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fix wrong code sample in helloworld-go README.md (#5746)

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yuzhipeng 2023-11-14 18:53:28 +08:00 committed by GitHub
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code-samples/eventing/helloworld/helloworld-go/README.md
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@ -34,50 +34,52 @@ cd knative-docs/code-samples/eventing/helloworld/helloworld-go
code creates a basic web server which listens on port 8080:
```go
package main
import (
"context"
"log"
cloudevents "github.com/cloudevents/sdk-go/v2"
"github.com/google/uuid"
"context"
"log"
cloudevents "github.com/cloudevents/sdk-go/v2"
"github.com/google/uuid"
)
func receive(ctx context.Context, event cloudevents.Event)( * cloudevents.Event, cloudevents.Result) {
// Here is where your code to process the event will go.
// In this example we will log the event msg
log.Printf("Event received. \n%s\n", event)
data: = & HelloWorld {}
if err: = event.DataAs(data);
err != nil {
log.Printf("Error while extracting cloudevent Data: %s\n", err.Error())
return nil, cloudevents.NewHTTPResult(400, "failed to convert data: %s", err)
}
log.Printf("Hello World Message from received event %q", data.Msg)
// Respond with another event (optional)
// This is optional and is intended to show how to respond back with another event after processing.
// The response will go back into the knative eventing system just like any other event
newEvent: = cloudevents.NewEvent()
newEvent.SetID(uuid.New().String())
newEvent.SetSource("knative/eventing/samples/hello-world")
newEvent.SetType("dev.knative.samples.hifromknative")
if err: = newEvent.SetData(cloudevents.ApplicationJSON, HiFromKnative {
Msg: "Hi from helloworld-go app!"
});
err != nil {
return nil, cloudevents.NewHTTPResult(500, "failed to set response data: %s", err)
}
log.Printf("Responding with event\n%s\n", newEvent)
return &newEvent, nil
func receive(ctx context.Context, event cloudevents.Event) (*cloudevents.Event, cloudevents.Result) {
// Here is where your code to process the event will go.
// In this example we will log the event msg
log.Printf("Event received. \n%s\n", event)
data := &HelloWorld{}
if err := event.DataAs(data); err != nil {
log.Printf("Error while extracting cloudevent Data: %s\n", err.Error())
return nil, cloudevents.NewHTTPResult(400, "failed to convert data: %s", err)
}
log.Printf("Hello World Message from received event %q", data.Msg)
// Respond with another event (optional)
// This is optional and is intended to show how to respond back with another event after processing.
// The response will go back into the knative eventing system just like any other event
newEvent := cloudevents.NewEvent()
// Setting the ID here is not necessary. When using NewDefaultClient the ID is set
// automatically. We set the ID anyway so it appears in the log.
newEvent.SetID(uuid.New().String())
newEvent.SetSource("knative/eventing/samples/hello-world")
newEvent.SetType("dev.knative.samples.hifromknative")
if err := newEvent.SetData(cloudevents.ApplicationJSON, HiFromKnative{Msg: "Hi from helloworld-go app!"}); err != nil {
return nil, cloudevents.NewHTTPResult(500, "failed to set response data: %s", err)
}
log.Printf("Responding with event\n%s\n", newEvent)
return &newEvent, nil
}
func main() {
log.Print("Hello world sample started.")
c, err: = cloudevents.NewDefaultClient()
if err != nil {
log.Fatalf("failed to create client, %v", err)
}
log.Fatal(c.StartReceiver(context.Background(), receive))
log.Print("Hello world sample started.")
c, err := cloudevents.NewDefaultClient()
if err != nil {
log.Fatalf("failed to create client, %v", err)
}
log.Fatal(c.StartReceiver(context.Background(), receive))
}
```
```
1. Create a new file named `eventschemas.go` and paste the following code. This
defines the data schema of the CloudEvents.
@ -87,14 +89,14 @@ cd knative-docs/code-samples/eventing/helloworld/helloworld-go
// HelloWorld defines the Data of CloudEvent with type=dev.knative.samples.helloworld
type HelloWorld struct {
// Msg holds the message from the event
Msg string `json:"msg,omitempty,string"`
// Msg holds the message from the event
Msg string `json:"msg,omitempty"`
}
// HiFromKnative defines the Data of CloudEvent with type=dev.knative.samples.hifromknative
type HiFromKnative struct {
// Msg holds the message from the event
Msg string `json:"msg,omitempty,string"`
// Msg holds the message from the event
Msg string `json:"msg,omitempty"`
}
```