PM2 Usage Guide

PM2 Commands Overview

PM2 is a production process manager for Node.js applications, which ensures that your apps stay online 24/7. Below are some common commands and setups for working with PM2.

1. Fetch Latest Code and Set Up the Project

Before deploying or running the application, it's important to ensure you have the latest code and dependencies set up:

# Fetch the latest changes from the repository and reset to a specific branch (e.g., release/vatan)
git fetch origin && git reset origin/release/vatan --hard
 
# Remove existing node modules and the yarn lock file
rm -rf node_modules
rm yarn.lock
 
# Install dependencies
yarn install
 
# Build the project
yarn build
 
# Reload all PM2 processes with the updated environment variables
pm2 reload all --update-env

2. Starting and Managing PM2 Processes

PM2 allows you to manage your Node.js application processes. Below are the commands to start and manage your app:

# Install PM2 globally (if not installed)
npm install -g pm2
 
# Start the app using PM2 (this starts the app from the package.json "start" script)
pm2 start npm -- start
 
# Reload all PM2 processes with updated environment variables
pm2 reload all --update-env
 
# Start the app directly with PM2 (this starts the app from the package.json "start" script)
pm2 start
 
# Reload all PM2 processes with updated environment variables (again)
pm2 reload all --update-env

3. Managing PM2 Processes

Once PM2 is running your application, you can manage the processes in various ways.

# List all running PM2 processes
pm2 list
 
# Show detailed information about a specific PM2 process (e.g., process ID 0)
pm2 show 0
 
# Stop a PM2 process (e.g., process ID 0)
pm2 stop 0
 
# Restart a PM2 process (e.g., process ID 0)
pm2 restart 0
 
# Stop all PM2 processes
pm2 stop all
 
# Restart all PM2 processes
pm2 restart all
 
# Delete a PM2 process (e.g., process ID 0)
pm2 delete 0
 
# Delete all PM2 processes
pm2 delete all

4. Monitoring PM2 Processes

PM2 allows you to monitor the status of running processes, including logs and performance metrics.

# View logs for a specific PM2 process (e.g., process ID 0)
pm2 logs 0
 
# View logs for all PM2 processes
pm2 logs
 
# Monitor CPU and memory usage of all PM2 processes
pm2 monit
 
# View real-time CPU and memory usage of a specific PM2 process (e.g., process ID 0)
pm2 show 0 --json

5. Managing Environments and Configurations

PM2 also allows you to manage environment-specific configurations for different stages of deployment (development, production, etc.).

# Start an app with a specific environment (e.g., production)
pm2 start app.js --env production
 
# Start an app with environment variables (e.g., API_KEY)
pm2 start app.js --env production --env API_KEY=your-api-key
 
# Save the PM2 process list and environment settings for reboot persistence
pm2 save
 
# Generate the PM2 startup script to keep your app running after a server restart
pm2 startup
 
# To restart the app on system reboot, use the saved process list
pm2 resurrect

6. Automating PM2 Process Management with Ecosystem File

You can use a PM2 ecosystem file to define the configuration for your app, making it easier to manage multiple environments.

# Start the app using the ecosystem file (ecosystem.config.js)
pm2 start ecosystem.config.js
 
# Reload all processes defined in the ecosystem file
pm2 reload ecosystem.config.js
 
# Delete processes defined in the ecosystem file
pm2 delete ecosystem.config.js

Development Setup

Follow these steps to set up the development environment for your project.

Git Pull: Fetch the latest changes from the repository.
```
git pull origin main
```
Set Up .env: Configure the environment variables for the project by creating or updating the .env file.
Install Node 18: Ensure Node.js version 18 is installed. You can use tools like nvm to manage the Node.js versions.
```
nvm install 18
nvm use 18
```
Install Yarn Globally: Install Yarn package manager globally.
```
npm install --global yarn
```
Install Dependencies: Install the project dependencies using Yarn.
```
yarn install
```
Build the Project: Compile or build the project files.
```
yarn build
```
Start the Development Server: Run the development server.
```
yarn start
```

ILTA Setup (for specific environment)

If you are setting up the ILTA (International Legal Technology Association) environment, follow these specific instructions:

Git Pull: Fetch the latest changes from the repository.
```
git pull origin ilta
```
Set Up .env: Set up the .env file for the ILTA environment, which may differ from the normal build setup.
Install Node 18: Ensure Node.js version 18 is installed.
```
nvm install 18
nvm use 18
```
Install Yarn Globally:
```
npm install -g yarn
```
Install Dependencies: Install the project dependencies using Yarn.
```
yarn install
```
Build the ILTA Version: Build the project for the ILTA environment.
```
yarn build:ilta
```
Start the ILTA Server: Run the server for the ILTA environment.
```
yarn start
```

Summary of PM2 Commands

Here’s a quick reference to the important PM2 commands used in this guide:

Process Management: pm2 start, pm2 stop, pm2 restart, pm2 delete, pm2 reload
Monitoring: pm2 monit, pm2 logs, pm2 show, pm2 list
Startup and Persistence: pm2 save, pm2 startup, pm2 resurrect
Environment Configuration: pm2 start app.js --env production
Ecosystem File Management: pm2 start ecosystem.config.js, pm2 reload ecosystem.config.js

Key Updates:

All PM2 commands included: From starting processes to managing environments and monitoring logs.
Clear explanations: Each command is paired with a clear description of its function.
Complete guide: Covers both development and production setups, as well as specific instructions for different environments like ILTA.

Let me know if you need any additional modifications!

Nvm Commands