[yocto] How and where does yocto find lighttpd-module-fastcgi?

[Andre McCurdy]

On Thu, Mar 8, 2018 at 1:52 PM, Wayne Witzke <wwitzke at asgrp.com> wrote:
>
> However, now I am attempting to determine if mod_openssl is installed on my
> server, and using "CORE_EXTRA_IMAGES_INSTALL += 'lighttpd-module-openssl'"
> to simply add it does NOT magically work like it did with
> lighttpd-module-fastcgi. My original guess was that adding
> "CORE_EXTRA_IMAGES_INSTALL += 'lighttpd-module-fastcgi'" caused a
> configuration option to be matched in the lighttpd.bb file so that the
> appropriate build option was used when building lighttpd.

No, that's not how it works. A very key point to understand with OE is
that options associated with one recipe can never affect the build of
another recipe (in this case, the image recipe can't affect the build
of the lighttpd recipe).

If adding lighttpd-module-fastcgi to your image worked, it's because
the lighttpd recipe was already creating that package.

> However, fastcgi
> doesn't actually show up in that file at all, and openssl does, so that
> clearly isn't the option . . . furthermore, mod_fastcgi doesn't appear in
> *any* of the layers I'm using to build, except in the lighttpd.conf portion
> of the recipe-extended/lighttpd directory structure.

If lighttpd doesn't have a configure option to control building of the
fastcgi module, then there won't be a PACKAGECONFIG option for it in
the recipe - it will just always be built.

(Even if lighttpd does have a configure option for the fastcgi module,
there's no guarantee that the recipe will allow it to be controlled -
it's common for PACKAGECONFIG options in recipes to only reflect the
configure options which people care about the most).

> So, my question is, how does bitbake know what to do when I add
> lighttpd-module-fastcgi,

The build for lighttpd isn't affected by whether or not you add
lighttpd-module-fastcgi to your image.

ie running "bitbake lighttpd", should always result in a package for
lighttpd-module-fastcgi being placed in tmp/deploy/ipk/i586/ (or
whatever your packaging format / architecture combination is). It
doesn't matter what image you may choose to build later, or what
packages you choose to include in it.

> and where in the world does it find the source for
> mod_fastcgi?

The source which gets compiled into lighttpd-module-fastcgi must be
coming from lighttpd.

> Thank you in advance for your help :)
>
> Wayne
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