nicer retry error message

app/nose/bin/counter.tsx

@@ -0,0 +1,14 @@
+import { stream } from "@/stream"
+
+export default async function () {
+  let count = 1
+
+  return stream(<p>{count}</p>, async ({ replace }) => {
+    for (let i = 1; i < 10; i++) {
+      await Bun.sleep(250)
+
+      count++
+      replace(<p>{count}</p>)
+    }
+  })
+}

app/src/dispatch.ts

@@ -20,7 +20,7 @@ export async function dispatchMessage(ws: any, msg: Message) {
 }
 
 async function inputMessage(ws: any, msg: Message) {
-  const result = await runCommand(msg.session || "", msg.id || "", msg.data as string)
+  const result = await runCommand(msg.session || "", msg.id || "", msg.data as string, ws)
   send(ws, { id: msg.id, type: "output", data: result })
 }
 

app/src/js/scrollback.ts

@@ -3,6 +3,7 @@
 // input, output, etc
 
 import { scrollback, $$ } from "./dom.js"
+import { randomId } from "../shared/utils.js"
 import type { CommandOutput } from "../shared/types.js"
 
 type InputStatus = "waiting" | "streaming" | "ok" | "error"
@@ -48,7 +49,7 @@ export function setStatus(id: string, status: InputStatus) {
 export function addOutput(id: string, output: CommandOutput) {
     const item = $$("li")
     item.classList.add("output")
-    item.dataset.id = id
+    item.dataset.id = id || randomId()
 
     const [format, content] = processOutput(output)
 
@@ -61,12 +62,55 @@ export function addOutput(id: string, output: CommandOutput) {
     autoScroll()
 }
 
+export function addErrorMessage(message: string) {
+    addOutput("", { html: `<span class="red">${message}</span>` })
+}
+
+
+export function appendOutput(id: string, output: CommandOutput) {
+    const item = document.querySelector(`[data-id="${id}"].output`)
+
+    if (!item) {
+        console.error(`output id ${id} not found`)
+        return
+    }
+
+    const [format, content] = processOutput(output)
+
+    if (format === "html")
+        item.innerHTML += content
+    else
+        item.textContent += content
+
+    autoScroll()
+}
+
+export function replaceOutput(id: string, output: CommandOutput) {
+    const item = document.querySelector(`[data-id="${id}"].output`)
+
+    if (!item) {
+        console.error(`output id ${id} not found`)
+        return
+    }
+
+    const [format, content] = processOutput(output)
+
+    if (format === "html")
+        item.innerHTML = content
+    else
+        item.textContent = content
+
+    autoScroll()
+}
+
 function processOutput(output: CommandOutput): ["html" | "text", string] {
     let content = ""
     let html = false
 
     if (typeof output === "string") {
         content = output
+    } else if (Array.isArray(output)) {
+        content = output.join(" ")
     } else if (output.html !== undefined) {
         html = true
         content = output.html

app/src/js/shell.ts

@@ -1,8 +1,8 @@
 ////
 // The shell runs on the server and processes input, returning output.
 
-import type { Message, CommandResult } from "../shared/types.js"
-import { addInput, setStatus, addOutput } from "./scrollback.js"
+import type { Message, CommandResult, CommandOutput } from "../shared/types.js"
+import { addInput, setStatus, addOutput, appendOutput, replaceOutput } from "./scrollback.js"
 import { send } from "./websocket.js"
 import { randomId } from "../shared/utils.js"
 import { addToHistory } from "./history.js"
@@ -16,7 +16,7 @@ export function runCommand(input: string) {
     addToHistory(input)
     addInput(id, input)
 
-    const [cmd = "", ...args] = input.split(" ")
+    const [cmd = "", ..._args] = input.split(" ")
 
     if (browserCommands[cmd]) {
         const result = browserCommands[cmd]()
@@ -30,13 +30,22 @@ export function runCommand(input: string) {
 
 // message received from server
 export function handleMessage(msg: Message) {
-    if (msg.type === "output") {
-        handleOutput(msg)
-    } else if (msg.type === "commands") {
-        cacheCommands(msg.data as string[])
-    } else if (msg.type === "error") {
-        console.error(msg.data)
-    } else {
+    switch (msg.type) {
+        case "output":
+            handleOutput(msg); break
+        case "commands":
+            cacheCommands(msg.data as string[]); break
+        case "error":
+            console.error(msg.data); break
+        case "stream:start":
+            handleStreamStart(msg); break
+        case "stream:end":
+            handleStreamEnd(msg); break
+        case "stream:append":
+            handleStreamAppend(msg); break
+        case "stream:replace":
+            handleStreamReplace(msg); break
+        default:
             console.error("unknown message type", msg)
     }
 }
@@ -46,3 +55,26 @@ function handleOutput(msg: Message) {
     setStatus(msg.id!, result.status)
     addOutput(msg.id!, result.output)
 }
+
+function handleStreamStart(msg: Message) {
+    const id = msg.id!
+
+    const status = document.querySelector(`[data-id="${id}"].input .status`)
+    if (!status) return
+
+    addOutput(id, msg.data as CommandOutput)
+
+    status.classList.remove("yellow")
+    status.classList.add("purple")
+}
+
+function handleStreamAppend(msg: Message) {
+    appendOutput(msg.id!, msg.data as CommandOutput)
+}
+
+function handleStreamReplace(msg: Message) {
+    replaceOutput(msg.id!, msg.data as CommandOutput)
+}
+
+function handleStreamEnd(_msg: Message) {
+}

app/src/js/websocket.ts

@@ -4,6 +4,10 @@
 import type { Message } from "../shared/types.js"
 import { sessionID } from "./session.js"
 import { handleMessage } from "./shell.js"
+import { addErrorMessage } from "./scrollback.js"
+
+const MAX_RETRIES = 5
+let retries = 0
 
 let ws: WebSocket | null = null
 
@@ -13,9 +17,8 @@ export function startConnection() {
     url.protocol = url.protocol.replace('http', 'ws')
     ws = new WebSocket(url)
 
-    ws.onopen = () => console.log('WS connected')
     ws.onmessage = receive
-    ws.onclose = () => setTimeout(startConnection, 1000) // simple retry
+    ws.onclose = retryConnection
     ws.onerror = () => ws?.close()
 }
 
@@ -37,3 +40,13 @@ export function close() {
     ws?.close(1000, 'bye')
 }
 
+function retryConnection() {
+    if (retries >= MAX_RETRIES) {
+        addErrorMessage(`!! Failed to reconnect ${retries} times. Server is down.`)
+        if (ws) ws.onclose = () => { }
+        return
+    }
+    retries++
+    addErrorMessage(`!! Connection lost. Retrying...`)
+    setTimeout(startConnection, 1000)
+}

app/src/session.ts

@@ -7,6 +7,7 @@ export type Session = {
     taskId?: string
     sessionId?: string
     project?: string
+    ws?: any
 }
 
 // Ensure "ALS" lives between bun's hot reloads

app/src/shared/types.ts

@@ -2,12 +2,13 @@ export type Message = {
     session?: string
     id?: string
     type: MessageType
-    data: CommandResult | string | string[]
+    data?: CommandResult | CommandOutput
 }
 
 export type MessageType = "error" | "input" | "output" | "commands" | "save-file"
+    | "stream:start" | "stream:end" | "stream:append" | "stream:replace"
 
-export type CommandOutput = string | { html: string }
+export type CommandOutput = string | string[] | { html: string }
 
 export type CommandResult = {
     status: "ok" | "error"

app/src/shell.ts

@@ -11,16 +11,15 @@ import { ALS } from "./session"
 
 const sessions: Map<string, Session> = new Map()
 
-export async function runCommand(sessionId: string, taskId: string, input: string): Promise<CommandResult> {
+export async function runCommand(sessionId: string, taskId: string, input: string, ws?: any): Promise<CommandResult> {
     const [cmd = "", ...args] = input.split(" ")
 
-    if (!commandExists(cmd)) {
+    if (!commandExists(cmd))
         return { status: "error", output: `${cmd} not found` }
-    }
 
     let status: "ok" | "error" = "ok"
     let output: CommandOutput = ""
-    const state = getState(sessionId, taskId)
+    const state = getState(sessionId, taskId, ws)
 
     try {
         [status, output] = await ALS.run(state, async () => await exec(cmd, args))
@@ -41,7 +40,7 @@ async function exec(cmd: string, args: string[]): Promise<["ok" | "error", Comma
     return processExecOutput(await module.default(...args))
 }
 
-function processExecOutput(output: string | any): ["ok" | "error", CommandOutput] {
+export function processExecOutput(output: string | any): ["ok" | "error", CommandOutput] {
     if (typeof output === "string") {
         return ["ok", output]
     } else if (typeof output === "object") {
@@ -52,18 +51,21 @@ function processExecOutput(output: string | any): ["ok" | "error", CommandOutput
         } else {
             return ["ok", output]
         }
+    } else if (output === undefined) {
+        return ["ok", ""]
     } else {
         return ["ok", String(output)]
     }
 }
 
-function getState(sessionId: string, taskId: string): Session {
+function getState(sessionId: string, taskId: string, ws?: any): Session {
     let state = sessions.get(sessionId)
     if (!state) {
         state = { sessionId: sessionId, project: "" }
         sessions.set(sessionId, state)
     }
     state.taskId = taskId
+    if (ws) state.ws = ws
     return state
 }
 

app/src/stream.ts

@@ -0,0 +1,51 @@
+import { send as sendWs } from "./websocket"
+import { getState } from "./session"
+import { processExecOutput } from "./shell"
+import type { Child } from "hono/jsx"
+import type { CommandOutput, Message } from "./shared/types"
+
+type StreamFn = (output: Child) => Promise<void>
+type StreamFns = { replace: StreamFn, append: StreamFn }
+type StreamParamFn = (fns: StreamFns) => Promise<void>
+
+export async function stream(initOrFn: StreamParamFn | string | any, fn?: StreamParamFn) {
+  const state = getState()
+  if (!state) throw "stream() called outside runCommand()"
+
+  let error = false
+  const taskId = state.taskId
+  const session = state.sessionId
+
+  const send = (msg: Message) => {
+    sendWs(state.ws, { ...msg, id: taskId, session })
+  }
+
+  const append = async (output: string | any) => {
+    const [status, data] = processExecOutput(output)
+    if (status === "error") error = true
+    send({ type: "stream:append", data })
+  }
+
+  const replace = async (output: string | any) => {
+    const [status, data] = processExecOutput(output)
+    if (status === "error") error = true
+    send({ type: "stream:replace", data })
+  }
+
+  let init: CommandOutput = ""
+  let func
+
+  if (typeof initOrFn === "function") {
+    func = initOrFn
+  } else {
+    init = processExecOutput(initOrFn)[1]
+    func = fn
+  }
+
+  return new Promise<void>(async resolve => {
+    send({ type: "stream:start", data: init })
+    await func({ replace, append })
+    send({ type: "stream:end", data: error ? "error" : "ok" })
+    resolve()
+  })
+}