CODEWITHSUNDEEP
makefile
user3810188
user3810188

Reputation: 311

set env variable from a Makefile command and use in another Make command

I'm trying to connect to some API using python script. that API requires an env variable to be available. to get that env I have another command. I combined both commands in one single Makefile command

# Current Makefile
cmd_1:
    $(eval MY_ENV := $somevalue)
    MY_ENV=$(MY_ENV) python myscript.py cmd_1

cmd_2:
    $(eval MY_ENV := $somevalue)
    MY_ENV=$(MY_ENV) python myscript.py cmd_2

Now as you can see some part(1st line) is same in both above commands. I want to get rid of that duplicacy. I want something like the below so that I can reuse it even if in future I have more than 2 mgmt commands.

# Desired Makefile (Using DRY)?
get_env:
        $(eval MY_ENV := $somevalue)
    
cmd_1:
        MY_ENV=$(MY_ENV) python myscript.py cmd_1

cmd_2:
        MY_ENV=$(MY_ENV) python myscript.py cmd_2

I tried to wrap these two commands and create another Make command, like below. but no luck.

mycmd:
    @$(MAKE) get_env
    @$(MAKE) cmd_1

So I'm wondering if there is a better way to do this?

Upvotes: 1

Views: 942

Answers (1)

Edouard Thiel
Edouard Thiel

Reputation: 6218

Let me suggest this:

get_env ::
    $(eval MY_ENV := $somevalue)

cmd_1 cmd_2 :: get_env
    MY_ENV=$(MY_ENV) python myscript.py $@

Some explanations:

  • :: makes the targets phony, so you won't have to add a line .PHONY: get_env cmd_1 cmd_2 in the Makefile;
  • $@ is the current target

The key point is to add a dependency to get_env in the rule, so that MY_ENV is kept.

For a simpler trial, run make bar or make baz with this toy Makefile:

foo ::
    $(eval qux := `pwd`)

bar baz :: foo
    @echo "qux = $(qux) and target = $@"

Upvotes: 2

Related Questions