Application Accelerator quickstart

This guide instructs you through your first cache setting that varies the cache key. The example is a listing page whose response changes with one query string argument.

Turn on Application Accelerator on an application.
Create a cache setting that holds the listing for 30 seconds and varies by the category argument.
Add a Rules Engine rule that applies the cache setting to requests for /products.
Request the listing twice, with two values of category, and read the cache key of each response.

Three objects produce that result, and each one depends on the one before it:

The Application Accelerator switch belongs to the application. It unlocks the fields that vary the cache key, and it removes the 60-second floor on the cache TTL.
The cache setting holds the cache behavior, the Max Age, and the variation. It names what the cache does, not which requests it does it to.
The Rules Engine rule applies the cache setting with the Set Cache Policy behavior. Its criteria decide which requests the cache setting covers.

Creating a cache setting changes no traffic. A cache setting that no rule applies never reaches a request.

azion.config.js and Azion Lib carry the same settings. For the field each interface sets, refer to Application Accelerator settings.

Select the interface you will use. The prerequisites and every stage below follow that choice.

Prerequisites

An Azion account. To create one, refer to How to create an account on Azion.
The Edit Applications permission on the account. It grants permission to edit, create, and remove applications, and it also requires the permission View Applications. Refer to Teams permissions.
An application that serves a path whose response changes with a query string argument. This guide uses the /products path and the category argument. To create an application, refer to Applications quickstart.

Access to Azion Console. To sign in, refer to Access Azion Console.

Turn on Application Accelerator

The module is off by default, and it belongs to one application at a time.

To turn on the module in Azion Console:

Open the Applications page

Access Azion Console > Applications.

Select the application that serves the listing

Go to the Main Settings tab

Turn on the module

In the Modules section, turn on Application Accelerator.

Select Save

The application now accepts the cache fields the rest of this guide uses.

Turning on a module can generate usage-related costs. For more information, refer to Pricing.

Create a cache setting that varies by query string

A cache setting is where the cache behavior and the variation live. The Max Age of 30 seconds below is the point of the exercise: without Application Accelerator, the shortest cache TTL an application accepts is 60 seconds.

To create the cache setting in Azion Console:

Go to the Cache Settings tab

Select + Cache

Name the cache setting

Enter a value in Name. For example: product-listing.

Set the cache behavior and the TTL

Under Cache, select Override cache behavior and set Max Age to 30.

Vary the cache key by the query string

Under Application Accelerator, open Cache vary by Query String and set Behavior to Allowlist.

Name the argument that varies the key

Add category to the field list under Behavior.

Sort the query string arguments

Turn on Sort.

Select Save

The cache setting appears in the Cache Settings tab. It holds an object for 30 seconds and gives each value of category its own cached object.

Apply the cache setting with a rule

A cache setting reaches a request only when a rule applies it.

To apply the cache setting to the listing path in Azion Console:

Go to the Rules Engine tab

Select + Rule

Name the rule

Enter a name for the rule. For example: Cache the product listing.

Set the phase

Select Request Phase.

Select the variable

In the Criteria section, select the ${uri} variable.

Select the comparison operator

Select starts with as the comparison operator.

Enter the argument

Enter /products as the argument.

Select the behavior

In the Behaviors section, select Set Cache Policy.

Select the cache setting you created

Select Save

The rule applies the cache setting to every request whose URI starts with /products.

A new rule takes a few minutes to propagate. Wait before you request the path.

Read the cache key

Azion returns the cache key of an object when the request carries the Azion debug header Pragma: azion-debug-cache. Reading that key for two values of category shows the variation the cache setting created.

Your application answers on a domain in the format xxxxxxxxx.map.azionedge.net. To set the domain for your application, refer to Add a custom domain to a workload.

Replace <your-azion-domain> with that domain, and request the listing with one value:

curl -I -H "Pragma: azion-debug-cache" "https://<your-azion-domain>/products?category=shoes"

The response carries two Azion debug headers. This excerpt is from an application served at www.example.com, and HTTP/2 sends header names in lowercase:

Text

01x-cache: MISS from 203.0.113.10 with HTTP/2.0

02x-cache-key: httpswww.example.com/products?category=shoes

x-cache carries the cache status, the address of the data center that answered, and the protocol of the request. x-cache-key carries the cache key, which concatenates the scheme, the host, the path, and the query string arguments the allowlist named.

Request the same path with a different value:

curl -I -H "Pragma: azion-debug-cache" "https://<your-azion-domain>/products?category=hats"

The argument changed, so the key changed with it:

x-cache-key: httpswww.example.com/products?category=hats

Two keys are two cached objects, which is what the allowlist asked for. For the full format of a cache key, refer to Cache key format.

Your application now caches the /products listing for 30 seconds and keeps one object per value of category.

Next steps

Cache variationWhat each distinct value of a varying attribute costs, and how a cache TTL of zero differs from Bypass Cache.Application Accelerator settingsThe name, type, and default of every field this guide set, per interface.LimitsThe values that bound a cache setting, including the TTL floor and ceiling.Configure Advanced Cache KeyVary the cache key by cookie and by device group, beyond the query string.Real-Time PurgeRemove an object that varies, which a URL purge alone does not reach.Verify cache indicatorsRead the same Azion debug headers in a browser instead of a terminal.