feat: multi-agent orchestration with locking and streaming output by dukex · Pull Request #25 · benedicta-tech/crewbit

dukex · 2026-04-04T10:39:38Z

Add support for running multiple concurrent agents with file-based locking
to prevent duplicate issue processing. Each agent's output is prefixed with
[issueKey] for real-time visibility into what each agent is doing.

File-based lock mechanism in .crewbit.locks/ with acquire/release/isLocked
resolveNextActions() returns up to N issues respecting locks
daemon.maxConcurrent config option (default 1 for backward compat)
Session pool with graceful shutdown on SIGINT/SIGTERM
Streaming output multiplexed with [issueKey] prefix per line

dukex · 2026-04-04T10:40:08Z

+import { existsSync, mkdirSync, readdirSync, rmSync, writeFileSync } from "node:fs";
+import { join } from "node:path";
+
+export const LOCK_DIR = ".crewbit.locks";


Suggested change

export const LOCK_DIR = ".crewbit.locks";

export const LOCK_DIR = ".crewbit/locks";

Copilot

Pull request overview

Adds multi-agent orchestration to the crewbit daemon by introducing file-based issue locking, allowing multiple concurrent sessions, and adding a multi-issue resolver to fill available concurrency slots.

Changes:

Introduces .crewbit.locks/ file locks and helper APIs to prevent duplicate issue processing.
Adds resolveNextActions() to fetch up to N runnable issues while skipping locked ones.
Updates daemon.ts to run multiple sessions concurrently with polling/backoff and signal-based graceful shutdown.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
src/workflow.ts	Refactors action building and adds `resolveNextActions()` for multi-issue selection.
src/workflow.test.ts	Adds unit tests covering multi-issue selection, limits, locks, and prompt formatting.
src/types.ts	Extends `WorkflowConfig.daemon` with `maxConcurrent`.
src/lock.ts	Adds lock acquire/release/isLocked/list helpers using `.crewbit.locks`.
src/lock.test.ts	Adds tests for lock lifecycle and lock listing.
daemon.ts	Adds session pool orchestration, lock integration, and shutdown handling.

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Copilot · 2026-04-04T10:43:51Z

+  if (existsSync(lockPath)) return false;
+  if (!existsSync(lockDir)) mkdirSync(lockDir, { recursive: true });
+  const metadata = JSON.stringify({
+    pid: process.pid,
+    timestamp: new Date().toISOString(),
+  });
+  writeFileSync(lockPath, metadata);
+  return true;


acquireLock is not atomic: checking existsSync() then writeFileSync() can race across concurrent processes, allowing two daemons to both “acquire” the same lock. Use an atomic create (e.g., writeFileSync with flag 'wx' and handle EEXIST, or open with 'wx') so only one process can create the lock file.

Suggested change

if (existsSync(lockPath)) return false;

if (!existsSync(lockDir)) mkdirSync(lockDir, { recursive: true });

const metadata = JSON.stringify({

pid: process.pid,

timestamp: new Date().toISOString(),

});

writeFileSync(lockPath, metadata);

return true;

if (!existsSync(lockDir)) mkdirSync(lockDir, { recursive: true });

const metadata = JSON.stringify({

pid: process.pid,

timestamp: new Date().toISOString(),

});

try {

writeFileSync(lockPath, metadata, { flag: "wx" });

return true;

} catch (error: unknown) {

if (

typeof error === "object" &&

error !== null &&

"code" in error &&

error.code === "EEXIST"

) {

return false;

}

throw error;

}

Copilot · 2026-04-04T10:43:52Z

+export function acquireLock(lockDir: string, issueKey: string): boolean {
+  const lockPath = join(lockDir, `${issueKey}.lock`);
+  if (existsSync(lockPath)) return false;
+  if (!existsSync(lockDir)) mkdirSync(lockDir, { recursive: true });


Lock filenames are derived directly from issueKey. Some providers use keys containing '/' (e.g. "owner/repo#123"), which will create subpaths and can throw ENOENT (and also enables path traversal if issueKey is ever untrusted). Encode/sanitize issueKey (e.g., replace non-file-safe chars or base64url) before using it in the lock filename, and decode in getLockedKeys().

Copilot · 2026-04-04T10:43:52Z

+  const metadata = JSON.stringify({
+    pid: process.pid,
+    timestamp: new Date().toISOString(),
+  });
+  writeFileSync(lockPath, metadata);
+  return true;


Lock metadata (pid, timestamp) is written but never used. If the daemon crashes, stale lock files will block issues indefinitely. Consider validating/removing stale locks (e.g., check whether pid is still alive and/or enforce a TTL) when acquiring/reading locks.

Copilot · 2026-04-04T10:43:53Z

+  const sessions = new Map<string, ActiveSession>();
+
  process.on("SIGINT", () => {
-    log("Stopped.");
-    process.exit(0);
+    log("Stopping... waiting for in-flight sessions to finish.");
+    Promise.allSettled([...sessions.values()].map((session) => session.promise)).then(() => {
+      log("Stopped.");
+      process.exit(0);
+    });
  });
  process.on("SIGTERM", () => {
-    log("Stopped.");
-    process.exit(0);
+    log("Stopping... waiting for in-flight sessions to finish.");
+    Promise.allSettled([...sessions.values()].map((session) => session.promise)).then(() => {
+      log("Stopped.");
+      process.exit(0);
+    });
  });


SIGINT/SIGTERM handlers wait for the current sessions promises, but the main loop keeps running and can start new sessions after shutdown begins. Also, sessions started after the handler captures sessions.values() won’t be awaited, and process.exit(0) can terminate them abruptly (leaving locks behind). Add a shutdown flag to stop scheduling new work, and ensure the awaited set includes all in-flight sessions until exit.

Copilot · 2026-04-04T10:43:53Z

+  const logPrefix = `[${action.issueKey}]`;
+  const prefixedLog = (message: string) => {
+    log(`${logPrefix} ${message}`);
+  };
+  const runner = createRunner(config, REPO_ROOT, prefixedLog);
+  try {
+    return await runner.run(action, config, dryRun);


The daemon prefixes messages sent through log(), but ClaudeCodeRunner streams child stdout/stderr directly to process.stdout/process.stderr (unprefixed). With multiple concurrent sessions, output will interleave without the promised per-line [issueKey] prefix. To deliver the stated behavior, route runner stdout/stderr through a callback that prefixes each line (or have the daemon own stream multiplexing).

Copilot · 2026-04-04T10:43:53Z

+  let emptyBackoffExp = 1;
+  let failureBackoffExp = 1;
+  const lockDir = join(REPO_ROOT, LOCK_DIR);



The lock directory is created under the repo root (.crewbit.locks). Without a corresponding .gitignore entry, these lock files will appear as untracked changes and can be accidentally committed. Consider ignoring the lock dir (and any test lock dirs) in .gitignore.

Add support for running multiple concurrent agents with file-based locking to prevent duplicate issue processing. Each agent's output is prefixed with [issueKey] for real-time visibility into what each agent is doing. - File-based lock mechanism in .crewbit.locks/ with acquire/release/isLocked - resolveNextActions() returns up to N issues respecting locks - daemon.maxConcurrent config option (default 1 for backward compat) - Session pool with graceful shutdown on SIGINT/SIGTERM - Streaming output multiplexed with [issueKey] prefix per line Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Extract reapFinishedSessions() and startNewSessions() to bring the main loop cognitive complexity below the allowed threshold. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

sonarqubecloud · 2026-04-10T01:03:57Z

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

Copilot AI review requested due to automatic review settings April 4, 2026 10:39

dukex commented Apr 4, 2026

View reviewed changes

Copilot started reviewing on behalf of dukex April 4, 2026 10:40 View session

Copilot AI reviewed Apr 4, 2026

View reviewed changes

dukex force-pushed the feat/multi-agent-orchestration branch from e10ce20 to c3afb0f Compare April 10, 2026 00:56

dukex and others added 2 commits April 9, 2026 21:59

chore: improve lock

63fa950

refactor: reduce cognitive complexity of runDaemonCommand

9ae2646

Extract reapFinishedSessions() and startNewSessions() to bring the main loop cognitive complexity below the allowed threshold. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

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feat: multi-agent orchestration with locking and streaming output - #25

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	export const LOCK_DIR = ".crewbit.locks";
	export const LOCK_DIR = ".crewbit/locks";

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Pull request overview

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sonarqubecloud Bot commented Apr 10, 2026

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