Docker: npm install behind proxy

I also had the same issue and did not want to set any proxy information in my image as I did not want be dependant of my company environment.

My solution was to use a cntlm running in gateway mode. To do so I put the flag Gateway set to yes the following allow rules in my cntlm configuration file:

 Gateway         yes
 # Allow local
 Allow           127.0.0.1
 # Allow docker subnetwork
 Allow           172.17.0.0/16

Then I was able to run my docker file by getting the dokcer0 interface address (got with ifconfigcommand):

docker build -t my-image --build-arg HTTP_PROXY=http://172.17.0.1:3128 --build-arg HTTPS_PROXY=http://172.17.0.1:3128 .

Same with docker run:

docker run --rm -e HTTP_PROXY=http://172.17.0.1:3128 --build-arg HTTPS_PROXY=http://172.17.0.1:3128 my-image

However please note that since docker 17.07 you can simply configure the docker client proxy.

Hence your ~/.docker/config.json will be like

{
  "proxies": {
      "default":{
          "httpProxy": "http://172.17.0.1:3128/",
          "httpsProxy": "http://172.17.0.1:3128/",
          "noProxy": "127.0.0.1,172.17.0.0/16,*.some.compagny.domain"
      }
}

First the https_proxy should use an http url, not an https url.

Second, you don't need to embed your proxy settings in your Dockfile: you can use build time variables

docker build --build-arg HTTP_PROXY=http://user:[email protected]:3128 --build-arg HTTPS_PROXY=http://user:[email protected]:3128 .

Finally, proxy settings at the docker service level allows the docker daemon to pull images from internet. It does not mean the unix command executed (RUN directive) by docker build would benefit from them. Hence the need to pass them as build-time environment variables.