IdentityServer4.Contrib.Caching

IdentityServer4.Contrib.Caching.Redis

This library written in c# and targeting netcoreapp3.0, provides an implementation of IPersistedGrantStore for IdentityServer4 using the IDistributedCache interface and Redis implementation located in Microsoft.Extensions.Caching.StackExchangeRedis, that can easily be registered using provided extension methods for IIdentityServerBuilder.

It also makes use of RedLock for pessimistic locking of resources in Redis.

How it works

IdentityServer4 provides an interface called IPersistedGrantStore located in the package IdentityServer4.Stores. Any store can be registered using a simple extensions method provided by IdentityServer4. This package makes use of it and implements a store that is distributed and can therefor be easily used in a load-balanced environment.

There are four keyed combinations stored:

Key of PersistedGrant
Subject-Id of PersistedGrant
Combination of Subject- and Client-Id of PersistedGrant
Combination of Subject-, Client-Id and Type of PersistedGrant

While a key is unique and therefor only stored as a single object, all other combinations are not. For instance a given subject-id can be a user-id and a user might log into services using multiple front-ends. Those instances are appended and that's where RedLock kicks in. To ensure that no values are overwritten, RedLock is used to temporally lock the resource that is then loaded, appended, released and stored.

Installation

This package is available via nuget. You can install it using Visual-Studio-Nuget-Browser or by using the dotnet-cli.

dotnet add package IdentityServer4.Contrib.Caching.Redis

If you want to add a specific version of this package

dotnet add package IdentityServer4.Contrib.Caching.Redis --version 1.0.0

For more information please visit the official dotnet-cli documentation.

Usage

Only thing you need to do is call an extension method on the IIdentityServerBuilder that you are already using.

public void ConfigureServices(IServiceCollection services)
{
    services.AddIdentityServer()
        // more code here
        .AddDistributedRedisCache(configuration: "127.0.0.1:6379", instanceName: "my-redis-instance-name"); // <- this!
        
    // more code here 
}

Optionally you can pass in a caching prefix. The default is "IdentityServer_Distributed_Caching".

public void ConfigureServices(IServiceCollection services)
{
    services.AddIdentityServer()
        // more code here
        .AddDistributedRedisCache(configuration: "127.0.0.1:6379", instanceName: "my-redis-instance-name", 
            cachingPrefix: "_my-identityserver-caching-prefix_); // <- this!
        
    // more code here 
}

You can also pass in your on configuration-builder for RedisCacheOptions and RedisCacheGrantStoreConfiguration

public void ConfigureServices(IServiceCollection services)
{
    services.AddIdentityServer()
        // more code here
        .AddDistributedRedisCache(options =>  // <- this!
            {
            options.Configuration: "127.0.0.1:6379";
            options.InstanceName: "my-redis-instance-name";
            }, 
            options => options.CachingPrefix = "_my-identityserver-caching-prefix_");
        
    // more code here 
}

Third option also allows you to configure the RedLockOptions to configure the retry-count and retry-timeout.

public void ConfigureServices(IServiceCollection services)
{
    services.AddIdentityServer()
        // more code here
        .AddDistributedRedisCache(options =>  // <- this!
            {
            options.Configuration: "127.0.0.1:6379";
            options.InstanceName: "my-redis-instance-name";
            }, 
            options => options.CachingPrefix = "_my-identityserver-caching-prefix_",
            options => 
            {
                options.LockRetryCount = 1,
                options.LockRetryDelay = TimeSpan.FromSeconds(1)
            });
        
    // more code here 
}

That's it! You are good to go and everything required to use IDistributedCache for Redis and IdentityServer has been setup.

For more details and information, have a look at the tests.

alsami / IdentityServer4.Contrib.Caching

IdentityServer4.Contrib.Caching