StackExchange.Redis: How to configure Redis instance

You can have an extension method like this:

public static IServiceCollection AddRedisQueue(this IServiceCollection services, IConfiguration configuration)
    {
        var options = configuration.GetOptions<RedisOptions>(SectionName);
        var multiplexer = ConnectionMultiplexer.Connect(options.ConnectionString);
        services.AddSingleton<IConnectionMultiplexer>(multiplexer);

        return services;
    }

Where RedisOptions is a class like this and section name is redis config name in your settings file:

public class RedisOptions
{
    public string ConnectionString { get; set; }
    public string Instance { get; set; }
}

Then you can inject it in Startup.cs ConfigureServices method like this:

services.AddRedisQueue(Configuration);

Later in code you just inject IConnectionMultiplexer from the constructor of the class where you would like to use redis, and get database by calling IConnectionMultiplexer's GetDatabase() method. About Instance property of redis options, you use it when providing a key:

var key = $"{redisOptions.Value.Instance}some_key";

Then use this key when dealing with IDatabase instance of stack exchange.