| // Copyright 2014 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 "google.golang.org/cloud/pubsub" |
| |
| import ( |
| "fmt" |
| "os" |
| |
| raw "google.golang.org/api/pubsub/v1" |
| "google.golang.org/cloud" |
| "google.golang.org/cloud/internal/transport" |
| |
| "golang.org/x/net/context" |
| ) |
| |
| const ( |
| // ScopePubSub grants permissions to view and manage Pub/Sub |
| // topics and subscriptions. |
| ScopePubSub = "https://www.googleapis.com/auth/pubsub" |
| |
| // ScopeCloudPlatform grants permissions to view and manage your data |
| // across Google Cloud Platform services. |
| ScopeCloudPlatform = "https://www.googleapis.com/auth/cloud-platform" |
| ) |
| |
| const prodAddr = "https://pubsub.googleapis.com/" |
| const userAgent = "gcloud-golang-pubsub/20151008" |
| |
| // Client is a Google Pub/Sub client, which may be used to perform Pub/Sub operations with a project. |
| // It must be constructed via NewClient. |
| type Client struct { |
| projectID string |
| s service |
| } |
| |
| // NewClient creates a new PubSub client. |
| func NewClient(ctx context.Context, projectID string, opts ...cloud.ClientOption) (*Client, error) { |
| o := []cloud.ClientOption{ |
| cloud.WithEndpoint(baseAddr()), |
| cloud.WithScopes(raw.PubsubScope, raw.CloudPlatformScope), |
| cloud.WithUserAgent(userAgent), |
| } |
| o = append(o, opts...) |
| httpClient, endpoint, err := transport.NewHTTPClient(ctx, o...) |
| if err != nil { |
| return nil, fmt.Errorf("dialing: %v", err) |
| } |
| |
| s, err := newPubSubService(httpClient, endpoint) |
| if err != nil { |
| return nil, fmt.Errorf("constructing pubsub client: %v", err) |
| } |
| |
| c := &Client{ |
| projectID: projectID, |
| s: s, |
| } |
| |
| return c, nil |
| } |
| |
| func (c *Client) fullyQualifiedProjectName() string { |
| return fmt.Sprintf("projects/%s", c.projectID) |
| } |
| |
| func baseAddr() string { |
| // Environment variables for gcloud emulator: |
| // https://cloud.google.com/sdk/gcloud/reference/beta/emulators/pubsub/ |
| if host := os.Getenv("PUBSUB_EMULATOR_HOST"); host != "" { |
| return "http://" + host + "/" |
| } |
| return prodAddr |
| } |
| |
| // pageToken stores the next page token for a server response which is split over multiple pages. |
| type pageToken struct { |
| tok string |
| explicit bool |
| } |
| |
| func (pt *pageToken) set(tok string) { |
| pt.tok = tok |
| pt.explicit = true |
| } |
| |
| func (pt *pageToken) get() string { |
| return pt.tok |
| } |
| |
| // more returns whether further pages should be fetched from the server. |
| func (pt *pageToken) more() bool { |
| return pt.tok != "" || !pt.explicit |
| } |
| |
| // stringsIterator provides an iterator API for a sequence of API page fetches that return lists of strings. |
| type stringsIterator struct { |
| ctx context.Context |
| strings []string |
| token pageToken |
| fetch func(ctx context.Context, tok string) (*stringsPage, error) |
| } |
| |
| // Next returns the next string. If there are no more strings, Done will be returned. |
| func (si *stringsIterator) Next() (string, error) { |
| for len(si.strings) == 0 && si.token.more() { |
| page, err := si.fetch(si.ctx, si.token.get()) |
| if err != nil { |
| return "", err |
| } |
| si.token.set(page.tok) |
| si.strings = page.strings |
| } |
| |
| if len(si.strings) == 0 { |
| return "", Done |
| } |
| |
| s := si.strings[0] |
| si.strings = si.strings[1:] |
| |
| return s, nil |
| } |