middleware: trace middleware change to using OpenTelemetry (#781)

README.md

@@ -37,10 +37,10 @@ Kratos boosts your productivity. With the integration of excellent resources and
 * Config: Multiple data sources are supported for configurations and integrations such that dynamic configurations are offered through the manner of *Atomic* operations.
 * Logger: The standard log interfaces ease the integration of the third-party log libs and logs are collected through the *Fluentd*.
 * Metrics: *Prometheus* integrated by default. Furthermore, with the uniform metric interfaces, you can implement your own metric system more flexible.
-* Tracing: The OpenTracing is conformed to achieve the tracing of microservices chains.
+* Tracing: The OpenTelemetry is conformed to achieve the tracing of microservices chains.
 * Encoding: The selection of the content encoding is automatically supported by Accept and Content-Type.
 * Transport: The uniform plugins for Middleware are supported by HTTP/gRPC.
- * Registry: The interfaces of the centralized registry is able to be connected with various other centralized registries through plug-ins.
+* Registry: The interfaces of the centralized registry is able to be connected with various other centralized registries through plug-ins.
 
 ## Getting Started
 ### Required

README_zh.md

@@ -37,7 +37,7 @@ Kratos 一套轻量级 Go 微服务框架，包含大量微服务相关框架及
 * Config：支持多数据源方式，进行配置合并铺平，通过 Atomic 方式支持动态配置；
 * Logger：标准日志接口，可方便集成三方 log 库，并可通过 fluentd 收集日志；
 * Metrics：统一指标接口，可以实现各种指标系统，默认集成 Prometheus；
-* Tracing：遵循 OpenTracing 规范定义，以实现微服务链路追踪；
+* Tracing：遵循 OpenTelemetry 规范定义，以实现微服务链路追踪；
 * Encoding：支持 Accept 和 Content-Type 进行自动选择内容编码；
 * Transport：通用的 HTTP/gRPC 传输层，实现统一的 Middleware 插件支持；
 * Registry：实现统一注册中心接口，可插件化对接各种注册中心；

go.mod

@@ -8,7 +8,8 @@ require (
 	github.com/google/uuid v1.1.2
 	github.com/gorilla/mux v1.8.0
 	github.com/imdario/mergo v0.3.6
-	github.com/opentracing/opentracing-go v1.2.0
+	go.opentelemetry.io/otel v0.18.0
+	go.opentelemetry.io/otel/trace v0.18.0
 	golang.org/x/sync v0.0.0-20190423024810-112230192c58
 	google.golang.org/genproto v0.0.0-20210114201628-6edceaf6022f
 	google.golang.org/grpc v1.35.0

go.sum

@@ -1,17 +1,26 @@
+cloud.google.com/go v0.26.0 h1:e0WKqKTd5BnrG8aKH3J3h+QvEIQtSUcf2n5UZ5ZgLtQ=
 cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
+github.com/BurntSushi/toml v0.3.1 h1:WXkYYl6Yr3qBf1K79EBnL4mak0OimBfB0XUf9Vl28OQ=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
+github.com/census-instrumentation/opencensus-proto v0.2.1 h1:glEXhBS5PSLLv4IXzLA5yPRVX4bilULVyxxbrfOtDAk=
 github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
+github.com/client9/misspell v0.3.4 h1:ta993UF76GwbvJcIo3Y68y/M3WxlpEHPWIGDkJYwzJI=
 github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=
+github.com/cncf/udpa/go v0.0.0-20201120205902-5459f2c99403 h1:cqQfy1jclcSy/FwLjemeg3SR1yaINm74aQyupQ0Bl8M=
 github.com/cncf/udpa/go v0.0.0-20201120205902-5459f2c99403/go.mod h1:WmhPx2Nbnhtbo57+VJT5O0JRkEi1Wbu0z5j0R8u5Hbk=
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/envoyproxy/go-control-plane v0.9.0/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
 github.com/envoyproxy/go-control-plane v0.9.1-0.20191026205805-5f8ba28d4473/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
+github.com/envoyproxy/go-control-plane v0.9.9-0.20201210154907-fd9021fe5dad h1:EmNYJhPYy0pOFjCx2PrgtaBXmee0iUX9hLlxE1xHOJE=
 github.com/envoyproxy/go-control-plane v0.9.9-0.20201210154907-fd9021fe5dad/go.mod h1:cXg6YxExXjJnVBQHBLXeUAgxn2UodCpnH306RInaBQk=
+github.com/envoyproxy/protoc-gen-validate v0.1.0 h1:EQciDnbrYxy13PgWoY8AqoxGiPrpgBZ1R8UNe3ddc+A=
 github.com/envoyproxy/protoc-gen-validate v0.1.0/go.mod h1:iSmxcyjqTsJpI2R4NaDN7+kN2VEUnK/pcBlmesArF7c=
 github.com/fsnotify/fsnotify v1.4.9 h1:hsms1Qyu0jgnwNXIxa+/V/PDsU6CfLf6CNO8H7IWoS4=
 github.com/fsnotify/fsnotify v1.4.9/go.mod h1:znqG4EE+3YCdAaPaxE2ZRY/06pZUdp0tY4IgpuI1SZQ=
+github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b h1:VKtxabqXZkF25pY9ekfRL6a582T4P37/31XEstQ5p58=
 github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b/go.mod h1:SBH7ygxi8pfUlaOkMMuAQtPIUF8ecWP5IEl/CR7VP2Q=
+github.com/golang/mock v1.1.1 h1:G5FRp8JnTd7RQH5kemVNlMeyXQAztQ3mOWV95KxsXH8=
 github.com/golang/mock v1.1.1/go.mod h1:oTYuIxOrZwtPieC+H1uAHpcLFnEyAGVDL/k47Jfbm0A=
 github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/golang/protobuf v1.3.2/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
@@ -28,33 +37,46 @@ github.com/google/go-cmp v0.2.0/go.mod h1:oXzfMopK8JAjlY9xF4vHSVASa0yLyX7SntLO5a
 github.com/google/go-cmp v0.3.0/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
 github.com/google/go-cmp v0.3.1/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
 github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/google/go-cmp v0.5.0 h1:/QaMHBdZ26BB3SSst0Iwl10Epc+xhTquomWX0oZEB6w=
 github.com/google/go-cmp v0.5.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/google/go-cmp v0.5.4 h1:L8R9j+yAqZuZjsqh/z+F1NCffTKKLShY6zXTItVIZ8M=
+github.com/google/go-cmp v0.5.4/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/uuid v1.1.2 h1:EVhdT+1Kseyi1/pUmXKaFxYsDNy9RQYkMWRH68J/W7Y=
 github.com/google/uuid v1.1.2/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/gorilla/mux v1.8.0 h1:i40aqfkR1h2SlN9hojwV5ZA91wcXFOvkdNIeFDP5koI=
 github.com/gorilla/mux v1.8.0/go.mod h1:DVbg23sWSpFRCP0SfiEN6jmj59UnW/n46BH5rLB71So=
 github.com/imdario/mergo v0.3.6 h1:xTNEAn+kxVO7dTZGu0CegyqKZmoWFI0rF8UxjlB2d28=
 github.com/imdario/mergo v0.3.6/go.mod h1:2EnlNZ0deacrJVfApfmtdGgDfMuh/nq6Ok1EcJh5FfA=
-github.com/opentracing/opentracing-go v1.2.0 h1:uEJPy/1a5RIPAJ0Ov+OIO8OxWu77jEv+1B0VhjKrZUs=
-github.com/opentracing/opentracing-go v1.2.0/go.mod h1:GxEUsuufX4nBwe+T+Wl9TAgYrxe9dPLANfrWvHYVTgc=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/prometheus/client_model v0.0.0-20190812154241-14fe0d1b01d4 h1:gQz4mCbXsO+nc9n1hCxHcGA3Zx3Eo+UHZoInFGUIXNM=
 github.com/prometheus/client_model v0.0.0-20190812154241-14fe0d1b01d4/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=
+github.com/stretchr/objx v0.1.0 h1:4G4v2dO3VZwixGIRoQ5Lfboy6nUhCyYzaqnIAPPhYs4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
-github.com/stretchr/testify v1.5.1 h1:nOGnQDM7FYENwehXlg/kFVnos3rEvtKTjRvOWSzb6H4=
 github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5cxcmMvtA=
+github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+go.opentelemetry.io/otel v0.18.0 h1:d5Of7+Zw4ANFOJB+TIn2K3QWsgS2Ht7OU9DqZHI6qu8=
+go.opentelemetry.io/otel v0.18.0/go.mod h1:PT5zQj4lTsR1YeARt8YNKcFb88/c2IKoSABK9mX0r78=
+go.opentelemetry.io/otel/metric v0.18.0 h1:yuZCmY9e1ZTaMlZXLrrbAPmYW6tW1A5ozOZeOYGaTaY=
+go.opentelemetry.io/otel/metric v0.18.0/go.mod h1:kEH2QtzAyBy3xDVQfGZKIcok4ZZFvd5xyKPfPcuK6pE=
+go.opentelemetry.io/otel/oteltest v0.18.0 h1:FbKDFm/LnQDOHuGjED+fy3s5YMVg0z019GJ9Er66hYo=
+go.opentelemetry.io/otel/oteltest v0.18.0/go.mod h1:NyierCU3/G8DLTva7KRzGii2fdxdR89zXKH1bNWY7Bo=
+go.opentelemetry.io/otel/trace v0.18.0 h1:ilCfc/fptVKaDMK1vWk0elxpolurJbEgey9J6g6s+wk=
+go.opentelemetry.io/otel/trace v0.18.0/go.mod h1:FzdUu3BPwZSZebfQ1vl5/tAa8LyMLXSJN57AXIt/iDk=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2 h1:VklqNMn3ovrHsnt90PveolxSbWFaJdECFbxSq0Mqo2M=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/exp v0.0.0-20190121172915-509febef88a4 h1:c2HOrn5iMezYjSlGPncknSEr/8x5LELb/ilJbXi9DEA=
 golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 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 h1:XQyxROzUlZH+WIQwySDgnISgOivlhjIEwaQaJEJrrN0=
 golang.org/x/lint v0.0.0-20190313153728-d0100b6bd8b3/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
 golang.org/x/net v0.0.0-20180724234803-3673e40ba225/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20180826012351-8a410e7b638d/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20190213061140-3a22650c66bd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20190311183353-d8887717615a h1:oWX7TPOiFAMXLq8o0ikBYfCJVlRHBcsciT5bXOrH628=
 golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be h1:vEDujvNQGv4jgYKudGeI/+DAX4Jffq6hpD55MmoEvKs=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
@@ -69,10 +91,12 @@ golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 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=
 golang.org/x/tools v0.0.0-20190311212946-11955173bddd/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs=
+golang.org/x/tools v0.0.0-20190524140312-2c0ae7006135 h1:5Beo0mZN8dRzgrMMkDp0jc8YXQKx9DiJ2k1dkvGsn5A=
 golang.org/x/tools v0.0.0-20190524140312-2c0ae7006135/go.mod h1:RgjU9mgBXZiqYHBnxXauZ1Gv1EHHAz9KjViQ78xBX0Q=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 google.golang.org/appengine v1.1.0/go.mod h1:EbEs0AVv82hx2wNQdGPgUI5lhzA/G0D9YwlJXL52JkM=
+google.golang.org/appengine v1.4.0 h1:/wp5JvzpHIxhs/dumFmF7BXTf3Z+dd4uXta4kVyO508=
 google.golang.org/appengine v1.4.0/go.mod h1:xpcJRLb0r/rnEns0DIKYYv+WjYCduHsrkT7/EB5XEv4=
 google.golang.org/genproto v0.0.0-20180817151627-c66870c02cf8/go.mod h1:JiN7NxoALGmiZfu7CAH4rXhgtRTLTxftemlI0sWmxmc=
 google.golang.org/genproto v0.0.0-20190819201941-24fa4b261c55/go.mod h1:DMBHOl98Agz4BDEuKkezgsaosCRResVns1a3J2ZsMNc=
@@ -100,5 +124,8 @@ gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
+honnef.co/go/tools v0.0.0-20190523083050-ea95bdfd59fc h1:/hemPrYIhOhy8zYrNj+069zDB68us2sMGsfkFJO0iZs=
 honnef.co/go/tools v0.0.0-20190523083050-ea95bdfd59fc/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=

middleware/tracing/tracing.go

@@ -6,9 +6,10 @@ import (
 	"github.com/go-kratos/kratos/v2/middleware"
 	"github.com/go-kratos/kratos/v2/transport/grpc"
 	"github.com/go-kratos/kratos/v2/transport/http"
-	"github.com/opentracing/opentracing-go"
+	"go.opentelemetry.io/otel"
-	"github.com/opentracing/opentracing-go/ext"
+	"go.opentelemetry.io/otel/attribute"
-	"github.com/opentracing/opentracing-go/log"
+	"go.opentelemetry.io/otel/propagation"
+	oteltrace "go.opentelemetry.io/otel/trace"
 	"google.golang.org/grpc/metadata"
 )
 
@@ -16,61 +17,92 @@ import (
 type Option func(*options)
 
 type options struct {
-	tracer opentracing.Tracer
+	TracerProvider oteltrace.TracerProvider
+	Propagators    propagation.TextMapPropagator
 }
 
-// WithTracer sets a custom tracer to be used for this middleware, otherwise the opentracing.GlobalTracer is used.
+func WithPropagators(propagators propagation.TextMapPropagator) Option {
-func WithTracer(tracer opentracing.Tracer) Option {
+	return func(opts *options) {
-	return func(o *options) {
+		opts.Propagators = propagators
-		o.tracer = tracer
 	}
 }
 
-// Server returns a new server middleware for OpenTracing.
+func WithTracerProvider(provider oteltrace.TracerProvider) Option {
+	return func(opts *options) {
+		opts.TracerProvider = provider
+	}
+}
+
+type MetadataCarrier struct {
+	md *metadata.MD
+}
+
+var _ propagation.TextMapCarrier = &MetadataCarrier{}
+
+func (mc MetadataCarrier) Get(key string) string {
+	values := mc.md.Get(key)
+	if len(values) == 0 {
+		return ""
+	}
+	return values[0]
+}
+
+// Set stores the key-value pair.
+func (mc MetadataCarrier) Set(key string, value string) {
+	mc.md.Set(key, value)
+}
+
+// Set stores the key-value pair.
+func (mc MetadataCarrier) Keys() []string {
+	keys := make([]string, 0, mc.md.Len())
+	for key := range *mc.md {
+		keys = append(keys, key)
+	}
+	return keys
+}
+
+// Server returns a new server middleware for OpenTelemetry.
 func Server(opts ...Option) middleware.Middleware {
 	options := options{
-		tracer: opentracing.GlobalTracer(),
+		TracerProvider: otel.GetTracerProvider(),
+		Propagators:    otel.GetTextMapPropagator(),
 	}
 	for _, o := range opts {
 		o(&options)
 	}
+	tracer := options.TracerProvider.Tracer("server")
 	return func(handler middleware.Handler) middleware.Handler {
 		return func(ctx context.Context, req interface{}) (reply interface{}, err error) {
 			var (
-				component   string
+				component string
-				operation   string
+				operation string
-				spanContext opentracing.SpanContext
 			)
 			if info, ok := http.FromServerContext(ctx); ok {
 				// HTTP span
 				component = "HTTP"
 				operation = info.Request.RequestURI
-				spanContext, _ = options.tracer.Extract(
+				ctx = propagation.NewCompositeTextMapPropagator(options.Propagators).
-					opentracing.HTTPHeaders,
+					Extract(ctx, propagation.HeaderCarrier(info.Request.Header))
-					opentracing.HTTPHeadersCarrier(info.Request.Header),
-				)
 			} else if info, ok := grpc.FromServerContext(ctx); ok {
 				// gRPC span
 				component = "gRPC"
 				operation = info.FullMethod
 				if md, ok := metadata.FromIncomingContext(ctx); ok {
-					spanContext, _ = options.tracer.Extract(
+					ctx = propagation.NewCompositeTextMapPropagator(options.Propagators).
-						opentracing.HTTPHeaders,
+						Extract(ctx, MetadataCarrier{md: &md})
-						opentracing.HTTPHeadersCarrier(md),
-					)
 				}
 			}
-			span := options.tracer.StartSpan(
+			ctx, span := tracer.Start(ctx,
 				operation,
-				ext.RPCServerOption(spanContext),
+				oteltrace.WithAttributes(attribute.String("component", component)),
-				opentracing.Tag{Key: string(ext.Component), Value: component},
+				oteltrace.WithSpanKind(oteltrace.SpanKindServer),
 			)
-			defer span.Finish()
+			defer span.End()
 			if reply, err = handler(ctx, req); err != nil {
-				ext.Error.Set(span, true)
+				span.RecordError(err)
-				span.LogFields(
+				span.SetAttributes(
-					log.String("event", "error"),
+					attribute.String("event", "error"),
-					log.String("message", err.Error()),
+					attribute.String("message", err.Error()),
 				)
 			}
 			return
@@ -78,52 +110,51 @@ func Server(opts ...Option) middleware.Middleware {
 	}
 }
 
-// Client returns a new client middleware for OpenTracing.
+// Client returns a new client middleware for OpenTelemetry.
 func Client(opts ...Option) middleware.Middleware {
-	options := options{}
+	options := options{
+		TracerProvider: otel.GetTracerProvider(),
+		Propagators:    otel.GetTextMapPropagator(),
+	}
 	for _, o := range opts {
 		o(&options)
 	}
+	tracer := options.TracerProvider.Tracer("client")
 	return func(handler middleware.Handler) middleware.Handler {
 		return func(ctx context.Context, req interface{}) (reply interface{}, err error) {
 			var (
+				component string
 				operation string
-				parent    opentracing.SpanContext
+				carrier   propagation.TextMapCarrier
-				carrier   opentracing.HTTPHeadersCarrier
 			)
-			if span := opentracing.SpanFromContext(ctx); span != nil {
-				parent = span.Context()
-			}
 			if info, ok := http.FromClientContext(ctx); ok {
 				// HTTP span
+				component = "HTTP"
 				operation = info.Request.RequestURI
-				carrier = opentracing.HTTPHeadersCarrier(info.Request.Header)
+				carrier = propagation.HeaderCarrier(info.Request.Header)
 			} else if info, ok := grpc.FromClientContext(ctx); ok {
 				// gRPC span
+				component = "gRPC"
 				operation = info.FullMethod
-				if md, ok := metadata.FromOutgoingContext(ctx); ok {
+				md, ok := metadata.FromOutgoingContext(ctx)
-					carrier = opentracing.HTTPHeadersCarrier(md)
+				if !ok {
-					ctx = metadata.NewOutgoingContext(ctx, md)
-				} else {
 					md = metadata.Pairs()
-					carrier = opentracing.HTTPHeadersCarrier(md)
-					ctx = metadata.NewOutgoingContext(ctx, md)
 				}
+				carrier = MetadataCarrier{md: &md}
+				ctx = metadata.NewOutgoingContext(ctx, md)
 			}
-			span := options.tracer.StartSpan(
+			ctx, span := tracer.Start(ctx,
 				operation,
-				opentracing.ChildOf(parent),
+				oteltrace.WithAttributes(attribute.String("component", component)),
-				ext.SpanKindRPCClient,
+				oteltrace.WithSpanKind(oteltrace.SpanKindClient),
 			)
-			defer span.Finish()
+			defer span.End()
-			options.tracer.Inject(span.Context(), opentracing.HTTPHeaders, carrier)
+			propagation.NewCompositeTextMapPropagator(options.Propagators).Inject(ctx, carrier)
-			ctx = opentracing.ContextWithSpan(ctx, span)
-			// send handler
 			if reply, err = handler(ctx, req); err != nil {
-				ext.Error.Set(span, true)
+				span.RecordError(err)
-				span.LogFields(
+				span.SetAttributes(
-					log.String("event", "error"),
+					attribute.String("event", "error"),
-					log.String("message", err.Error()),
+					attribute.String("message", err.Error()),
 				)
 			}
 			return