npm install fails in jenkins pipeline in docker

Question

I'm following a tutorial about Jenkins pipeline and I can get a "hello world" working under at node 6.10 docker container.

But, when I added a default EmberJS app (using ember init) to the repo and attempt to build that in the pipeline, it fails when running npm install (because of directory access issues). The Jenkinsfile can be seen here: https://github.com/CloudTrap/pipeline-tutorial/blob/fix-build/Jenkinsfile

The error message printed by the build is (which is installed locally and run using java -jar jenkins.war on a Macbook, not relevant but included just in case) is:

npm ERR! Linux 4.9.12-moby
npm ERR! argv "/usr/local/bin/node" "/usr/local/bin/npm" "install"
npm ERR! node v6.10.0
npm ERR! npm  v3.10.10
npm ERR! path /.npm
npm ERR! code EACCES
npm ERR! errno -13
npm ERR! syscall mkdir

npm ERR! Error: EACCES: permission denied, mkdir '/.npm'
npm ERR!     at Error (native)
npm ERR!  { Error: EACCES: permission denied, mkdir '/.npm'
npm ERR!     at Error (native)
npm ERR!   errno: -13,
npm ERR!   code: 'EACCES',
npm ERR!   syscall: 'mkdir',
npm ERR!   path: '/.npm',
npm ERR!   parent: 'pipeline-tutorial' }
npm ERR! 
npm ERR! Please try running this command again as root/Administrator.

Note: I would like to not run npm install as root / sudo.

UPDATE: I have been able to make some progress as follows:

I found the command that Jenkins uses to build using the container from the logs:

[Pipeline] withDockerContainer
$ docker run -t -d -u 501:20 -w /long-workspace-directory -v /long-workspace-directory:/long-workspace-directory:rw -v /long-workspace-directory@tmp:/long-workspace-directory@tmp:rw -e

So when the docker image runs, it's work directory is a /long-workspace-directory (it's really a cryptic looking jenkins workspace path) and the user id is 501 (group id 20), etc. The user doesn't have a name (which is apparently breaking other things not related to this question).

1. Changed agent to use a Dockefile:

   agent {
     dockerfile {
       filename 'Dockerfile'
       args '-v /.cache/ -v /.bower/  -v /.config/configstore/'
     }
   }
   

2. Specify args '-v ...' for creating volumes for the directories npm install / bower needs.

Answer 1

Adding the environments and setting the Home to '.' solves this as below.

pipeline {
    agent { docker { image 'node:8.12.0' } }
    environment {
        HOME = '.'
    }
    stages {
        stage('Clone') {
            steps {
                git branch: 'master',
                    credentialsId: '121231k3jkj2kjkjk',
                    url: 'https://myserver.com/my-repo.git'
            }
        }
        stage('Build') {
            steps {
                sh "npm install"
            }
        }
    }
}