Can't run official Docker tutorial container: npm ERR! missing script: start

Question

I'm trying to go through this part 2 of Docker's tutorial.

Here is my issue:

After creating successfully an image for the app, I try the command line (sudo) docker run --publish 8000:8080 --detach --name bb bulletinboard:1.0 which should run a container and allow me to access the app at localhost:8000.

But when checking out docker ps, nothing, so I used docker ps -a to find back my container, and find it with STATUS Exited (1). Then I try docker logs bb to find out more, and get this:

npm ERR! missing script: start.

This is more than surprising, knowing that it comes from the docs, I don't know what to do next. If anybody has any clue, it would be really nice. Thank you in advance

Answer 1

The error message means that npm can't find a package.json file which includes a script named start. So make sure that your package.json contains a script named start! Might already be the issue.

// Simple package.json example that contains a script with name test.
{
    "scripts": {
      "test": "echo \"Error: no test specified\" && exit 1"
    },
}

When you look at the tutorial's dockerfile:

This makes sure that the commands are executed in a specific folder, e.g. copying files:

# Set the working directory.
WORKDIR /usr/src/app

This makes sure that the package.json file is copied into the workdir:

# Copy the file from your host to your current location.
COPY package.json .

Here it defines that npm start will be executed when you run the container:

# Run the specified command within the container.
CMD [ "npm", "start" ]

To further investigate I would execute the following command to start the container:

docker run -it -d <container-id> /bin/sh

Then go to the workdir and check if the app can be started manually:

# Go to workdir
cd /usr/src/app
# Here check if the package.json is part of the directory.
ls
# Manually run npm script
npm start

Answer 2

It worked to add these lines to package.json

  "scripts": {
  "start": "node server.js"
}

and the remake a new image etc...

Answer 3

I ran to the same issue, but the missing script this time is "debug" there is no note in the package.json about this script only this:

  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },

however the docker-compose.dev.yml contains this command: npm run debug apparently the npm that I am using is a bit different, because this is the file generated by $npm init -y command.

$npm --version
6.14.4 
$node --version 
v10.19.0