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{{Warning|This page has not been revisited since 2014. Please refer to the GNU Octave manual for information about {{manual|pkg}}.}}
== Abstract ==
This document attempts to design a solution for this.
The main idea of the solution is to keep database files have multiple databases with each package locationinformation from installed packagesand dependenciesin different locations in the filesystem. While this is similar to the current implementation, and allow we plan to design solutions for the merge of such fileswhen package installations clash.
To allow reinstallation of the packages, we propose This proposal also suggests to keep the source of the packagepackages.This will allow forThis would also make it easier to run the tests easy reinstall of packages (after an Octave upgrade) and test of .oct files frompackages(since their tests are in the .cc sources).
== Rationale and examples ==This design is meant to make allow the following: * keeping keep multiple versions of the same package installed and load a specific oneside-by-side * keep packages installed for multiple versions of Octave, specially in a system using the case ofsame installed packages .oct files which need to be rebuilt for each octave function * reinstall a package from its cache after installing new octave versiondeal with dependencies correctly when multiple Octave and packages co-exist * run the tests from allow use of packages (find tests in .cc sources)that may have been installed anywhere * clean the reinstall a package cache * usage of alternate database files * usage of test installed packages in remote directories which may not be available at all times
See the user cases section below for several examples. The definition of a package manager according to wikipedia: * Verifying file checksums to ensure correct and complete packages;* Verifying digital signatures to authenticate the origin of packages;* Applying file archivers to manage encapsulated files;* Upgrading software with latest versions, typically from a software repository;* Grouping of packages by function to reduce user confusion;* Managing dependencies to ensure a package is installed with all packages it requires. This resolved the problem known as Dependency Hell. ==Available vs Loaded = Case =To avoid problems reading this document, the distinction between available and loadedpackage should be done early. An available package is a package that is currently available to pkg for loading,unloading or reinstall. It is already installed but not necessarily loaded. A loaded package is an installed package whose functions have been added to Octave'sfunction search path. == Types of package installs ==This design supports 3 types of package installations: global (relative to theOctave installation), local (user specific) and external (in any other place). ;global install: available from startup to everyone.;local install: available from startup only for the user that installed it.;external install: needs to be made available first. Octave install has no information about it. Note that Octave itself can be installed in some different ways. It might be a system-wideinstallation (located somewhere in {{Path|/usr/local/}} for example), a local installationof a normal user ({{Path|/home/user/anywhere}}), or installed in the homedirectory of a system user (anywhere really). === Global installs ===Packages installed globally will be available to everyone from startup. This is thetype of package installation that a system administrator would most likely do. Themeaning of global here is relative to the Octave installation though. If an Octaveinstallation is local (installed by a user in {{Path|~/my-builds}}), a global installationof a package will still place its files in the home directory of the user (in{{Path|~/my-builds}}). A global installation is performed automatically if the user installing the packagehas write permissions to those directories (''localfcnfiledir'' and ''localapioctfiledir'').In case it has no permissions, a local package installation is performed instead. === Local installs ===Local packages are specific to a user. They are located in that user home directoryinto an {{Path|.octave}} directory. As with global package installations, they are availablefrom startup. Unlike global, they are user specific, only available to the user thatinstalled it. A local install for a user can be an external install for some otheruser. This are the type of package installation done by users that want to have the latestpackage version before is available in their system repository, but are not going tobuild Octave themselves. Also to be used by those who run Octave in a system that theydo not maintain where Octave is installed but not packages. === External installs ===These are like local packages but in a non-standard location. Octave does not knowabout this installations at startup even though they might have been installing thesame Octave that is running at the moment. These can be packages installed in afilesystem that is not always mounted, local packages installs from another userin the same system, or anything else really. An external package was still installed with pkg, the difference being that therecord is not kept by Octave after it. An external package install will have a dbassociated file just like the db files for the local installs. To load an externalpackage, the path for the db file needs to be passed to pkg and the db named (becausethere may be more than one db. These are most like the less used type of packages and will require a bit moreknowledge (they will need to point pkg to a .db file, that is all). They will bemostly used for places that develop their own packages and people who don't want toinstall the package themselves, instead simply using a local install of others asan external package. === Playing nice with downstream packagers ===The recommended method for installing Octave and its packages is to use their OS packagingsystem. Downstream packagers should have the packaging systems make global installs of thepackages. If a user wants to install a new version of a package that is not yet availableon its system repository, it should make a local package install (default since has a normaluser he won't have write permissions to the Octave directory). If the user decides to make a global package install (install the package using pkg whilerunning Octave with sudo), then he's trying to act as system administrator and should knowwhat he's doing. If he breaks it, its his own fault. Installation of system-wide softwareis meant to be handled by the system packaging tool. It is just not possible to make pkgcover all of them. == Package names ==For the parsing of the commands and files, some limitations on package names are required. This willlimit what pkg commands can do. For example, if a package name is allowed to use a hyphen, thencommands such as "pkg load image-2.0.0" can no longer be used to load a specific package version.Something such as "pkg load image::2.0.0" would have to be used. Using this alternative syntaxmeans that package names cannot have colons. This is not only limited to package versions. As pkg is to be expanded to load pkg databases fromother files (packages in a not always mounted directory for example), it becomes a possibility tohave more than one package with the same version available to "pkg load". This means that itbecomes necessary to specify which package to load. Something like "pkg load image-lab-2.0.0" canbe used. A nice thing would also be "pkg load image-2.0.0 from lab" but that would add one of following2 limitations: either no package can be named from; or pkg load becomes limited to load onlyone package. Also, supporting multiple packages versions means that the word "all" to refer to allpackages has new limitations. Should we load only the latest version of each package?And if there's multiple packages with the same version on various db, which one shouldbe loaded? I'd propose the default to be: - load the latest version available- load the local install of the package- load the global install of the package- load the package from the external .db, starting from the latest added in case there's more than one. For package names, the proposal is to limit package names to the same as variablenames (makes it even easier to check validity with isvarname). So package namemust start with a letter, and otherwise be comprised of alphanumeric and underscorescharacters. Unlike variable names, package names will not be case sensitive sinceit would create problems when installing packages in filesystems that are not casesensitive (creating directories named Image and image would not be possible in FATsystems). == Version numbers == === specifying version ===Actions dependent on a package version can be specified with a -version modifier for thataction. It is however necessary to define the default order. Comparison operatorsshould be used to specify versions. If no comparison is use then greater than orequal is assumed. So that the following: ;pkg load image: loads latest version of the image package. If package is not installed, give error;pkg load -version 1.0.5 image: load the latest version greater than or equal to 1.0.5. If no such version found, give error;pkg load -version >=1.0.5 image: same as not specifying comparison;pkg load -version >1.0.5 image: load anything above that version (does it make sense supporting this? It's not a lot of trouble...);pkg load -version =1.0.5 image: load image package only if the same version (should we use == instead? Why not only =? Should not support both syntax);pkg load -version !1.0.5 image: load any image package available except 1.0.5 (because regressions do exist) For the other 2 remaining comparisons (< and <=), the question used for > and >=is the same. Does it make sense to support both? For ''greater than'', the onlything that makes sense is ''greater than or equal'' and for ''lesser than'', theonly think that makes sense is ''only lesser than'' since people will mark themas the first release that implemented, or the first release that no longer had,a specific feature. Whatever code is used on this section should also be used for solving packagedependencies. Should versions take precedence over the database for loading order? For example,if there is a global installation of image 1.0.5 and a 2.0.0 version on an externaldatabase named labdev, what version should be loaded? ;pkg load image: load version 1.0.5 from global (database takes precedence over version);pkg load -version >1.0.0 image: load version 1.0.5 from global (database takes precedence over version);pkg load -version >2.0.0 image: load version 2.0.0 from labdev (only version that meets the requirements);pkg load -version >1.0.0 -db labdev image: load version 2.0.0 from labdev (while database takes precedence, labdev was specified so we load the latest) Should the -db modifier make pkg ignore completely version? If a system has signalversion 1.0.0 on an external named labdev, and 1.2.0 on a global, what should be loaded? ;pkg load signal: load version 1 .2.0 from global;pkg load -db labdev image: load latest version from global or from labdev? === version definition ===The current implementation only accepts versions on the format x.y.z. This doesnot allow for dev versions, beta or release candidates releases such x.y.z-rc0, x.y.z+, etc We have compare_versions in core to check for version numbers, whatever is decidedshould be used with compare_version (or compare_version should be made to support it). == User cases ===== User case #1: global, local and external ===Jenny is using Octave on the department cluster. She is not the administrator butthere's already a system-wide installation of Octave with the general andsignal image installed. She starts Octave and has these 2 packages available toher. These are globally installed packages, available to everyone that startsOctave. But Jenny also requires the image package and she installs it with "pkg install -forge image". Shedoes not have permissions to administer the system so the image package is installedlocally in her home directory. When she starts Octave, she now has 3 packages available,general and signal package which are global (available to everyone that starts Octave), andthe image package which is local (available only to her). Jenny's supervisor is working on a new package (img_analysis) that he makes availablefor all his students and wants Jenny to use it. Rather than sending them the packages,he wants them to use the package he has installed on his own home directory and tellsthem to load it as an external package. Jenny uses"pkg load-db boss /home/supervisor/.octave/octave_packages.db" to make his supervisorpackages available to her. She now has 4 available packages, the new one (img_analysis)being an external package. However, relative to her supervisor, the same package is alocal installation. The next time she starts Octave, there is no trace of the external packages, pkg stillonly have 3 available packages so she adds the "pkg load-db" command to her {{Path|.octaverc}}file. In this case however, her supervisor would do better in installing his img_analysis packagein some other place to avoid clash with his own local packages. For example, he couldhave installed it at {{Path|/home/supervisor/group/octave}}. Or he could have a filesystemon the network that his students could mount whenever they needed it. === User case #2: keeping tarball ===
Denise installs Octave 3.4.3 and installs the latest version of the financial (1.0.4) and
image (2.0.0) package with "pkg install -forge financial image". After installing the packages,
tests in the package (using the cached package to run the tests in the .cc files).
==== different package versions ====
Later, Denise installs Octave 3.6.2 but keeps the previous version of Octave on the
system since some of her old code no longer runs correctly. Loading the financial
While using Octave 3.6.2, Denise installs the new version of the package
"pkg install -forge financial". The files for the previous version of the package
are kept altough although "pkg load financial" will only load the latest version. However, when
Denise is using Octave 3.4.3, as financial 1.2.0 requires Octave 3.6.0, pkg load
will only load financial 1.0.4.
==== comments ==== shouldn't `rebuild` be used instead of `reinstall` ? === Case 2 User case #3: installing and loading different package versions ===
Owen is stuck using the financial package 1.0.4 because some of his code no
longer works in the latest versions. However the latest version of financial
while "pkg load financial" always loads the latest version of the package.
=== Case 3 User case #4: Local installation of packages and Octave ===
Lisa is using Octave in a remote machine on the biochemistry department. The
system administrator installed Octave 3.6.2, signal package 1.2.0, and
general 1.0.0. Lisas Lisa uses all of them but she also requires the image package.
However, the system administrator does not have time to access security issues
with the package and tells her to install that package locally. She runs "pkg
When Octave 3.6.3 is released, Lisa wants to use the new version since it fixes
one bug that has been aanoying annoying her for a long time but the system administrator
does not want to make the update and tells her to build it herself locally
=== Case 4 User case #5: users (no sudo) sharing Octave installation with local & global packages ===
Diana is a student that wants to run her code in the departmental cluster. However,
the system does not have an installation of Octave and she needs to install it on
to her own list of available packages. which she can load.
==== comments ==== why not store the "packages.db" together with the packages? instead of loading the a packages database file,then, Diana could just say pkg addpath ~Ligia/octave === Case 5 User case #6: Automatic dependency tracking ===
John is a professor of biomechanics and uses Octave on his classes. Most of the
exercises he gives to the class require the use of multiple packages in Octave
metapackage for his student listing all required packages. The students install
it with "pkg install -url path-to-his-metapackage". The metapackage has no file
it simply lists a bunch of package has as dependencies. Since pkg solves this
dependencies automatically, a message showing which packages will be installed
is displayed before doing it.
=== User case #7: Package testing ==="pkg test" command that would run all tests for a given package. == Where to install things ===
These should not be hardcoded and taken from octave_config_info. There's many paths there whose purpose is explained on octave sources [http://hg.savannah.gnu.org/hgweb/octave/file/default/build-aux/common.mk buil-aux/common.mk] (see the ''Where To Install Things'' and ''Octave-specific directories'' sections on that file.)
 
[[Category:Packages]]

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