Add option to set enroll key via file for Docker swarm secrets

[sebastianhaas]

When using Docker in swarm mode, the use of environmental variables for secrets is discouraged. Instead, swarm secrets are the way how sensitive data is managed: https://docs.docker.com/engine/swarm/secrets/

With swarm secrets, it is by design impossible to mount them as environment variables. Swarm secrets will be mounted as a file, containing the secret's value. To tackle this issue, it is common practice to add another configuration option for Docker images as environment variable, ususally called VAR_NAME_FILE for a environment variable VAR_NAME, that will instead point to a file containing the sensitive configuration value.
A popular example of this would be https://hub.docker.com/_/postgres#docker-secrets.

This pull requests adds a new environment variable ENROLL_KEY_FILE in addition to the already existing ENROLL_KEY, allowing to pass an enroll key in swarm setup using swarm secrets.

I am aware, that the crowdsec image does already support swarm secrets for bouncer API keys, however, I feel like the mechanics differ from what is preferable for the enroll key.

[github-actions]

@sebastianhaas: There are no 'kind' label on this PR. You need a 'kind' label to generate the release automatically.

• /kind feature
• /kind enhancement
• /kind refactoring
• /kind fix
• /kind chore
• /kind dependencies

Details

I am a bot created to help the crowdsecurity developers manage community feedback and contributions. You can check out my manifest file to understand my behavior and what I can do. If you want to use this for your project, you can check out the BirthdayResearch/oss-governance-bot repository.

[github-actions]

@sebastianhaas: There are no area labels on this PR. You can add as many areas as you see fit.

• /area agent
• /area local-api
• /area cscli
• /area appsec
• /area security
• /area configuration

Details

I am a bot created to help the crowdsecurity developers manage community feedback and contributions. You can check out my manifest file to understand my behavior and what I can do. If you want to use this for your project, you can check out the BirthdayResearch/oss-governance-bot repository.