Google Cloud Pub/Sub

Overview

Pub/Sub brings the flexibility and reliability of enterprise message-oriented middleware to the cloud. At the same time, Pub/Sub is a scalable, durable event ingestion and delivery system that serves as a foundation for modern stream analytics pipelines. By providing many-to-many, asynchronous messaging that decouples senders and receivers, it allows for secure and highly available communication among independently written applications. Pub/Sub delivers low-latency, durable messaging that helps developers quickly integrate systems hosted on the Google Cloud Platform and externally.

At a glance

Features

• Balancing workloads in network clusters. For example, a large queue of tasks can be efficiently distributed among multiple workers, such as Google Compute Engine instances.
• Implementing asynchronous workflows. For example, an order processing application can place an order on a topic, from which it can be processed by one or more workers.
• Distributing event notifications. For example, a service that accepts user signups can send notifications whenever a new user registers, and downstream services can subscribe to receive notifications of the event.
• Refreshing distributed caches. For example, an application can publish invalidation events to update the IDs of objects that have changed.
• Logging to multiple systems. For example, a Google Compute Engine instance can write logs to the monitoring system, to a database for later querying, and so on.
• Data streaming from various processes or devices. For example, a residential sensor can stream data to backend servers hosted in the cloud.
• Reliability improvement. For example, a single-zone Compute Engine service can operate in additional zones by subscribing to a common topic, to recover from failures in a zone or region.

Technical specification

Main properties

The principal published / public properties used to configure and drive the component. Consult the online help for the full list.

Main methods

The principal public methods exposed by the component.

Quick Start

Drop the component on a form, configure the properties below and activate it. The snippet that follows shows the typical Publish a message configuration sourced from the online help.

Delphi (VCL / FireMonkey)

oPubSub := TsgcHTTPGoogleCloud_PubSub_Client.Create(nil);
oPubSub.GoogleCloudOptions.OAuth2.ClientId := '... your google client id...';
oPubSub.GoogleCloudOptions.OAuth2.ClientSecret := '... your google client secret...';
oPubSub.Publish('pubsub-270909', 'topic-1', 'My First Message from sgcWebSockets.'));

C++ Builder

oPubSub = new TsgcHTTPGoogleCloud_PubSub_Client();
oPubSub->GoogleCloudOptions->OAuth2->ClientId = "... your google client id...";
oPubSub->GoogleCloudOptions->OAuth2->ClientSecret = "... your google client secret...";
oPubSub->Publish("pubsub-270909", "topic-1", "My First Message from sgcWebSockets."));

.NET (C#)

oPubSub = new TsgcHTTPGoogleCloud_PubSub_Client();
oPubSub.GoogleCloudOptions.OAuth2.ClientId = "... your google client id...";
oPubSub.GoogleCloudOptions.OAuth2.ClientSecret = "... your google client secret...";
oPubSub.Publish("pubsub-270909", "topic-1", "My First Message from sgcWebSockets."));

Common scenarios

The following scenarios are lifted verbatim from the online help. Each shows the configuration and method calls needed to drive the component through a specific real-world flow.

1 · Authorization

Google Pub/Sub component client can login to Google Servers using the following methods:

oPubSub := TsgcHTTPGoogleCloud_PubSub_Client.Create(nil);
oPubSub.TLSOptions.IOHandler := iohOpenSSL;
oPubSub.TLSOptions.Version := tls1_3;
oPubSub.TLSOptions.VerifyCertificate := True;
oPubSub.TLSOptions.OpenSSL_Options.LibPath := oslpDefaultFolder;

TsgcHTTPGoogleCloud_PubSub_Client *oPubSub = new TsgcHTTPGoogleCloud_PubSub_Client(NULL);
oPubSub->TLSOptions->IOHandler = iohOpenSSL;
oPubSub->TLSOptions->Version = tls1_3;
oPubSub->TLSOptions->VerifyCertificate = true;
oPubSub->TLSOptions->OpenSSL_Options->LibPath = oslpDefaultFolder;

oPubSub = new TsgcHTTPGoogleCloud_PubSub_Client();
oPubSub.TLSOptions.IOHandler = TwsTLSIOHandler.iohOpenSSL;
oPubSub.TLSOptions.Version = TwsTLSVersions.tls1_3;
oPubSub.TLSOptions.VerifyCertificate = true;
oPubSub.TLSOptions.OpenSSL_Options.LibPath = oslpDefaultFolder;

2 · How to Create a new Subscription

Create a new subscription for project with id: pubsub-270909, with subscription name subscription-1 and topic-1

oPubSub := TsgcHTTPGoogleCloud_PubSub_Client.Create(nil);
oPubSub.GoogleCloudOptions.OAuth2.ClientId := '... your google client id...';
oPubSub.GoogleCloudOptions.OAuth2.ClientSecret := '... your google client secret...';
oPubSub.CreateSubscription('pubsub-270909', 'subscription-1', 'topic-1');

oPubSub = new TsgcHTTPGoogleCloud_PubSub_Client();
oPubSub->GoogleCloudOptions->OAuth2->ClientId = "... your google client id...";
oPubSub->GoogleCloudOptions->OAuth2->ClientSecret = "... your google client secret...";
oPubSub->CreateSubscription("pubsub-270909", "subscription-1", "topic-1");

oPubSub = new TsgcHTTPGoogleCloud_PubSub_Client();
oPubSub.GoogleCloudOptions.OAuth2.ClientId = "... your google client id...";
oPubSub.GoogleCloudOptions.OAuth2.ClientSecret = "... your google client secret...";
oPubSub.CreateSubscription("pubsub-270909", "subscription-1", "topic-1");

3 · How to Read messages from a Subscription

Read messages from previous subscription created.

oPubSub := TsgcHTTPGoogleCloud_PubSub_Client.Create(nil);
oPubSub.GoogleCloudOptions.OAuth2.ClientId := '... your google client id...';
oPubSub.GoogleCloudOptions.OAuth2.ClientSecret := '... your google client secret...';
oPubSub.pubsub.Pull('pubsub-270909', 'subscription-1');

oPubSub = new TsgcHTTPGoogleCloud_PubSub_Client();
oPubSub->GoogleCloudOptions->OAuth2->ClientId = "... your google client id...";
oPubSub->GoogleCloudOptions->OAuth2->ClientSecret = "... your google client secret...";
oPubSub->pubsub->Pull("pubsub-270909", "subscription-1");

oPubSub = new TsgcHTTPGoogleCloud_PubSub_Client();
oPubSub.GoogleCloudOptions.OAuth2.ClientId = "... your google client id...";
oPubSub.GoogleCloudOptions.OAuth2.ClientSecret = "... your google client secret...";
oPubSub.pubsub.Pull("pubsub-270909", "subscription-1");

4 · How to create a new Topic

Create a new topic for project with id: pubsub-270909 and topic name topic-1.

oPubSub := TsgcHTTPGoogleCloud_PubSub_Client.Create(nil);
oPubSub.GoogleCloudOptions.OAuth2.ClientId := '... your google client id...';
oPubSub.GoogleCloudOptions.OAuth2.ClientSecret := '... your google client secret...';
oPubSub.CreateTopic('pubsub-270909', 'topic-1');

oPubSub = new TsgcHTTPGoogleCloud_PubSub_Client();
oPubSub->GoogleCloudOptions->OAuth2->ClientId = "... your google client id...";
oPubSub->GoogleCloudOptions->OAuth2->ClientSecret = "... your google client secret...";
oPubSub->CreateTopic("pubsub-270909", "topic-1");

oPubSub = new TsgcHTTPGoogleCloud_PubSub_Client();
oPubSub.GoogleCloudOptions.OAuth2.ClientId = "... your google client id...";
oPubSub.GoogleCloudOptions.OAuth2.ClientSecret = "... your google client secret...";
oPubSub.CreateTopic("pubsub-270909", "topic-1");

5 · Publish a Message with Attributes

Pub/Sub brings the flexibility and reliability of enterprise message-oriented middleware to the cloud. At the same time, Pub/Sub is a scalable, durable event ingestion and delivery system that serves as a foundation for modern stream analytics pipelines. By providing many-to-many, asynchronous messaging that decouples senders and receivers, it allows for secure and highly available communication among independently written applications. Pub/Sub delivers low-latency, durable messaging that helps developers quickly integrate systems hosted on the Google Cloud Platform and externally.

oPubSub := TsgcHTTPGoogleCloud_PubSub_Client.Create(nil);
oPubSub.GoogleCloudOptions.OAuth2.ClientId := '... your google client id...';
oPubSub.GoogleCloudOptions.OAuth2.ClientSecret := '... your google client secret...';
oAttributes := TStringList.Create;
Try
  oAttributes.CommaText := 'origin=gcloud-sample,username=gcp';
  oPubSub.Publish('pubsub-270909', 'topic-1', 'My First Message from sgcWebSockets.', oAttributes, 'username'));
Finally
  oAttributes.Free;
end;

TsgcHTTPGoogleCloud_PubSub_Client *oPubSub = new TsgcHTTPGoogleCloud_PubSub_Client();
oPubSub->GoogleCloudOptions->OAuth2->ClientId = "... your google client id...";
oPubSub->GoogleCloudOptions->OAuth2->ClientSecret = "... your google client secret...";
oAttributes = new TStringList();
try
{
  oAttributes->CommaText = "origin=gcloud-sample,username=gcp";
  oPubSub->Publish("pubsub-270909", "topic-1", "My First Message from sgcWebSockets.", oAttributes, "username"));
}
__finally
{
  oAttributes->Free();
}

oPubSub = new TsgcHTTPGoogleCloud_PubSub_Client();
oPubSub.GoogleCloudOptions.OAuth2.ClientId = "... your google client id...";
oPubSub.GoogleCloudOptions.OAuth2.ClientSecret = "... your google client secret...";
oPubSub.Publish("pubsub-270909", "topic-1", "My First Message from sgcWebSockets.", "origin=gcloud-sample,username=gcp", "username"));

6 · Google Pub/Sub Client

Pub/Sub brings the flexibility and reliability of enterprise message-oriented middleware to the cloud. At the same time, Pub/Sub is a scalable, durable event ingestion and delivery system that serves as a foundation for modern stream analytics pipelines. By providing many-to-many, asynchronous messaging that decouples senders and receivers, it allows for secure and highly available communication among independently written applications. Pub/Sub delivers low-latency, durable messaging that helps developers quickly integrate systems hosted on the Google Cloud Platform and externally.

oPubSub := TsgcHTTPGoogleCloud_PubSub_Client.Create(nil);
oPubSub.GoogleCloudOptions.Authorization := gcaOAuth2;
oPubSub.GoogleCloudOptions.OAuth2.ClientId := '... your google client id...';
oPubSub.GoogleCloudOptions.OAuth2.ClientSecret := '... your google client secret...';

oPubSub = new TsgcHTTPGoogleCloud_PubSub_Client();
oPubSub->GoogleCloudOptions->Authorization = gcaOAuth2;
oPubSub->GoogleCloudOptions->OAuth2->ClientId = "... your google client id...";
oPubSub->GoogleCloudOptions->OAuth2->ClientSecret = "... your google client secret...";

oPubSub = new TsgcHTTPGoogleCloud_PubSub_Client();
oPubSub.GoogleCloudOptions.Authorization = gcaOAuth2;
oPubSub.GoogleCloudOptions.OAuth2.ClientId = "... your google client id...";
oPubSub.GoogleCloudOptions.OAuth2.ClientSecret = "... your google client secret...";

Sources used to build this document

Every external claim links back to a primary source. The online-help references decode the canonical deep-link the company maintains for this component.