Configuration Files Recommended for Connecting

Configuration files are an important component of your workflow. They provide both security when sharing code and standardization when working across multiple environments (e.g. Stata and R). Standardization will help alleviate certain headaches when revisiting code that hadn't been used in many months or years. An example of standardization may be the selection of the most recent driver for connecting to the MariaDB server, or which account username and password to use when connecting. The latter example is particularly important as you should not be hardcoding usernames and passwords within your code!.

Local vs System

Configuration files are found at the system-level as well as locally in your home directory. Anything that is specific to your workflow, such as account details, should be kept in the local configuration file. More general details, such as the driver paths, are available within the system-level configuration file.

Finding Your Home Directory, on the Grid and on your Local Mac or PC

The following configuration files are meant to be stored within your home directory. This is because many programs will look for configuration files first throughout the system, and then will look within your home directory for any settings that are specific to you. It is therefore important for you to know where your home directory is. Please use the table below to identify where your home directory is.

System	Command
Research Grid	[within Terminal] echo ~
Local Mac	[within Terminal] echo ~
Local Windows	[within Command Prompt] echo %USERPROFILE% OR echo %HOMEDRIVE%%HOMEPATH%

Any Surprises About Home Directories?

Some tools, such as R, do not assign the home directory based on the system home directory. For instance, Windows users will find that R may set the home directory as C:\Users\USERNAME\Documents whereas the system home directory is C:\Users\USERNAME. Please note that RCS will refer to the home directory as the system home directory. Please contact us at research@hbs.edu for assistance.

.my.cnf

The .my.cnf is a local configuration file found within your home directory. This file is used to store connection details to the MariaDB server, such as account details and connection parameters.

Do I need this file?

Many programs will automatically search for this file to gather connection details to the MariaDB server, such as username, password and server address. As a result, our guides are geared towards use of .my.cnf. The programs which do not use this file are those using ODBC connections, such as Stata. If you will be using R, Python, or directly connecting via the mysql / mariadb client, then you should use this file.

I don't have this file (on the Grid). How do I create one?

You may request a template or create your own with the following details

[mysql]
      host=HOSTNAME
      port=3306
      ssl-ca=PATH_TO_SSL_CERT
      database=jharvard
      user=jharvard
      password=PASSWORD

Please note that you will substitute jharvard and PASSWORD with your MariaDB username and password. For the other parameters such as HOSTNAME, please contact us at research@hbs.edu.

Once your .my.cnf is ready, move it your home directory and adjust file privileges to ensure no one else can read the file. On the Grid or on a linux or Mac local machine, you may prevent others from reading the file via the command:

chmod 700 ~/.my.cnf

Window users will need to right-click on the file, select Properties, and then

1) under the General tab, toggle ON the Hidden attribute

2) under the Security tab, ensure only the following users or groups have access: System, Administrators, and you.

Can I use the same .my.cnf on the Grid and on my local machine?

There will be one parameter which is different based on whether you are working on the Grid or on your local machine. This parameter is ssl-ca which defines the path to your SSL CA certificate file. The path to the SSL CA certificate file will be different across machines as a result. Please contact us at research@hbs.edu for assistance.