Re: [PATCH] debootstrap: Add fallback apt cache support

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

Hi Alex,

On 2018-05-14 11:40, Alexander Smirnov wrote:
> 
> On 05/14/2018 12:27 PM, Claudius Heine wrote:
>> Hi Alex,
>>
>> so I guess that this patch replaces the 'isar-bootstrap: Increase 
>> cache room' one right?
>>
>> On 2018-05-11 17:35, Alexander Smirnov wrote:
>>> Add apt config file to switch caching mechanism from MMap to 
>>> array-based.
>>> This needed to provide possibility to build fresh Isar suites on old 
>>> hosts.
>>> For example, building Isar stretch on jessie host fails with the 
>>> following
>>> error:
>>>
>>>    Hit:1 http://security.debian.org stretch/updates InRelease
>>>    Ign:2 http://ftp.de.debian.org/debian stretch InRelease
>>>    Hit:3 http://ftp.de.debian.org/debian stretch-updates InRelease
>>>    Hit:4 http://ftp.de.debian.org/debian stretch Release
>>>    E: Dynamic MMap ran out of room. Please increase the size of 
>>> APT::Cache-Start. Current value: 25165824. (man 5 apt.conf)
>>>    qemu: uncaught target signal 11 (Segmentation fault) - core dumped
>>>    Segmentation fault
>>>
>>> Now Isar performs the following:
>>> 1. Checking if user attempts to build stretch on old kernels
>>> 2. Temporarly installing this apt config file.
>>> 3. Removing this file after image rootfs creation
>>>
>>> So this file will not go to target rootfs.
>>>
>>> Signed-off-by: Alexander Smirnov <asmirnov@ilbers.de>
>>> ---
>>>   meta-isar/recipes-core/images/isar-image-base.bb        |  2 ++
>>>   .../isar-bootstrap/files/isar-apt-fallback.conf         |  4 ++++
>>>   meta/recipes-core/isar-bootstrap/isar-bootstrap.bb      | 17 
>>> ++++++++++++++++-
>>>   3 files changed, 22 insertions(+), 1 deletion(-)
>>>   create mode 100644 
>>> meta/recipes-core/isar-bootstrap/files/isar-apt-fallback.conf
>>>
>>> diff --git a/meta-isar/recipes-core/images/isar-image-base.bb 
>>> b/meta-isar/recipes-core/images/isar-image-base.bb
>>> index 00e926a..d65b1f1 100644
>>> --- a/meta-isar/recipes-core/images/isar-image-base.bb
>>> +++ b/meta-isar/recipes-core/images/isar-image-base.bb
>>> @@ -53,4 +53,6 @@ do_rootfs() {
>>>       sudo rmdir ${IMAGE_ROOTFS}/isar-apt
>>>       sudo umount -l ${IMAGE_ROOTFS}/dev
>>>       sudo umount -l ${IMAGE_ROOTFS}/proc
>>> +    [ -e "${IMAGE_ROOTFS}/etc/apt/apt.conf.d/55isar-fallback.conf" ] 
>>> && \
>>> +        sudo rm 
>>> "${IMAGE_ROOTFS}/etc/apt/apt.conf.d/55isar-fallback.conf" || true
>>
>> Why not just 'sudo rm -f 
>> "${IMAGE_ROOTFS}/etc/apt/apt.conf.d/55isar-fallback.conf"' ?
>>
> 
> Matter of taste, I don't like to remove things that don't exist.

I guess it is a matter of taste. I do think '|| true' is ugly and 
testing the existence of the file before removing it redundant.

Cheers,
Claudius

> 
>>
>>>   }
>>> diff --git 
>>> a/meta/recipes-core/isar-bootstrap/files/isar-apt-fallback.conf 
>>> b/meta/recipes-core/isar-bootstrap/files/isar-apt-fallback.conf
>>> new file mode 100644
>>> index 0000000..12ddbea
>>> --- /dev/null
>>> +++ b/meta/recipes-core/isar-bootstrap/files/isar-apt-fallback.conf
>>> @@ -0,0 +1,4 @@
>>> +# Switch apt caching mechanism from mmap to array-based.
>>> +# This helps to build fresh Isar suites on old hosts.
>>> +
>>> +APT::Cache-Fallback "1";
>>> diff --git a/meta/recipes-core/isar-bootstrap/isar-bootstrap.bb 
>>> b/meta/recipes-core/isar-bootstrap/isar-bootstrap.bb
>>> index a38dd88..a3a3a2b 100644
>>> --- a/meta/recipes-core/isar-bootstrap/isar-bootstrap.bb
>>> +++ b/meta/recipes-core/isar-bootstrap/isar-bootstrap.bb
>>> @@ -10,7 +10,9 @@ Description = "Minimal debian root file system"
>>>   LICENSE = "gpl-2.0"
>>>   LIC_FILES_CHKSUM = 
>>> "file://${LAYERDIR_isar}/licenses/COPYING.GPLv2;md5=751419260aa954499f7abaabaa882bbe" 
>>>
>>>   FILESPATH_prepend := "${THISDIR}/files:"
>>> -SRC_URI = "file://isar-apt.conf"
>>> +SRC_URI = " \
>>> +    file://isar-apt.conf \
>>> +    file://isar-apt-fallback.conf"
>>>   PV = "1.0"
>>>   WORKDIR = "${TMPDIR}/work/${DISTRO}-${DISTRO_ARCH}/${PN}"
>>> @@ -165,6 +167,13 @@ do_bootstrap() {
>>>   }
>>>   addtask bootstrap before do_build after do_apt_config_prepare
>>> +def get_host_release():
>>> +    import platform
>>> +    rel = platform.release()
>>> +    return rel
>>> +
>>> +HOST_KERN_VER = "${@get_host_release().split('.')[0]}"
>> If you need this variable in just one place. It might be useful to 
>> just add it there.
>>
> 
> I've added the separate variable, because probably some additional 
> version specification could be needed later, like HOST_KERN_MAJOR etc., 
> in this case python inlining could be difficult for reading.
> 
> But for today I have only one case, so could drop it in v3.
> 
> Alex
> 
>>> +
>>>   do_apt_config_install[stamp-extra-info] = "${DISTRO}-${DISTRO_ARCH}"
>>>   do_apt_config_install() {
>>>       sudo mkdir -p "${ROOTFSDIR}/etc/apt/preferences.d"
>>> @@ -177,6 +186,12 @@ do_apt_config_install() {
>>>       sudo mkdir -p "${ROOTFSDIR}/etc/apt/apt.conf.d"
>>>       sudo install -v -m644 "${WORKDIR}/isar-apt.conf" \
>>>                             
>>> "${ROOTFSDIR}/etc/apt/apt.conf.d/50isar.conf"
>>> +
>>> +    if [ "${@get_distro_suite(d)}" = "stretch" ] && [ 
>>> "${HOST_KERN_VER}" -lt "4" ]; then
>>
>> Like this:
>>
>>      if [ "${@get_distro_suite(d)}" = "stretch" ] && [ 
>> "${@get_host_release().split('.')[0]}" -lt "4" ]; then
>>
>> Or is it useful to overwrite this variable somewhere?
>>
>>> +        sudo install -v -m644 "${WORKDIR}/isar-apt-fallback.conf" \
>>> + "${ROOTFSDIR}/etc/apt/apt.conf.d/55isar-fallback.conf"
>>> +    fi
>>> +
>>>   }
>>>   addtask apt_config_install before do_build after do_bootstrap
>>
>> Apart from those small nitpicks it looks good,
>> Claudius
>>

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