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Rate Limits

A rate limit is a strategy for limiting the usage of a shared resource across parallel components in a Benthos instance, or potentially across multiple instances. They are configured as a resource:

- label: foobar
count: 500
interval: 1s

And most components that hit external services have a field rate_limit for specifying a rate limit resource to use, identified by the label field. For example, if we wanted to use our foobar rate limit with an http_client input it would look like this:

url: TODO
verb: GET
rate_limit: foobar

By using a rate limit in this way we can guarantee that our input will only poll our HTTP source at the rate of 500 requests per second.

Some components don't have a rate_limit field but we might still wish to throttle them by a rate limit, in which case we can use the rate_limit processor that applies back pressure to a processing pipeline when the limit is reached. For example, if we wished to limit the consumption of lines of a [csv file input][inputs.csv] to a specified rate limit we can do that with the following:

- ./foo.csv
- rate_limit:
resource: foobar

You can find out more about resources in this document.