feat(cassandra): Env vars

[michaelkro]

Updates the Cassandra recipes to be able to accept required user input as environment variables. This is necessary so that we can add Cassandra as a target to ansible-install.

Notes

• Tested on debian10 and AL2 during development

Testing
Happy path

1. Log in to machine that is running Cassandra
2. Clone this repo and switch to this PR branch
3. Run the installation with --localRecipes /path/to/recipes
4. Use the standard test credentials when prompted

Hostname

1. You can test the hostname input behavior by providing 0.0.0.0 as an invalid value and running with --localRecipes

Custom port

1. Search for JMX_PORT in cassandra-env.sh and change it from 7199. Find the script on your host at:

   // Debian
   /etc/cassandra
   
   // RHEL
   /etc/cassandra/conf
   

2. Restart Cassandra

   sudo service casssandra restart
   

3. Run the installation with --localRecipes and the CLI should prompt you for a port

Install in non-interactive mode with environment variables

1. Add the environment variables to your installation command as well as the -y flag

   ... sudo NEW_RELIC_CASSANDRA_USERNAME=<username> NEW_RELIC_CASSANDRA_PASSWORD=<password> NEW_RELIC_CASSANDRA_PORT=<port> NEW_RELIC_CASSANDRA_HOSTNAME=<hostname> ... /usr/local/bin newrelic install -n cassandra-open-source-integration --localRecipes /path/to/recipes -y
   

2. To test invalid inputs, add the --debug flag to see error output

Legacy environment variables

NR_CLI_DB_USERNAME
NR_CLI_DB_PASSWORD
NR_CLI_DB_HOSTNAME

1. You should be able to use the new and legacy environment variables interchangeably.