Error installing Composer on Ubuntu - hyperledger-composer

Question

I am trying to install Composer on Ubuntu 14.04. I was able to install the prerequisites. When installing composer, I get the following error. How to fix it?
npm install -g composer-cli
npm WARN deprecated fs-promise#1.0.0: Use mz or fs-extra^3.0 with Promise Support
npm WARN deprecated crypto#0.0.3: This package is no longer supported. It's now a built-in Node module. If you've depended on crypto, you should switch to the one that's built-in.
npm WARN deprecated node-uuid#1.4.8: Use uuid module instead
npm WARN deprecated jade#1.11.0: Jade has been renamed to pug, please install the latest version of pug instead of jade
npm WARN deprecated transformers#2.1.0: Deprecated, use jstransformer
npm WARN deprecated nodemailer#2.7.2: All versions below 4.0.1 of Nodemailer are deprecated. See https://nodemailer.com/status/
/root/.nvm/versions/node/v6.11.2/bin/composer -> /root/.nvm/versions/node/v6.11.2/lib/node_modules/composer-cli/cli.js
> hashtable#2.0.2 install /root/.nvm/versions/node/v6.11.2/lib/node_modules/composer-cli/node_modules/hashtable
> node-gyp configure build
sh: 1: node-gyp: Permission denied
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents#1.1.2 (node_modules/composer-cli/node_modules/fsevents):
npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for fsevents#1.1.2: wanted {"os":"darwin","arch":"any"} (current: {"os":"linux","arch":"x64"})
npm ERR! file sh
npm ERR! code ELIFECYCLE
npm ERR! errno ENOENT
npm ERR! syscall spawn
npm ERR! hashtable#2.0.2 install: `node-gyp configure build`
npm ERR! spawn ENOENT
npm ERR!
npm ERR! Failed at the hashtable#2.0.2 install script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
npm ERR! A complete log of this run can be found in:
npm ERR! /root/.npm/_logs/2017-08-22T16_31_22_412Z-debug.log

Answer 1

So firstly you should not install Hyperledger Composer as 'root'. You need to read the docs here before you proceed https://hyperledger.github.io/composer/installing/development-tools.html
So fundamentally this is an npm issue (in that it causes problems for npm, when you npm install as 'root' or 'sudo' privileges for installing modules).
I suggest you create a non-root user in your Ubuntu system. Then log in as that user. Then install the pre-reqs using the supplied prereqs-ubuntu.sh script from the link above. Then follow the instructions, installing as your non-privileged user.
Normal route to fixing a non-root install npm issue, is one of these shown here https://docs.npmjs.com/getting-started/fixing-npm-permissions
When you install composer modules globally (eg. composer-cli) you should install using a designated, non-root user as mentioned. If there are issues (eg, on Ubuntu with permissions to write/update node directories located in system directories like /usr/local) - one solution (but see link earlier) is perform the npm install to a directory you have access to - rather than resort to root or superuser access, as this is not good practice. Here is what to do to set the npm prefix to a given directory, ...
"npm config set prefix /home/myuser/"
In this case, global binaries are placed in /home/myuser/bin which is in your PATH, and the modules are placed in /home/myuser/lib ...