不同 Python 脚本之间的共享计数器

Question

How do I implement a counter between two python scripts. The counter must be incremented once by each script and should be unique. ie Both scripts should not read the same value and also update the same value. Counter is in an imported file and its a database field. Help!

Answer 1

If the counter is in the database, when you update it you should add or subtract from it rather than setting it's value.

For example rather than (assuming counter was at 5 initially and we wanted to add 5):

update example_table set counter = 10;

Do:

update example_table set counter = counter+5;

That way when your scripts are running, possibly concurrently, the database will automatically account for the value to change while the script was running.

This does assume that the starting value of the counter doesn't really matter since you'll only be passing the delta.