![]() ![]() Often Redis is used for variety of purposes and we do not want to evict important jobs because too much RAM is used for caching. One thing to be cautious of is running out of Redis RAM. Sidekiq has rich UI / API and since data is stored in Redis it can be easily extracted for custom purposes. We can implement Redis with multi-AZ failover (important if we are using Redis to store other data). Fortunately there are many reliable and affordable hosting services (AWS ElastiCache, RedisCloud). Hosting Redis does introduce more complexity to our infrastructure. Sidekiq also has a number of plugins which create their own Redis records. Sidekiq is a mature library with free and commercial versions with uses many of the powerful data structures Redis provides. Since adding items to list is O(1) operation queueing jobs is very fast. Redis can be used for variety of tasks (caching, pub/sub) but it also makes a great queue with its Lists data structure. ![]() Not a problem when running thousands of daily jobs but can be a challenge when running millions. Plus it will need to persist this data to disk. As our application grows the primary DB will become very busy. Having rich data structure such as SQL table gives us lots of flexibility. Data is stored in regular DB (just columns in a table) so we can view contents of delayed_jobs table or use Delayed::Job class to build simple GUI. We can give job higher priority w/in a queue. ![]() We can create separate queues w/in delayed_job and start different delayed_job processes on different servers. delayed_job supports scheduling the job to execute in the future and we can configure recurring job with delayed_cron_job MyJob. When job fails it will go back to DB and be executed again. queue_adapter = :sidekiq def perform end end queue_adapter = :delayed_job # app/jobs/ class MyJob < ApplicationJob self. Ruby on Rails provides Active Job framework which allows to configure queue backend globally at application level but also to customize it per environment (dev vs prod) or even per job. delayed_job also has integrations with deployment (Capistrano, Chef) and monitoring ( New Relic) tools. It is usually faster to record data in local DB than talking to an external API (sending email). Using primary DB as a queue means there is no need to introduce other technologies. delayed_job will create a table in MySQL / Postgres (there is also delayed_job_mongoid for MongoDB). Ruby on Rails has a robust delayed_job library (other languages / frameworks have alternative tools). But which technology should we use a queue backend? Sending email via background process will be faster UX plus we can retry in case of failure. We record data in the User table and separately call API of email service provider. User registers and we need to send a welcome email. Queues can be useful tool to scale applications or integrate complex systems. The opinions expressed here are my own and not necessarily those of my employer. Map args = new HashMap() Ĭhannel.Facebook twitter google reddit linkedin email ![]() This example in Java creates a queue which expires after it has been unused for 30 minutes. The following policy makes all queues expire after 30 minutes since last use: rabbitmqctl set_policy expiry ".*" '' -apply-to queuesĭefine Queue TTL for Queues Using x-arguments During Declaration Thus a value of 1000 means a queue which is unused for 1 second will be deleted.ĭefine Queue TTL for Queues Using a Policy It must be a positive integer (unlike message TTL it cannot be 0). The value of the x-expires argument or expires policy describes the expiration period in milliseconds. Unused means the queue has no consumers, the queue has not been recently redeclared (redeclaring renews the lease), and basic.get has not been invoked for a duration of at least the expiration period. This controls for how long a queue can be unused before it is automatically deleted. This feature can be used together with the auto-delete queue property.Įxpiry time can be set for a given queue by setting the x-expires argument to clare, or by setting the expires policy. Queues will expire after a period of time only when they are not used (e.g. TTL can also be set on queues, not just queue contents. ![]()
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