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piotrpioJarema
piotrpio
and
Jarema
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[ADDED] Service api improvements (nats-io#1160)
Co-authored-by: Tomasz Pietrek <[email protected]>
1 parent 95a7e50 commit 32b9daa

15 files changed

+2151
-698
lines changed

‎js.go

Lines changed: 1 addition & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -1528,13 +1528,11 @@ func (js *js) subscribe(subj, queue string, cb MsgHandler, ch chan *Msg, isSync,
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}
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15301530
// Find the stream mapped to the subject if not bound to a stream already.
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if o.stream == _EMPTY_ {
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if stream == _EMPTY_ {
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stream, err = js.StreamNameBySubject(subj)
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if err != nil {
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return nil, err
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}
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} else {
1537-
stream = o.stream
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}
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// With an explicit durable name, we can lookup the consumer first

‎micro/example_package_test.go

Lines changed: 84 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,84 @@
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// Copyright 2022 The NATS Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package micro
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import (
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"fmt"
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"log"
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"strconv"
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"time"
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"github.com/nats-io/nats.go"
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)
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func Example() {
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s := RunServerOnPort(-1)
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defer s.Shutdown()
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nc, err := nats.Connect(s.ClientURL())
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if err != nil {
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log.Fatal(err)
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}
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defer nc.Close()
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// Service handler is a function which takes Service.Request as argument.
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// req.Respond or req.Error should be used to respond to the request.
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incrementHandler := func(req *Request) error {
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val, err := strconv.Atoi(string(req.Data))
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if err != nil {
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req.Error("400", "request data should be a number", nil)
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return nil
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}
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responseData := val + 1
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req.Respond([]byte(strconv.Itoa(responseData)))
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return nil
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}
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config := Config{
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Name: "IncrementService",
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Version: "0.1.0",
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Description: "Increment numbers",
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Endpoint: Endpoint{
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// service handler
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Handler: incrementHandler,
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// a unique subject serving as a service endpoint
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Subject: "numbers.increment",
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},
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}
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// Multiple instances of the servcice with the same name can be created.
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// Requests to a service with the same name will be load-balanced.
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for i := 0; i < 5; i++ {
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svc, err := AddService(nc, config)
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if err != nil {
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log.Fatal(err)
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}
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defer svc.Stop()
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}
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// send a request to a service
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resp, err := nc.Request("numbers.increment", []byte("3"), 1*time.Second)
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if err != nil {
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log.Fatal(err)
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}
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responseVal, err := strconv.Atoi(string(resp.Data))
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if err != nil {
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log.Fatal(err)
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}
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fmt.Println(responseVal)
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//
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// Output: 4
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//
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}

‎micro/example_test.go

Lines changed: 267 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,267 @@
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// Copyright 2022 The NATS Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11+
// See the License for the specific language governing permissions and
12+
// limitations under the License.
13+
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package micro
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import (
17+
"fmt"
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"log"
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"reflect"
20+
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"github.com/nats-io/nats.go"
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)
23+
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func ExampleAddService() {
25+
nc, err := nats.Connect("127.0.0.1:4222")
26+
if err != nil {
27+
log.Fatal(err)
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}
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defer nc.Close()
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echoHandler := func(req *Request) error {
32+
req.Respond(req.Data)
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return nil
34+
}
35+
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config := Config{
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Name: "EchoService",
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Version: "v1.0.0",
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Description: "Send back what you receive",
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Endpoint: Endpoint{
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Subject: "echo",
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Handler: echoHandler,
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},
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// DoneHandler can be set to customize behavior on stopping a service.
46+
DoneHandler: func(srv Service) {
47+
info := srv.Info()
48+
fmt.Printf("stopped service %q with ID %q\n", info.Name, info.ID)
49+
},
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// ErrorHandler can be used to customize behavior on service execution error.
52+
ErrorHandler: func(srv Service, err *NATSError) {
53+
info := srv.Info()
54+
fmt.Printf("Service %q returned an error on subject %q: %s", info.Name, err.Subject, err.Description)
55+
},
56+
}
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srv, err := AddService(nc, config)
59+
if err != nil {
60+
log.Fatal(err)
61+
}
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defer srv.Stop()
63+
}
64+
65+
func ExampleService_Info() {
66+
nc, err := nats.Connect("127.0.0.1:4222")
67+
if err != nil {
68+
log.Fatal(err)
69+
}
70+
defer nc.Close()
71+
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config := Config{
73+
Name: "EchoService",
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Endpoint: Endpoint{
75+
Subject: "echo",
76+
Handler: func(*Request) error { return nil },
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},
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}
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80+
srv, _ := AddService(nc, config)
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// service info
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info := srv.Info()
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fmt.Println(info.ID)
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fmt.Println(info.Name)
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fmt.Println(info.Description)
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fmt.Println(info.Version)
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fmt.Println(info.Subject)
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}
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func ExampleService_Stats() {
93+
nc, err := nats.Connect("127.0.0.1:4222")
94+
if err != nil {
95+
log.Fatal(err)
96+
}
97+
defer nc.Close()
98+
99+
config := Config{
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Name: "EchoService",
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Version: "0.1.0",
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Endpoint: Endpoint{
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Subject: "echo",
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Handler: func(*Request) error { return nil },
105+
},
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}
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108+
srv, _ := AddService(nc, config)
109+
110+
// stats of a service instance
111+
stats := srv.Stats()
112+
113+
fmt.Println(stats.AverageProcessingTime)
114+
fmt.Println(stats.ProcessingTime)
115+
116+
}
117+
118+
func ExampleService_Stop() {
119+
nc, err := nats.Connect("127.0.0.1:4222")
120+
if err != nil {
121+
log.Fatal(err)
122+
}
123+
defer nc.Close()
124+
125+
config := Config{
126+
Name: "EchoService",
127+
Version: "0.1.0",
128+
Endpoint: Endpoint{
129+
Subject: "echo",
130+
Handler: func(*Request) error { return nil },
131+
},
132+
}
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134+
srv, _ := AddService(nc, config)
135+
136+
// stop a service
137+
err = srv.Stop()
138+
if err != nil {
139+
log.Fatal(err)
140+
}
141+
142+
// stop is idempotent so multiple executions will not return an error
143+
err = srv.Stop()
144+
if err != nil {
145+
log.Fatal(err)
146+
}
147+
}
148+
149+
func ExampleService_Stopped() {
150+
nc, err := nats.Connect("127.0.0.1:4222")
151+
if err != nil {
152+
log.Fatal(err)
153+
}
154+
defer nc.Close()
155+
156+
config := Config{
157+
Name: "EchoService",
158+
Version: "0.1.0",
159+
Endpoint: Endpoint{
160+
Subject: "echo",
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Handler: func(*Request) error { return nil },
162+
},
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}
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165+
srv, _ := AddService(nc, config)
166+
167+
// stop a service
168+
err = srv.Stop()
169+
if err != nil {
170+
log.Fatal(err)
171+
}
172+
173+
if srv.Stopped() {
174+
fmt.Println("service stopped")
175+
}
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}
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func ExampleService_Reset() {
179+
nc, err := nats.Connect("127.0.0.1:4222")
180+
if err != nil {
181+
log.Fatal(err)
182+
}
183+
defer nc.Close()
184+
185+
config := Config{
186+
Name: "EchoService",
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Version: "0.1.0",
188+
Endpoint: Endpoint{
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Subject: "echo",
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Handler: func(*Request) error { return nil },
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},
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}
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194+
srv, _ := AddService(nc, config)
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// reset endpoint stats on this service
197+
srv.Reset()
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empty := Stats{
200+
ServiceIdentity: srv.Info().ServiceIdentity,
201+
}
202+
if !reflect.DeepEqual(srv.Stats(), empty) {
203+
log.Fatal("Expected endpoint stats to be empty")
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}
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}
206+
207+
func ExampleControlSubject() {
208+
209+
// subject used to get PING from all services
210+
subjectPINGAll, _ := ControlSubject(PingVerb, "", "")
211+
fmt.Println(subjectPINGAll)
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213+
// subject used to get PING from services with provided name
214+
subjectPINGName, _ := ControlSubject(PingVerb, "CoolService", "")
215+
fmt.Println(subjectPINGName)
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217+
// subject used to get PING from a service with provided name and ID
218+
subjectPINGInstance, _ := ControlSubject(PingVerb, "CoolService", "123")
219+
fmt.Println(subjectPINGInstance)
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// Output:
222+
// $SRV.PING
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// $SRV.PING.COOLSERVICE
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// $SRV.PING.COOLSERVICE.123
225+
}
226+
227+
func ExampleRequest_Respond() {
228+
handler := func(req *Request) {
229+
// respond to the request
230+
if err := req.Respond(req.Data); err != nil {
231+
log.Fatal(err)
232+
}
233+
}
234+
235+
fmt.Printf("%T", handler)
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}
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238+
func ExampleRequest_RespondJSON() {
239+
type Point struct {
240+
X int `json:"x"`
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Y int `json:"y"`
242+
}
243+
244+
handler := func(req *Request) {
245+
resp := Point{5, 10}
246+
// respond to the request
247+
// response will be serialized to {"x":5,"y":10}
248+
if err := req.RespondJSON(resp); err != nil {
249+
log.Fatal(err)
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}
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}
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fmt.Printf("%T", handler)
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}
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256+
func ExampleRequest_Error() {
257+
handler := func(req *Request) error {
258+
// respond with an error
259+
// Error sets Nats-Service-Error and Nats-Service-Error-Code headers in the response
260+
if err := req.Error("400", "bad request", []byte(`{"error": "value should be a number"}`)); err != nil {
261+
return err
262+
}
263+
return nil
264+
}
265+
266+
fmt.Printf("%T", handler)
267+
}

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