Recipes that update a shared file

Recipes that update a shared file

[seth bollinger]

Hello All,

What's the best practice for recipes that need to update a shared file 
provided by a different recipe?  For example let's say that the 
widget-watcher recipe creates /etc/ww.conf and the widget1, and widget2 
recipes need to append a line to the config.  I've searched through the 
recipes a bit and can't find a good example.  The closest that I've seen 
is pkg_postinst().  Is that the best method?

Thanks!

Seth

Re: Recipes that update a shared file

[Paul Eggleton]

Hi Seth,

On Wednesday 09 October 2013 19:16:15 seth bollinger wrote:
> What's the best practice for recipes that need to update a shared file
> provided by a different recipe?  For example let's say that the
> widget-watcher recipe creates /etc/ww.conf and the widget1, and widget2
> recipes need to append a line to the config.  I've searched through the
> recipes a bit and can't find a good example.  The closest that I've seen
> is pkg_postinst().  Is that the best method?

That's really the recommended way to do it. If the software being configured 
supports it, another way is to set it up to read all configuration files from a 
directory and then you can simply install a new file into that directory from 
the other recipe (e.g. Apache is usually configured to read all configuration 
files in /etc/httpd/conf.d or similar).

Cheers,
Paul

-- 

Paul Eggleton
Intel Open Source Technology Centre

Re: Recipes that update a shared file

[Seth Bollinger]

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On Thu, Oct 10, 2013 at 4:31 AM, Paul Eggleton <
paul.eggleton@linux.intel.com> wrote:

> That's really the recommended way to do it. If the software being
> configured
> supports it, another way is to set it up to read all configuration files
> from a
> directory and then you can simply install a new file into that directory
> from
> the other recipe (e.g. Apache is usually configured to read all
> configuration
> files in /etc/httpd/conf.d or similar).
>

Yes, I would have liked to solve the problem that way, but unfortunately
the software doesn't support it, and we don't want to make changes
currently. :)

I'm having a lot of trouble getting pkg_postinst() to work.  From what I've
read, it should happen during rootfs generation, but I'm not see the file
in the rootfs.

I found an example in the xfce4-session_4.10.0.bb recipe.  It looks like
/etc/hosts is installed by netbase, so this is very similar to what my
recipe is doing.
# protect from frightening message that xfce might not work correctly
pkg_postinst_${PN} () {
    echo 127.0.0.1    ${MACHINE} >> /etc/hosts
}

I've tried this in my recipe, and the file that I expect to be present in
the rootfs is not there...not sure what I'm doing wrong.
pkg_postinst_${PN} () {
    echo test >> /etc/inittest2
}

Also, the documentation states that this mechanism can be used to do things
on first boot.  Do I need to add code to make sure that this doesn't happen
on first boot?

Thanks!

Seth

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Re: Recipes that update a shared file

[Burton, Ross]

On 10 October 2013 15:36, Seth Bollinger <seth.boll@gmail.com> wrote:
> pkg_postinst_${PN} () {
>     echo 127.0.0.1    ${MACHINE} >> /etc/hosts
> }

Yeah, that's broken.

> I've tried this in my recipe, and the file that I expect to be present in
> the rootfs is not there...not sure what I'm doing wrong.
> pkg_postinst_${PN} () {
>     echo test >> /etc/inittest2
> }

You need to use $D so that you're not attempting to write to the *host's* /etc:

echo test >> $D/etc/inittest2

In a postinst $D may be set, and if it is then the postinst is being
ran on the host at rootfs time, and points to where the rootfs is
being constructed.

Ross

Re: Recipes that update a shared file

[Seth Bollinger]

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On Thu, Oct 10, 2013 at 9:40 AM, Burton, Ross <ross.burton@intel.com> wrote:

> You need to use $D so that you're not attempting to write to the *host's*
> /etc:
>
> echo test >> $D/etc/inittest2
>
> In a postinst $D may be set, and if it is then the postinst is being
> ran on the host at rootfs time, and points to where the rootfs is
> being constructed.
>

Ok, I changed to as follows:
pkg_postinst_${PN} () {
    echo "testtest" >> ${D}/etc/inittest
}

After that I do a find and the file is only populated in the recipe's image
directory, not the rootfs.

$ find . -iname inittest
./tmp/work/armv5te-dbl-linux-gnueabi/widget/1.0-r0/image/etc/inittest

Thanks!

Seth

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Re: Recipes that update a shared file

[Burton, Ross]

On 10 October 2013 16:02, Seth Bollinger <seth.boll@gmail.com> wrote:
>> You need to use $D so that you're not attempting to write to the *host's*
>> /etc:
>>
>> echo test >> $D/etc/inittest2
>>
>> In a postinst $D may be set, and if it is then the postinst is being
>> ran on the host at rootfs time, and points to where the rootfs is
>> being constructed.
>
>
> Ok, I changed to as follows:
> pkg_postinst_${PN} () {
>     echo "testtest" >> ${D}/etc/inittest
> }
>
> After that I do a find and the file is only populated in the recipe's image
> directory, not the rootfs.

Use $D instead of ${D}. ${D} will get expanded when the package is
created but you want to use the environment variable $D.

Ross

Re: Recipes that update a shared file

[Seth Bollinger]

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On Thu, Oct 10, 2013 at 10:09 AM, Burton, Ross <ross.burton@intel.com>wrote:

> Use $D instead of ${D}. ${D} will get expanded when the package is
> created but you want to use the environment variable $D.
>

Looks like that worked!  I apologize for missing the curly braces in your
previous response.

Thanks very much!

Seth

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