StackHead v2

[saitho]

This issue is used to collect all requirements for StackHead v2.
Based on the discussion on the Miro board: https://miro.com/app/board/o9J_lI-wpQM=/

Move StackHead CLI back to main repository

StackHead CLI will be the only way to execute StackHead, it will therefore be the main component and is moved to this main repository.

Replace Ansible by custom Golang implementation

Ansible is dropped as we only use it for SSH connecting to the target server, install software there and process the project definition file. The CLI will take over all responsibilities of our Ansible usage.

It needs to do:

• Establish SSH connection
• Copy files to the target server via SSH
• Execute commands on the target server via SSH
  • always: e.g. apt, mkdir
  • setup only: sudo, create users and groups
• Setup all required software (as Ansible did before) (with sudo access)
• Deploy the project (certificates, Terraform files, apply Terraform) with non-root stackhead user
• Parse configuration files (project definition)
• Generate Terraform files (and maybe others) from a template
• Allow extending its functionality with Go plugins (see below)

Plugin system see #152

• Golang plugins: https://medium.com/learning-the-go-programming-language/writing-modular-go-programs-with-plugins-ec46381ee1a9
• .so files need to be placed at a special location on the executing system (folder: TBD)
• plugins are expected to be hosted on GitHub. We may provide a plugin search endpoint which is a cached GitHub repository results view with a repository tag
• required plugin structure: TBD

New block-based configuration schema

While YAML files are easy to process, a different, block-based config schema may be easier to maintain.
Furthermore the idea of configuration blocks is easier to grasp, as the documentation would describe the structure of each block and where they can be used.
Lower prio as this requires implementing a new parser. See #131

Additional features

Features planned for v1 may see implementation in v2:

• Secret Storage / Environment variables in project definition #112
• Generate Terraform files in project root for customization #134
• Stackhead user for deployment #109
• Automated system updates #53
• Extract services from existing docker-compose file #1