Deploying Code on GitHub and EC2 Using AWS CodeDeploy (2)

This is the second writing about deploying a Node.js app using CI/CD tools, AWS CodeDeploy and AWS CodePipeline. The first article focuses on creating an EC2 instance and deploying a Node.js app in the instance using GitHub, CodeDeploy and CodePipeline. The below is about how to update codes and deploy them.

Table of Contents

• Updating appspec.yml
• npm and pm2 Not Found
• Final Comment

---

Updating appspec.yml

In the previous article, I used the following appspec.yml to upload my files to my EC2 instance:

version: 0.0
os: linux
files:
  - source: ./index.js
    destination: /home/ubuntu/your-app-name
  - source: ./package.json
    destination: /home/ubuntu/your-app-name
permissions:
  - object: /home/ubuntu
    owner: ubuntu
    group: ubuntu
    type:
      - directory
      - file

For my node.js app, I use npm and pm2. To automate the entire deployment process (e.g, npm install and pm2 reload all), we can use hooks of CodeDeploy. The npm install and pm2 reload install can be run during the AfterInstall lifecycle. The updated appspec.yml would be:

version: 0.0
os: linux
files:
  - source: ./index.js
    destination: /home/ubuntu/your-app-name
  - source: ./package.json
    destination: /home/ubuntu/your-app-name
hooks:
  AfterInstall:
    - location: scripts/AfterInstall.sh
      timeout: 1000
permissions:
  - object: /home/ubuntu
    owner: ubuntu
    group: ubuntu
    type:
      - directory
      - file

In scripts directory, create and save AfterInstall.sh:

#!/bin/bash
export NVM_DIR="$HOME/.nvm"
[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"  # This loads nvm
[ -s "$NVM_DIR/bash_completion" ] && \. "$NVM_DIR/bash_completion"  # This loads nvm bash_completion
export HOME="/home/ubuntu/"
sudo PM2_HOME=/home/ubuntu/.pm2 pm2 list
cd /home/ubuntu/api
npm install
pm2 start /home/ubuntu/api/ecosystem.config.js

---

npm and pm2 Not Found

In AfterInstall.sh, if only the last three lines are included, it will not be working because it cannot find npm and pm2. The npm issue can be solved by adding the following three lines:

export NVM_DIR="$HOME/.nvm"
[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"  # This loads nvm
[ -s "$NVM_DIR/bash_completion" ] && \. "$NVM_DIR/bash_completion"  # This loads 

The above does not solve an issue related to pm2. For example, when you read the logs on CodeDeploy, your build would fail, and you are likely to see the following messages:

[PM2][Initialization] Environment variable HOME (Linux) or HOMEPATH (Windows) are not set!
[PM2][Initialization] Defaulting to /etc/.pm2

It is because "pm2 needs to know your HOME path." By adding export HOME="/home/ubuntu/" in the AfterInstall.sh, that problem is solved.

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Final Comment

In my case, none of the processes appeared in the pm2 table (using sudo pm2 status) even though I followed the instructions. It was because my app was launched at a different PM2_HOME location. By entering and saving sudo PM2_HOME=/home/ubuntu/.pm2 pm2 list in my `AfterInstall.sh, the process would appear in the status table.