What is the best way to provide execution arguments to an app through PM2?

Question

What is the best way to provide execution arguments to an app through PM2?

While attempting to start my app using pm2, I encountered an issue with passing arguments. Despite using the command pm2 start app.js -- dev, I was unable to pass the argument successfully. Interestingly, this worked without any issues when using forever.

node.js express forever pm2

Answer 1

Answer №1

To execute node arguments through the CLI, use this command:

pm2 start myServer.js --node-args="--production --port=1337"

Updated Version

You have the flexibility to include any arguments after --

pm2 start app.js -- --prod --second-arg --third-arg

For more information on deployments, refer to the Sails documentation on deployment.

Answer 2

To execute node arguments through the CLI, use this command:

pm2 start myServer.js --node-args="--production --port=1337"

Updated Version

You have the flexibility to include any arguments after --

pm2 start app.js -- --prod --second-arg --third-arg

For more information on deployments, refer to the Sails documentation on deployment.

Answer 3

Answer №2

If you're looking for a solution, you can follow the instructions provided in this ticket: https://github.com/Unitech/pm2/issues/13

Consider using environment variables when passing the environment configuration. By creating a variable accessible by any process within that environment with process.env.*.

For example, let's say you have a configuration file called config.json:

{
   "dev": {
        "db": {
            "hosts":["localhost"],
            "database": "api"
        },
        "redis": {
            "hosts": ["localhost"]
        }
   },
   ...
}

To import your config:

var config = require('./config.json')[process.env.NODE_ENV || 'dev'];

db.connect(config.db.hosts, config.db.database);

You can set the variable in your environment through the shell:

export NODE_ENV=staging
pm2 start app.js

The environment variable will persist throughout your session. To make it last beyond the session, modify the ~/.bashrc file accordingly. PM2 offers a deploy system, enabling you to set environment variables before daemonizing your app. This practice is commonly used in POSIX systems to retain parameters across processes.

Additionally, consider stop/starting locally and restarting (if in cluster mode) as needed to minimize downtime in production.

Answer 4

If you're looking for a solution, you can follow the instructions provided in this ticket: https://github.com/Unitech/pm2/issues/13

Consider using environment variables when passing the environment configuration. By creating a variable accessible by any process within that environment with process.env.*.

For example, let's say you have a configuration file called config.json:

{
   "dev": {
        "db": {
            "hosts":["localhost"],
            "database": "api"
        },
        "redis": {
            "hosts": ["localhost"]
        }
   },
   ...
}

To import your config:

var config = require('./config.json')[process.env.NODE_ENV || 'dev'];

db.connect(config.db.hosts, config.db.database);

You can set the variable in your environment through the shell:

export NODE_ENV=staging
pm2 start app.js

The environment variable will persist throughout your session. To make it last beyond the session, modify the ~/.bashrc file accordingly. PM2 offers a deploy system, enabling you to set environment variables before daemonizing your app. This practice is commonly used in POSIX systems to retain parameters across processes.

Additionally, consider stop/starting locally and restarting (if in cluster mode) as needed to minimize downtime in production.

Answer 5

Answer №3

Defining arguments within a process is achievable.

To create a new process in the `ecosystem.config.js` file, include an `args` key as shown below:

{
  name            : 'my-service',
  script          : './src/service.js',
  args            : 'firstArg secondArg',
},
{
  name            : 'my-service-alternate',
  script          : './src/service.js',
  args            : 'altFirstArg altSecondArg',
}

In this setup, both processes utilize the same file (`service.js`) but pass different sets of arguments to it.

It's important to note that handling these arguments should be done within the `service.js` file. For instance, using `process.argv[2]` retrieves the first argument and so forth in my scenario.

Answer 6

Defining arguments within a process is achievable.

To create a new process in the `ecosystem.config.js` file, include an `args` key as shown below:

{
  name            : 'my-service',
  script          : './src/service.js',
  args            : 'firstArg secondArg',
},
{
  name            : 'my-service-alternate',
  script          : './src/service.js',
  args            : 'altFirstArg altSecondArg',
}

In this setup, both processes utilize the same file (`service.js`) but pass different sets of arguments to it.

It's important to note that handling these arguments should be done within the `service.js` file. For instance, using `process.argv[2]` retrieves the first argument and so forth in my scenario.

Answer 7

Answer №4

After conducting thorough testing on my Windows machine, I can confirm that the solution below successfully allows for passing arguments to a Node.js application using pm2.

** There are two types of arguments:

node-args - to be used before npm start
args - to be used within your node program

There are two methods to pass arguments with pm2.

Option 1: passing arguments via pm2 commands.

Option 2: utilizing a config file such as ecosystem.config.js

Option 1 (Passing args through commands):

pm2 start app/myapp1.js --node-args="--max-http-header-size=80000" -- arg1 arg2

//To access the arguments in your node program:
console.log(process.argv[2]); // arg1
console.log(process.argv[3]); // arg2

Option 2 (Using a config file): If you are utilizing ecosystem.config.js, you can define the configuration as follows:

    {
      name: 'my-app',
      script: 'app\\myapp1.js',
      env: {
        NODE_ENV: 'DEV',
        PORT : 5051
      },
      node_args: '--max-http-header-size=80000',
      args : 'arg1 arg2',
      instances: 1,
      exec_mode: 'fork'
    }

To begin in dev mode:

pm2 start --name myapp  app/myapp1.js -- .\ecosystem.config.js

To start in production mode, simply add --env=production

pm2 start --name myapp  app/myapp1.js -- .\ecosystem.config.js --env=production

//To access the arguments in your node program:
console.log(process.argv[2]); // arg1
console.log(process.argv[3]); // arg2

Answer 8

After conducting thorough testing on my Windows machine, I can confirm that the solution below successfully allows for passing arguments to a Node.js application using pm2.

** There are two types of arguments:

node-args - to be used before npm start
args - to be used within your node program

There are two methods to pass arguments with pm2.

Option 1: passing arguments via pm2 commands.

Option 2: utilizing a config file such as ecosystem.config.js

Option 1 (Passing args through commands):

pm2 start app/myapp1.js --node-args="--max-http-header-size=80000" -- arg1 arg2

//To access the arguments in your node program:
console.log(process.argv[2]); // arg1
console.log(process.argv[3]); // arg2

Option 2 (Using a config file): If you are utilizing ecosystem.config.js, you can define the configuration as follows:

    {
      name: 'my-app',
      script: 'app\\myapp1.js',
      env: {
        NODE_ENV: 'DEV',
        PORT : 5051
      },
      node_args: '--max-http-header-size=80000',
      args : 'arg1 arg2',
      instances: 1,
      exec_mode: 'fork'
    }

To begin in dev mode:

pm2 start --name myapp  app/myapp1.js -- .\ecosystem.config.js

To start in production mode, simply add --env=production

pm2 start --name myapp  app/myapp1.js -- .\ecosystem.config.js --env=production

//To access the arguments in your node program:
console.log(process.argv[2]); // arg1
console.log(process.argv[3]); // arg2

Answer 9

Answer №5

To send parameters to your script, simply add them after --. Here's an example:

pm2 start app.js -i max -- -a 23 // Remember to pass arguments after the -- to app.js!

Answer 10

To send parameters to your script, simply add them after --. Here's an example:

pm2 start app.js -i max -- -a 23 // Remember to pass arguments after the -- to app.js!

Answer 11

Answer №6

When it comes to running Python scripts in a Linux environment, I always rely on PM2. If you have a script with a single parameter that needs to run continuously at set intervals, you can use the following command:

pm2 start <filename.py> --name <nameForJob> --interpreter <InterpreterName> --restart-delay <timeinMilliseconds> -- <param1> <param2>

filename.py represents the name of the Python script that will be executed using PM2
nameForJob should be a meaningful identifier for the job being performed
InterpreterName refers to the Python interpreter used to run the script, typically 'python3' in a Linux environment
timeinMilliseconds denotes the time interval before the script is rerun
param1 and param2 are parameters required by the script.

Answer 12

When it comes to running Python scripts in a Linux environment, I always rely on PM2. If you have a script with a single parameter that needs to run continuously at set intervals, you can use the following command:

pm2 start <filename.py> --name <nameForJob> --interpreter <InterpreterName> --restart-delay <timeinMilliseconds> -- <param1> <param2>

filename.py represents the name of the Python script that will be executed using PM2
nameForJob should be a meaningful identifier for the job being performed
InterpreterName refers to the Python interpreter used to run the script, typically 'python3' in a Linux environment
timeinMilliseconds denotes the time interval before the script is rerun
param1 and param2 are parameters required by the script.

Answer 13

Answer №7

There are two methods to pass parameters from pm2 to nodejs in CLI:

pm2 start app.js -- dev --port=1234 (be sure to include an extra space between -- and dev)
pm2 start app.js --node-args="dev --port=1234"

Using either of these approaches, you will find the values in process.argv as follows: ['dev','--port=1234']

Answer 14

There are two methods to pass parameters from pm2 to nodejs in CLI:

pm2 start app.js -- dev --port=1234 (be sure to include an extra space between -- and dev)
pm2 start app.js --node-args="dev --port=1234"

Using either of these approaches, you will find the values in process.argv as follows: ['dev','--port=1234']

Answer 15

Answer №8

To specify arguments for a node, you can simply do the following:

NODE_TLS_REJECT_UNAUTHORIZED=0 NODE_ENV=dev pm2 start server.js --name web-server

Answer 16

To specify arguments for a node, you can simply do the following:

NODE_TLS_REJECT_UNAUTHORIZED=0 NODE_ENV=dev pm2 start server.js --name web-server

Answer 17

Answer №9

I must add on to the responses provided regarding npm scripts

Regarding npm scripts

// package.json
{
  "scripts": {
    "start": "pm2 start --node-args=\"-r dotenv/config\" index.js"
  }
}

npm run start initiates pm2 start for index.js with additional node-args -r dotenv/config that includes environment variables from a .env file using dotenv

Answer 18

I must add on to the responses provided regarding npm scripts

Regarding npm scripts

// package.json
{
  "scripts": {
    "start": "pm2 start --node-args=\"-r dotenv/config\" index.js"
  }
}

npm run start initiates pm2 start for index.js with additional node-args -r dotenv/config that includes environment variables from a .env file using dotenv

Answer 19

Answer №10

Explained in the pm2 documentation

//Activate settings for production environment
$ pm2 start app.js --env production 

//Apply settings for staging environment
$ pm2 restart app.js --env staging

Answer 20

Explained in the pm2 documentation

//Activate settings for production environment
$ pm2 start app.js --env production 

//Apply settings for staging environment
$ pm2 restart app.js --env staging

Answer 21

Answer №11

To initiate pm2, use the following command: pm2 launch app.js --name "app_name" -- arg1 arg2

In your script, retrieve the arguments like so: console.log(process.argv);

The process.argv variable contains an array with the following elements: [ '/usr/local/bin/node', '/usr/local/lib/node_modules/pm2/lib/ProcessContainerFork.js', 'arg1', 'arg2' ]

Answer 22

To initiate pm2, use the following command: pm2 launch app.js --name "app_name" -- arg1 arg2

In your script, retrieve the arguments like so: console.log(process.argv);

The process.argv variable contains an array with the following elements: [ '/usr/local/bin/node', '/usr/local/lib/node_modules/pm2/lib/ProcessContainerFork.js', 'arg1', 'arg2' ]

What is the best way to provide execution arguments to an app through PM2?

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

Answer №6

Answer №7

Answer №8

Answer №9

Regarding npm scripts

Answer №10

Answer №11

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