ASWA (Application Status Watch Agent)

ASWA is a specialized monitoring tool designed to perform HTTP-based health checks on a variety of web endpoints. It is engineered to ping specified URLs and validate their HTTP status codes and content against pre-configured expectations. This enables real-time, automated verification of service availability and data integrity.

Usage

ASWA supports three types of application environments:

• Development (dev): For testing and development purposes.
• Production (prod): For monitoring live, production-level services.
• Software-as-a-Service (saas): For third-party or cloud-based services.

Configuration files are stored in the config directory. You can specify which config file to load (dev, prod, saas) by setting the YAML_PATH environment variable. If no config file is specified, it will default to dev.applications.yml

Run a synthetic test in a docker container:

docker compose run aswa $APP_NAME

docker compose run aswa

Run a synthetic test locally:

./aswa $APP_NAME

./aswa 

Building ASWA binary

To build the ASWA binary, execute the following command:

go build -o aswa ./cmd

YAML config

The configuration is defined in a YAML file and must adhere to the following schema:

Required Fields

• name: The name of the application, must be non-empty.
• url: The URL to ping, must be a valid URL and non-empty.
• expected_status: The expected HTTP status code, must be non-zero.

Optional Fields

• expected_content: A string to match against the content returned by the URL.
• expected_location: The expected final URL after all redirects, if any.
• timeout: The maximum time to wait for a response, in milliseconds.
• expected_csp: The expected Content Security Policy (CSP) header value.

applications:
  - name: specialcollections
    url: 'https://specialcollections.library.nyu.edu/search/'
    expected_status: 200
    timeout: 600ms

Environment variables

In the docker-compose.yml file, you can configure the environment variables for the ASWA service. Here is an explanation of the key environment variables:

• ENV: Specifies the environment in which ASWA is running (default is dev).
• DEBUG_MODE: Enables or disables debug mode (default is false).
• CLUSTER_INFO: Includes cluster information in the output.
• OUTPUT_SLACK: If set to true, results are sent to Slack; otherwise, they are sent to PAG (default is false).
• PROM_AGGREGATION_GATEWAY_URL: URL for the Prom Aggregation Gateway.
• SLACK_WEBHOOK_URL: Slack webhook URL for notifications.
• YAML_PATH: Path to the YAML configuration file (default is config/dev.applications.yml).

Notifications

ASWA can post the results of its checks to respective Slack channels (dev, prod, saas) based on the environment. To enable this feature, set the SLACK_WEBHOOK_URL environment variable with your Slack webhook URL.

By default, OUTPUT_SLACK is set to false. If OUTPUT_SLACK is set to true, the results are sent to Slack. If OUTPUT_SLACK is set to false, the results are sent to PAG (Prom Aggregation Gateway of Prometheus).

Deployment

ASWA is designed to run as a cron job in a Kubernetes (K8s) cluster. To include cluster information in the output, set the CLUSTER_INFO environment variable.

Tests

To run the tests, execute the following command:

Run tests locally:

go test -cover ./...

Run tests in a docker container:

docker compose run test