Load .env file in Makefile

Question

Is there a simple way to automatically load a file containing local configurations into a Makefile?

I have a file, .env, containing key=value pairs on each line:

var1=val1
var2=val2

Currently I am importing each variable into my Makefile manually like this:

  var1=$$(grep '^var1=' .env | cut -d= -f2-)

This feels clumsy and prone to bugs when adding more variables.

I have also tried adding an extra target to the Makefile to read each line of .env and pass it to export, but values exported in one target are not available to others.

I expect there is a built in feature for doing this in make, but I have not been able to find documentation for it.

Answer 1

Assuming your include file is comprised entirely of valid make assignments then the include directive is likely what you want here.

The include directive tells make to suspend reading the current makefile and read one or more other makefiles before continuing. The directive is a line in the makefile that looks like this:

include filenames…

filenames can contain shell file name patterns.