Caching

Ocelot supports some very rudimentary caching at the moment provider by the CacheManager project. This is an amazing project that is solving a lot of caching problems. We would recommend using this package to cache with Ocelot.

The following example shows how to add CacheManager to Ocelot so that you can do output caching.

Install

First of all, add the following Ocelot.Cache.CacheManager package:

Install-Package Ocelot.Cache.CacheManager

This will give you access to the Ocelot cache manager extension methods. The second step is to add the following to your Program:

using Ocelot.Cache.CacheManager;

builder.Services
    .AddOcelot(builder.Configuration)
    .AddCacheManager(x => x.WithDictionaryHandle());

Configuration

Finally, in order to use caching on a route in your route configuration add this setting:

"FileCacheOptions": {
  "TtlSeconds": 15,
  "Region": "europe-central",
  "Header": "OC-Caching-Control",
  "EnableContentHashing": false // my route has GET verb only, assigning 'true' for requests with body: POST, PUT etc.
}

  • In this example TtlSeconds is set to 15 which means the cache will expire after 15 seconds.

  • The Region represents a region of caching. The cache for a region can be cleared by calling Ocelot’s Administration API.

  • If a header name is defined in the Header property, that header value is looked up by the key (header name) in the HttpRequest headers, and if the header is found, its value will be included in caching key. This causes the cache to become invalid due to the header value changing.

EnableContentHashing option

In version 23.0, the new property EnableContentHashing has been introduced. Previously, the request body was utilized to compute the cache key. However, due to potential performance issues arising from request body hashing, it has been disabled by default. Clearly, this constitutes a breaking change and presents challenges for users who require cache key calculations that consider the request body (e.g., for the POST method). To address this issue, it is recommended to enable the option either at the route level or globally in the Global Configuration section:

"CacheOptions": {
  // ...
  "EnableContentHashing": true
}

Global Configuration

The positive update is that copying route-level properties for each route is no longer necessary, as version 23.3 allows for setting their values in the GlobalConfiguration. This convenience extends to Header and Region as well. However, an alternative is still being sought for TtlSeconds, which must be explicitly set for each route to enable caching.

Notes

Ocelot currently supports caching on the URL of the downstream service and setting a TTL in seconds to expire the cache. You can also clear the cache for a region by calling Ocelot’s Administration API.

Your Own Caching

If you want to add your own caching method, implement the following interfaces and register them in DI e.g.

builder.Services
    .AddSingleton<IOcelotCache<CachedResponse>, MyCache>();

  • IOcelotCache<CachedResponse> this is for output caching.

  • IOcelotCache<FileConfiguration> this is for caching the file configuration if you are calling something remote to get your config such as Consul.

Future

Please dig into the Ocelot source code to find more. We would really appreciate it if anyone wants to implement Redis, Memcached etc. Please, open a new Show and tell thread in Discussions space of the repository.