I’m trying to create a real-time streaming output of a shell script execution using Bun and Hono. Currently, the output is buffered and only shows up all at once when the script finishes, but I need it to stream in real-time as the script produces output.

Shell Script (deploy-container.sh):

#!/bin/bash
# Script that deploys a container and shows progress
echo "🚀 Starting deployment process..."
echo "  → Deploying Docker container..."
# ... more echo statements and actual deployment logic
echo "✅ Deployed successfully!"

Current Implementation:

(deploy.ts):

import { $ } from "bun";

export const runDeployment = async (
  imageName: string,
  subDomain: string,
  port: number
) => {
  try {
    const res =
      await $`echo ${process.env.SYSTEM_PASSWORD} | sudo -S deploy-container.sh ${imageName} ${subDomain} ${port}`;

    return res.stdout.toString();
  } catch (e) {
    console.error("Error running deployment:", e);
    throw {
      success: false,
      error: e,
    };
  }
};

(index.ts):

import { stream } from "hono/streaming";
import { runDeployment } from "../lib/deploy";

app.post("/deployContainer/:repoName", async (c) => {
  try {
    const repoName = c.req.param("repoName");
    const imageName = `${repoName}:latest`;

    const port = generateRandomPort();
    const subDomain = generateSubdomain(repoName);
    const deployData = runDeployment(imageName, subDomain, port);
    return stream(c, async (clientStream) => {
      const heartbeat = setInterval(async () => {
        try {
          await clientStream.write(" ");
        } catch (err) {
          console.error("Heartbeat failed:", err);
        }
      }, 1000);

      try {
        const res = await deployData;
        clientStream.writeln(res);
      } catch (error) {
        console.error("Error deploying container:", error);
        clientStream.write(`Error deploying container: ${error}n`);
      } finally {
        clearInterval(heartbeat);
      }
    });
  } catch (e) {
    console.error(e);
    return c.json({ success: false, error: e }, 500);
  }
});

Current Behavior:

• The script executes successfully
• Output is collected but only shown all at once when the script completes
• No real-time streaming of the output

Expected Behavior:

• Each line of output should appear in real-time as the script produces it
• Similar to watching the output in a terminal

Any help would be appreciated in getting the output to stream in real-time rather than being buffered until the end.