Ruby: begin, sleep, retry: where to put incrementer - ruby

Question

I have a method 'rate_limited_follow' that takes my Twitter useraccount and follows all the users in an array 'users'. Twitter's got strict rate limits, so the method deals with that contingency by sleeping for 15 minutes and then retrying again. (I didn't write this method, rather got it from the Twitter ruby gem api). You'll notice that it checks to see if the number of attempts are less than the MAX_ATTEMPTS.
My users array has about 400 users that I'm trying to follow. It's adding 15 users at a time (when the rate limits seems to kick in), then sleeping for 15 minutes. Since I set the MAX_ATTEMPTS constant to 3 (just to test it), I expected it to stop trying once it had added 45 users (3 times 15) but it's gone past that, continuing to add 15 users around every fifteen minutes, so it seems as if num_attempts is somehow remaining below 3, even though it's gone through this cycle more than 3 times. Is there something I don't understand about the code? Once 'sleep' is finished and it hits 'retry', where does it start again? Is there some reason num_attempts isn't incrementing?
Calling the method in the loop
>> users.each do |i|
?> rate_limited_follow(myuseraccount, i)
>> end
Method definition with constant
MAX_ATTEMPTS = 3
def rate_limited_follow (account, user)
num_attempts = 0
begin
num_attempts += 1
account.twitter.follow(user)
rescue Twitter::Error::TooManyRequests => error
if num_attempts <= MAX_ATTEMPTS
sleep(15*60) # minutes * 60 seconds
retry
else
raise
end
end
end

Answer 1

Each call to rate_limited_follow resets your number of attempts - or, to rephrase, you are keeping track of attempts per user rather than attempts over your entire array of users.
Hoist num_attempt's initialization out of rate_limited_follow, so that it isn't being reset by each call, and you'll have the behavior that you're looking for.