Merge lp:~ltrager/flash-kernel/get_machine_deps into lp:flash-kernel

[Lee Trager]

Add --get-machine-required-packages to show the required packages needed to run.

In lp:~ltrager/curtin/lp1640519 I needed to modify curtin to install the required machine dependencies so flash-kernel successfully runs. There wasn't a straight forward way to do this so I ended up writing my own script which sources the flash-kernel functions and retrieves the 'Required-Packages' field. This adds a command line option to do just that.

[Scott Moser (smoser)]

So someone would use this by then doing something like:

if flash-kernel --supported; then
   pkgs=$(flash-kernel --get-machine-required-packages) || fail "failed getting required packages"
   apt-get install -qy $pkgs
fi

right ? I'm not sure that the 'check_supported' usage in your addition helps at all, because the user of this somehow has to determine the difference between failure due to "not supported" or other failure. So they end up having to do the above, right?

One thing i might suggest is just changing it to be more generic and allow getting of any field.

if [ "$1" = "--get-machine-field" ]; then
   get_machine_field "$machine" "$2"
   exit
fi

[Scott Moser (smoser)]

Lee, Thanks for doing this!

[lp:~ltrager/flash-kernel/get_machine_deps]

994. By Lee Trager on 2016-11-30

* Add generic --get-machine-field
* Remove check_supported, get_machien_field will return 0 if the machine isn't support

[Lee Trager (ltrager)]

Thanks for the review. I've made the argument more generic as you suggested. I also confirmed check_supported isn't needed, get_machine_field will exit 1 if its not found.

[Scott Moser (smoser)]

"I also confirmed check_supported isn't needed, get_machine_field will exit 1 if its not found."

Well, thats unfortunate.

What we want to have a program do is say : give me a list of packages that I shoudl install

and allow for that list to be "".

As I understand it right now, if the hardware should not install any, it will exit 1.

But then the caller cannot determine the differnce between failure for unexpected return
and "no packages to install".

Perhaps we then almost need a specific path for this.

Does that make sense ?

[lp:~ltrager/flash-kernel/get_machine_deps]

995. By Lee Trager on 2016-12-01

Always exit 0 when using --get-machine-field

[Lee Trager (ltrager)]

I've updated the MP so --get-machine-field always exit's 0. If the machine isn't supported or doesn't have the matching field nothing will be printed.

Unmerged revisions

995. By Lee Trager on 2016-12-01

Always exit 0 when using --get-machine-field

994. By Lee Trager on 2016-11-30

* Add generic --get-machine-field
* Remove check_supported, get_machien_field will return 0 if the machine isn't support

993. By Lee Trager on 2016-11-17

Add --get-machine-required-packages to show the required packages needed to run.

=== modified file 'functions'
--- functions	2016-08-06 02:00:32 +0000
+++ functions	2016-12-01 00:14:08 +0000
@@ -646,6 +646,11 @@
 	exit 1
 fi
 
+if [ "x$1" = "x--get-machine-field" ]; then
+	get_machine_field "$machine" $2 ||:
+	exit 0
+fi
+
 # $FK_KERNEL_HOOK_SCRIPT is set when main() is called from
 # /etc/kernel/* to be able to differentiate between being called
 # upon kernel installation or kernel removal