[Code Freeze] Restructuring the code

[kradalby]

Juan and I are currently undertaking a large code refactor to make the code more maintainable.

Currently the goal is to split a lot of the code into modules, which forces us to have separate concerns and make sure that more of the code does one thing, and does it well. We had a lot of cycling dependencies (allowed by one large package) and it made everything very tightly knitted, and testing very hard as you had to set up a massive dependency chain.

Rough plan for how we want to do it:

1. Move control go code to package hscontrol (Code reorg step 1 #1444)
2. Split "core" code into packages (types, db, policy) (code reorg part 2, the database #1458)

• This is mainly a reorg change, where the code change is only to be able to move code
• types contains all our datatypes, and functions attached to them without dependencies
• db contains all functions that manipulate and changes the database
• policy contains all functions related to ACLs, a big change is that it does no longer depend on db

3. Split and potentially rewrite hscontrol into packages (this might change) (Code reorg part 3 #1477)

• mapper, all code related to generating MapResponses (the map clients need to find their peers)
• api, the code that implements our gRPC interface (For now, leave grpc in root)
• derp, derp related code
• dns, related code

4. Rewrite policy package (Codereorg: Part 4, policy improvement #1487)

• Generate filter and ssh rules per node

5. Rewrite polling and global state (Codereorg: Part 5, state  #1492)
6. Rename Machine to Node (Rename Machine to Node #1553)

[kev-the-dev]

For clarity, this issue is tagged [Code Freeze] as the maintainers will wait to merge any non-reorg changes until after the re-org? Makes sense to me but wanted to clarify

[kradalby]

@kev-the-dev, I realise that I have not actually written that out. Thanks for asking.

Yes, we are not taking contributions at the moment.

[kradalby]

This has been implemented, and we are preparing to get these changes out as alpha soon, closing.