triggers-getting-started

Triggers Getting Started

Simple starter examples that showcase using SQS triggers or NATS triggers in all Scaleway Functions supported languages.

In each example, a function is triggered by a SQS queue or a NATS subject with a message containing a number. The function will then print the factorial of this number to the logs.

Requirements

This example requires Terraform.

Also,SQS must be activated on your project, and you must have a NATS account.

Setup

The Terraform configuration will deploy a function for each language, showing how to use triggers with each language.

It will also create a SQS queue per function and a NATS account to trigger it.

After exporting SCW_ACCESS_KEY, SCW_SECRET_KEY and SCW_DEFAULT_PROJECT_ID variables (for authentication), you can:

terraform init
terraform apply

You should be able to see your resources in the Scaleway console:

• Queues can be found in the Messaging section under SQS
• NATS account can be found in the Messaging section under NATS
• Functions can be found in the triggers-getting-started namespace in the Serverless functions section

Running

You can trigger your functions by sending messages to any of the associated SQS queues or NATS subject. Below is a description of how to do this with our dummy tests/send_[sqs|nats]_messages.py script.

Setup

First, you need to expose your SQS access and secret keys:

export AWS_ACCESS_KEY_ID=$(terraform output -raw sqs_access_key)
export AWS_SECRET_ACCESS_KEY=$(terraform output -raw sqs_secret_key)

Or configure NATS credentials:

export NATS_CREDS_FILE=$(terraform output -raw creds_file)
export SUBJECT_NAME=$(terraform output -raw subject_name)

Then you can set up a Python environment in the tests directory, e.g.

cd tests
python3 -m venv venv
source venv/bin/activate
pip3 install -r requirements.txt

Sending messages

Now you can run the send_sqs_messages.py script to send a message to the SQS queue of each function:

python3 send_sqs_messages.py

Or you can run the send_nats_messages.py script to send a message to the NATS subject:

python3 send_nats_messages.py

Viewing function logs

In your Cockpit, you can access the logs from your queues, NATS account and functions.

Navigate from your Cockpit to Grafana, and find the Serverless Functions Logs dashboard. There you should see something like the following, showing that your functions were triggered by messages on the queues/NATS subject:

...
DEBUG - php: factorial of 17 is 355687428096000 source=user stream=stdout
2023-09-11 10:36:19.994 DEBUG - Function Triggered: / source=core
2023-09-11 10:36:19.993 DEBUG - php: factorial of 13 is 6227020800 source=user stream=stdout
2023-09-11 10:36:19.991 DEBUG - Function Triggered: / source=core
2023-09-11 10:36:19.977 DEBUG - php: factorial of 12 is 479001600 source=user stream=stdout
2023-09-11 10:36:19.976 DEBUG - php: factorial of 11 is 39916800 source=user stream=stdout
2023-09-11 10:36:19.975 DEBUG - php: factorial of 10 is 3628800 source=user stream=stdout
2023-09-11 10:36:19.964 DEBUG - Function Triggered: / source=core
2023-09-11 10:36:19.954 DEBUG - php: factorial of 3 is 6 source=user stream=stdout
2023-09-11 10:36:19.954 DEBUG - php: factorial of 4 is 24 source=user stream=stdout
2023-09-11 10:36:19.948 DEBUG - php: factorial of 0 is 1 source=user stream=stdout
... (truncated)

If you don't see these logs, make sure you have selected one of the "triggers getting started" functions in the Function name dropdown.

Costs

Configuring and managing triggers is free, you only pay for the execution of your functions. For more information, please consult the Scaleway Serverless pricing. You will also be billed for the SQS queue usage and NATS account when sending messages to it.

Cleanup

To delete all the resources used in this example, you can run the following from the root of the project:

terraform destroy