pro tip: use scriptlets instead of custom plugins

[Olivier Tilloy]

On Mon, Feb 20, 2017 at 5:55 PM, Kyle Fazzari
<kyle.fazzari at canonical.com> wrote:
> On Feb 20, 2017 6:23 AM, "Olivier Tilloy" <olivier.tilloy at canonical.com>
> wrote:
>
> On Fri, Feb 17, 2017 at 12:11 AM, Leo Arias <leo.arias at canonical.com> wrote:
>> Hello!
>>
>> This week I've been cleaning a few of my old snaps, using some of the
>> new features in more recent versions of snapcraft. At first I wasn't
>> convinced about scriptlets, but now I think they are great. Take a
>> look at this diff:
>>
>> 5 additions and 144 deletions
>>
>>
>> https://github.com/elopio/ipfs-snap/commit/06f32696c1b461b1068e803e71e22bad50fe52eb
>>
>> Here is more info:
>>
>> https://insights.ubuntu.com/2017/02/02/run-scripts-during-snapcraft-builds-with-scriptlets/
>
> Very useful, thanks for highlighting it Leo!
> I've been able to replace the custom plugin for the 0AD snap with
> scriptlets, and that simplifies the packaging quite a bit.
>
> One thing that bit me is that I was expecting the 'install' scriptlet
> to replace the `make install` step when using the make plugin, but it
> doesn't. It runs `make`, `make install`, and then the install
> scriptlet. Note that the documentation is reasonably clear about it,
> but it looks a bit counterintuitive to me.
>
>
> Note that the lifecycle doesn't have an 'install' step. The install actually
> happens in the 'build' step, which you can replace via the 'build'
> scriptlet. The three scriptlet surround the 'build' step:
>
> - 'prepare' runs before build
> - 'build' replaces plugin build (including install)
> - 'install' runs after build. This is useful e.g. for a Makefile with no
> installation targets, or copying over some config files after the plugin
> does its thing.
>
>
> One thing I haven't been able to figure out: is the
> parallel_build_count property exposed to scriptlets as a variable?
> That would be useful for custom build scripts that call make.
>
>
> I don't believe so, but I agree it would be useful.

I filed https://launchpad.net/bugs/1666271 to track the feature request.