Class: Google::Cloud::Pubsub::Project

Inherits:
Object
  • Object
show all
Defined in:
lib/google/cloud/pubsub/project.rb

Overview

Project

Represents the project that pubsub messages are pushed to and pulled from. Topic is a named resource to which messages are sent by publishers. Subscription is a named resource representing the stream of messages from a single, specific topic, to be delivered to the subscribing application. Message is a combination of data and attributes that a publisher sends to a topic and is eventually delivered to subscribers.

See Google::Cloud#pubsub

Examples:

require "google/cloud/pubsub"

pubsub = Google::Cloud::Pubsub.new

topic = pubsub.topic "my-topic"
topic.publish "task completed"

Instance Method Summary collapse

Instance Method Details

#create_topic(topic_name, async: nil) ⇒ Google::Cloud::Pubsub::Topic Also known as: new_topic

Creates a new topic.

Examples:

require "google/cloud/pubsub"

pubsub = Google::Cloud::Pubsub.new
topic = pubsub.create_topic "my-topic"

Parameters:

  • topic_name (String) —

    Name of a topic.

  • async (Hash) —

    A hash of values to configure the topic's AsyncPublisher that is created when Topic#publish_async is called. Optional.

    Hash keys and values may include the following:

    • :max_bytes (Integer) The maximum size of messages to be collected before the batch is published. Default is 10,000,000 (10MB).
    • :max_messages (Integer) The maximum number of messages to be collected before the batch is published. Default is 1,000.
    • :interval (Numeric) The number of seconds to collect messages before the batch is published. Default is 0.25.
    • :threads (Hash) The number of threads to create to handle concurrent calls by the publisher:
      • :publish (Integer) The number of threads used to publish messages. Default is 4.
      • :callback (Integer) The number of threads to handle the published messages' callbacks. Default is 8.

Returns:



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# File 'lib/google/cloud/pubsub/project.rb', line 203

def create_topic topic_name, async: nil
  ensure_service!
  grpc = service.create_topic topic_name
  Topic.from_grpc grpc, service, async: async
end

#project ⇒ Object

The Pub/Sub project connected to.

Examples:

require "google/cloud/pubsub"

pubsub = Google::Cloud::Pubsub.new(
  project: "my-project",
  keyfile: "/path/to/keyfile.json"
)

pubsub.project #=> "my-project"


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# File 'lib/google/cloud/pubsub/project.rb', line 71

def project
  service.project
end

#snapshots(token: nil, max: nil) ⇒ Array<Google::Cloud::Pubsub::Snapshot> Also known as: find_snapshots, list_snapshots

Retrieves a list of snapshots for the given project.

Examples:

require "google/cloud/pubsub"

pubsub = Google::Cloud::Pubsub.new

snapshots = pubsub.snapshots
snapshots.each do |snapshot|
  puts snapshot.name
end

Retrieve all snapshots: (See Snapshot::List#all)

require "google/cloud/pubsub"

pubsub = Google::Cloud::Pubsub.new

snapshots = pubsub.snapshots
snapshots.all do |snapshot|
  puts snapshot.name
end

Parameters:

  • token (String) —

    A previously-returned page token representing part of the larger set of results to view.

  • max (Integer) —

    Maximum number of snapshots to return.

Returns:



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# File 'lib/google/cloud/pubsub/project.rb', line 366

def snapshots token: nil, max: nil
  ensure_service!
  options = { token: token, max: max }
  grpc = service.list_snapshots options
  Snapshot::List.from_grpc grpc, service, max
end

#subscription(subscription_name, project: nil, skip_lookup: nil) ⇒ Google::Cloud::Pubsub::Subscription? Also known as: get_subscription, find_subscription

Retrieves subscription by name.

Examples:

require "google/cloud/pubsub"

pubsub = Google::Cloud::Pubsub.new

sub = pubsub.subscription "my-sub"
sub.name #=> "projects/my-project/subscriptions/my-sub"

Skip the lookup against the service with skip_lookup:

require "google/cloud/pubsub"

pubsub = Google::Cloud::Pubsub.new

# No API call is made to retrieve the subscription information.
sub = pubsub.subscription "my-sub", skip_lookup: true
sub.name #=> "projects/my-project/subscriptions/my-sub"

Parameters:

  • subscription_name (String) —

    Name of a subscription.

  • project (String) —

    If the subscription belongs to a project other than the one currently connected to, the alternate project ID can be specified here.

  • skip_lookup (Boolean) —

    Optionally create a Subscription object without verifying the subscription resource exists on the Pub/Sub service. Calls made on this object will raise errors if the service resource does not exist. Default is false.

Returns:



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# File 'lib/google/cloud/pubsub/project.rb', line 282

def subscription subscription_name, project: nil, skip_lookup: nil
  ensure_service!
  options = { project: project }
  if skip_lookup
    return Subscription.new_lazy subscription_name, service, options
  end
  grpc = service.get_subscription subscription_name
  Subscription.from_grpc grpc, service
rescue Google::Cloud::NotFoundError
  nil
end

#subscriptions(token: nil, max: nil) ⇒ Array<Google::Cloud::Pubsub::Subscription> Also known as: find_subscriptions, list_subscriptions

Retrieves a list of subscriptions for the given project.

Examples:

require "google/cloud/pubsub"

pubsub = Google::Cloud::Pubsub.new

subs = pubsub.subscriptions
subs.each do |sub|
  puts sub.name
end

Retrieve all subscriptions: (See Subscription::List#all)

require "google/cloud/pubsub"

pubsub = Google::Cloud::Pubsub.new

subs = pubsub.subscriptions
subs.all do |sub|
  puts sub.name
end

Parameters:

  • token (String) —

    A previously-returned page token representing part of the larger set of results to view.

  • max (Integer) —

    Maximum number of subscriptions to return.

Returns:



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# File 'lib/google/cloud/pubsub/project.rb', line 326

def subscriptions token: nil, max: nil
  ensure_service!
  options = { token: token, max: max }
  grpc = service.list_subscriptions options
  Subscription::List.from_grpc grpc, service, max
end

#topic(topic_name, project: nil, skip_lookup: nil, async: nil) ⇒ Google::Cloud::Pubsub::Topic? Also known as: get_topic, find_topic

Retrieves topic by name.

Examples:

require "google/cloud/pubsub"

pubsub = Google::Cloud::Pubsub.new
topic = pubsub.topic "existing-topic"

By default nil will be returned if topic does not exist.

require "google/cloud/pubsub"

pubsub = Google::Cloud::Pubsub.new
topic = pubsub.topic "non-existing-topic" # nil

Create topic in a different project with the project flag.

require "google/cloud/pubsub"

pubsub = Google::Cloud::Pubsub.new
topic = pubsub.topic "another-topic", project: "another-project"

Skip the lookup against the service with skip_lookup:

require "google/cloud/pubsub"

pubsub = Google::Cloud::Pubsub.new
topic = pubsub.topic "another-topic", skip_lookup: true

Configuring AsyncPublisher to increase concurrent callbacks:

require "google/cloud/pubsub"

pubsub = Google::Cloud::Pubsub.new
topic = pubsub.topic "my-topic",
                     async: { threads: { callback: 16 } }

topic.publish_async "task completed" do |result|
  if result.succeeded?
    log_publish_success result.data
  else
    log_publish_failure result.data, result.error
  end
end

topic.async_publisher.stop.wait!

Parameters:

  • topic_name (String) —

    Name of a topic.

  • project (String) —

    If the topic belongs to a project other than the one currently connected to, the alternate project ID can be specified here. Optional.

  • skip_lookup (Boolean) —

    Optionally create a Topic object without verifying the topic resource exists on the Pub/Sub service. Calls made on this object will raise errors if the topic resource does not exist. Default is false. Optional.

  • async (Hash) —

    A hash of values to configure the topic's AsyncPublisher that is created when Topic#publish_async is called. Optional.

    Hash keys and values may include the following:

    • :max_bytes (Integer) The maximum size of messages to be collected before the batch is published. Default is 10,000,000 (10MB).
    • :max_messages (Integer) The maximum number of messages to be collected before the batch is published. Default is 1,000.
    • :interval (Numeric) The number of seconds to collect messages before the batch is published. Default is 0.25.
    • :threads (Hash) The number of threads to create to handle concurrent calls by the publisher:
      • :publish (Integer) The number of threads used to publish messages. Default is 4.
      • :callback (Integer) The number of threads to handle the published messages' callbacks. Default is 8.

Returns:



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# File 'lib/google/cloud/pubsub/project.rb', line 159

def topic topic_name, project: nil, skip_lookup: nil, async: nil
  ensure_service!
  options = { project: project }
  return Topic.new_lazy(topic_name, service, options) if skip_lookup
  grpc = service.get_topic topic_name
  Topic.from_grpc grpc, service, async: async
rescue Google::Cloud::NotFoundError
  nil
end

#topics(token: nil, max: nil) ⇒ Array<Google::Cloud::Pubsub::Topic> Also known as: find_topics, list_topics

Retrieves a list of topics for the given project.

Examples:

require "google/cloud/pubsub"

pubsub = Google::Cloud::Pubsub.new

topics = pubsub.topics
topics.each do |topic|
  puts topic.name
end

Retrieve all topics: (See Topic::List#all)

require "google/cloud/pubsub"

pubsub = Google::Cloud::Pubsub.new

topics = pubsub.topics
topics.all do |topic|
  puts topic.name
end

Parameters:

  • token (String) —

    The token value returned by the last call to topics; indicates that this is a continuation of a call, and that the system should return the next page of data.

  • max (Integer) —

    Maximum number of topics to return.

Returns:



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# File 'lib/google/cloud/pubsub/project.rb', line 241

def topics token: nil, max: nil
  ensure_service!
  options = { token: token, max: max }
  grpc = service.list_topics options
  Topic::List.from_grpc grpc, service, max
end