Contents
Package Management Ideas
This page is a place to hash out ideas regarding Haiku's package management (and creation). The following is a draft specification for the package management system to be included in R1. It is based on (1), (2) and the discussion in (5). The draft does not yet cover everything from (1), however.
Requirements
This section describes the intended user experience.
HaikuBits
HaikuBits is a complete directory of software for the Haiku platform. It is the one place a user needs when looking for Haiku software. While it does not host all software binaries, it does list 99.9% of all software available for Haiku.
Software is classified into a number of categories. For each software, HaikuBits provides a short description, one or more screenshots, a link to the author's homepage and a download link. Additionally, a software's page has a community rating and important information such as security notices.
Bundles
A bundle is a single file that contains the binaries, data files and documentation. This makes software self-contained and easy to handle. An application can be run by double-clicking the bundle icon. Obvious exceptions to this rule are drivers and libraries. These have to be installed to be of any use. The contents of a bundle can be inspected by opening the bundle by means of a context-menu option which opens the bundle in Tracker just like a directory.
Optionally, an application bundle can be installed by moving it to /boot/apps (system-wide) or in /boot/home/<user>/apps (user-local). Another option is to right-click the icon and select "install for everyone" (only admins) or "install only for me". Any initial configuration (accepting a license) can be performed the first time a bundle is being run.
Libaries can be installed the same way. The user normally does not have to install libraries manually, as the package manager will do so when it is needed, asking the user for permission.
When an application bundle has been installed, shortcuts to the application appear in the Deskbar menu. This menu is subdivided into a number of a predefined categories (games, graphics, internet, ...) that match those on HaikuBits.
Drivers ... ?
brecht: I don't like Waldemar's idea of having bundles spread all around the filesystem, hence the clear distinction between installed and non-installed bundles. This might be a necessity for multi-user too.
axeld: I have to agree with brecht. And also, I like the package file system best, as it also solves on how to deal with ported software, and libraries as well. Only drivers would probably need special treatment (depends on how early the package file system is available, but I guess that could be made work as well, like having a "actually install on disk" option for driver packages).
wkornewald: My original intention was to not force the user through any installation procedure. Simply download the app and run it directly from the downloads folder to see if it works well and if yes the user can move it to the "Apps" folder.
Management
Uninstallation is performed by simply removing the bundle from /boot/apps or /boot/home/<user>/apps.
A user's application settings are kept when a bundle is uninstalled or deleted. The system however provides a comprehensive listing of applications for which user settings exist. The user can choose to delete settings for each of the bundles.
Application folders (/boot/apps and /boot/home/<user>/apps) display the list of installed bundles including information (description, availability of updates, security risk warning), just like the mail folder in BeOS displays emails.
wkornewald: The system should automatically remove settings of deleted apps after a certain amount of time. You don't really want the user to manually clean up his system. The cleanup delay should be long enough to allow the user to update an app by deleting the old version and downloading the new version and it should be long enough to allow the user to "undo" his action. Maybe 1-2 months is fine.
pulkomandy: Deleting files without asking doesn't look right to me. Either delete them as soon as the app is removed, or keep them forever. I like Debian/apt way of doing it : when you delete a package, it's listed in the package manager as 'removed, residual config files' and you can remove these from there.
Dependencies
The user does not have to worry about dependencies. If a bundle depends on other bundles, the package manager should make sure they are fulfilled (on run). If a dependency is not fulfilled, the system will ask the user for confirmation and automatically install any required bundles. This requires an internet connection.
Alternatively, a user can download a fat bundle that includes the dependencies as well.
Updates
All installed software can be checked for new versions. For each of the installed applications, the changes with respect to the installed version can be displayed. Updates are flagged as 'strongly recommended' when security problems are known. The user can select which applications he/she would like to update and have the system perform the updates.
By default, the updater tool does not show libraries in order to keep the list of updates as short as possible and understandable by the non-technical user. Libaries should only be updated when there are known problems with them.
Implementation
In this section the implementation of the system is discussed.
Bundles
A bundle is a compressed disk image that contains:
- application executable(s) & data
- metadata
- name
- version
- (revision?)
- hash (integrity-check)
- author
- homepage
- license
- category (for grouping applications in the Deskbar menu)
- shortcuts to appear in the Deskbar menu
- a default shortcut to run when the bundle is being "run"
- right-clicking bundle could offer the option of opening a help document about the application
There are a number of different bundle types:
- application
- library
- driver
- font
- ...
Library, driver and font bundles have to be installed.
Install or not?
As bundles have to be compressed for distribution, they will need to be uncompressed at some point. There are two options:
- Before using a bundle, it is decompressed. This is very similar to installing, which many wanted to avoid.
- The bundle's contents are decompressed on access. This is less efficient as decompression needs to be performed on each access, as opposed to only one time during installation. Performance of large applications and heavy games in particular will suffer.
It is possible to split application bundles into two sub-types; those that have to be installed, and those that can be run as-is.
brecht: While I initially liked the idea of not having to install software, I now feel that it is not suited for all types of applications and games. While we can make a differentiate between 'large' and 'small' applications and require installation of large apps (or suffer from poor performance), this feels like a bit of a kludge. Is is really that bad to 'install' software once? Installing can be reduced to decompressing and should not bother the user much. If the user knows he has to install all bundles, there can be no confusion.
wkornewald: I don't fully remember my original proposal (it's been several years :), but I think there's a middle-path: When the bundle is opened for the first time it's decompressed and cached automatically. When the bundle is deleted from the file system the cache is cleaned, too. That way you have the best of both worlds and the user only has a slow first start, but all subsequent app starts will be fast. Maybe the cache itself could be a single uncompressed bundle/image file if that's more efficient than having lots of small files spread over the main file system. A large coherent file can probably be read into memory much faster and should speed up app starts noticeably.
File System Organization
Native Haiku applications are contained in their own directory as before. Organization of ports is more complicated.
Merged
By means of a union pkgfs (3). All ports are mounted under /boot/common.
It is not clear how multiple versions of libraries and applications can be handled in this scheme.
Self-contained
By means of assignfs (4). Each port receives its own unique assign: /boot/apps/<port>-<version>-<revision>
axeld: I think the best solution would be a unionfs approach: the package file system would just blend in the packages where needed. User packages would be merged with the contents of config/, while system wide ones would be merged with the contents of /boot/common/.
Settings
global settings/user settings
Multiple Application Version
how to handle
Dependency Hell
Dependency hell is a problem mostly for ports. That does not mean it can be ignored. At least in the early years of Haiku, ports will be an important source of software.
Avoiding
Bundles are always fat bundles. All required libraries are included in the bundle. Problem solved! However, this very area-inefficient. Nor is it a realistic solution for bundles that depend on large packages like Python or Perl.
Tackling
In order to solve conflicting dependencies, it is necessary to be able to have multiple versions of a library installed. Even worse, some libraries can be built with different options.
To make this work, it is obvious that a central bundle repository is required: HaikuBits. Alongside offering a browsable directory of software like BeBits, it stores information about dependencies. Dependency information (problems arising from certain combinations of bundles) is updated by the community.
An example. When ABC-1.0 is released, its dependency libfoo is at version 1.2.10. Bundle ABC-1.0 specifies "libfoo >= 1.2.10" as a dependency. Later, when libfoo 1.2.12 is released, it appears that this breaks ABC-1.0. HaikuBits is updated to indicate this: "libfoo >= 1.2.10 && != 1.2.12". When ABC-1.0 is now downloaded from HaikuBits, the bundle contains the updated information. A software updating tool can also check HaikuBits to see whether dependencies are still OK.
Because the act of porting can introduce additional incompatibilities, each port should be tagged with a revision number to uniquely identify it. Revisions can also be used to differentiate between ports with different build options. Specifying build options in the dependency information seems overkill anyway, as we should strive to have as few port revisions as possible (developers should have dependencies installed as bundles before porting).
The bundle metadata needs to be extended to include information about the dependencies:
- minimum/maximum version
- preferred version/revision
- non-working versions/revisions
While bundles will not be available for download for retail software, it still makes sense to record dependency information about it on HaikuBits.
Having an application use a particular library version can be done by manipulating LD_LIBRARY_PATH or by virtually placing the library in the applications directory by means of assignfs or pkgfs.
Note the important difference with typical Linux package management systems. In Linux, the repository typically offers only one version of a particular package. This is the result of keeping all packages in the repository in sync, in order to avoid conflicting dependencies. In the proposed system however, the user is free to install any version of a bundle, as there is no need for any global synchronization of all bundles.
axeld: while having a central repository is a good thing, I don't think our package manager should be based on that idea. I would allow each package to define its own sources (the user can prevent that, of course). That way, we avoid the situation of having to choose between outdated repositories, and unstable software (or even having to build it on your own) like you usually have to do in a Linux distribution. The central repository should also be a fallback, though, and try to host most library packages.
Since we do care about binary compatibility, and stable APIs, having a central repository is not necessary, or something desirable at all IMO.
brecht: I agree. I see the repository more as a central entity keeping track of all software versions and the dependencies between them. This dependency information is updated based on user feedback. I don't think it is necessary to have the repository be the one and only source for bundles, however. It can keep instead a list of available mirrors. However, it is probably a good idea to have one large reliable mirror (hosting the most important bundles) managed by Haiku Inc. alongside the repository in order not to be too dependent on third parties.
libalpm
(and it's tool: pacman)
libalpm is the package management library used on ArchLinux, most people know it as "pacman" since that's the main tool to use, however, all the functionality is part of the libalpm library which could be utilized to create a nice GUI frontend for the package manager. It of course can also be adapted.
It uses libarchive to extract archives, and either libdownload or libfetch to download files - although one can also have it use an external command, like curl or wget.
The current status is this:
As far as libfetch is concerned: compiles and is linked to, but it doesn't really work, so I'm using curl instead - it works like a charm.
The important part: libarchive needed some work to support zip files in a useful way. Basically, it now supports seeking (which it didn't before), the central-directory headers for ZIP files (so it supports stuff like symlinks), and BeOS file attributes! Also, when reading from a source which doesn't allow seeking (... which are... none - on our case) it simply reads the local headers, but can also - if explicitly requested - provide "update"-entries to update the raw data when the central directory is reached (but those are of no importance anymore).
What's good about libalpm? Well, it provides useful configuring mechanisms, it stores dependencies and can also give you a list of which packages require a certain package. It keeps a database containing package information, including a file list. Configuration files in packages can be listed as such, which causes them to be installed as *.pacnew when they are upgraded (unless the new and old files equal - an md5 sum check is used there.) It provides the ability to use different database directories which allows us to have an automated way of creating package bundles. For instance, I can set the installdir to /tmp/mypackage and install the game "einstein" including its dependencies there, then move /tmp/mypackage/einstein/common/lib to /tmp/mypackage/einstein/lib, remove the unnecessary manpages, share files (well, usually anything else which is in the common/ folder), and then strip those dependencies from einstein's .PKGINFO file and create a bundled package which I can then install normally to say /boot/apps.
Another useful feature is the possibility to change the root directory. When a package contains a .INSTALL script, libalpm chroot()s into the root directory, cd()s into the installation directory, and then executes the .INSTALL script (which means, that install-scripts can and should work relative to the installation directory, although, if necessary, the absolute path is available in $PWD)
Also, libalpm works similar to an actual database. It doesn't blindly attempt to install a package, but first check for file conflicts, see if any files need backups or configuration files need to be installed as .pacnew, and then installs a package. If you install multiple packages at once, then it only either installs all of them, or none. It allows you to find the owning package of a file in the filesystem as well as listing all the files and dependencies of a package.
Where does it get the packages form? Two possibilities: One can use package files directly - which could be made in such a way that you could also just unzip them. In fact, it might be useful to put the .PKGINFO into the zip file as some extra data which is not unzipped when simply using `unzip´, although package creation is easier if it's just a file. The other one being repositories. The pacman utility currently allows you to list repositories like this in pacman.conf:
[core] Server = file:///MyRepositories [devel] Server = file:///MyRepositories [public] Server = http://www.public-repository.com/
When you synchronize the repository databases, pacman downloads the file <Server>/<Reponame>.db.tar.gz which contains a list of packages with dependencies.
When you install a package from such a repository, it downloads them from the very same location: <Server>/<Package File>
The repo.db.tar.gz files are currently created using the tools repo-add and repo-remove provided in the pacman package. Those extract information from the .PKGINFO file and put it into the database which can be used as a repository then.
Here's a little log of using pacman to install a package file, and bundle a package with dependencies together into one package file. http://stud4.tuwien.ac.at/~e0725517/using-pacman-on-haiku.log.txt
Pros
- It has been used on archlinux for a long time - so it works.
- It's obviously possibly to compile and use it on haiku
- Since most of its functionality is part of a library, it can be reused to build a GUI-application utilizing libalpm
- pacman also provides scripts for building packages using a PKGBUILD script.
Cons
- Likely to cause unwanted restrictions in the package management system.
brecht: I don't have a detailed view of pacman yet, but as far as I can see it is very similar to your average Linux package manager. As we want software management to be fundamentally different from the way Linux distributions handle it (because it simply is not a very elegant solution), I don't think pacman is a good choice.
Blub: Let me clarify: I was not suggesting to use 'pacman' as a package manager, I was just thinking that its library could be a useful codebase for a package-database, to keep track of dependencies, available packages and updates. It 'could' be used to unpack/install packages into a 'specified' folder, like /boot/apps (and even install dependencies into the same folder if wanted), or, it could just as well be used to simply keep track of where which package has been installed to without worrying about the actual contents.
Although when stripping the code to unpack the archives and keeping track of their files it is indeed better to create something new.
Brainstorming Results from BeGeistert
These features were discussed/written down at BeGeistert:
- Integrated app to add packages
- Knows about repositories
- Defined protocol to add repositories that everyone can use (for example through description files with a special MIME type)
- Multiple installations of the same package (if the software supports it)
- Maintain shared libraries
- runtime_loader uses package info to resolve libraries
- Install packages per user
- Repositories support keys to verify packages
- Package database of installed packages
- Packagemanagement API
- Binary diffing for packages
- Export/publish the set of installed packages to another system
- System updates
- Quality of packages (QA integrated into the process of releasing a package)
- Property of live update possible
Package Format
A package format has to meet the following requirements:
- It must be able to store BeOS/Haiku file attributes.
- If the package shall be used directly (i.e. without prior extracting) by a package file system, fast random access to the file data must be possible. This disqualifies zipped TAR like formats.
[PackageFormat The Haiku Package format] specifies a format meeting these requirements.
References
(1) http://www.haiku-os.org/glass_elevator/rfc/installer
(2) http://www.freelists.org/post/haiku-development/software-management-proposal
(3) http://www.freelists.org/post/haiku-development/software-organizationinstallation,8 and http://www.freelists.org/post/haiku-development/software-organizationinstallation,55
jonas.kirilla: I hope it's clear enough in reference 3 (above) that my ideas on package management approach it from a different angle. Which may or may not overlap with the use of libalpm. FWIW, I'm not ready to endorse all aspects of this proposal.
(4) http://www.freelists.org/post/haiku-development/Pathrelocatable-software-and-assigns
(5) http://www.freelists.org/post/haiku-development/software-organizationinstallation
Other package managers to steal ideas from:
Useful articles:
- OSNews: Decentralised Installation Systems - article by the 0install author
- Package management system
Misc.
