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I am considering to create a Debian package from an existing library (paho-mqtt-c). The project uses CMake as its build system. After some research I think I need to create two or three different packages:

  • libpaho-mqtt3 (with library .so files and related stuff)
  • libpaho-mqtt3-dev (with header files)
  • also maybe I need a third package with sample files or documentation (called paho-mqtt3?)

I have done some research and it seems there exist at least three different ways how I can create a Debian package when I use CMake as my build system:

  1. Use debmake procedure described in Debian documentation (Chapter 8).
  2. Use cmake-debhelper.
  3. Use dh-cmake

I have looked into all three methods and it seems each has some advantages and disadvantages.

Debmake

As far as I have understood using debmake assumes I have an upstream tarball with the sources and the build system and then I invoke debmake on the extracted tarball. Afterwards I get a lot of templates which I need to manually adjust to fill in the missing gaps. I started doing this but it seems quite complex.

cmake-debhelper

I tried to use it but received lots of errors. The github page has an open issue with no solution so I stopped looking at this. This is also what the paho-mqtt-c build system is currently using, but it does not work due to the issue linked.

dh-cmake

I briefly looked into this and it seems to be the most modern solution and it should be possible to combine this with CPack. However, it seems dh-cmake is only available for Ubuntu 18.04 and 16.04, but I am using Ubuntu 19.10 so I was not able to install dh-cmake on my system.

Have I missed anything in my research? What are the recommended steps to create a Debian package from a software managed with CMake and which documentation is useful to read?

lanoxx
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2 Answers2

1

In short, on Ubuntu you need to create at least these files:

debian/
 changelog
 control
 copyright
 rules

And then run debuild and it will run cmake install to temporary folder and pack an installable deb package from it. To quickly create those debian files run dh_make --createorig and press s for source package. Then you'll need to carefully edit debian files as described in Chapter 4. Required files under the debian directory of Debian New Maintainers' Guide.

If you need to set cmake properties or make any other configuration then you'll need to adjust override_dh_auto_configure in rules:

#!/usr/bin/make -f
# See debhelper(7) (uncomment to enable)
export DH_VERBOSE = 1

%:
    dh $@

override_dh_auto_configure:
    dh_auto_configure -- \
    -DCMAKE_LIBRARY_PATH=$(DEB_HOST_MULTIARCH) \
    -DIWINFO_SUPPORT=OFF

Here the -DCMAKE_LIBRARY_PATH=$(DEB_HOST_MULTIARCH) and -DIWINFO_SUPPORT=OFF will be directly passed to cmake.

You can then upload your package to Ubuntu PPA:

debuild -S -I
dput dput ppa:your-launchpad-user/your-ppa ../*_source.changes

After that PPA build bot will compile and publish your package to PPA and you'll see them on https://launchpad.net/~your-launchpad-user/+archive/ubuntu/your-ppa/+packages

Unfortunately there is a lot of other steps, I just described briefly.

The dh-cmake is needed for more sophisticated things. CPack won't work for you if you want to publish to PPA because its buildbot will anyway run debhelper (short version of debuild) so it needs for the debian folder

Sergey Ponomarev
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    Thanks for this answer. From what I have gathered so far, I thought that `dh_make` (with an underscore) is an older solution and the more modern approach is to use `debmake` to generate the Debian files, not sure if thats right. Anyway, I was not aware of the `--createorig` option of `dh_make`, that is certainly useful, this way I would not need a `source tarball` to start off with. If your sources are in git, then your folder is probably not in the `package-version` format, so I would either need to rename the folder or use the `-p _` option. – lanoxx Jan 06 '21 at 17:05
1

or you could use cpack with cmake to generate a deb fairly easy to do but cmake and cpack are poorly documented still they work well I suggest adding the following to the bottom of CMakeLists.txt

# generate postinst file in ${CMAKE_BINARY_DIR} from template                        #
CONFIGURE_FILE("${CMAKE_SOURCE_DIR}/contrib/postinst.in" "postinst" @ONLY IMMEDIATE)


    # generate a DEB when cpack is run
    SET(CPACK_GENERATOR "DEB")
    SET(CPACK_PACKAGE_NAME ${CMAKE_PROJECT_NAME})
    SET(CPACK_SET_DESTDIR TRUE)
    SET(CPACK_DEBIAN_PACKAGE_MAINTAINER "grizzlysmit@smit.id.au")
    SET(CPACK_PACKAGE_VERSION_MAJOR "0")
    SET(CPACK_PACKAGE_VERSION_MINOR "0")
    SET(CPACK_PACKAGE_VERSION_PATCH "1")
    include(GNUInstallDirs)
    SET(CPACK_PACKAGE_DESCRIPTION_FILE "${CMAKE_SOURCE_DIR}/docs/CPack.Description.txt")
    SET(CPACK_RESOURCE_FILE_README "${CMAKE_SOURCE_DIR}/docs/README.md")
    SET(CPACK_RESOURCE_FILE_LICENSE "${CMAKE_SOURCE_DIR}/docs/LICENCE")
    SET(CPACK_DEBIAN_PACKAGE_DEPENDS "libreadline8, libreadline-dev")
    SET(CPACK_PACKAGE_VENDOR "Grizzly")
    # make postinst run after install                                                #
    SET(CPACK_DEBIAN_PACKAGE_CONTROL_EXTRA "${CMAKE_BINARY_DIR}/postinst;")
    
    
    include(CPack)

the postisnt is to run a script after the install see CMAKE/CPACK:I want to the deb executes a bash script after installed, but it doesn't work for more on that.

grizzlysmit
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