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// Copyright 2014 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
//
// 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 "cloud.google.com/go/pubsub"
import (
"context"
"fmt"
"os"
"runtime"
"time"
"cloud.google.com/go/internal/version"
vkit "cloud.google.com/go/pubsub/apiv1"
"google.golang.org/api/option"
"google.golang.org/grpc"
"google.golang.org/grpc/keepalive"
)
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"
maxAckDeadline = 10 * time.Minute
)
// Client is a Google Pub/Sub client scoped to a single project.
//
// Clients should be reused rather than being created as needed.
// A Client may be shared by multiple goroutines.
type Client struct {
projectID string
pubc *vkit.PublisherClient
subc *vkit.SubscriberClient
}
// NewClient creates a new PubSub client.
func NewClient(ctx context.Context, projectID string, opts ...option.ClientOption) (c *Client, err error) {
var o []option.ClientOption
// Environment variables for gcloud emulator:
// https://cloud.google.com/sdk/gcloud/reference/beta/emulators/pubsub/
if addr := os.Getenv("PUBSUB_EMULATOR_HOST"); addr != "" {
conn, err := grpc.Dial(addr, grpc.WithInsecure())
if err != nil {
return nil, fmt.Errorf("grpc.Dial: %v", err)
}
o = []option.ClientOption{option.WithGRPCConn(conn)}
} else {
numConns := runtime.GOMAXPROCS(0)
if numConns > 4 {
numConns = 4
}
o = []option.ClientOption{
// Create multiple connections to increase throughput.
option.WithGRPCConnectionPool(numConns),
option.WithGRPCDialOption(grpc.WithKeepaliveParams(keepalive.ClientParameters{
Time: 5 * time.Minute,
})),
}
o = append(o, openCensusOptions()...)
}
o = append(o, opts...)
pubc, err := vkit.NewPublisherClient(ctx, o...)
if err != nil {
return nil, fmt.Errorf("pubsub: %v", err)
}
subc, err := vkit.NewSubscriberClient(ctx, option.WithGRPCConn(pubc.Connection()))
if err != nil {
// Should never happen, since we are passing in the connection.
// If it does, we cannot close, because the user may have passed in their
// own connection originally.
return nil, fmt.Errorf("pubsub: %v", err)
}
pubc.SetGoogleClientInfo("gccl", version.Repo)
return &Client{
projectID: projectID,
pubc: pubc,
subc: subc,
}, nil
}
// Close releases any resources held by the client,
// such as memory and goroutines.
//
// If the client is available for the lifetime of the program, then Close need not be
// called at exit.
func (c *Client) Close() error {
// Return the first error, because the first call closes the connection.
err := c.pubc.Close()
_ = c.subc.Close()
return err
}
func (c *Client) fullyQualifiedProjectName() string {
return fmt.Sprintf("projects/%s", c.projectID)
}
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