1, Usage scenario

When deploying and publishing the node.js project, SSH is often used to connect multiple servers respectively. For each server, the latest git pull code should be executed to compile and start the application. The operation is trivial and easy to forget some of them. pm2 can solve this problem. It can be completed automatically with only one command. It can also monitor and view the operation of node.js application in real time.

2, Solution

Step 1: server environment configuration

• Install node.js: No, look here!
• Install PM2: npm install pm2@latest -g or yarn global add pm2
• Install git: No, look here
• Configure SSH so that the server can run git clone without secret, No, look here!

Step 2: develop machine environment configuration

• Install node.js: No, look here!
• Install PM2: npm install pm2@latest -g or yarn global add pm2
• Configure SSH, log in to the server without secret, No, look here!

Step 3: node.js project operation step configuration

1. Open the terminal, switch to the root directory of node.js project, execute pm2 ecosystem, and generate the configuration file as follows:

   // ecosystem.config.js
   module.exports = {
       apps: [{
           script: 'index.js',
           watch: '.',
           env_production: {
               NODE_ENV: "production"
           },
           env_development: {
               NODE_ENV: "development"
           }
       }],
     
           // Deployment Configuration
       deploy: {
           production: {
               user: 'SSH_USERNAME',
               host: 'SSH_HOSTMACHINE',
               ref: 'origin/master',
               repo: 'GIT_REPOSITORY',
               path: 'DESTINATION_PATH',
               'pre-deploy-local': '',
               'post-deploy': 'npm install && pm2 reload ecosystem.config.js --env production',
               'pre-setup': ''
           }
       }
   }

2. Modify the above configuration file to correct the server and git related information;

3. Execute the following command in the directory of ecosystem.config.js to initialize the node.js project to the server

   pm2 deploy production setup
   // pm2 connects to the server and notifies it of initialization such as git clone code.

4. Start or update the node.js project:

   pm2 deploy production --force;
   // Let the server git pull code, compile and start the application
   // --Function of force: if the local code of the server is changed, give up the change and update the project with the latest code of git warehouse.

3, Detailed explanation of deploy command

1. Command format

pm2 deploy <configuration_file> <environment> <command>

2,configuration_file

If the configuration file name is ecosystem.config.js or pm2.config.js, the above command does not need to write < configuration_ file>.

pm2 deploy production setup
// This command is executed by default by looking for the ecosystem.config.js or pm2.config.js configuration file

3,environment

Set env in configuration file_ Production and env_development, you can call it when executing the command and pass the environment variable to the node.js project: pm2 deploy production --force;

// ecosystem.config.js
module.exports = {
    apps: [{
        script: 'index.js',
        watch: '.',
        env_production: {
            NODE_ENV: "production"
        },
        env_development: {
            NODE_ENV: "development"
        }
    }],
}

4,command

setup                    run remote setup commands
update                   update deploy to the latest release
revert[n]               revert to[n]th last deployment or 1
curr[ent]                output current release commit
prev[ious]               output previous release commit
exec | run < cmd >         execute the given < cmd >
list                     list previous deploy commits
[ref]                    deploy to[ref], the "ref" setting, or latest tag

4, Other important matters

1. exec allows all servers to execute commands once

pm2 deploy production exec "pm2 reload all"

2. Rollback to previous deployment version

pm2 deploy production revert 1

3. Several time points of deployment

"pre-setup"         : "stay setup A command or script that runs before execution",
"post-setup"        : "In code clone Command or script to execute after completion",
"pre-deploy"        : "pm2 startOrRestart ecosystem.json --env production",
"post-deploy"       : "pm2 startOrRestart ecosystem.json --env production",
"pre-deploy-local"  : "echo 'This is a local executed command'"

4. To operate multiple servers, you only need to modify the host

"host" : ["212.83.163.1", "212.83.163.2", "212.83.163.3"],

5, Error reporting

1. Error message

npm: command not found
post-deploy hook failed
Deploy failed

2. Solution

During pm2 deployment, the above error occurs, but npm -v is normal. The reason is the pm2 configuration file. Follow the steps below to solve it.

# 1. Open terminal
$ cd ~
$ nano .bashrc

# 2. Comment out the following
#If not running interactively, don 't do anything
case $ - in
*
i * );;
*) return;;
esac

# 3. Update environment variables
$ source .bashrc

6, Reference documents

• PM2 one click, multiple servers deploy and publish Node.js project at the same time!