Overriding the configuration with environment vars

Document updated on Jul 10, 2020

When KrakenD runs, all the behavior is loaded from the configuration file. For each configuration value that isn’t nested (meaning first-level properties of the configuration), you can override its value with an environment variable.

All configuration environment variables must have the prefix KRAKEND_ and declared in uppercase. The variable name after the prefix must match the property in the configuration value.

For instance, take the following krakend.json configuration as an example:

{
    "version": 2,
    "timeout": "3s",
    "name": "Example gateway."
}

Now run krakend with the following command:

$KRAKEND_NAME="Build ABC0123" KRAKEND_TIMEOUT="500ms" krakend run -c krakend.json

The resulting configuration will be:

{
    "version": 2,
    "timeout": "500ms",
    "name": "Build ABC0123"
}

NOTE: The configuration file is not changed. The values above are a representation of the final mapped values.