Added notes about docker setups and distinction from debuggers (#68)

Author: nikelborm

.changeset/sour-trains-clap.md

@@ -0,0 +1,5 @@
+---
+"effect-vscode": patch
+---
+
+Added notes about docker setups and distinction of DevTools from debuggers in terms of client/server model

README.md

@@ -22,15 +22,39 @@ const program = Effect.log("Hello!").pipe(
   Effect.withSpan("Hi", { attributes: { foo: "bar" } }),
   Effect.forever,
 )
-const DevToolsLive = DevTools.layerWebSocket().pipe(
-  Layer.provide(NodeSocket.layerWebSocketConstructor),
-)
+const DevToolsLive = DevTools.layer()
 
 program.pipe(Effect.provide(DevToolsLive), NodeRuntime.runMain)
 ```
 
+The code above expects the DevTools server to be available at `localhost:34437`. If you are not running the DevTools client (e. g. backend) on the same machine, or if it's not available at localhost, you'll have to manully specify the websocket server url like so:
+```ts
+const DevToolsLive = DevTools.layer('ws://localhost:34437')
+```
+
 If you are using `@effect/opentelemetry` in your project, then it is important that you provide the `DevTools` layer **before** your tracing layers, so the tracer is patched correctly.
 
+Beware, that Effect DevTools extension does not behave like typical debugger UI, which connects to debugger port of target process. It's the other way around here. One of the reasons for that is to enable tracing of web applications, which are not able to expose ports, as servers do.
+
+### Docker
+
+In case you're using docker for local development and want to connect from your containerized application to DevTools server in VS Code, you'll have to do 2 things.
+
+1. You'll have to make your host machine addressable from within the container, by adding extra host.
+
+```yaml
+services:
+  effect-backend:
+    extra_hosts:
+      - host.docker.internal:host-gateway
+```
+
+2. You'll have to specify connection URL in your application to be
+
+```ts
+DevTools.layer('ws://host.docker.internal:34437');
+```
+
 ## Usage
 
 Once you have added the Layer to your project, open the Effect Dev Tools panel in vscode & click "Start the server" in the "Clients" panel.