Local server implementation

[teodosin]

It is increasingly looking like Karta would benefit from being primarily a server application. The graph that it maintains of the file system's relations could conceivably be accessed and modified by multiple applications at the same time. Interoperability = utility. This initial local server implementation would pave the way for sharing and interconnecting graphs across multiple computers as well.

Roughly, these are the steps:

• Turn Graph into a trait: define a GraphTrait that encapsulates the core operations. This will allow for multiple implementations.

• The "greedy" local implementation: keep the current Graph struct and implement the GraphTrait for it. This will preserve the existing functionality for direct database access. teodosin/karta_server#3

• Convert the trait to support async operations. teodosin/karta#95

• Implement a local server version: create a new struct, let's call it ServerGraph, that also implements GraphTrait. This implementation will handle communication with the server process.

• Automatic server process management: In the ServerGraph implementation, we can add logic to:

• • Check if a server is already running for the given database
• • Start a new server process if one isn't running
• • Connect to the existing server if it's already running

• Inter-process management: some resources to perhaps look into:

• • https://3tilley.github.io/posts/simple-ipc-ping-pong/
• • https://github.com/kotauskas/interprocess
• • https://docs.rs/nng/latest/nng/

[teodosin]

Tracking tasks

• [x] Initial server implementation, axum process
• [x] Http route for open root node, open node
• [x] Http route for opening node connections
• [x] Mutable queries support, implementing RwLock
• [x] Indexing node connections via POST request
• [ ] Route for creating a node
• [ ] ?
• [ ] ?