Rate Limiting configuration - policy validation #45684
Description
Background and Motivation
The ASP.NET Core rate limiting middleware is great, but "limited" in terms of policy validation. Let's start with some code that you can write today in .NET 7:
builder.Services.AddRateLimiter(options =>
{
options.AddFixedWindowLimiter("customPolicy", opt =>
{
opt.PermitLimit = 4;
opt.Window = TimeSpan.FromSeconds(12);
opt.QueueProcessingOrder = QueueProcessingOrder.OldestFirst;
opt.QueueLimit = 2;
});
// ...
});There is no way to validate that customPolicy actually exists. This is useful when configuring multiple routes from configuration such as is the case for YARP. See dotnet/yarp#1967
Proposed API
It would be preferred to something similar to IAuthorizationPolicyProvider implemented via DefaultAuthorizationPolicyProvider and ICorsPolicyProvider implemented via DefaultCorsPolicyProvider
namespace Microsoft.AspNetCore.RateLimiting;
- internal struct DefaultKeyType
+ public struct DefaultKeyType
{
// omitted ...
}
+
+ public interface IRateLimiterPolicyProvider
+ {
+ ValueTask<IRateLimiterPolicy<DefaultKeyType>?> GetDefaultPolicyAsync();
+ ValueTask<IRateLimiterPolicy<DefaultKeyType>?> GetPolicyAsync(string policyName);
+ }
+
+ public class DefaultRateLimiterPolicyProvider : IRateLimiterPolicyProvider
+ {
+ private readonly RateLimiterOptions _options;
+
+ public DefaultRateLimiterPolicyProvider(IOptions<RateLimiterOptions> options)
+ {
+
+ }
+
+ public ValueTask<IRateLimiterPolicy<DefaultKeyType>?> GetPolicyAsync(string policyName)
+ {
+ options.PolicyMap[policyName] ?? options.UnactivatedPolicyMap[policyName];
+ }
+ }RateLimiterOptions.PolicyMap is internal hence this feature cannot be added in another library or the final application.
Usage Examples
Alternative Designs
None
Risks
None