Best way to compose a limit on a large timespan.

[mattheys]

Hi,

I'm trying to consume an API that iterates a folder and file structure and that has a limit of 2000 calls per 600 seconds.

I'm trying to come up with the best approach so that after the 600 seconds I am as close to using all 2000 calls possible without exhausting all the calls in the first 100 seconds and letting the user wait 500 seconds for the next update.

var constraint = new CountByIntervalAwaitableConstraint(4, TimeSpan.FromSeconds(1));
var constraint2 = new CountByIntervalAwaitableConstraint(1950, TimeSpan.FromSeconds(600));
limiter = TimeLimiter.Compose(constraint, constraint2);

I've gone with this to start with, but after the 600 seconds were up I still had anywhere between 50 to 600 requests remaining meaning I was leaving performance on the table.

To note is that the API also returns how many requests I have left and how long until the next reset period if I can use those values somehow as well.

When my service is left to iterate a folder structure on it's own it's more like 50 requets remaining at the end, however if the time period included a time when the user was left to select some options before clicking start then it can be more like 600.

Basically I want it to start off with about 3 requests per second, then if for some reason it isn't going to get close to 0 calls left at the end have the ability to speed up and use all the available performance.

Can I reassign to the private field? Is it thread safe to do so? Could after every 100 calls used re-evaluate the remaining performance and regenerate the limiter?
e.g.

var timeLeft = 200; //seconds
var callsLeft = 1200; //api calls

var callsPerSecond = callsLeft/timeLeft;
var constraint1 = new CountByIntervalAwaitableConstraint(callsPerSecond, TimeSpan.FromSeconds(1));
var constraint2 = new CountByIntervalAwaitableConstraint(callsLeft , TimeSpan.FromSeconds(timeLeft));
limiter = TimeLimiter.Compose(constraint1, constraint2);