RateLimiter rejects all events when Limit is between 0 and 1

[aschiffmann]

Checklist

• Dependencies installed
• No typos
• Searched existing issues and docs

Issue Description

When using the RateLimiter Middleware with a rate between 0 and 1 all events will be rejected instead of applying the specified rate. E.g.: e.Use(middleware.RateLimiter(middleware.NewRateLimiterMemoryStore(0.5)))

I am not saying that it is a common use case to have a rate.Limit between 0 and 1, but it is very confusing that NewRateLimiterMemoryStore() accepts a value of type float, the docs don't mention any restrictions for non-zero values but still the argument is interpreted as zero instead of its actual value.

Expected behaviour

One of those:

• the docs explains how a fractional rate.Limit is handled
• NewRateLimiterMemoryStore() only accepts integer values
• the RateLimiter interprets a fractional rate.Limit correctly, e.g. a limit of 0.5 will result in an equivalent rate of 30 requests/minute

Actual behaviour

a fractional rate.Limit between 0 and 1 is surprisingly interpreted like a zero Limit

Version/commit

v4.2.2

[aldas]

As ratelimiter middleware (default implementation) is wrapper around https://pkg.go.dev/golang.org/x/time/rate library and rate value goes directly to that library I think the docs explains how a fractional rate.Limit is handled would be correct solution.

[LukaJaj]

NewRateLimiterMemoryStore documentation states example like that

Example (with 20 requests/sec):

limiterStore := middleware.NewRateLimiterMemoryStore(20)

So if we pass float value like 0.5 in NewRateLimiterMemoryStore it should limit amount request per second or per minute?

@aschiffmann says per minute but in the docs we have second

[aldas]

This is actual documentation https://pkg.go.dev/golang.org/x/time/rate#Limit

[LukaJaj]

From listed solutions (

• the docs explains how a fractional rate.Limit is handled
• NewRateLimiterMemoryStore() only accepts integer values
• the RateLimiter interprets a fractional rate.Limit correctly, e.g. a limit of 0.5 will result in an equivalent rate of 30 requests/minute

) which one should I work on ?

[aldas]

Changing from rate.Limit to int* would probably break others existing code.

As this middleware just wraps x/time/rate code it would be best to add comments inside middleware where we have rate.Limit about 0-1 behaviour and link to actual limiter library docs. And also note of that behavior in https://github.com/labstack/echox/blob/master/website/content/middleware/rate-limiter.md

[aschiffmann]

So if we pass float value like 0.5 in NewRateLimiterMemoryStore it should limit amount request per second or per minute?

@aschiffmann says per minute but in the docs we have second

You are right, the rate is "per second" and not "per minute". Sorry for the confusion