fix: add optional dynamic linking to boost::log

[aduskett]

When building boost as a dynamic library, hundreds of undefined reference to boost::log` errors occur during linking. As the default behavior currently is to link against boost::log statically, it is best to add a new option that explicitly enables dynamic linking to boost::log. This new option is called MENDER_USE_DYNAMIC_BOOST_LOG.

Changelog: None
Ticket: None

[mender-test-bot]

@aduskett, Let me know if you want to start the integration pipeline by mentioning me and the command "start pipeline".

---

my commands and options

You can trigger a pipeline on multiple prs with:

• mentioning me and start pipeline --pr mender/127 --pr mender-connect/255

You can start a fast pipeline, disabling full integration tests with:

• mentioning me and start pipeline --fast

You can trigger GitHub->GitLab branch sync with:

• mentioning me and sync

You can cherry pick to a given branch or branches with:

• mentioning me and:

 cherry-pick to:
 * 1.0.x
 * 2.0.x

[aduskett]

@mender-test-bot start pipeline --pr mender/127 --pr mender-connect/255

[mender-test-bot]

Hello 😺 I created a pipeline for you here: Pipeline-1445846749

Build Configuration Matrix

Key	Value
AUDITLOGS_REV	master
BUILD_BEAGLEBONEBLACK	true
BUILD_CLIENT	true
BUILD_QEMUX86_64_BIOS_GRUB	true
BUILD_QEMUX86_64_BIOS_GRUB_GPT	true
BUILD_QEMUX86_64_UEFI_GRUB	true
BUILD_VEXPRESS_QEMU	true
BUILD_VEXPRESS_QEMU_FLASH	true
BUILD_VEXPRESS_QEMU_UBOOT_UEFI_GRUB	true
CREATE_ARTIFACT_WORKER_REV	master
DEPLOYMENTS_ENTERPRISE_REV	master
DEPLOYMENTS_REV	master
DEVICEAUTH_ENTERPRISE_REV	master
DEVICEAUTH_REV	master
DEVICECONFIG_REV	master
DEVICECONNECT_REV	master
DEVICEMONITOR_REV	master
GENERATE_DELTA_WORKER_REV	master
GUI_REV	master
INTEGRATION_REV	master
INVENTORY_ENTERPRISE_REV	master
INVENTORY_REV	master
IOT_MANAGER_REV	master
MENDER_ARTIFACT_REV	master
MENDER_BINARY_DELTA_REV	master
MENDER_CLI_REV	master
MENDER_CONFIGURE_MODULE_REV	master
MENDER_CONNECT_REV	pull/255/head
MENDER_CONVERT_REV	master
MENDER_GATEWAY_REV	master
MENDER_REV	pull/1663/head
MENDER_SETUP_REV	master
MENDER_SNAPSHOT_REV	master
MONITOR_CLIENT_REV	master
RUN_BACKEND_INTEGRATION_TESTS	true
RUN_INTEGRATION_TESTS	true
TENANTADM_REV	master
TEST_QEMUX86_64_BIOS_GRUB	true
TEST_QEMUX86_64_BIOS_GRUB_GPT	true
TEST_QEMUX86_64_UEFI_GRUB	true
TEST_VEXPRESS_QEMU	true
TEST_VEXPRESS_QEMU_FLASH	true
TEST_VEXPRESS_QEMU_UBOOT_UEFI_GRUB	true
USERADM_ENTERPRISE_REV	master
USERADM_REV	master
WORKFLOWS_ENTERPRISE_REV	master
WORKFLOWS_REV	master

[aduskett]

I would like to see what failed, but the pipeline URL goes to a 404 :(

[lluiscampos]

@mender-test-bot start pipeline

[mender-test-bot]

Hello 😺 I created a pipeline for you here: Pipeline-1447273009

Build Configuration Matrix

Key	Value
AUDITLOGS_REV	master
BUILD_BEAGLEBONEBLACK	true
BUILD_CLIENT	true
BUILD_QEMUX86_64_BIOS_GRUB	true
BUILD_QEMUX86_64_BIOS_GRUB_GPT	true
BUILD_QEMUX86_64_UEFI_GRUB	true
BUILD_VEXPRESS_QEMU	true
BUILD_VEXPRESS_QEMU_FLASH	true
BUILD_VEXPRESS_QEMU_UBOOT_UEFI_GRUB	true
CREATE_ARTIFACT_WORKER_REV	master
DEPLOYMENTS_ENTERPRISE_REV	master
DEPLOYMENTS_REV	master
DEVICEAUTH_ENTERPRISE_REV	master
DEVICEAUTH_REV	master
DEVICECONFIG_REV	master
DEVICECONNECT_REV	master
DEVICEMONITOR_REV	master
GENERATE_DELTA_WORKER_REV	master
GUI_REV	master
INTEGRATION_REV	master
INVENTORY_ENTERPRISE_REV	master
INVENTORY_REV	master
IOT_MANAGER_REV	master
MENDER_ARTIFACT_REV	master
MENDER_BINARY_DELTA_REV	master
MENDER_CLI_REV	master
MENDER_CONFIGURE_MODULE_REV	master
MENDER_CONNECT_REV	master
MENDER_CONVERT_REV	master
MENDER_GATEWAY_REV	master
MENDER_REV	pull/1663/head
MENDER_SETUP_REV	master
MENDER_SNAPSHOT_REV	master
MONITOR_CLIENT_REV	master
RUN_BACKEND_INTEGRATION_TESTS	true
RUN_INTEGRATION_TESTS	true
TENANTADM_REV	master
TEST_QEMUX86_64_BIOS_GRUB	true
TEST_QEMUX86_64_BIOS_GRUB_GPT	true
TEST_QEMUX86_64_UEFI_GRUB	true
TEST_VEXPRESS_QEMU	true
TEST_VEXPRESS_QEMU_FLASH	true
TEST_VEXPRESS_QEMU_UBOOT_UEFI_GRUB	true
USERADM_ENTERPRISE_REV	master
USERADM_REV	master
WORKFLOWS_ENTERPRISE_REV	master
WORKFLOWS_REV	master

[lluiscampos]

I would like to see what failed,

You copied the example start, pointing the bot to old or non-existing PR for mender and mender-connect. I started it for you.

but the pipeline URL goes to a 404 :(

Yeah, this pipeline is internal to the Mender team, sorry.

[aduskett]

I would like to see what failed,

You copied the example start, pointing the bot to old or non-existing PR for mender and mender-connect. I started it for you.

but the pipeline URL goes to a 404 :(

Yeah, this pipeline is internal to the Mender team, sorry.

Thank you so much!

[danielskinstad]

Hey 😃 Thank you for your contribution!

I have some comments/questions.

As far as I know, and can see from the pre-existing code, it defaults to dynamically linking boost, not statically (unless you set MENDER_DOWNLOAD_BOOST).

• ldd of mender-auth after a clean build: libboost_log.so.1.74.0 => /lib/x86_64-linux-gnu/libboost_log.so.1.74.0

Secondly, I don't get any undefined reference errors when linking boost, and I don't see it any pipelines either. Might it be your setup? Does the same happen with a completely, unmodified, fresh build of mender (and following the build guide in the README)?

[kacf]

Indeed, Boost is already linked dynamically. The proposed fix was removed earlier for this reason. It must be something in the environment.

[aduskett]

What this looks like is Buildroot not setting BOOST_LOG_DYN_LINK or BOOST_ALL_DYN_LINKS as found in boosts config.hpp:238

#   if defined(BOOST_LOG_DYN_LINK) || defined(BOOST_ALL_DYN_LINKS)
#       define BOOST_LOG_DLL
#   endif

Which causes the above issue. Both Fedora and Debian do indeed define BOOST_LOG_DYN_LINK which is why the autobuilders aren't having the problem. Now, as to how to set BOOST_LOG_DYN_LINK is the issue.

[kacf]

@aduskett: Can you elaborate on how Debian and Fedora define this? I cannot find this on my system, nor on a fresh one, in fact, it's quite clearly not turned on (in Debian):

/usr/include/boost/config/user.hpp:90:// #define BOOST_ALL_DYN_LINK

(BOOST_LOG_DYN_LINK doesn't have a define anywhere, as far as I can see)

There are also some other issues with the proposal:

• The PR doesn't appear to have any effect on my system when turning it off. This is probably because the absence of definition is having the "default" effect, which appears to be to link dynamically anyway, on my system. But this means the toggle does not work correctly.
• add_definitions has been superseded by other variants, see here, and should anyway be lowercase to match the rest of the code.

I'm wondering if it isn't better to just do this in autobuild with direct flags instead of having an option (which has some pitfalls, as we have seen). Something like this, for example:

cmake -D CMAKE_CXX_FLAGS=-DBOOST_LOG_DYN_LINK -D CMAKE_EXE_LINKER_FLAGS=-DBOOST_LOG_DYN_LINK .

Would that work for autobuild?

[aduskett]

Hey! So I * did * figure out the problem with buildroot, which is from commit 4349746dac6f55b0b0faca21a7e609fb67d1471b

Author: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Date:   Thu Apr 18 11:13:50 2019 +0200

    package/boost: don't install boost cmake files
    
    Since version 1.70.0, boost installs its own cmake files which are
    utterly broken so don't install them otherwise all cmake packages using
    boost (host-thrift, domoticz, i2pd ...) will fail because
    BOOST_INCLUDE_DIRS will be empty
    
    Fixes:
     - http://autobuild.buildroot.org/results/4ada26bab5c1e6504c7d8c92672326ced1d336df
    
    Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
    Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

Five years ago! The fix is to remove --no-cmake-config from boost.mk in buildroot and let boost configure the .cmake file before installing them. Sorry about the junk merge request!

[kacf]

No worries, great that you figured it out!