Scheduling is a feature that is often required within applications. Traditionally, SQL Jobs were a good way to schedule when your application already needed a database. However, SQL Azure lacks the support of SQL Jobs so something else must be used. The Windows Azure PaaS environment offers ways to implement a scheduler but we still wait for the real Windows Azure Scheduler as a platform feature…
The worker role
It is relatively straight forward to create a worker role that acts as a scheduler. Most of the time the worker role sleeps and when it’s time it calls a pre-configured URL and so starts a task. It is the responsibility of the worker role logic to plan the scheduled tasks. This method works fine but has some drawbacks. First of all a worker role is a relative expensive Azure resource especially when high availability is required and the worker role must have at least 2 instances. Often, scheduling functionality can be integrated in an existing web or worker role but this enhances complexity. Another disadvantage is the lack of a good interface to provision the scheduled tasks. One has to build some kind of management interface (API) to be able to add, delete and reschedule tasks. Often, both an API as well as a user interface is required.
The existing code
Why should one build scheduler code when is it available on the internet? Google on “Azure scheduler” and many hits are found. Complete code samples can be downloaded and used. Unfortunately, those also lack a user interface for provisioning scheduled tasks. Scheduled tasks must be managed interacting directly to a database or Azure table storage.
The Azure Store
Recently, the Azure Store also became available in western Europe. In this Azure Store SaaS products can be bought and an example of such a service is the Scheduler developed by Aditi Product Services. They developed a cloud based CRON scheduler. This service basically allows the user to create schedule tasks using a set of HTTP webhooks that run CRON schedules, being either simple or complex. This scheduler is fully integrated in the Windows Azure Store and currently offers a 5000 jobs/month free trail. To start using this service go to the Azure Management Portal and chose New at the bottom. Then select Store and scroll down to the Scheduler.
Click next and select the Free Trial plan. Then select the correct Azure subscription, specify a name for the Scheduler and the location.
Finally, review the summary and purchase. The “Getting started” section on the Aditi website provides code samples. A disadvantage of using an Azure Store scheduler is the dependency to a third party and the availability of the service in the future as well as the lack of a user interface for managing scheduled tasks.
The Azure Scheduler as a platform feature…
Microsoft is still enhancing the Windows Azure PaaS environment and I can imagine that a CRON-based Scheduler as a platform service being a high priority feature on their roadmap. When a Scheduler is provided as a platform service I expect a seamless integration in the existing Azure Management Portal and thus providing a user interface for managing scheduled tasks in addition to an API. It is only guessing when this feature will be announced but I am sure it will be there. Next June release perhaps…?
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