Dynamically add_action() based upon number of posts - php

Question

I have a wp_cron which I run every hour.
The cron calls a function which iterates through a custom post type. The title and some meta data is then used to scrape results from a remote server.
The problem is that the scraping takes a long because of the number of posts. I want to split the scraping into chunks by only iterating through 25 posts at a time. This is easy using the offset parameter in query_posts, but how do I dynamically add_action() and pass the offset variable?
In functions.php
if ( ! wp_next_scheduled( 'my_task_hook' ) ) {
wp_schedule_event( time(), 'hourly', 'my_task_hook' );
}
add_action( 'my_task_hook', 'rock_n_roll' );
My scraper.php looks something like this
function rock_n_roll($offset) {
query_posts(array(
'post_type' => 'wine',
'order' => 'ASC',
'posts_per_page' => -1,
'offset' => $offset
));
while (have_posts()) : the_post();
//compare values against scraped results
//write results to DB with update_post_meta
endwhile;
}
Basically I need a way to dynamically add_action(), incrementing the value of $offset by 25 each time.

Answer 1

You can pass a variable to your add_action():
add_action( $tag, $function_to_add, $arg );
But you can also use do_action() instead of adding action every time your cron runs:
do_action( $tag, $arg )
Anyway, is good to store your $offset somewhere, so I see two options:
Store your persistent values in WP_Object_Cache. Maybe reading this documentation, you can find another elegant solution for your performance with large query results.
Recording in the database your actual $offset value using add_option() and get_option().
If you store your $offset variable, your rock_and_roll function don't need to receive a parameter anymore, you just need to retrieve it inside the function.
function rock_n_roll() {
// Retrieve $offset value from WP_Object_Cache
// or from database with get_option()
query_posts(array(
'post_type' => 'wine',
'order' => 'ASC',
'posts_per_page' => -1,
'offset' => $offset
));
while (have_posts()) : the_post();
//compare values against scraped results
//write results to DB with update_post_meta
endwhile;
}

Answer 2

Your $Offset is passed to the function from another source.. So I could imagine, something like:
$Var = $Pre_definedoffset;
$Var = $Pre_definedoffset + 25;
rock_n_roll($var);
This is just assumptions from what I can see from your code.
You will need to modify the variable containing the integer which is passed through to your function, before the code pushes it through the function.