Threads in google-cloud-pubsub

docker-compose.yml

---
version: '3.6'

services:
  pubsub:
    image: adhawk/google-pubsub-emulator
    ports:
      - 8085:8085

publisher.rb

require 'google/cloud/pubsub'

ENV['PUBSUB_EMULATOR_HOST'] ||= 'localhost:8085'

QUEUE = Queue.new

pubsub = Google::Cloud::Pubsub.new(
  project_id: 'my-project'
)

# Retrieve a topic
topic = pubsub.topic 'my-topic'
msg = topic.publish 'new-message'

subscriber.rb

require 'google/cloud/pubsub'

ENV['PUBSUB_EMULATOR_HOST'] ||= 'localhost:8085'

QUEUE = Queue.new

pubsub = Google::Cloud::Pubsub.new(
  project_id: 'my-project'
)

# Retrieve a topic
topic = pubsub.find_topic('my-topic') || pubsub.create_topic('my-topic')

# Retrieve a subscription
sub = topic.find_subscription('my-topic-sub') || topic.create_subscription('my-topic-sub')

# Create a subscriber to listen for available messages
subscriber = sub.listen do |received_message|
  QUEUE << 'msg received'
  received_message.acknowledge!
end

subscriber.start

# Generate a backtrace string for given exception.
# Generated string is a series of lines, each beginning with a tab and "at ".
def pretty_backtrace(thread)
  "\tat #{thread.backtrace.join("\n\tat ")}"
end

# Generate a string containing exception message followed by backtrace.
def pretty_thread(thread)
  "#{thread.inspect}: #{thread.status}\n#{pretty_backtrace(thread)}"
end

begin
  loop do
    puts
    puts '==========='
    puts '=== Backtraces ==='
    puts Thread.list.map { |thr| pretty_thread(thr) }.join("\n\n")

    puts '=== Info ==='
    puts 'Thread count:' + Thread.list.count.to_s
    puts '==========='
    puts QUEUE.pop
  end
rescue Interrupt
  subscriber.stop.wait!
end