tessl/npm-wait-on

Cross-platform command line utility and Node.js API which will wait for files, ports, sockets, and http(s) resources to become available

—

Pending

Overview

Eval results

Files

Command Line Interface

Name: tessl/npm-wait-on
Author: tessl

Command-line utility providing full access to wait-on functionality through CLI arguments and configuration files. Supports time interval parsing and environment-specific options.

Capabilities

Basic Command Structure

wait-on [options] resource1 [resource2 ...]

The CLI waits for all specified resources to become available, then exits with code 0 (success) or non-zero (error/timeout).

Usage Examples:

# Wait for single file
wait-on file1

# Wait for multiple resources
wait-on file1 file2 http://localhost:8000

# Chain with another command
wait-on http://localhost:3000 && npm start

# Wait for service shutdown in reverse mode
wait-on -r tcp:8080 && echo "Service stopped"

Command Line Options

Configuration Options

# Configuration file (JavaScript or JSON)
-c, --config <file>

# Example usage
wait-on --config ./wait-config.js

Configuration file format:

module.exports = {
  resources: ['http://localhost:3000'],
  timeout: 30000,
  interval: 1000,
  log: true,
  // Any other options from the Node.js API
};

Timing Options

# Initial delay before checking resources (ms)
-d, --delay <ms>

# Poll interval (supports time units: ms, s, m, h)
-i, --interval <time>

# Overall timeout (supports time units)
-t, --timeout <time>

# Stability window (supports time units), default 750ms
# Time that resource needs to have not changed before signaling success
# If less than interval, it will be reset to the value of interval
# This is only used for files, other resources are considered available on first detection
-w, --window <time>

# HTTP request timeout (ms), default 0 (uses OS default)
--httpTimeout <ms>

# TCP connection timeout (ms), default 300ms
--tcpTimeout <ms>

Usage Examples:

# Wait 5 seconds before starting, check every 2 seconds
wait-on -d 5000 -i 2s http://localhost:3000

# 30 second timeout with custom intervals
wait-on -t 30s -i 500ms tcp:3306

# File stability window
wait-on -w 2s file:/tmp/output.log

Behavior Options

# Enable logging to stdout
-l, --log

# Enable verbose/debug logging
-v, --verbose  

# Reverse mode - wait for resources to become unavailable
-r, --reverse

# Limit concurrent connections
-s, --simultaneous <count>

# Show help
-h, --help

Usage Examples:

# Verbose logging
wait-on -v http://localhost:3000

# Reverse mode with logging
wait-on -r -l tcp:8080

# Limit to 3 concurrent connections
wait-on -s 3 http://api1.com http://api2.com http://api3.com

Time Interval Parsing

The CLI supports human-readable time intervals for timing options:

# Time unit suffixes
ms    # milliseconds (default)
s     # seconds  
m     # minutes
h     # hours

# Examples
--timeout 30s      # 30 seconds
--interval 2m      # 2 minutes  
--delay 500ms      # 500 milliseconds
--window 1h        # 1 hour

Usage Examples:

# Various time formats
wait-on --timeout 5m --interval 10s http://localhost:3000
wait-on --delay 30s --window 2m file:/tmp/data.json
wait-on -t 1h -i 30s tcp:database:5432

Resource Specification

Resources can be specified directly as command arguments or in configuration files:

# Command line resources (take precedence over config file)
wait-on resource1 resource2 resource3

# Resources from config file only
wait-on --config myconfig.js

Exit Codes

0    # Success - all resources became available
1    # Error - timeout, resource unavailable, or other error

Usage Examples:

# Use in shell scripts
if wait-on -t 30s http://localhost:3000; then
  echo "Server is ready"
  npm start
else
  echo "Server failed to start" >&2
  exit 1
fi

# Chain commands
wait-on tcp:5432 && wait-on http://localhost:8080 && echo "All services ready"

Configuration File Support

Configuration files provide access to all Node.js API options:

// wait-config.js
module.exports = {
  resources: [
    'http://localhost:3000',
    'tcp:database:5432'
  ],
  timeout: 30000,
  interval: 1000,
  log: true,
  
  // HTTP-specific options not available via CLI flags
  auth: {
    username: process.env.API_USER,
    password: process.env.API_PASS
  },
  headers: {
    'User-Agent': 'MyApp/1.0'
  },
  validateStatus: (status) => status < 500
};

Usage:

wait-on --config wait-config.js

Help Output

wait-on --help

Displays comprehensive usage information including:

Command syntax
All available options
Resource type descriptions
Time interval format
Exit code information
Configuration file examples

Usage Examples:

# Complete examples for different scenarios

# Web application startup
wait-on tcp:3306 tcp:6379 && wait-on http://localhost:3000/health && echo "App ready"

# Microservices orchestration  
wait-on http://auth:8080/health http://api:8080/health http://ui:3000 && echo "All services online"

# File processing pipeline
wait-on file:/input/data.csv && process-data && wait-on file:/output/results.json

# Development workflow
wait-on http://localhost:3000 && npm run test:e2e

# Docker container coordination
wait-on tcp:postgres:5432 && wait-on tcp:redis:6379 && npm start

Install with Tessl CLI