[PHP] Limiting php execution for webservices

[Augmented]

I'm working on a project that interfaces with a number of REST webservices that typically have a limit on the number of requests an IP can make in a block of time. Amazon ECS, for example, asks for no more than 1 request/s.

My query is about the best way to go about preventing PHP from making more requests than desired. My concern is not about one instance of a script executing too fast, but rather many instances running concurrently. I'm using cURL for all connections and PHP5, if that helps, and I can't make use of a database.

I was thinking of generating a lock file for each webservice (requiring each instance obtaining an exclusive lock on it before making a query), but that immediately strikes me as something that will be slow and problematic.

Stuck for ideas, any suggestions?

/edit - Oh, and on a completely different note, does anyone here use Textpattern? Just curious really.

 

[Augmented]

Thanks for the reply , but as I mentioned in my post I'm not able to use any database functionality. I am considering a lock file, but I'm hoping there might be some other solution to consider.

 

[Augmented]

Will give the lock file a go and see how things get on - doesn't seem like that cumbersome a solution when I see it like that. What I'm doing is writing a plugin for textpattern, so I want to keep the code as minimal and efficient as possible.
Thanks for the replies .