# Build a docker Image

### Steps

- Create a file in root directory of the project
- Add in these contents
- Base Image
`FROM node:14`
- Create app working directory
`WORKDIR /usr/src/app`
- Copy Dependencies

    COPY package*.json ./
    COPY yarn.lock ./

- Install dependencies
`RUN npm install`
- Copy other source files
`COPY . .`
- Expose a port if required
`EXPOSE 8080`
- Run program
`CMD ["node","index.js"]`

- Should look like

# Base Image
FROM node:14

# Create app directory
WORKDIR /usr/src/app


# Install app dependencies
# A wildcard is used to ensure both package.json
# AND package-lock.json are copied
# where available (npm@5+)
COPY package*.json ./
COPY yarn.lock ./


## Install dependencies
RUN npm install
# If you are building your code for production
# RUN npm ci --only=production

# Bundle app source
COPY . .

# expose port
EXPOSE 8080

# last command to execute the node program `node index`
CMD [ "node", "index.js" ]

- Create a `.dockerignore` file in the same directory

node_modules
npm-debug.log

- Building image

Go to the directory that has your Dockerfile and run the following command to build the Docker image. The -t flag lets you tag your image so it's easier to find later using the docker images command:

docker build . -t <your username>/node-web-app

- Check and list your docker images

docker images

- Run your image

docker run -p 49160:8080 -d <your username>/node-web-app

- Limit CPU or other resources

$ docker run --cpus=2 -m 512m <image>