How to update PATH environment variable while deploying in Cloud Foundry

Question

I want to deploy my Node.js application in Pivotal Cloud Foundry using manifest.yml. I need to update the PATH variable of the container before the application starts, to include the path of a directory in my application's src directory. Can this be achieved?

manifest.yml:

---
applications:
  - name: node-apollo-graphql-server
    command: npm start
    instances: 1
    memory: 512M
    buildpack: dicf_nodejs_buildpack_rc
    stack: cflinuxfs3

Answer 1

You cannot do this by setting env variables with cf push -e or the env: block in manifest.yml. If you set path using one of these methods, you'll override path when what you likely want to do is append to it.

To append to $PATH, add a file .profile to the root of your project (directory from which you're running cf push). In that file, put one line export PATH=$PATH:<new loc> where <new loc> is the path you want to append to the $PATH env variable.

The .profile file is sourced before your application starts so you can use this to dynamically set environment variables or apply configuration before your application starts up.

The only caveat is that this happens before your application starts so it blocks the starting of your application. As such, you should avoid running expensive/time-consuming processes here. Otherwise, you will delay the start of your application, or possibly even cause app failures if you exceed the startup timeout (cf push -t).