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Packaging

Revision as of 15:33, 1 February 2010

Creating Packages for Maemo

Since Maemo is based on the Debian operating system, creating packages for Maemo borrows a lot of tools and techniques from Debian.

Further reading

The following list of resources gives in-depth information on packaging in Debian and Maemo. These links largely discuss packaging Python apps but can be used for any programming language.

• Debian New Maintainers Guide: The best place for information if you have never built a .deb before
• Debian's Python Modules Team: definitive documentation for packaging Python modules for Debian
• Python Modules Policy: Reference document.
• Creating debs on Ubuntu: A great screencast and tutorial showing how to package a simple python application as a deb on Ubuntu!
• Ubuntu Packaging Guide
• Deploying and distributing software on Maemo 5: Detailed documentation on packaging for Maemo, including how to ship your software afterwards
• Forum Nokia developer documentation: General developer documentation reference
• Packaging a Qt application and how it differs from the packaging described here
• User:Jebba has created a package building howto with details on every step

Checking Maemo Packages

Lintian dissects Debian packages and reports bugs and policy violations. It contains automated checks for many aspects of Debian policy as well as some checks for common errors. Unfortunately it does not check conformance to the additional Maemo policy.

Currently Maemo is creating Maemian to check its policy.

A concrete example - rot13

Prerequisites

./configure; make; sudo make install

For the purposes of our article, we will be packaging a simple command-lie utility called "rot13", which will perform a simple rot13 cipher on all text input from stdin.

Packaging a .deb

The easiest way to package a .deb file is to use Debian's build helpers.

Package your application as you would distribute it in a .tar.gz (when using autotools, this is done with "make distcheck"). In our example, we uncompress rot13-0.1.tar.gz, and change the current directory to rot13-0.1.

$ tar xfz rot13-0.1.tar.gz
$ cd rot13-0.1

Then we run dh_make, which initialises the Debian package management file structure (among other things):

$ dh_make -e <my email address> -f ../rot13-0.1.tar.gz -c GPL

You can of course choose a different licence for your package.

Answer the resulting questions - in this case, we are packaging a single binary.

We can now edit the files in the debian/ directory which has been created to their desired values, before packaging the software. In fact, we can delete many of these files. All of the files ending in “.ex” or “.EX” are example files, intended to help you package different types of software.

If you use a standard configure script, you do not need to modify any files in here at all.

Before creating a .deb, you should set a changelog entry. .deb changelogs follow a special format, so rather than editing the files by hand, use the dch helper application. This will allow you to add what new features went into this application, give credit, and so on. It is an especially important file because it sets the version and revision of the source and binary packages. On saving, a syntax check is performed which ensures that the resulting file is OK. The file format is completely documented in the Debian packaging guide.

Finally, we generate a .deb from the source code using the command:

dpkg-buildpackage -sa -rfakeroot -k<my email address>

You should now have several files created in the parent directory to where you unpacked the source code. I have;

rot13_0.1.orig.tar.gz
rot13_0.1-1_i386.deb
rot13_0.1-1.diff.gz
rot13_0.1-1.dsc
rot13_0.1-1_i386.changes

Now change the target architecture to ARMEL and rebuild it, to generate rot13_0.1-1_arm.deb

Additional information

If you use git then you may not want to include the entire git repo in your source bundle. With dpkg-source version 1.13.25 the -i option is not git-aware so you can do:

 dpkg-buildpackage -rfakeroot -sa  -i -I.git

You may verify that your Build-Depends field in debian/control is complete by running:

dpkg-depcheck -m dpkg-buildpackage -rfakeroot -b

in the source tree. (You will need to fakeroot apt-get install devscripts for this to work).

Uploading to extras-devel

Porting an existing Debian package

Finding your package in Debian

If you want to port a Debian package to Maemo, you should check and see if it is already packaged for Debian and use that package if you can - this will save you time and effort. You can search in Debian's Package Tracking System (PTS) to see if it is there. There is a search system on the PTS page, under the "distribution" drop-down, select 'any', this will search throughout Debian's repositories to find the package. Debian has more than 20,000 packages just in its stable distribution so your application is likely already packaged.

If you find the package already exists in Debian, you can get the source, including the packaging source, with apt-get. To do this, you'll have to edit your /etc/apt/sources.list, you can follow this recipe;

$ echo "deb http://ftp.it.debian.org/debian/ unstable main contrib non-free" >> /etc/apt/source.list
$ apt-get update
$ apt-cache search "application name"
$ apt-get source "application name"

To learn more about the /etc/apt/sources.list</ocde> you can do a 'man sources.list' if you are running Debian or a Debian-based GNU/Linux distro.

The maintainer field (in the <code>debian/control file) MUST be changed if the upstream package is modified.

Maemo-specific packaging information

Packaging policy

Maemo packages follow the Debian Policy, but there are some items where Maemo:

• Is more strict (it is an embedded distribution)
• Is more relaxed:
  • A single target device (per release)
  • A single specified UI (Hildon)
  • A single user
• Differs from Debian because Maemo has different:
  • Objectives
  • Maintainers
  • Infrastructure

Most of the specifics for Maemo packaging are outlined in the Maemo packaging policy. The policy is still in the draft stage, so certain parts are still incomplete or not entirely up to date.

Sections

This is the list used in Fremantle/Maemo5 and is the same as the final list for Diablo as discussed in the task.

If the package's section starts "user/", but is not any of the above, the Application Manager forces them into an "Other" section.

Maemo-specific fields

There are a number of Maemo-specific package fields that are handled by Application manager. The Application manager documentation outlines them.

Displaying an icon in the Application Manager next to your package

Displaying an icon in the Application Manager next to your package makes it look pretty and makes your package stand out, and it is not that hard to do.

1. Make an image that is 48x48 pixels. The image can be saved in any format that is supported by GdkPixbufLoader on Maemo, but PNG is commonly used.
2. base64 encode the image. This can be done in many ways, depending on the platform, but assuming you are in scratchbox:

apt-get update
apt-get install sharutils
uuencode -m <name of 48x48 image> <name of 48x48 image> > <name of 48x48 image>.base64

1. Add the field XB-Maemo-Icon-26 to your debian/control (in Maemo4 the size of the icons was 26x26, hence the name of the field, which has not changed)
2. Open the base64 version of your image and copy from the line under begin-base64 644 <name of 48x48 image> to the line above the ===
3. Add this to the XB-Maemo-Icon-26 field
4. Add a space in front of every line of the encoded icon

Here is an example of a properly formatted Maemo-Icon-26: (of wrong image size)

Description: Chess...
XB-Maemo-Icon-26: 
 iVBORw0KGgoAAAANSUhEUgAAABoAAAAaCAYAAACpSkzOAAAABGdBTUEAAK/INwWK6QAAABl0
 RVh0U29mdHdhcmUAQWRvYmUgSW1hZ2VSZWFkeXHJZTwAAALxSURBVHja3FZNTBNREP669J/S
 XYxtKRWl1JOSFBIPhkitCQeNiaKBmzdj9Ggk0ZOBxHDWixcTjV6MF+WiIB40YEyMBMGYEqQK
 tLS2lG7pdre0pF3WtxslgJRuD2J0kpfdTN7O976Z782sRpIk7IZR2C2TGW1cv8xaY5WuXLy8
 iW5XV5fk8/kkr9e7ya/T6SSNRiOViikvbbmDDD590SusZBGYDiDwJbDud7vdvYIgIJfLYXV1
 tSwhrQrSfRX6/26N/j+gkjW6ce06HE4HGEctGuj9oEwUzFYz5ubmEA6HQVEUisUi8vn8b4rd
 zjRbNxCZrr+3t7XTzjrnvMfdxMi7xj6OIRaPIbWcQjabVdRWKBTkrX4SZ2SjvCtKXf+tkxxD
 M5MetwfHj/lwwueHy+WCVqvdehdHKq7R6JvbpfNMAGiGhs1mg9ls3sS+4hodbDqCwef9mA9P
 7vhhVVWV3BGUOomiaCSufEWMxNwimlweMFYbpoMfyp70J6t8xanLZgWs8Ak07N0Hau0P3qOs
 wIHnl5FJx2E1WlUFuXrzIS713KusRplMCoLAgl2O4N34ODQ4VRaot6cbUzMRNNQ/w/uJWXWM
 eH5JARkYHsLQMIe1NZEpB7Sn1uKFhkL3maO4cL5NHVAo+hkPnrzEq2HqQIf/3ICzvr7FXmeH
 3qBXlslkgtFoVBS3YfbcKRRFfJpagE6vUwd0//FbjI7mkcvnGoNfg51ORx3sNju+hWYxMxsk
 jHlF2jJgdXU1DAaDrDx/kQAVRREJlldXo8kJoPlQ8wHSevosFgs5MmE5H0IingDP8eAzPAQC
 tkJakDz05Hsks+poPzwg6+Luo9chVb2O3Hilv7V6W5nO02cVX3wxjsj3CMKRBUSjUcQWY0iy
 SQVoi6XJaiQxubKpI02yj2xk6BoaBr0BqXRKCZpYSiCZlIXCguM4pWtvY0ypyUtt87PSIj/t
 pJ/JICzLKiBLySTYVArpdFrp3DuMhRZVqfvnJ+wPAQYA1hdr5EDqltYAAAAASUVORK5CYII=

Bugtracker location

As a requirement for your package being promoted from Extras-testing to Extras, your debian/control file must have a link to a bugtracker. It is possible to request a component at bugs.maemo.org or use a Garage project bugtracker, or even an email address.

1. Add the field ‘XSBC-Bugtracker’ to your debian/control, for example:
   

   XSBC-Bugtracker: https://bugs.maemo.org/enter_bug.cgi?product=mypackage

Maemo revision string

If an upstream package is re-packaged or modified for Maemo, the Maemo revision string should be appended to the upstream revision, in the debian/changelog file. So if in Debian the package name was something like "Myapp-0.4-2" in maemo this package will be called "Myapp-0.4-2maemo0". The number after the "maemo" string is a progressive number.

Debhelper 7

A backport of Debhelper 7 for Fremantle is available in extras-devel. It works transparently and can coexist with debhelper 5 in the SDK. It even works on the autobuilder, if you specify the correct build-dependency of debhelper7. Read the mails about debhelper7 and cdbs-dh7.

Alternatively, you can try to use debhelper 5 in some cases:

Debian packages that requires level 7 needs some changes, for example:

• debian/compat: 7 -> 5
• debian/control: Build-Depends: debhelper (>= 7) -> debhelper (>= 5)
• And maybe comment out a few dh_* calls from debian/rules, which might not exist on level 5

Things might get complex if the packaging already uses some new features of level 7, like those CDBS-like helper rules. In such cases, looking at versions prior to the compatibility level upgrade might help doing the downgrade (and most Debian packages are kept in public SCMs like svn.debian.org).