Lots of ways! So this is one of those things that's subtly quite interesting -- Make will both take
all variables from the environment, and make them Make variables. So this command:
$ USER=my_name make psql
The above example is the creation of a temporary ENV variable (assuming your shell supports this feature, it's equivalent to doing an export but only for that line), and the USER variable (accessed by using $(USER) or ${USER} in your makefile somewhere) will be automatically populated.
That is distinct from the following:
$ make psql USER=my_name
What you've done there is actually make-specific, you're giving make a Make variable, so Make will know about $(USER)/${USER}, and it will
also show up, because Make exposes it's variables to shells (each line is it's own shell) that is run[0]. So this Makefile:
.PHONY: my-tgt
my-tgt:
echo -e "double dollar to print a bash var => $$MYVAR"
Produces the
same thing -- $$MYVAR is actually a way to use a shell variable (the $ has to be escaped), but you get the same result putting USER= before and after:
$ MYVAR=from-the-shell make my-tgt
double dollar to print a bash var => [from-the-shell]
$ make my-tgt MYVAR=from-make
double dollar to print a bash var => [from-make]
All that said, if you don't need to ever change the name then just make the target `psql-` or `psql_username`, problem solved! For example, I use kubie on my kubernetes cluster, and I have explicitly named clusters, so when I want to enter a kubie context (just so I can avoid some typing), I run `make -kubie` and I'm off -- I didn't feel the need to do `make kubie CLUSTER=` though I easily could have. Here's what it actually looks like:
mycluster-kubie:
CLUSTER=mycluster $(KUBIE) ctx -f secrets/ansible/the.dns.name.of.my.server/var/lib/k0s/pki/admin.conf
I don't strictly need that CLUSTER=mycluster there, but if the command cared, then it could be easily "hard coded".
> Bash scripts almost could be illegal :- ) I'm thinking about writing scripts in Deno in the future, instead
Bash is super powerful, and some people are good at it, but it just hasn't stuck enough for me to be comfortable. Plus, it still feels like another language to be wrangled while Make's only purpose is to do the things (whatever that thing is) that build your software.
[EDIT] figured I might share some more nice pieces of software that I use and love (also so you don't think I'm just willy nilly checking in secrets to my repository):
- direnv[1] for managing local ENV settings in a given folder (like your project folder)
- git-crypt[2] for simple encryption of secrets in a git repository, with gpg support
- entr[3] it re-runs a given command when files change, really good for reducing feedback loops when working with tooling that doesn't have --watch/fsnotify functionality
[0]: https://www.gnu.org/software/make/manual/html_node/Environme...
[1]: https://direnv.net/docs/hook.html
[2]: https://www.agwa.name/projects/git-crypt/
[3]: https://eradman.com/entrproject/