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orbit/examples/event-protocol/main.go

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// event-protocol 验证冻结结果、连接切换与ACK重报;不执行业务写入。
package main
import (
"context"
"encoding/json"
"errors"
"fmt"
"os"
"time"
orbit "git.yuntuo.hk/k2safe/orbit/sdk/go"
)
func main() {
if err := run(); err != nil {
fmt.Fprintln(os.Stderr, err)
os.Exit(1)
}
}
func run() error {
token, queue := os.Getenv("ORBIT_TOKEN"), os.Getenv("ORBIT_QUEUE_ID")
if path := os.Getenv("ORBIT_CREDENTIALS_FILE"); path != "" {
raw, err := os.ReadFile(path)
if err != nil {
return err
}
var credential struct {
Token string `json:"token"`
QueueID string `json:"queue_id"`
}
if json.Unmarshal(raw, &credential) != nil {
return errors.New("invalid credential file")
}
if token == "" {
token = credential.Token
}
if queue == "" {
queue = credential.QueueID
}
}
if token == "" || queue == "" {
return errors.New("event-enabled token and isolated example queue are required")
}
api, err := orbit.NewClient(os.Getenv("ORBIT_URL"), orbit.Options{Token: token})
if err != nil {
return err
}
ctx, stop := context.WithTimeout(context.Background(), 15*time.Second)
defer stop()
id, err := orbit.NewEventMessageID()
if err != nil {
return err
}
created, err := api.CreateSubscription(ctx, "sub-"+id, orbit.CreateSubscriptionRequest{Name: "protocol-" + id, QueueID: queue, Types: []string{"task.cancelled"}, MaxPending: 10, MaxAttempts: 3})
if err != nil {
return err
}
sub := created.Subscription
task, err := api.SubmitTask(ctx, "task-"+id, orbit.SubmitTaskRequest{QueueID: queue, Handler: "object.prepare", HandlerVersion: "v1", PayloadVersion: "v1", Payload: json.RawMessage(`{}`)})
if err != nil {
return err
}
if _, err = api.CancelTask(ctx, task.Task.ID, "cancel-"+id, orbit.CancelTaskRequest{ExpectedRevision: task.Task.Revision, Reason: "event protocol example"}); err != nil {
return err
}
first, err := api.DialEvents(ctx, orbit.EventRegistration{SubscriptionID: sub.ID, Capacity: 1})
if err != nil {
return err
}
defer first.Close()
grant, err := first.Next(ctx)
if err != nil {
return err
}
if grant.Event.Snapshot.TaskID != task.Task.ID || grant.Event.Snapshot.State != orbit.TaskCancelled {
return errors.New("unexpected example queue event")
}
// 本例只读取并验证结果,没有业务数据库写入;业务处理必须先提交Inbox事务再ACK。
ackID, err := orbit.NewEventMessageID()
if err != nil {
return err
}
confirmed, err := first.Ack(ctx, ackID, grant.Proof())
if err != nil {
return err
}
first.Close()
second, err := api.DialEvents(ctx, orbit.EventRegistration{SubscriptionID: sub.ID, Capacity: 1})
if err != nil {
return err
}
defer second.Close()
replayID, err := orbit.NewEventMessageID()
if err != nil {
return err
}
replayed, err := second.Ack(ctx, replayID, grant.Proof())
if err != nil {
return err
}
if !replayed.Deduplicated || !replayed.AcknowledgedAt.Equal(confirmed.AcknowledgedAt) {
return errors.New("acknowledgement receipt changed across connections")
}
paused, err := api.ConfigureSubscription(ctx, sub.ID, "pause-"+id, orbit.ConfigureSubscriptionRequest{ExpectedRevision: sub.Revision, Enabled: false, Reason: "protocol example completed"})
if err != nil {
return err
}
fmt.Printf("event=%s task=%s state=%s\n", grant.Event.ID, task.Task.ID, grant.Event.Snapshot.State)
fmt.Printf("ack_replayed=%t same_receipt=true pending=%d subscription_enabled=%t\n", replayed.Deduplicated, paused.Subscription.PendingCount, paused.Subscription.Enabled)
return nil
}