Implement unary client interceptors

clientconn.go

@@ -14,9 +14,10 @@ import (
 )
 
 type ClientConn struct {
-	controller *StreamController
-	tracer     trace.Tracer
-	logger     *zap.Logger
+	controller  *StreamController
+	interceptor grpc.UnaryClientInterceptor
+	tracer      trace.Tracer
+	logger      *zap.Logger
 }
 
 var _ grpc.ClientConnInterface = (*ClientConn)(nil)
@@ -30,6 +31,21 @@ func (cc *ClientConn) Invoke(
 	req any,
 	reply any,
 	callOpts ...grpc.CallOption,
+) error {
+	if cc.interceptor != nil {
+		// Important: the interceptor is called with a nil *grpc.ClientConn.
+		return cc.interceptor(ctx, method, req, reply, nil, cc.invoke, callOpts...)
+	}
+	return cc.invoke(ctx, method, req, reply, nil, callOpts...)
+}
+
+func (cc *ClientConn) invoke(
+	ctx context.Context,
+	method string,
+	req any,
+	reply any,
+	_ *grpc.ClientConn,
+	callOpts ...grpc.CallOption,
 ) error {
 	var serviceName, methodName string
 	if method != Forward {

go.mod

@@ -5,24 +5,24 @@ go 1.18
 require (
 	github.com/charmbracelet/lipgloss v0.6.0
 	github.com/google/uuid v1.3.0
-	github.com/jhump/protoreflect v1.14.0
+	github.com/jhump/protoreflect v1.14.1
 	github.com/kralicky/gpkg v0.0.0-20220311205216-0d8ea9557555
 	github.com/kralicky/ragu v1.0.0-rc4
 	github.com/magefile/mage v1.14.0
-	github.com/onsi/ginkgo/v2 v2.6.1
-	github.com/onsi/gomega v1.24.2
-	go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.37.0
-	go.opentelemetry.io/contrib/propagators/autoprop v0.37.0
-	go.opentelemetry.io/otel v1.11.2
-	go.opentelemetry.io/otel/exporters/jaeger v1.11.2
-	go.opentelemetry.io/otel/sdk v1.11.2
-	go.opentelemetry.io/otel/trace v1.11.2
+	github.com/onsi/ginkgo/v2 v2.8.0
+	github.com/onsi/gomega v1.26.0
+	go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.38.0
+	go.opentelemetry.io/contrib/propagators/autoprop v0.38.0
+	go.opentelemetry.io/otel v1.13.0
+	go.opentelemetry.io/otel/exporters/jaeger v1.13.0
+	go.opentelemetry.io/otel/sdk v1.13.0
+	go.opentelemetry.io/otel/trace v1.13.0
 	go.uber.org/atomic v1.10.0
 	go.uber.org/zap v1.24.0
-	golang.org/x/exp v0.0.0-20221217163422-3c43f8badb15
-	golang.org/x/net v0.4.0
-	google.golang.org/genproto v0.0.0-20221207170731-23e4bf6bdc37
-	google.golang.org/grpc v1.51.0
+	golang.org/x/exp v0.0.0-20230206171751-46f607a40771
+	golang.org/x/net v0.5.0
+	google.golang.org/genproto v0.0.0-20230202175211-008b39050e57
+	google.golang.org/grpc v1.52.3
 	google.golang.org/protobuf v1.28.1
 )
 
@@ -44,14 +44,14 @@ require (
 	github.com/muesli/termenv v0.11.1-0.20220204035834-5ac8409525e0 // indirect
 	github.com/rivo/uniseg v0.2.0 // indirect
 	github.com/samber/lo v1.28.2 // indirect
-	go.opentelemetry.io/contrib/propagators/aws v1.12.0 // indirect
-	go.opentelemetry.io/contrib/propagators/b3 v1.12.0 // indirect
-	go.opentelemetry.io/contrib/propagators/jaeger v1.12.0 // indirect
-	go.opentelemetry.io/contrib/propagators/ot v1.12.0 // indirect
-	go.opentelemetry.io/otel/metric v0.34.0 // indirect
-	go.uber.org/multierr v1.8.0 // indirect
+	go.opentelemetry.io/contrib/propagators/aws v1.13.0 // indirect
+	go.opentelemetry.io/contrib/propagators/b3 v1.13.0 // indirect
+	go.opentelemetry.io/contrib/propagators/jaeger v1.13.0 // indirect
+	go.opentelemetry.io/contrib/propagators/ot v1.13.0 // indirect
+	go.opentelemetry.io/otel/metric v0.35.0 // indirect
+	go.uber.org/multierr v1.9.0 // indirect
 	golang.org/x/mod v0.7.0 // indirect
-	golang.org/x/sys v0.3.0 // indirect
-	golang.org/x/text v0.5.0 // indirect
+	golang.org/x/sys v0.4.0 // indirect
+	golang.org/x/text v0.6.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -61,6 +61,8 @@ github.com/jhump/goprotoc v0.5.0/go.mod h1:VrbvcYrQOrTi3i0Vf+m+oqQWk9l72mjkJCYo7
 github.com/jhump/protoreflect v1.11.0/go.mod h1:U7aMIjN0NWq9swDP7xDdoMfRHb35uiuTd3Z9nFXJf5E=
 github.com/jhump/protoreflect v1.14.0 h1:MBbQK392K3u8NTLbKOCIi3XdI+y+c6yt5oMq0X3xviw=
 github.com/jhump/protoreflect v1.14.0/go.mod h1:JytZfP5d0r8pVNLZvai7U/MCuTWITgrI4tTg7puQFKI=
+github.com/jhump/protoreflect v1.14.1 h1:N88q7JkxTHWFEqReuTsYH1dPIwXxA0ITNQp7avLY10s=
+github.com/jhump/protoreflect v1.14.1/go.mod h1:JytZfP5d0r8pVNLZvai7U/MCuTWITgrI4tTg7puQFKI=
 github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
 github.com/kr/pretty v0.2.1 h1:Fmg33tUaq4/8ym9TJN1x7sLJnHVwhP33CNkpYV/7rwI=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
@@ -87,8 +89,13 @@ github.com/muesli/termenv v0.11.1-0.20220204035834-5ac8409525e0 h1:STjmj0uFfRryL
 github.com/muesli/termenv v0.11.1-0.20220204035834-5ac8409525e0/go.mod h1:Bd5NYQ7pd+SrtBSrSNoBBmXlcY8+Xj4BMJgh8qcZrvs=
 github.com/onsi/ginkgo/v2 v2.6.1 h1:1xQPCjcqYw/J5LchOcp4/2q/jzJFjiAOc25chhnDw+Q=
 github.com/onsi/ginkgo/v2 v2.6.1/go.mod h1:yjiuMwPokqY1XauOgju45q3sJt6VzQ/Fict1LFVcsAo=
+github.com/onsi/ginkgo/v2 v2.8.0 h1:pAM+oBNPrpXRs+E/8spkeGx9QgekbRVyr74EUvRVOUI=
+github.com/onsi/ginkgo/v2 v2.8.0/go.mod h1:6JsQiECmxCa3V5st74AL/AmsV482EDdVrGaVW6z3oYU=
 github.com/onsi/gomega v1.24.2 h1:J/tulyYK6JwBldPViHJReihxxZ+22FHs0piGjQAvoUE=
 github.com/onsi/gomega v1.24.2/go.mod h1:gs3J10IS7Z7r7eXRoNJIrNqU4ToQukCJhFtKrWgHWnk=
+github.com/onsi/gomega v1.25.0/go.mod h1:r+zV744Re+DiYCIPRlYOTxn0YkOLcAnW8k1xXdMPGhM=
+github.com/onsi/gomega v1.26.0 h1:03cDLK28U6hWvCAns6NeydX3zIm4SF3ci69ulidS32Q=
+github.com/onsi/gomega v1.26.0/go.mod h1:r+zV744Re+DiYCIPRlYOTxn0YkOLcAnW8k1xXdMPGhM=
 github.com/pkg/errors v0.8.1 h1:iURUrRGxPUNPdy5/HRSm+Yj6okJ6UtLINN0Q9M4+h3I=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
@@ -107,39 +114,71 @@ github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKs
 github.com/thoas/go-funk v0.9.1 h1:O549iLZqPpTUQ10ykd26sZhzD+rmR5pWhuElrhbC20M=
 go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.37.0 h1:+uFejS4DCfNH6d3xODVIGsdhzgzhh45p9gpbHQMbdZI=
 go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.37.0/go.mod h1:HSmzQvagH8pS2/xrK7ScWsk0vAMtRTGbMFgInXCi8Tc=
+go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.38.0 h1:g/BAN5o90Pr6D8xMRezjzGOHBpc15U+4oE53nZLiae4=
+go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.38.0/go.mod h1:+F41JBSkye7aYJELRvIMF0Z66reIwIOL0St75ZVwSJs=
 go.opentelemetry.io/contrib/propagators/autoprop v0.37.0 h1:7BO8yg+5TE8QWzA6apuj8nPjoIdQUw8OhsFSYU6DPeo=
 go.opentelemetry.io/contrib/propagators/autoprop v0.37.0/go.mod h1:bV3y2INa2Fe69LVRzszdM/knfKRBtJmI8VbHQi9ySpM=
+go.opentelemetry.io/contrib/propagators/autoprop v0.38.0 h1:WZwiLCwOL0XW/6TVT7LTtdRDveoHZ6q3wL+0iYsBcdE=
+go.opentelemetry.io/contrib/propagators/autoprop v0.38.0/go.mod h1:JBebP2d0HiffbfelbIEoBOCl4790g7Z8lD1scUd3Vd8=
 go.opentelemetry.io/contrib/propagators/aws v1.12.0 h1:n3lNyZs2ytVEfFhcn2QO5Z80lgrMXyP1Ncx0C7rUU8A=
 go.opentelemetry.io/contrib/propagators/aws v1.12.0/go.mod h1:xZSOQIixr40Cq3NHn/YsvkDOzpVaR0j19WJRZnOKwbk=
+go.opentelemetry.io/contrib/propagators/aws v1.13.0 h1:9qOAQhTeJGiaYNfCCnRmL12XZGIaxclqS5yfkSXpn8o=
+go.opentelemetry.io/contrib/propagators/aws v1.13.0/go.mod h1:XXahyNfhmY382jrQPE1sKXxTgfnXbx3KzNOweRJV8+A=
 go.opentelemetry.io/contrib/propagators/b3 v1.12.0 h1:OtfTF8bneN8qTeo/j92kcvc0iDDm4bm/c3RzaUJfiu0=
 go.opentelemetry.io/contrib/propagators/b3 v1.12.0/go.mod h1:0JDB4elfPUWGsCH/qhaMkDzP1l8nB0ANVx8zXuAYEwg=
+go.opentelemetry.io/contrib/propagators/b3 v1.13.0 h1:f17PBmZK60RoHvOpJVqEka8oS2EXjpjHquESD/8zZ50=
+go.opentelemetry.io/contrib/propagators/b3 v1.13.0/go.mod h1:zy2hz1TpGUoJzSwlBchVGvVAFQS8s2pglKLbrAFZ+Sc=
 go.opentelemetry.io/contrib/propagators/jaeger v1.12.0 h1:fQBEhLiGQihBAAmiozZihHvO0t/+NFZMOLx80bmAi+s=
 go.opentelemetry.io/contrib/propagators/jaeger v1.12.0/go.mod h1:hryAK4MKIBKRaUh8n0/vHWuu4fzhR0XB1Q8B4wz3qhw=
+go.opentelemetry.io/contrib/propagators/jaeger v1.13.0 h1:+tVlvpiQMOCzi4EYCaBjblibpyKfqoph0fcITmtXMws=
+go.opentelemetry.io/contrib/propagators/jaeger v1.13.0/go.mod h1:Qf7eVCLYawiNIB+A81kk8aFDFwYqXSqmt0N2RcvkLLI=
 go.opentelemetry.io/contrib/propagators/ot v1.12.0 h1:6yNXAAQW08uIwgQKQvGC/0/5KkUCZmOcwSjj8zYg1ZU=
 go.opentelemetry.io/contrib/propagators/ot v1.12.0/go.mod h1:t2n1RTxGm14/AEMSELd0jJo3NBjeEHnDtCRYXKTl0Ak=
+go.opentelemetry.io/contrib/propagators/ot v1.13.0 h1:tHWNd0WRS6w9keZoZg9aF3zYohdaBacQfojPYZJgATQ=
+go.opentelemetry.io/contrib/propagators/ot v1.13.0/go.mod h1:R6Op9T6LxNaMRVlGD0wVwz40LSsAq296CXiEydKLQBU=
 go.opentelemetry.io/otel v1.11.2 h1:YBZcQlsVekzFsFbjygXMOXSs6pialIZxcjfO/mBDmR0=
 go.opentelemetry.io/otel v1.11.2/go.mod h1:7p4EUV+AqgdlNV9gL97IgUZiVR3yrFXYo53f9BM3tRI=
+go.opentelemetry.io/otel v1.12.0 h1:IgfC7kqQrRccIKuB7Cl+SRUmsKbEwSGPr0Eu+/ht1SQ=
+go.opentelemetry.io/otel v1.12.0/go.mod h1:geaoz0L0r1BEOR81k7/n9W4TCXYCJ7bPO7K374jQHG0=
+go.opentelemetry.io/otel v1.13.0 h1:1ZAKnNQKwBBxFtww/GwxNUyTf0AxkZzrukO8MeXqe4Y=
+go.opentelemetry.io/otel v1.13.0/go.mod h1:FH3RtdZCzRkJYFTCsAKDy9l/XYjMdNv6QrkFFB8DvVg=
 go.opentelemetry.io/otel/exporters/jaeger v1.11.2 h1:ES8/j2+aB+3/BUw51ioxa50V9btN1eew/2J7N7n1tsE=
 go.opentelemetry.io/otel/exporters/jaeger v1.11.2/go.mod h1:nwcF/DK4Hk0auZ/a5vw20uMsaJSXbzeeimhN5f9d0Lc=
+go.opentelemetry.io/otel/exporters/jaeger v1.13.0 h1:VAMoGujbVV8Q0JNM/cEbhzUIWWBxnEqH45HP9iBKN04=
+go.opentelemetry.io/otel/exporters/jaeger v1.13.0/go.mod h1:fHwbmle6mBFJA1p2ZIhilvffCdq/dM5UTIiCOmEjS+w=
 go.opentelemetry.io/otel/metric v0.34.0 h1:MCPoQxcg/26EuuJwpYN1mZTeCYAUGx8ABxfW07YkjP8=
 go.opentelemetry.io/otel/metric v0.34.0/go.mod h1:ZFuI4yQGNCupurTXCwkeD/zHBt+C2bR7bw5JqUm/AP8=
+go.opentelemetry.io/otel/metric v0.35.0 h1:aPT5jk/w7F9zW51L7WgRqNKDElBdyRLGuBtI5MX34e8=
+go.opentelemetry.io/otel/metric v0.35.0/go.mod h1:qAcbhaTRFU6uG8QM7dDo7XvFsWcugziq/5YI065TokQ=
 go.opentelemetry.io/otel/sdk v1.11.2 h1:GF4JoaEx7iihdMFu30sOyRx52HDHOkl9xQ8SMqNXUiU=
 go.opentelemetry.io/otel/sdk v1.11.2/go.mod h1:wZ1WxImwpq+lVRo4vsmSOxdd+xwoUJ6rqyLc3SyX9aU=
+go.opentelemetry.io/otel/sdk v1.12.0 h1:8npliVYV7qc0t1FKdpU08eMnOjgPFMnriPhn0HH4q3o=
+go.opentelemetry.io/otel/sdk v1.12.0/go.mod h1:WYcvtgquYvgODEvxOry5owO2y9MyciW7JqMz6cpXShE=
+go.opentelemetry.io/otel/sdk v1.13.0 h1:BHib5g8MvdqS65yo2vV1s6Le42Hm6rrw08qU6yz5JaM=
+go.opentelemetry.io/otel/sdk v1.13.0/go.mod h1:YLKPx5+6Vx/o1TCUYYs+bpymtkmazOMT6zoRrC7AQ7I=
 go.opentelemetry.io/otel/trace v1.11.2 h1:Xf7hWSF2Glv0DE3MH7fBHvtpSBsjcBUe5MYAmZM/+y0=
 go.opentelemetry.io/otel/trace v1.11.2/go.mod h1:4N+yC7QEz7TTsG9BSRLNAa63eg5E06ObSbKPmxQ/pKA=
+go.opentelemetry.io/otel/trace v1.12.0 h1:p28in++7Kd0r2d8gSt931O57fdjUyWxkVbESuILAeUc=
+go.opentelemetry.io/otel/trace v1.12.0/go.mod h1:pHlgBynn6s25qJ2szD+Bv+iwKJttjHSI3lUAyf0GNuQ=
+go.opentelemetry.io/otel/trace v1.13.0 h1:CBgRZ6ntv+Amuj1jDsMhZtlAPT6gbyIRdaIzFhfBSdY=
+go.opentelemetry.io/otel/trace v1.13.0/go.mod h1:muCvmmO9KKpvuXSf3KKAXXB2ygNYHQ+ZfI5X08d3tds=
 go.uber.org/atomic v1.7.0/go.mod h1:fEN4uk6kAWBTFdckzkM89CLk9XfWZrxpCo0nPH17wJc=
 go.uber.org/atomic v1.10.0 h1:9qC72Qh0+3MqyJbAn8YU5xVq1frD8bn3JtD2oXtafVQ=
 go.uber.org/atomic v1.10.0/go.mod h1:LUxbIzbOniOlMKjJjyPfpl4v+PKK2cNJn91OQbhoJI0=
 go.uber.org/goleak v1.1.11 h1:wy28qYRKZgnJTxGxvye5/wgWr1EKjmUDGYox5mGlRlI=
 go.uber.org/multierr v1.8.0 h1:dg6GjLku4EH+249NNmoIciG9N/jURbDG+pFlTkhzIC8=
 go.uber.org/multierr v1.8.0/go.mod h1:7EAYxJLBy9rStEaz58O2t4Uvip6FSURkq8/ppBp95ak=
+go.uber.org/multierr v1.9.0 h1:7fIwc/ZtS0q++VgcfqFDxSBZVv/Xo49/SYnDFupUwlI=
+go.uber.org/multierr v1.9.0/go.mod h1:X2jQV1h+kxSjClGpnseKVIxpmcjrj7MNnI0bnlfKTVQ=
 go.uber.org/zap v1.24.0 h1:FiJd5l1UOLj0wCgbSE0rwwXHzEdAZS6hiiSnxJN/D60=
 go.uber.org/zap v1.24.0/go.mod h1:2kMP+WWQ8aoFoedH3T2sq6iJ2yDWpHbP0f6MQbS9Gkg=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/exp v0.0.0-20221217163422-3c43f8badb15 h1:5oN1Pz/eDhCpbMbLstvIPa0b/BEQo6g6nwV3pLjfM6w=
 golang.org/x/exp v0.0.0-20221217163422-3c43f8badb15/go.mod h1:CxIveKay+FTh1D0yPZemJVgC/95VzuuOLq5Qi4xnoYc=
+golang.org/x/exp v0.0.0-20230206171751-46f607a40771 h1:xP7rWLUr1e1n2xkK5YB4LI0hPEy3LJC6Wk+D4pGlOJg=
+golang.org/x/exp v0.0.0-20230206171751-46f607a40771/go.mod h1:CxIveKay+FTh1D0yPZemJVgC/95VzuuOLq5Qi4xnoYc=
 golang.org/x/lint v0.0.0-20181026193005-c67002cb31c3/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=
 golang.org/x/lint v0.0.0-20190227174305-5b3e6a55c961/go.mod h1:wehouNa3lNwaWXcvxsM5YxQ5yQlVC4a0KAMCusXpPoU=
 golang.org/x/lint v0.0.0-20190313153728-d0100b6bd8b3/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
@@ -153,6 +192,8 @@ golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn
 golang.org/x/net v0.0.0-20200625001655-4c5254603344/go.mod h1:/O7V0waA8r7cgGh81Ro3o1hOxt32SMVPicZroKQ2sZA=
 golang.org/x/net v0.4.0 h1:Q5QPcMlvfxFTAPV0+07Xz/MpK9NTXu2VDUuy0FeMfaU=
 golang.org/x/net v0.4.0/go.mod h1:MBQ8lrhLObU/6UmLb4fmbmk5OcyYmqtbGd/9yIeKjEE=
+golang.org/x/net v0.5.0 h1:GyT4nK/YDHSqa1c4753ouYCDajOYKTja9Xb/OHtgvSw=
+golang.org/x/net v0.5.0/go.mod h1:DivGGAXEgPSlEBzxGzZI+ZLohi+xUj054jfeKui00ws=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.0.0-20220822191816-0ebed06d0094 h1:2o1E+E8TpNLklK9nHiPiK1uzIYrIHt+cQx3ynCwq9V8=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
@@ -166,10 +207,14 @@ golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20210630005230-0f9fa26af87c/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.3.0 h1:w8ZOecv6NaNa/zC8944JTU3vz4u6Lagfk4RPQxv92NQ=
 golang.org/x/sys v0.3.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.4.0 h1:Zr2JFtRQNX3BCZ8YtxRE9hNJYC8J6I1MVbMg6owUp18=
+golang.org/x/sys v0.4.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
 golang.org/x/text v0.5.0 h1:OLmvp0KP+FVG99Ct/qFiL/Fhk4zp4QQnZ7b2U+5piUM=
 golang.org/x/text v0.5.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
+golang.org/x/text v0.6.0 h1:3XmdazWV+ubf7QgHSTWeykHOci5oeekaGJBLkrkaw4k=
+golang.org/x/text v0.6.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20190114222345-bf090417da8b/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20190226205152-f727befe758c/go.mod h1:9Yl7xja0Znq3iFh3HoIrodX9oNMXvdceNzlUR8zjMvY=
@@ -184,13 +229,19 @@ google.golang.org/genproto v0.0.0-20190819201941-24fa4b261c55/go.mod h1:DMBHOl98
 google.golang.org/genproto v0.0.0-20200526211855-cb27e3aa2013/go.mod h1:NbSheEEYHJ7i3ixzK3sjbqSGDJWnxyFXZblF3eUsNvo=
 google.golang.org/genproto v0.0.0-20221207170731-23e4bf6bdc37 h1:jmIfw8+gSvXcZSgaFAGyInDXeWzUhvYH57G/5GKMn70=
 google.golang.org/genproto v0.0.0-20221207170731-23e4bf6bdc37/go.mod h1:RGgjbofJ8xD9Sq1VVhDM1Vok1vRONV+rg+CjzG4SZKM=
+google.golang.org/genproto v0.0.0-20230202175211-008b39050e57 h1:vArvWooPH749rNHpBGgVl+U9B9dATjiEhJzcWGlovNs=
+google.golang.org/genproto v0.0.0-20230202175211-008b39050e57/go.mod h1:RGgjbofJ8xD9Sq1VVhDM1Vok1vRONV+rg+CjzG4SZKM=
 google.golang.org/grpc v1.19.0/go.mod h1:mqu4LbDTu4XGKhr4mRzUsmM4RtVoemTSY81AxZiDr8c=
 google.golang.org/grpc v1.23.0/go.mod h1:Y5yQAOtifL1yxbo5wqy6BxZv8vAUGQwXBOALyacEbxg=
 google.golang.org/grpc v1.25.1/go.mod h1:c3i+UQWmh7LiEpx4sFZnkU36qjEYZ0imhYfXVyQciAY=
 google.golang.org/grpc v1.27.0/go.mod h1:qbnxyOmOxrQa7FizSgH+ReBfzJrCY1pSN7KXBS8abTk=
 google.golang.org/grpc v1.38.0/go.mod h1:NREThFqKR1f3iQ6oBuvc5LadQuXVGo9rkm5ZGrQdJfM=
 google.golang.org/grpc v1.51.0 h1:E1eGv1FTqoLIdnBCZufiSHgKjlqG6fKFf6pPWtMTh8U=
 google.golang.org/grpc v1.51.0/go.mod h1:wgNDFcnuBGmxLKI/qn4T+m5BtEBYXJPvibbUPsAIPww=
+google.golang.org/grpc v1.52.0 h1:kd48UiU7EHsV4rnLyOJRuP/Il/UHE7gdDAQ+SZI7nZk=
+google.golang.org/grpc v1.52.0/go.mod h1:pu6fVzoFb+NBYNAvQL08ic+lvB2IojljRYuun5vorUY=
+google.golang.org/grpc v1.52.3 h1:pf7sOysg4LdgBqduXveGKrcEwbStiK2rtfghdzlUYDQ=
+google.golang.org/grpc v1.52.3/go.mod h1:pu6fVzoFb+NBYNAvQL08ic+lvB2IojljRYuun5vorUY=
 google.golang.org/protobuf v0.0.0-20200109180630-ec00e32a8dfd/go.mod h1:DFci5gLYBciE7Vtevhsrf46CRTquxDuWsQurQQe4oz8=
 google.golang.org/protobuf v0.0.0-20200221191635-4d8936d0db64/go.mod h1:kwYJMbMJ01Woi6D6+Kah6886xMZcty6N08ah7+eCXa0=
 google.golang.org/protobuf v0.0.0-20200228230310-ab0ca4ff8a60/go.mod h1:cfTl7dwQJ+fmap5saPgwCLgHXTUD7jkjRqWcaiX5VyM=

server.go

@@ -178,9 +178,37 @@ func (r *Server) register(serviceDesc *grpc.ServiceDesc, impl interface{}) {
 		newLocalServiceInvoker(impl, serviceDesc, r.logger, r.interceptor)))
 }
 
+type ServeOptions struct {
+	interceptor grpc.UnaryClientInterceptor
+}
+
+type ServeOption func(*ServeOptions)
+
+func (o *ServeOptions) apply(opts ...ServeOption) {
+	for _, op := range opts {
+		op(o)
+	}
+}
+
+// WithUnaryClientInterceptor sets a custom interceptor that will be used by
+// the [grpc.ClientConnInterface] returned by Serve.
+//
+// This interceptor functions similarly to a standard unary client interceptor,
+// with the one caveat that the [grpc.ClientConn] passed to the interceptor
+// will always be nil, and must not be used. The interceptor should still
+// forward the nil argument to the invoker for potential forward compatibility.
+func WithUnaryClientInterceptor(interceptor grpc.UnaryClientInterceptor) ServeOption {
+	return func(o *ServeOptions) {
+		o.interceptor = interceptor
+	}
+}
+
 // Serve starts the totem server, which takes control of the stream and begins
 // handling incoming and outgoing RPCs.
-func (r *Server) Serve() (grpc.ClientConnInterface, <-chan error) {
+func (r *Server) Serve(opts ...ServeOption) (grpc.ClientConnInterface, <-chan error) {
+	options := ServeOptions{}
+	options.apply(opts...)
+
 	r.logger.Debug("starting totem server")
 	r.lock.RLock()
 	ch := make(chan error, 2)
@@ -246,9 +274,10 @@ func (r *Server) Serve() (grpc.ClientConnInterface, <-chan error) {
 	}
 
 	return &ClientConn{
-		controller: r.controller,
-		tracer:     Tracer(),
-		logger:     r.logger.Named("cc"),
+		controller:  r.controller,
+		interceptor: options.interceptor,
+		tracer:      Tracer(),
+		logger:      r.logger.Named("cc"),
 	}, ch
 }