Cacher is the code snippet organizer for pro developers

# simple docker file
# assumes located in the same folder as the application itself

# start with node 5 base image
FROM node:5.0

# Create an app directory (in the Docker container)
RUN mkdir -p /usr/src/demo-server
WORKDIR /usr/src/demo-server

# Copy .npm settings and package.json into container
COPY package.json /usr/src/demo-server
COPY .npmrc /usr/src/demo-server
# and install dependencies
RUN npm install

# Copy our source into container
COPY src /usr/src/demo-server/src
COPY server.js /usr/src/demo-server

# If our server uses 1337 by default
# expose it from Docker container
EXPOSE 1337

# Finally start the container command
CMD ["node", "server.js"]

# See list of docker virtual machines on the local box
$ docker-machine ls
NAME      ACTIVE   URL          STATE     URL                         SWARM   DOCKER   ERRORS
default   *        virtualbox   Running   tcp://192.168.99.100:2376           v1.9.1 

# Note the host URL 192.168.99.100 - it will be used later!

# Build an image from current folder under given image name
$ docker build -t gleb/demo-app .

# see list of build images
$ docker images
REPOSITORY           TAG                 IMAGE ID            CREATED             VIRTUAL SIZE
gleb/demo-app        latest              506bf31537d4        17 minutes ago      904.5 MB
node                 5.0                 c4f955829812        10 weeks ago        642.2 MB

# Note both the original Node:5 and the built images are there

# Let us run the image under name 'demo'
$ docker run --name demo -p 5000:1337 -d gleb/demo-app
9f9f3ae62038805504c3c23cce4e9229008ba6bd9ea16b560a7a9e1cfa932e57

# Note: you can pass environment variable values to the `docker run` command
# docker run -e USER=name
# or, if the USER is already an environment var
# docker run -e USER
# or put all env variables into a file and pass its name
# docker run --env-file=<filename>
# You can check all the options passed into the running container
# docker inspect demo

# It prints the long container ID, but we can use our name "demo"
# We also mapped outside port 5000 to container's exposed port 1337
# Let us see running containers
$ docker ps
CONTAINER ID    IMAGE             COMMAND             CREATED              STATUS              PORTS                    NAMES
9f9f3ae62038    gleb/demo-app     "node server.js"    About a minute ago   Up About a minute   0.0.0.0:5000->1337/tcp   demo

# Let us make a dummy request to the app running inside the container
# We will use the virtual machine's IP and outside port 5000
$ curl 192.168.99.100:5000
Not Found

# Let us see the app's console log to confirm that it has received our request
$ docker logs demo
listening on port 1337 { subdomainOffset: 2, proxy: false, env: 'development' }
started server
  <-- GET /
  --> GET / 404 6ms -

# Jump into the running container to run any commands
# -i option means bind STDIO from the current shell
docker exec -it demo bash
root@9f9f3ae62038:/usr/src/demo-server# ls
... list of files
root@9f9f3ae62038:/usr/src/demo-server# exit

# If you want to quickly list files in the docker container (default folder)
# you can use `docker exec`
$ docker exec -t demo ls
# ... list of files in /usr/src folder

# We can even copy files from the container back into our system
docker cp demo:/usr/src/demo-server/file.txt file.txt
# look at file.txt locally

# Nice!
# To stop the running container
$ docker stop demo