Re: [PATCH 16/16] recipes-app/hello-bin: add example on how to use dpkg-bin

[Claudius Heine <claudius.heine.ext@siemens.com>]

On 08/02/2017 08:33 AM, [ext] Jan Kiszka wrote:
> On 2017-08-01 12:17, [ext] Henning Schild wrote:
>> Signed-off-by: Henning Schild <henning.schild@siemens.com>
>> ---
>>   meta-isar/recipes-app/hello-bin/files/README     |  1 +
>>   meta-isar/recipes-app/hello-bin/files/postinst   | 14 +++++++++++++
>>   meta-isar/recipes-app/hello-bin/hello-bin_0.1.bb | 26 ++++++++++++++++++++++++
>>   3 files changed, 41 insertions(+)
>>   create mode 100644 meta-isar/recipes-app/hello-bin/files/README
>>   create mode 100644 meta-isar/recipes-app/hello-bin/files/postinst
>>   create mode 100644 meta-isar/recipes-app/hello-bin/hello-bin_0.1.bb
>>
>> diff --git a/meta-isar/recipes-app/hello-bin/files/README b/meta-isar/recipes-app/hello-bin/files/README
>> new file mode 100644
>> index 0000000..6e2ce0f
>> --- /dev/null
>> +++ b/meta-isar/recipes-app/hello-bin/files/README
>> @@ -0,0 +1 @@
>> +This is an example file that we get from FILESDIR in recipe.
>> diff --git a/meta-isar/recipes-app/hello-bin/files/postinst b/meta-isar/recipes-app/hello-bin/files/postinst
>> new file mode 100644
>> index 0000000..2a9eab6
>> --- /dev/null
>> +++ b/meta-isar/recipes-app/hello-bin/files/postinst
>> @@ -0,0 +1,14 @@
>> +#!/bin/sh
>> +
>> +set -e
>> +
>> +if ! getent group hello >/dev/null; then
>> +	addgroup --quiet --system hello
>> +fi
>> +
>> +if ! getent passwd hello >/dev/null; then
>> +	adduser --system --ingroup hello --home /var/lib/hello hello \
>> +		--gecos "My hello user"
>> +fi
>> +
>> +chown -R hello:hello /var/lib/hello
> 
> Nice.
> 
>> diff --git a/meta-isar/recipes-app/hello-bin/hello-bin_0.1.bb b/meta-isar/recipes-app/hello-bin/hello-bin_0.1.bb
>> new file mode 100644
>> index 0000000..5ff12d3
>> --- /dev/null
>> +++ b/meta-isar/recipes-app/hello-bin/hello-bin_0.1.bb
>> @@ -0,0 +1,26 @@
>> +# Sample application using dpkg-bin, which turns a folder (${D}) of
>> +# files into a .deb
>> +#
>> +# This software is a part of ISAR.
>> +
>> +DESCRIPTION = "Sample bin application for ISAR"
>> +DEBIAN_MAINTAINER = "Your name here <you@domain.com>"
>> +
>> +inherit dpkg-bin
>> +
> 
> In contrast to OE/Yocto, we don't need to specify the files we want to
> install later on here via SRC_URI? I'm not sure right now that we do not
> lose some features when skipping this local fetching steps.

The fetch step is still there, but it doesn't do anything because 
SRC_URI is empty.

> 
>> +	install -v -d ${D}/usr/local/bin/
>> +	install -v -m 755 ${WORKDIR}/${PN} ${D}/usr/local/bin/${PN}
>> +
>> +	bbnote "Now copy ${FILESDIR}/README to overlay"
> 
> In OE, FILESDIR is deprecated and has been removed already. Probably not
> a good idea to introduce it here. FILESPATH is now the standard.

The README should be put into the SRC_URI and then fetched via the 
do_fetch step from the FILESDIR/FILESPATH into the WORKDIR.

> However:
> 
> "Usage of FILESPATH is discouraged, since it can make recipes harder
> to bbappend. Instead FILESEXTRAPATHS should be used to extend the path."
> 
>> +	install -v -d ${D}/usr/local/doc/
>> +	install -v -m 644 ${FILESDIR}/README ${D}/usr/local/doc/README-${P}
>> +
>> +	bbnote "Now for a debian hook, see dpkg-deb"
>> +	install -v -m 755 ${FILESDIR}/postinst ${D}/DEBIAN/postinst
> 
> Maybe this could be automated - to avoid boilerplate logic - by defining
> some DEBIAN_POSTINST var. dpkg-bin could evaluate that var and install
> everything mentioned in it without requiring the user to do this here
> manually.

Here is another idea, simpler but then you can put the additional steps 
easily into the recipe. Provide a variable to 
"${D}/DEBIAN/[postinst,...]" so you can simply do something like this:

cat >${DEBIAN_POSTINST_FILE} <<EOF
#!/bin/sh

set -e

if ! getent group hello >/dev/null; then
     addgroup --quiet --system hello
fi

if ! getent passwd hello >/dev/null; then
     adduser --system --ingroup hello --home /var/lib/hello hello \
             --gecos "My hello user"
fi

chown -R hello:hello /var/lib/hello
EOF

in the do_install step. This way you would have every step to setup the 
package and rootfs neatly in a single file and if this becomes to long, 
just add a file to the SRC_URI, fetch it to the workdir and copy/install 
it to this path in the do_install step.

Cheers,
Claudius