Getting to Know Rules Engine

Applies To:

HTTP LargeThis platform has been optimized to cache and deliver static content (e.g., HTML, CSS, JavaScript, ISO, multimedia, and software downloads, etc.) over HTTP or HTTPS.

HTTP SmallLegacy. If you are currently serving traffic over this platform, then you may continue to do so. However, we recommend that you serve your traffic over our more robust HTTP Large platform.

ADNThe Application Delivery Network platform has been optimized to deliver dynamic content (e.g., login credentials, account information, etc.) over HTTP or HTTPS. Typically, user-specific and database-driven content are served over this platform.

Rules EngineAllows the customization of how requests are handled by our CDN service. It may be used to override the default response provided by an origin server, CDN settings, and the default edge server behavior.

The configuration of Rules Engine requires an understanding of:

Key terms
Setup workflow

Key Terms

The following key terms are critical to understanding the workflow through which custom rules that control CDN behavior may be applied to live or test traffic.

Draft

A draft of a policy consists of one or more rules meant to identify requests and the set of actions that will be applied to them. A draft is a work in progress that allows frequent configuration updates without impacting site traffic. Once a draft is ready to be finalized, it should be converted into a read-only policy.

Rule

A rule identifies one or more types of requests and the set of actions that will be applied to them.

It consists of:

A set of conditional expressionRules Engine: Refers to the logic (i.e., IF and ELSE IF) through which one or more match conditions identify a type of request.s that define the logic through which requests are identified.
A set of matchRules Engine: Defines a prerequisite that must be met before one or more actions (i.e., features) may be applied to a request. conditions that define the criteria used to identify requests.
A set of featureRules Engine: Defines the type of action that will take place when a set of match conditions have been met.s that define how the CDN will handle the above requests.

These elements are identified in the following illustration.

Policy

A policy, which consists of a set of read-only rules, provides the means to:

Create, store, and manage multiple variants of your rules.
Roll back to a previously deployed version.
Prepare event-specific rules in advance (e.g., a rule that redirects traffic as a result of a customer origin maintenance.)

Although only a single policy per environment is allowed, policies may be deployed as needed.

Deploy Request

A deploy request provides a simple and streamlined procedure through which a policy may be quickly applied to the Staging or Production environment. A history of deploy requests is provided to facilitate the tracking of changes applied to those environments.

Only requests that do not pass our automated validation and error detection system will require manual review and approval.

Setup Workflow

Setting up Rules Engine involves deploying a policy to either the Staging or Production environment. The workflow through which this deployment takes place is illustrated below.

The steps in the above illustration are described below.

Step	Description
Create Draft	A draft consists of a set of rules that define how requests for your content should be handled by the CDN.
Lock Draft	Once a draft has been finalized, it should be locked and converted into a read-only policy.
Submit Deploy Request	A deploy request allows a policy to be applied to either test or production traffic. Submit a deploy request to either the Staging or Production environment.
Deploy Request Review	A deploy request undergoes automated validation and error detection. Although the majority of deploy requests are automatically approved, manual review is required for more complex policies.
Policy Deployment (Staging)	Upon approval of a deploy request to the Staging environment, a policy will be applied to the Staging environment. This environment allows a policy to be tested against mock site traffic. Once the policy is ready to be applied to live site traffic, a new deploy request for the Production environment should be submitted.
Policy Deployment (Production)	Upon approval of a deploy request to the Production environment, a policy will be applied to the Production environment. This environment allows a policy to act as the final authority for determining how the CDN should handle live traffic.