Rate limit

    • v3 API reference

    • This filter should be configured with the name envoy.filters.http.ratelimit.

    The HTTP rate limit filter will call the rate limit service when the request’s route or virtual host has one or more that match the filter stage setting. The route can optionally include the virtual host rate limit configurations. More than one configuration can apply to a request. Each configuration results in a descriptor being sent to the rate limit service.

    If the rate limit service is called, and the response for any of the descriptors is over limit, a 429 response is returned. The rate limit filter also sets the header, unless disable_x_envoy_ratelimited_header is set to true.

    If there is an error in calling rate limit service or rate limit service returns an error and is set to true, a 500 response is returned.

    Each rate limit action on the route or virtual host populates a descriptor entry. A vector of descriptor entries compose a descriptor. To create more complex rate limit descriptors, actions can be composed in any order. The descriptor will be populated in the order the actions are specified in the configuration.

    For example, to generate the following descriptor:

    The configuration would be:

    2.     - {generic_key: {descriptor_value: some_value}}

    If an action doesn’t append a descriptor entry, no descriptor is generated for the configuration.

    For the following configuration:

    If a request did not set , no descriptor is generated.

    If a request sets x-forwarded-for, the the following descriptor is generated:

    2. ("remote_address", "<trusted address from x-forwarded-for>")
    3. ("source_cluster", "from_cluster")

    Rate Limit Override

    A rate limit action can optionally contain a . The limit value will be appended to the descriptor produced by the action and sent to the ratelimit service, overriding the static service configuration.

    The following configuration

    Will lookup the value of the dynamic metadata. The value must be a structure with integer field “requests_per_unit” and a string field “unit” which is parseable to RateLimitUnit enum. For example, with the following dynamic metadata the rate limit override of 42 requests per hour will be appended to the rate limit descriptor.

    2.     test:

    Rate limit descriptors are extensible with custom descriptors. For example, extension allows using any of the request attributes as a descriptor value:

    Statistics

    The rate limit filter outputs statistics in the cluster.<route target cluster>.ratelimit. namespace. 429 responses are emitted to the normal cluster dynamic HTTP statistics.

    The ratelimit filter emits dynamic metadata as an opaque google.protobuf.Struct only when the gRPC ratelimit service returns a with a filled dynamic_metadata field.

    Runtime

    The HTTP rate limit filter supports the following runtime settings:

    ratelimit.http_filter_enabled

    % of requests that will call the rate limit service. Defaults to 100.

    ratelimit.http_filter_enforcing

    % of requests that that will have the rate limit service decision enforced. Defaults to 100. This can be used to test what would happen before fully enforcing the outcome.

    ratelimit.<route_key>.http_filter_enabled

    % of requests that will call the rate limit service for a given route_key specified in the rate limit configuration. Defaults to 100.