How can you specify property files in a MuleSoft application using environment variables?

• A. Use only a single, fixed properties file
• B. Use environment variables to set values at startup, but cannot use dynamic location for the placeholder
• C. Use hard-coded values in code
• D. Use environment variables to set values at startup and allow a dynamic location for the property placeholder

Answer: (D)

External configuration should be externalized so the app can run in different environments without code changes. The best approach uses environment variables to drive startup values and to locate the properties file itself, letting the property placeholder load the file from a path specified at startup. By configuring the property loading to use a path from an environment variable, you can point to different property files (dev, test, prod) simply by changing the environment, not the code. For example, set an environment variable with the full path to the needed properties file and configure the configuration to load from that path using ${env.YOUR_CONFIG_PATH}. This way, values can be overridden at startup and the location of the property file remains flexible and environment-specific.

Options that rely on a fixed file, hard-coded values, or claim you can’t use a dynamic location don’t meet the need for environment-driven startup configuration and flexible file location.