@livestore/webmesh

@livestore/webmesh

Webmesh is a library for connecting multiple nodes (windows/tabs, workers, threads, ...) in a network-like topology. It helps to establish communication channels between nodes.

There are three types of channels:

• ProxyChannel: a virtual channel by proxying messages along edges (via hop nodes)
• DirectChannel: an end-to-end channel with support for transferable objects (e.g. Uint8Array)
• BroadcastChannel: a virtual channel by broadcasting messages to all connected nodes

ProxyChannels and DirectChannels have the following properties (similar to TCP):

• Has a unique name across the network
• Auto-reconnects
• Ordered messages
• Reliable (buffers messages and acks each message)

Available edge connection implementations

• MessageChannel
• BroadcastChannel (both web and Node.js)
• WebSocket
• window.postMessage

Important notes

• Each node name needs to be unique in the network.
  • The node name is also used as a "tie-breaker" as part of the messaging protocol.
• It's using the WebChannel concept from the @livestore/utils package.
• We assume network edges to be low-latency (a few ms)
• Webmesh is used in LiveStore as the foundation for the LiveStore devtools protocol communication.
• The implementation should avoid timeout-based "solutions" as much as possible.

Tradeoffs

• Webmesh isn't meant for larger networks
• Nodes are mostly stateless to simplify the protocol / implementation

Inspiration

• Elixir Distribution / OTP
  • https://elixirschool.com/en/lessons/advanced/otp_distribution
    • https://serokell.io/blog/elixir-otp-guide
• Consul by HashiCorp
• Ethernet