### How this function works
This function will help you to reduce the cool start of your callable functions.
* You should have previous knowledge of **Pub/Sub**.
* Previous knowledge of GCP **Cloud Scheduler** is recommended.
### Function details
The function will be triggered by a Pub/Sub event published with the specific topic `KEEP_CALLABLES_WARM`. The message should contain the array of trigger URLs of the callables functions that you want to keep warm.
> It’s recommended to use GCP Cloud Scheduler to run this function every few minutes and thus keep the callable functions warm.
These callable functions must be implemented with our **keepWarm** policy. To install this function, add the required info to the form with the following parameters:
- **WARM_PROP**: The name of the warm prop.
- [GCP Cloud Scheduler](https://cloud.google.com/scheduler)