| // Copyright 2016 Google Inc. All Rights Reserved. |
| // |
| // 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 |
| // |
| // http://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 pubsub |
| |
| import ( |
| "fmt" |
| |
| "golang.org/x/net/context" |
| ) |
| |
| const MaxPublishBatchSize = 1000 |
| |
| // TopicHandle is a reference to a PubSub topic. |
| type TopicHandle struct { |
| c *Client |
| |
| // The fully qualified identifier for the topic, in the format "projects/<projid>/topics/<name>" |
| name string |
| } |
| |
| // NewTopic creates a new topic. |
| // The specified topic name must start with a letter, and contain only letters |
| // ([A-Za-z]), numbers ([0-9]), dashes (-), underscores (_), periods (.), |
| // tildes (~), plus (+) or percent signs (%). It must be between 3 and 255 |
| // characters in length, and must not start with "goog". |
| // If the topic already exists an error will be returned. |
| func (c *Client) NewTopic(ctx context.Context, name string) (*TopicHandle, error) { |
| t := c.Topic(name) |
| err := c.s.createTopic(ctx, t.Name()) |
| return t, err |
| } |
| |
| // Topic creates a reference to a topic. |
| func (c *Client) Topic(name string) *TopicHandle { |
| return &TopicHandle{c: c, name: fmt.Sprintf("projects/%s/topics/%s", c.projectID, name)} |
| } |
| |
| // Topics lists all of the topics for the client's project. |
| func (c *Client) Topics(ctx context.Context) ([]*TopicHandle, error) { |
| topicNames, err := c.s.listProjectTopics(ctx, c.fullyQualifiedProjectName()) |
| if err != nil { |
| return nil, err |
| } |
| |
| topics := []*TopicHandle{} |
| for _, t := range topicNames { |
| topics = append(topics, &TopicHandle{c: c, name: t}) |
| } |
| return topics, nil |
| } |
| |
| // Name returns the globally unique name for the topic. |
| func (t *TopicHandle) Name() string { |
| return t.name |
| } |
| |
| // Delete deletes the topic. |
| func (t *TopicHandle) Delete(ctx context.Context) error { |
| return t.c.s.deleteTopic(ctx, t.name) |
| } |
| |
| // Exists reports whether the topic exists on the server. |
| func (t *TopicHandle) Exists(ctx context.Context) (bool, error) { |
| if t.name == "_deleted-topic_" { |
| return false, nil |
| } |
| |
| return t.c.s.topicExists(ctx, t.name) |
| } |
| |
| // Subscriptions lists the subscriptions for this topic. |
| func (t *TopicHandle) Subscriptions(ctx context.Context) ([]*SubscriptionHandle, error) { |
| subNames, err := t.c.s.listTopicSubscriptions(ctx, t.name) |
| if err != nil { |
| return nil, err |
| } |
| |
| subs := []*SubscriptionHandle{} |
| for _, s := range subNames { |
| subs = append(subs, &SubscriptionHandle{c: t.c, name: s}) |
| } |
| return subs, nil |
| } |
| |
| // Publish publishes the supplied Messages to the topic. |
| // If successful, the server-assigned message IDs are returned in the same order as the supplied Messages. |
| // At most MaxPublishBatchSize messages may be supplied. |
| func (t *TopicHandle) Publish(ctx context.Context, msgs ...*Message) ([]string, error) { |
| if len(msgs) == 0 { |
| return nil, nil |
| } |
| if len(msgs) > MaxPublishBatchSize { |
| return nil, fmt.Errorf("pubsub: got %d messages, but maximum batch size is %d", len(msgs), MaxPublishBatchSize) |
| } |
| return t.c.s.publishMessages(ctx, t.name, msgs) |
| } |