Nuvolaris Scheduler

Nuvolaris Operator offers the possibility to deploy a simple "scheduler" to invoke repetitive or one-shot Nuvolaris actions. For example, an action executing a SQL script to create a PostgreSQL Database or inserting reference data, or simply an action that sends notifications with an API call every day at the same time.

How to Activate the Scheduler

Using the nuv CLI, you can enable the scheduler with the following command:

nuv config enable --cron

# if Nuvolaris is not yet deployed
nuv setup dev cluster

# alternatively if Nuvolaris is already deployed
nuv update apply

By default, the internal scheduler executes a job every minute that starts searching for Nuvolaris actions with special annotations.

How to Deploy a Repetitive Action

Let’s assume we want to deploy a Nuvolaris action to be executed every 30 minutes. The action source code is available in the file scheduled-action.py.

Suppose it’s an action that simply prints something, like this:

def main(args):
    print('Hello from a repeated action')
    return {
        'body': 'action invoked'
    }

To deploy the action and instruct Nuvolaris to execute it every 30 minutes, issue the following command:

nuv action create scheduled-action scheduled-action.py -a cron "*/30 * * * *"

So you can create the action in the classic way and at the end add -a cron yourCronExpression.

How to Deploy a One-Shot Execution Action

Now suppose we want to execute the same action scheduled-action.py only once.

To deploy an action and request a single execution automatically via the Nuvolaris Scheduler, issue the following command:

nuv action create scheduled-action scheduled-action.py -a autoexec true

If we now print activation logs with nuv activation poll, we will see our action execution log:

Activation: 'scheduled' (ebd532139a464e9d9532139a46ae9d8a)
[
    "2024-03-08T07:28:02.050739962Z stdout: Hello from a scheduled action"
]

Remarks

The scheduler executes the action according to the following rules:

Actions are called in a non-blocking fashion. To verify execution and logs, use the command nuv activation list.
Actions are invoked without any parameters. It is advised to deploy actions with self-contained parameters.