OS and ARCH

[runeimp]

It would be awesome if I could get variables that define OS_NAME=Windows, OS_VERSION_MAJOR=10, and ARCH=x86_64 on Windows 10 64-bit when launching external apps and making builds. Or to have just load Justfile.win10-x86_64 over Justfile.win10 over Justfile.win over Justfile in such a situation. This sort of feature is the main thing I've been missing in any build/task/automation tool. I could set environment variables for all of this. But that is not ideal when the OS changes or files are copied to another system by someone else that is 32-bit vs 64-bit, etc. This is the main reason I need #262 is for managing differences between os and arch versions in my Justfile. A great start would be those types of vars based on what just was compiled for. Maybe JUST_OS=Windows and JUST_ARCH=x86_64 being available while running the Justfile would be enough.

[TeddyDD]

On serious OS you can get this info using cli tools :P

ARCH=`uname -m`
OS_NAME=`uname -o`

Seriously - check if there is any command like this on Windows.
Personally I don't think that idea of introducing magic variables is good.

[runeimp]

Just needs to be run within a Cygwin/MinGW/MSYS based terminal. So they all have uname support. But what is returned is not consistent for uname -so. Luckily they all return x86_64 for uname -m though on my test computers for Windows and Linux. Here is the output:

POSIX Layer	uname -s	uname -o	uname -m
Cygwin	CYGWIN_NT-10.0	Cygwin	x86_64
Git Bash	MINGW64_NT-10.0	Msys	x86_64
macOS	Darwin	N/A	x86_64
MinGW32	MINGW32_NT-10.0	Msys	x86_64
MinGW64	MINGW64_NT-10.0	Msys	x86_64
MSYS2	MSYS_NT-10.0	Msys	x86_64
Raspian	Linux	GNU/Linux	armv6l
Ubuntu	Linux	GNU/Linux	x86_64

Note that macOS does not have a -o switch for uname. Also the arch/uname -m for Raspian should be armv6l in almost all cases.

So, little consistency for uname -s and some consistency for uname -o on Windows. And in the case of just all I need is to know is that it is Windows. I can write a script to handle this but it would just be so much better if just could put JUST_OS=Windows in the environment being executed. And some conditional logic support built in would be awesome. Then I could drop make entirely.

[casey]

I think this would be a great feature, and I would be happy to add it to just.

Detecting OS (MacOS/Linux/Windows/BSD, etc), arch (x86, x64, ARM, etc), and variants (Cygwin on windows, e.g.) reliably is a lot of work however, and there doesn't seem to be a crate out there that does this. I found os_info and os_type, but they don't do windows, and they rely on lsb_release being installed. (I have an nix box, and lsb_release isn't installed by default.)

Given all that, I think I'd like to wait for a more robust crate which does this before adding it.

[runeimp]

I appreciate the work it takes to maintain things. Thanks for considering the features. Hopefully that crate will become a thing in the near future. :-)

[runeimp]

For now I've written a Bash script that calls another Bash script to collect and process all that data and populates the environment with those variables and launches a subshell with that environment. I then run just and everything else from within that subshell. It works and was fun to write but it would be great not to need that solution. Just sayin'. 😄

[casey]

Added the functions os(), arch(), and os_family(). I wrote a tiny crate to extract this info from rust's conditional compilation flags: https://github.com/casey/target hopefully this is good enough.

No OS_VERSION_MAJOR, unfortunately, since rustc doesn't provide this.

[runeimp]

Thank you Casey! But unfortunately it's not working on at least the Mac and Windows build. 😞

$ cat Justfile

sys-info:
	@echo "os_family: {{os_family()}}"
	@echo "os: {{os()}}"
	@echo "arch: {{arch()}}"

$ ./macOS/just --version
just v0.3.4
$ ./macOS/just
error: Unknown start of token:
  |
4 |     @echo "os_family: {{os_family()}}"
  |                                  ^

Maybe I'm doing something wrong? I tried adding a period at the end like in your example in the readme and no change other than the addition to the period in the error output. Same error using the same Justfile on Windows 10 Pro 64-bit in Cygwin/MinGW32/MinGW64/MSYS2 all version 2.9.0.

[casey]

Ah, sorry, I need to cut a release with the new features. Just a sec.

[casey]

I just pushed 0.3.5, which has the system-info functions. The windows binaries build on Appveyor. They'll appear here once they're done building: https://github.com/casey/just/releases/tag/v0.3.5

[runeimp]

LOL, thanks for jumping on that Casey. 😉