go.mod h1:88MAG/4G7SMwSE3CeA0ZKzrT5CiOU3OJ+JlNzwDqpNU=
 github.com/alicebob/miniredis/v2 v2.37.0 h1:RheObYW32G1aiJIj81XVt78ZHJpHonHLHW7OLIshq68=
@@ -51,8 +51,8 @@ github.com/go-openapi/spec v0.21.1-0.20250328170532-a3928469592e h1:auobAirzhPsL
 github.com/go-openapi/spec v0.21.1-0.20250328170532-a3928469592e/go.mod h1:NAKTe9SplQBxIUlHlsuId1jk1I7bWTVV/2q/GtdRi6g=
 github.com/go-openapi/swag v0.23.1 h1:lpsStH0n2ittzTnbaSloVZLuB5+fvSY/+hnagBjSNZU=
 github.com/go-openapi/swag v0.23.1/go.mod h1:STZs8TbRvEQQKUA+JZNAm3EWlgaOBGpyFDqQnDHMef0=
-github.com/go-sql-driver/mysql v1.9.3 h1:U/N249h2WzJ3Ukj8SowVFjdtZKfu9vlLZxjPXV1aweo=
-github.com/go-sql-driver/mysql v1.9.3/go.mod h1:qn46aNg1333BRMNU69Lq93t8du/dwxI64Gl8i5p1WMU=
+github.com/go-sql-driver/mysql v1.10.0 h1:Q+1LV8DkHJvSYAdR83XzuhDaTykuDx0l6fkXxoWCWfw=
+github.com/go-sql-driver/mysql v1.10.0/go.mod h1:M+cqaI7+xxXGG9swrdeUIoPG3Y3KCkF0pZej+SK+nWk=
 github.com/go-task/slim-sprig v0.0.0-20230315185526-52ccab3ef572 h1:tfuBGBXKqDEevZMzYi5KSi8KkcZtzBcTgAUUtapy0OI=
 github.com/go-task/slim-sprig/v3 v3.0.0 h1:sUs3vkvUymDpBKi3qH1YSqBQk9+9D/8M2mN1vB6EwHI=
 github.com/go-task/slim-sprig/v3 v3.0.0/go.mod h1:W848ghGpv3Qj3dhTPRyJypKRiqCdHZiAzKg9hl15HA8=
@@ -72,8 +72,8 @@ github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
 github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/gookit/assert v0.1.1 h1:lh3GcawXe/p+cU7ESTZ5Ui3Sm/x8JWpIis4/1aF0mY0=
 github.com/gookit/assert v0.1.1/go.mod h1:jS5bmIVQZTIwk42uXl4lyj4iaaxx32tqH16CFj0VX2E=
-github.com/gookit/color v1.6.0 h1:JjJXBTk1ETNyqyilJhkTXJYYigHG24TM9Xa2M1xAhRA=
-github.com/gookit/color v1.6.0/go.mod h1:9ACFc7/1IpHGBW8RwuDm/0YEnhg3dwwXpoMsmtyHfjs=
+github.com/gookit/color v1.6.1 h1:KoTnDxJPRgrL0SoX0f8rCFg2zI0t4E3GZZBMo2nN8LU=
+github.com/gookit/color v1.6.1/go.mod h1:9ACFc7/1IpHGBW8RwuDm/0YEnhg3dwwXpoMsmtyHfjs=
 github.com/grafana/pyroscope-go v1.2.8 h1:UvCwIhlx9DeV7F6TW/z8q1Mi4PIm3vuUJ2ZlCEvmA4M=
 github.com/grafana/pyroscope-go v1.2.8/go.mod h1:SSi59eQ1/zmKoY/BKwa5rSFsJaq+242Bcrr4wPix1g8=
 github.com/grafana/pyroscope-go/godeltaprof v0.1.9 h1:c1Us8i6eSmkW+Ez05d3co8kasnuOY813tbMN8i/a3Og=
@@ -282,14 +282,14 @@ golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8T
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
-gonum.org/v1/gonum v0.16.0 h1:5+ul4Swaf3ESvrOnidPp4GZbzf0mxVQpDCYUQE7OJfk=
-gonum.org/v1/gonum v0.16.0/go.mod h1:fef3am4MQ93R2HHpKnLk4/Tbh/s0+wqD5nfa6Pnwy4E=
+gonum.org/v1/gonum v0.17.0 h1:VbpOemQlsSMrYmn7T2OUvQ4dqxQXU+ouZFQsZOx50z4=
+gonum.org/v1/gonum v0.17.0/go.mod h1:El3tOrEuMpv2UdMrbNlKEh9vd86bmQ6vqIcDwxEOc1E=
 google.golang.org/genproto/googleapis/api v0.0.0-20260128011058-8636f8732409 h1:merA0rdPeUV3YIIfHHcH4qBkiQAc1nfCKSI7lB4cV2M=
 google.golang.org/genproto/googleapis/api v0.0.0-20260128011058-8636f8732409/go.mod h1:fl8J1IvUjCilwZzQowmw2b7HQB2eAuYBabMXzWurF+I=
 google.golang.org/genproto/googleapis/rpc v0.0.0-20260128011058-8636f8732409 h1:H86B94AW+VfJWDqFeEbBPhEtHzJwJfTbgE2lZa54ZAQ=
 google.golang.org/genproto/googleapis/rpc v0.0.0-20260128011058-8636f8732409/go.mod h1:j9x/tPzZkyxcgEFkiKEEGxfvyumM01BEtsW8xzOahRQ=
-google.golang.org/grpc v1.79.3 h1:sybAEdRIEtvcD68Gx7dmnwjZKlyfuc61Dyo9pGXXkKE=
-google.golang.org/grpc v1.79.3/go.mod h1:KmT0Kjez+0dde/v2j9vzwoAScgEPx/Bw1CYChhHLrHQ=
+google.golang.org/grpc v1.80.0 h1:Xr6m2WmWZLETvUNvIUmeD5OAagMw3FiKmMlTdViWsHM=
+google.golang.org/grpc v1.80.0/go.mod h1:ho/dLnxwi3EDJA4Zghp7k2Ec1+c2jqup0bFkw07bwF4=
 google.golang.org/protobuf v1.36.11 h1:fV6ZwhNocDyBLK0dj+fg8ektcVegBBuEolpbTQyBNVE=
 google.golang.org/protobuf v1.36.11/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=

zrpc/resolver/internal/discovbuilder.go

@@ -13,10 +13,10 @@ type discovBuilder struct{}
 
 func (b *discovBuilder) Build(target resolver.Target, cc resolver.ClientConn, _ resolver.BuildOptions) (
 	resolver.Resolver, error) {
-	hosts := strings.FieldsFunc(targets.GetAuthority(target), func(r rune) bool {
+	hosts := strings.FieldsFunc(targets.GetHosts(target), func(r rune) bool {
 		return r == EndpointSepChar
 	})
-	sub, err := discov.NewSubscriber(hosts, targets.GetEndpoints(target))
+	sub, err := discov.NewSubscriber(hosts, targets.GetKey(target))
 	if err != nil {
 		return nil, err
 	}

zrpc/resolver/internal/discovbuilder_test.go

@@ -28,7 +28,7 @@ func TestDiscovBuilder_Build(t *testing.T) {
 	for _, server := range servers.Servers {
 		addrs = append(addrs, server.Address)
 	}
-	u, err := url.Parse(fmt.Sprintf("%s://%s", DiscovScheme, strings.Join(addrs, ",")))
+	u, err := url.Parse(fmt.Sprintf("%s:///%s?key=test", DiscovScheme, strings.Join(addrs, ",")))
 	assert.NoError(t, err)
 
 	var b discovBuilder

zrpc/resolver/internal/targets/endpoints.go

@@ -17,3 +17,29 @@ func GetAuthority(target resolver.Target) string {
 func GetEndpoints(target resolver.Target) string {
 	return strings.Trim(target.URL.Path, slashSeparator)
 }
+
+// GetHosts returns the comma-separated etcd hosts from the target URL.
+// It supports two formats:
+//   - New format (etcd:///h1:port,h2:port?key=k): hosts are in the URL path (empty authority)
+//   - Legacy format (etcd://h1:port/key): host is in the URL authority
+func GetHosts(target resolver.Target) string {
+	if target.URL.Host == "" {
+		// New format: hosts encoded in URL path to avoid RFC 3986 authority issues
+		return GetEndpoints(target)
+	}
+	// Legacy format: single host in authority
+	return target.URL.Host
+}
+
+// GetKey returns the etcd key from the target URL.
+// It supports two formats:
+//   - New format (etcd:///h1:port,h2:port?key=k): key is in the "key" query parameter
+//   - Legacy format (etcd://h1:port/key): key is in the URL path
+func GetKey(target resolver.Target) string {
+	if target.URL.Host == "" {
+		// New format: key is in the query parameter
+		return target.URL.Query().Get("key")
+	}
+	// Legacy format: key is in the path
+	return strings.Trim(target.URL.Path, slashSeparator)
+}

zrpc/resolver/internal/targets/endpoints_test.go

@@ -87,3 +87,83 @@ func TestGetEndpoints(t *testing.T) {
 		})
 	}
 }
+
+func TestGetHosts(t *testing.T) {
+	tests := []struct {
+		name string
+		url  string
+		want string
+	}{
+		{
+			name: "single host",
+			url:  "etcd:///localhost:2379?key=foo",
+			want: "localhost:2379",
+		},
+		{
+			name: "multiple hosts",
+			url:  "etcd:///host1:2379,host2:2379,host3:2379?key=foo",
+			want: "host1:2379,host2:2379,host3:2379",
+		},
+		{
+			name: "legacy single host in authority",
+			url:  "etcd://localhost:2379/my-service",
+			want: "localhost:2379",
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			uri, err := url.Parse(test.url)
+			assert.Nil(t, err)
+			target := resolver.Target{
+				URL: *uri,
+			}
+			assert.Equal(t, test.want, GetHosts(target))
+		})
+	}
+}
+
+func TestGetKey(t *testing.T) {
+	tests := []struct {
+		name string
+		url  string
+		want string
+	}{
+		{
+			name: "simple key",
+			url:  "etcd:///localhost:2379?key=my-service",
+			want: "my-service",
+		},
+		{
+			name: "key with slashes",
+			url:  "etcd:///localhost:2379?key=%2Fgrpc%2Fmy-service",
+			want: "/grpc/my-service",
+		},
+		{
+			name: "no key",
+			url:  "etcd:///localhost:2379",
+			want: "",
+		},
+		{
+			name: "legacy key in path",
+			url:  "etcd://localhost:2379/my-service",
+			want: "my-service",
+		},
+		{
+			name: "legacy key with leading slash",
+			url:  "etcd://localhost:2379/grpc/my-service",
+			want: "grpc/my-service",
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			uri, err := url.Parse(test.url)
+			assert.Nil(t, err)
+			target := resolver.Target{
+				URL: *uri,
+			}
+			assert.Equal(t, test.want, GetKey(target))
+		})
+	}
+}

zrpc/resolver/target.go

@@ -2,6 +2,7 @@ package resolver
 
 import (
 	"fmt"
+	"net/url"
 	"strings"
 
 	"github.com/zeromicro/go-zero/zrpc/resolver/internal"
@@ -14,7 +15,9 @@ func BuildDirectTarget(endpoints []string) string {
 }
 
 // BuildDiscovTarget returns a string that represents the given endpoints with discov schema.
+// The format is etcd:///host1:port,host2:port?key=<etcd-key> to avoid placing comma-separated
+// hosts in the URI authority, which Go 1.26+ rejects per RFC 3986.
 func BuildDiscovTarget(endpoints []string, key string) string {
-	return fmt.Sprintf("%s://%s/%s", internal.EtcdScheme,
-		strings.Join(endpoints, internal.EndpointSep), key)
+	return fmt.Sprintf("%s:///%s?key=%s", internal.EtcdScheme,
+		strings.Join(endpoints, internal.EndpointSep), url.QueryEscape(key))
 }

zrpc/resolver/target_test.go

@@ -13,5 +13,10 @@ func TestBuildDirectTarget(t *testing.T) {
 
 func TestBuildDiscovTarget(t *testing.T) {
 	target := BuildDiscovTarget([]string{"localhost:123", "localhost:456"}, "foo")
-	assert.Equal(t, "etcd://localhost:123,localhost:456/foo", target)
+	assert.Equal(t, "etcd:///localhost:123,localhost:456?key=foo", target)
+}
+
+func TestBuildDiscovTargetWithSlashKey(t *testing.T) {
+	target := BuildDiscovTarget([]string{"localhost:2379"}, "/grpc/my-service")
+	assert.Equal(t, "etcd:///localhost:2379?key=%2Fgrpc%2Fmy-service", target)
 }