/
publish_ordering.go
102 lines (89 loc) · 2.4 KB
/
publish_ordering.go
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// Copyright 2019 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package topics
// [START pubsub_publish_with_ordering_keys]
import (
"context"
"fmt"
"io"
"sync"
"sync/atomic"
"cloud.google.com/go/pubsub"
"google.golang.org/api/option"
)
func publishWithOrderingKey(w io.Writer, projectID, topicID string) {
// projectID := "my-project-id"
// topicID := "my-topic"
ctx := context.Background()
// Sending messages to the same region ensures they are received in order
// even when multiple publishers are used.
client, err := pubsub.NewClient(ctx, projectID,
option.WithEndpoint("us-east1-pubsub.googleapis.com:443"))
if err != nil {
fmt.Fprintf(w, "pubsub.NewClient: %v", err)
return
}
defer client.Close()
var wg sync.WaitGroup
var totalErrors uint64
t := client.Topic(topicID)
t.EnableMessageOrdering = true
messages := []struct {
message string
orderingKey string
}{
{
message: "message1",
orderingKey: "key1",
},
{
message: "message2",
orderingKey: "key2",
},
{
message: "message3",
orderingKey: "key1",
},
{
message: "message4",
orderingKey: "key2",
},
}
for _, m := range messages {
res := t.Publish(ctx, &pubsub.Message{
Data: []byte(m.message),
OrderingKey: m.orderingKey,
})
wg.Add(1)
go func(res *pubsub.PublishResult) {
defer wg.Done()
// The Get method blocks until a server-generated ID or
// an error is returned for the published message.
_, err := res.Get(ctx)
if err != nil {
// Error handling code can be added here.
fmt.Printf("Failed to publish: %s\n", err)
atomic.AddUint64(&totalErrors, 1)
return
}
}(res)
}
wg.Wait()
if totalErrors > 0 {
fmt.Fprintf(w, "%d of 4 messages did not publish successfully", totalErrors)
return
}
fmt.Fprint(w, "Published 4 messages with ordering keys successfully\n")
}
// [END pubsub_publish_with_ordering_keys]