/
metadata.go
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/
metadata.go
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// Copyright 2020 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
// Package publish contains utilities related to publishing messages.
package publish
import (
"fmt"
"strconv"
"strings"
)
// Metadata holds the result of publishing a message to the Pub/Sub Lite
// service.
type Metadata struct {
// The topic partition the message was published to.
Partition int
// The offset the message was assigned.
Offset int64
}
func (m *Metadata) String() string {
return fmt.Sprintf("%d:%d", m.Partition, m.Offset)
}
// ParseMetadata converts the ID string of a pubsub.PublishResult to Metadata.
//
// Example:
// result := publisher.Publish(ctx, &pubsub.Message{Data: []byte("payload")})
// id, err := result.Get(ctx)
// if err != nil {
// // TODO: Handle error.
// }
// metadata, err := publish.ParseMetadata(id)
// if err != nil {
// // TODO: Handle error.
// }
func ParseMetadata(id string) (*Metadata, error) {
parts := strings.Split(id, ":")
if len(parts) != 2 {
return nil, fmt.Errorf("pubsublite: invalid encoded publish metadata %q", id)
}
partition, pErr := strconv.ParseInt(parts[0], 10, 64)
offset, oErr := strconv.ParseInt(parts[1], 10, 64)
if pErr != nil || oErr != nil {
return nil, fmt.Errorf("pubsublite: invalid encoded publish metadata %q", id)
}
return &Metadata{Partition: int(partition), Offset: offset}, nil
}