Re: [RFC v2][PATCH 2/3] build-rep: Add helper class

[Alexander Smirnov <asmirnov@ilbers.de>]

On 01/12/2018 03:32 PM, Henning Schild wrote:
> Am Thu, 11 Jan 2018 14:19:38 +0300
> schrieb Alexander Smirnov <asmirnov@ilbers.de>:
> 
>> Add class that helps to implement build reproducibility. It implements
>> anonymous function that will get all the Debian dependencies that are
>> needed for current Isar tree.
>>
>> Until build reproducibility will be fully implemented, it's disabled
>> by default. To enable it just set ISAR_BUILD_REP to "1" in local.conf.
>>
>> Signed-off-by: Alexander Smirnov <asmirnov@ilbers.de>
>> ---
>>   meta-isar/conf/local.conf.sample                 |  6 +++++
>>   meta-isar/recipes-app/hello/hello.bb             |  2 ++
>>   meta/classes/build-rep.bbclass                   | 32
>> ++++++++++++++++++++++++
>> meta/classes/dpkg-base.bbclass                   |  2 ++
>> meta/classes/image.bbclass                       |  2 ++
>> meta/recipes-devtools/buildchroot/buildchroot.bb |  2 ++ 6 files
>> changed, 46 insertions(+) create mode 100644
>> meta/classes/build-rep.bbclass
>>
>> diff --git a/meta-isar/conf/local.conf.sample
>> b/meta-isar/conf/local.conf.sample index 660958f..45b8995 100644
>> --- a/meta-isar/conf/local.conf.sample
>> +++ b/meta-isar/conf/local.conf.sample
>> @@ -162,3 +162,9 @@ BB_NUMBER_THREADS = "4"
>>   #
>>   # Number of attempts to try to get reprepro lock for access to apt
>> cache REPREPRO_LOCK_ATTEMPTS = "16"
>> +
>> +# Isar build reproducibility feature creates local repository which
>> contains +# copies for all the upstream Debian packages that could be
>> used to build +# your Isar tree. So fetching them once will guarantee
>> that all the next Isar +# builds will be identically.
>> +ISAR_BUILD_REP ?= "0"
>> diff --git a/meta-isar/recipes-app/hello/hello.bb
>> b/meta-isar/recipes-app/hello/hello.bb index 44b8bc3..fafda2e 100644
>> --- a/meta-isar/recipes-app/hello/hello.bb
>> +++ b/meta-isar/recipes-app/hello/hello.bb
>> @@ -16,3 +16,5 @@ SRCREV = "ad7065ecc4840cc436bfcdac427386dbba4ea719"
>>   SRC_DIR = "git"
>>   
>>   inherit dpkg
>> +
>> +DEBIAN_DEPENDS = "debhelper (>= 9), autotools-dev"
> 
> If i understand it correctly, this approach is an absolute NoGo.
> 
> DEBIAN_DEPENDS as it is used today are runtime deps of pre-built
> packages. Here you include build-deps of a package that Isar needs to
> build. And you do so by introducing a copy of a string that is already
> included in the sources /debian/-folder. In fact you would have to
> put build and runtime deps into that one variable. And what about
> packages where the content depends on DISTRO_ARCH and friends?
> 
> I think we first need a working solution of two "inherit dpkg" packages
> actually depending on each-other. After that we will need a real build
> of the Image to fill the cache. That is the only reliable way to make
> sure that the repo will contain the runtime and the build deps of all
> packages. More "sed"-guesswork is not going to do that trick and is
> only getting us 95% of what we need. And maintaining copies of stuff
> that is in /debian/ should not be considered.

Let's look at this realistically:

1. The upstream Debian should be fetched via single operation. If you 
want to populate the cache during image build - you can't guarantee that 
all the packages were built in the same environment. As Christoph wrote, 
at any time the upstream apt could be updated. So the buildchroot and 
image filesystems should be generated using local static apt, otherwise 
it makes no sense to claim reproducibility.

2. Regarding 'debian/control' duplications. According to the idea, that 
'base-apt' should be generated first of all, in bitbake terms it means that:

  *.bb:do_build() should depends on base-apt:do_build().

On the other hand, base-apt:do_build() should already know the full list 
of all deps for *.bb. So for now I see two ways how to implement this:

  - Duplicate 'debian/control' in recipe and share this variable with 
base-apt (like it's done in this series).

  - Manually parse 'debian/control'. But in this case base-apt should 
depend on *.bb:do_unpack. Due to bitbake is 'statically configured' 
tool, base-apt should know the list of all the recipes, what is also 
impossible. In previous series I've tried to implement this by defining 
a list of images in some global variable.

2. Question how to get the list of build and runtime dependencies is 
still open, I've already asked about this in previous mail. So, the goal 
is to have the full list of packages that should be fetched. 
'debian/control' contains very specific format, so I can't feed this 
line to multistrap/apt-get as it is. I see the following solutions:
  - Implement custom tool to do this (apt/dpkg uses standard perl libs 
which contains all this stuff).
  - Manually parse 'debian/control'
  - Drop the requirement about single upstream fetch.

Alex

> 
> Henning
> 
>> diff --git a/meta/classes/build-rep.bbclass
>> b/meta/classes/build-rep.bbclass new file mode 100644
>> index 0000000..ede5a93
>> --- /dev/null
>> +++ b/meta/classes/build-rep.bbclass
>> @@ -0,0 +1,32 @@
>> +# This software is a part of ISAR.
>> +# Copyright (C) 2017 Siemens AG
>> +
>> +python __anonymous() {
>> +    rep = d.getVar('ISAR_BUILD_REP', True) or "0"
>> +    if rep == "0":
>> +        return
>> +
>> +    depsdir = d.getVar('BASE_APT_DIR', True)
>> +    if depsdir is None:
>> +        return
>> +
>> +    depsdir += '/deps/'
>> +
>> +    pn = d.getVar('PN', True)
>> +
>> +    if not os.path.exists(depsdir):
>> +        os.makedirs(depsdir, exist_ok=True)
>> +
>> +    if d.getVar('DEBIAN_DEPENDS', True):
>> +        with open(depsdir + '/' +  pn + '.depends', 'w') as the_file:
>> +            the_file.write(d.getVar('DEBIAN_DEPENDS', True))
>> +            the_file.close
>> +    elif d.getVar('BUILDCHROOT_PREINSTALL', True):
>> +        with open(depsdir + '/' +  pn + '.preinst', 'w') as the_file:
>> +            the_file.write(d.getVar('BUILDCHROOT_PREINSTALL', True))
>> +            the_file.close
>> +    elif d.getVar('IMAGE_PREINSTALL', True):
>> +        with open(depsdir + '/' +  pn + '.preinst', 'w') as the_file:
>> +            the_file.write(d.getVar('IMAGE_PREINSTALL', True))
>> +            the_file.close
>> +}
>> diff --git a/meta/classes/dpkg-base.bbclass
>> b/meta/classes/dpkg-base.bbclass index 4d220da..bf66e78 100644
>> --- a/meta/classes/dpkg-base.bbclass
>> +++ b/meta/classes/dpkg-base.bbclass
>> @@ -3,6 +3,8 @@
>>   
>>   DEBIAN_DEPENDS ?= ""
>>   
>> +inherit build-rep
>> +
>>   # Add dependency from buildchroot creation
>>   do_build[depends] = "buildchroot:do_build"
>>   
>> diff --git a/meta/classes/image.bbclass b/meta/classes/image.bbclass
>> index e2cb01b..67f5af8 100644
>> --- a/meta/classes/image.bbclass
>> +++ b/meta/classes/image.bbclass
>> @@ -5,6 +5,8 @@ IMAGE_INSTALL ?= ""
>>   IMAGE_TYPE    ?= "ext4-img"
>>   IMAGE_ROOTFS   = "${WORKDIR}/rootfs"
>>   
>> +inherit build-rep
>> +
>>   def get_image_name(d, name_link):
>>       S = d.getVar("IMAGE_ROOTFS", True)
>>       path_link = os.path.join(S, name_link)
>> diff --git a/meta/recipes-devtools/buildchroot/buildchroot.bb
>> b/meta/recipes-devtools/buildchroot/buildchroot.bb index
>> 51f9d5d..da18231 100644 ---
>> a/meta/recipes-devtools/buildchroot/buildchroot.bb +++
>> b/meta/recipes-devtools/buildchroot/buildchroot.bb @@ -16,6 +16,8 @@
>> SRC_URI = "file://multistrap.conf.in \ file://build.sh"
>>   PV = "1.0"
>>   
>> +inherit build-rep
>> +
>>   BUILDCHROOT_PREINSTALL ?= "gcc \
>>                              make \
>>                              build-essential \
> 

-- 
With best regards,
Alexander Smirnov

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