Managing Background Jobs with gob

Managing Background Jobs with gob

Overview

gob (Background Job Manager) runs tasks asynchronously while keeping context free. Essential for builds, tests, dev servers, and any long-running commands.

When to use:

• User explicitly asks for "parallel" or "simultaneous" commands → use gob add for each
• Long-running command that would block context → use gob add
• Multiple independent commands to run at once → use gob add for each

Why gob over parallel Bash tool calls: gob provides job IDs, output capture, status monitoring, and proper process control. Parallel Bash calls just fire and forget.

CRITICAL: Parallel Command Requests

When user says "run X and Y in parallel" or "run two parallel builds":

# ✅ CORRECT: Use gob add for each command
gob add pnpm build
gob add pnpm build

# Then await results
gob await-any
gob await-any

# ❌ WRONG: Do NOT use parallel Bash tool calls
# Bash(pnpm build) + Bash(pnpm build) in same message

Why this matters: Parallel Bash tool calls work but provide no job management. gob gives you job IDs, status checks, output streaming, and the ability to stop/​restart jobs.

Core Concepts

The Problem Without gob

# ❌ BLOCKS: Claude Code waits for this to finish
npm run build
npm test
npm run lint

# Total time: Sequential, slow, context locked

The Solution With gob

# ✅ DISPATCHES: Returns immediately with job IDs
gob add npm run build    # Job #1
gob add npm test         # Job #2
gob add npm run lint     # Job #3

# Continue working while jobs run...
# Then collect results when ready

Key insight: gob add starts a job and returns immediately. You never wait. You work. You collect results later.

Sequential Execution

Use sequential execution when:

• A command must complete before the next one starts
• Result of one command needed for the next
• Order matters
• Examples: build → test, compile → verify, database migrations → seed data

Pattern: Sequential with Await

# Dispatch first command
JOB_ID=$(gob add make build)

# Wait for it (blocks here, but only here)
gob await $JOB_ID

# If it passed, dispatch next
JOB_ID_2=$(gob add npm test)
gob await $JOB_ID_2

# Result known, proceed

Process

1. Dispatch: gob add <command> → returns job ID immediately
2. Await: gob await <job_id> → streams output, returns exit code
3. Check result: If exit code is 0, continue. If non-zero, handle error
4. Next command: Only run next command if previous succeeded

Key Points

• One await per command: Always explicitly wait for sequential commands
• Check exit codes: Know if a command succeeded or failed
• Error handling: Stop on first failure or continue gracefully
• Clear naming: Use descriptive job names in comments

Parallel Execution

Use parallel execution when:

• Commands are independent (don't depend on each other's output)
• Running them together is faster than sequential
• Examples: lint + typecheck, test suite 1 + test suite 2, API build + UI build

Pattern 1: Start All, Await All

Good when you have a few known parallel tasks:

# Dispatch all jobs
gob add npm run lint
gob add npm run typecheck
gob add npm test

# Collect results (order doesn't matter)
gob await-any
gob await-any
gob await-any

How it works:

1. gob add three times → all three start in parallel
2. gob await-any → waits for whichever finishes first, returns result
3. Call await-any three times total to wait for all three jobs

Pattern 2: Specific Job Await

Good when you need specific jobs' results:

# Dispatch parallel jobs
LINT_JOB=$(gob add npm run lint)
TYPE_JOB=$(gob add npm run typecheck)
TEST_JOB=$(gob add npm test)

# Wait for specific jobs
gob await $LINT_JOB
gob await $TYPE_JOB
gob await $TEST_JOB

# Check all passed before proceeding

Pattern 3: Parallel Build Steps

# Dispatch parallel compilation tasks
gob add npm run build:frontend
gob add npm run build:backend
gob add npm run build:types

# Wait for all to complete
gob await-any
gob await-any
gob await-any

# All complete, package everything
gob add npm run package

Key Points

• Independence: Jobs truly don't depend on each other
• Dispatch first: Start all jobs before awaiting any
• await-any: Call once per job when using this pattern
• gob list: Check job status anytime with gob list
• Latency: Parallel jobs reduce total time significantly

Common Patterns

Pattern: Long Test Run

# Start expensive test suite
TEST_JOB=$(gob add npm run test:integration)

# Implement feature or write docs
# (Tests run in background)

# Check if done:
gob list   # See status

# Wait for completion:
gob await $TEST_JOB

Job Management

View Job Status

gob list

Get Job Output

# Wait for job and stream output
gob await <job_id>

# Returns exit code (0 = success, non-zero = failure)

Stop a Job

# Graceful stop (allows cleanup)
gob stop <job_id>

# Force kill (immediate termination)
gob stop --force <job_id>

Restart a Job

# Stop and restart a specific job
gob restart <job_id>

Remove a Job

# Remove a stopped job from list
gob remove <job_id>

Real-Time Monitoring

# Watch jobs as they run
watch gob list

# Or check once
gob list

Best Practices

✅ DO

• Use gob add for all long-running commands (builds, tests, servers)
• Dispatch all parallel jobs before awaiting any (maximizes concurrency)
• Check exit codes after sequential operations
• Use descriptive comments to explain job purpose
• Clean up stopped jobs periodically with gob remove
• Monitor with gob list if uncertain about job status
• Use --prompt-only with CLI tools (smaller output)

❌ DON'T

• Don't use npm run build & - Use gob add npm run build instead
• Don't use command & - gob handles backgrounding
• Don't forget to await sequential commands - Result matters
• Don't mix bash backgrounding with gob - Creates confusion
• Don't await the same job twice - Job completes once
• Don't ignore exit codes - Errors need handling
• Don't let job list grow unbounded - Remove completed jobs

Conditional Parallel Execution

# Phase 1: Build must complete first
gob add npm run build
gob await-any

# Phase 2: Run quality checks in parallel (only if build succeeded)
gob add npm run lint
gob add npm run typecheck
gob add npm test

# Phase 3: Wait for all quality checks
gob await-any
gob await-any
gob await-any

# Phase 4: Package only if all checks pass
gob add npm run package