npm bcrypt installation error when using travis

I am getting a very strange error when I try to run Travis on my application after installing the bcrypt library. Everything installs and runs fine when on my local machine but when I try to use travis I get an error installing bcrypt from package.json. Anyone know how to fix this?

npm ERR! Linux 4.8.12-040812-generic
npm ERR! argv "/home/travis/.nvm/versions/node/v6.11.0/bin/node" "/home/travis/.nvm/versions/node/v6.11.0/bin/npm" "install"
npm ERR! node v6.11.0
npm ERR! npm  v3.10.10
npm ERR! code ELIFECYCLE
npm ERR! bcrypt@1.0.2 install: `node-pre-gyp install --fallback-to-build`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the bcrypt@1.0.2 install script 'node-pre-gyp install --fallback-to-build'.
npm ERR! Make sure you have the latest version of node.js and npm installed.
npm ERR! If you do, this is most likely a problem with the bcrypt package,
npm ERR! not with npm itself.
npm ERR! Tell the author that this fails on your system:
npm ERR!     node-pre-gyp install --fallback-to-build
npm ERR! You can get information on how to open an issue for this project with:
npm ERR!     npm bugs bcrypt
npm ERR! Or if that isn't available, you can get their info via:
npm ERR!     npm owner ls bcrypt
npm ERR! There is likely additional logging output above.
npm ERR! Please include the following file with any support request:
npm ERR!     /home/travis/build/SamKirkiles/Teller/Server/npm-debug.log
The command "cd $TEST_DIR && npm install && npm test" exited with 1.
Done. Your build exited with 1.

Solution

Do you have your Travis Node.js configuration set up for compiling native modules?

Try adding this to your .travis.yml under the node_js setting (merge the env: bit together with any existing settings; you only need global: if you're building using a matrix e.g. testing on more than one Node version):

env:
  global:
    - CXX=g++-4.8

addons:
  apt:
    sources:
      - ubuntu-toolchain-r-test
    packages:
      - g++-4.8

I extracted this from the Travis docs page linked above.

If that doesn't work, maybe try linking to your .travis.yml here so we can see more about your build process.