screenly / balena-prometheus-exporter

In the context of the screenly/balena-prometheus-exporter, secrets management, particularly for sensitive data like API tokens, is crucial for production environments. The project primarily utilizes environment variables to manage these secrets. Below is a detailed breakdown of how secrets are handled.

Storing Secrets

Secrets such as the BALENA_TOKEN can be set as environment variables when running the Docker container. This approach ensures that sensitive data is not hardcoded within the application’s source code.

Example of Setting Environment Variables

When creating and running the Docker container for the balena exporter, the BALENA_TOKEN must be provided as an environment variable. Here’s how to do it:

$ docker run -d \
--name balena-exporter \
-p 8000:8000 \
-e BALENA_TOKEN=YOUR_BALENA_TOKEN_HERE \
balena-exporter

In the above example, replace YOUR_BALENA_TOKEN_HERE with the actual token. This method keeps the token out of the source code and limits exposure.

Accessing Secrets in Code

Once the environment variable is set, the application can access it using Python’s os module. Here’s how to retrieve the BALENA_TOKEN within the application’s code.

Code Example for Accessing Environment Variables

import os

class BalenaCollector:
    def __init__(self):
        self.balena_token = os.getenv('BALENA_TOKEN')
        if not self.balena_token:
            raise ValueError("BALENA_TOKEN environment variable is required")

# Use the collected token in your API requests

This code ensures that the BALENA_TOKEN is retrieved from the environment and raises an error if it is not set, thus preventing potential issues related to missing API credentials.

Best Practices for Managing Secrets

  1. Environment Variables: Always use environment variables to store sensitive information like API tokens. This minimizes the risk of exposure in version control systems.

  2. Configuration Management: Use a configuration management tool (e.g., Docker secrets, Kubernetes secrets) to better manage environment variables in production.

  3. Documentation: Document the required environment variables clearly so that operational staff are aware of which secrets need to be configured.

  4. Access Control: Ensure strict access control is in place for the environment where the secrets are stored. Only authorized personnel should have access to sensitive configurations.

  5. Rotate Secrets Regularly: Implement a strategy for rotating secrets, such as API tokens, to improve security.

Following these practices will help in maintaining a secure environment for the screenly/balena-prometheus-exporter in production.

Sources:

  • The handling of the BALENA_TOKEN as an environment variable is derived from the provided Docker run command.
  • Accessing secrets within the Python application is demonstrated through the use of os.getenv().