Manjaro Difference between pages "Create Manjaro Packages" and "Fstab - Use SystemD automount"

Difference between pages "Create Manjaro Packages" and "Fstab - Use SystemD automount"

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=Guidelines for creating Manjaro packages=
=Introduction=


This article aims to assist users creating their own packages using for Manjaro optimized [[devtools]], also for submission in Manjaro binary repositories. It covers creation of a [[PKGBUILD]] – a package build description file sourced by {{ic|makepkg}} to create a binary package from source. If already in possession of a {{ic|PKGBUILD}} - see [[makepkg]]. For instructions regarding existing rules and ways to improve package quality see [[Manjaro Packaging Standards]].
I found a combination of systemd options (on the ArchWiki [https://wiki.archlinux.org/index.php/Systemd#Automount] that can be used in the /etc/fstab when mounting storage devices - be they internal external or network shares.  


== Overview ==
The magic these mount options bring (to me) is that if a network share or an external drive that is being called via /etc/fstab is not present, they save your machine from hanging for a minute or two during the boot process.


Packages in Manjaro Linux are built using the [[makepkg]] utility and the information stored in a [[PKGBUILD]] file. When {{ic|makepkg}} is run, it searches for a {{ic|PKGBUILD}} in the current directory and follows the instructions therein to either compile or otherwise acquire the required files to be packaged within a package file ({{ic|pkgname.pkg.tar.xz}}). The resulting package contains binary files and installation instructions; readily installed with [[pacman]].
A device called this way via /etc/fstab is mounted the first time data is attempted to be accessed from it. Only on this first mount is there any (minor) noticeable delay, when compared to having the device mounted the "old" way.


An Manjaro package is no more than a tar archive, or 'tarball', compressed using xz, which contains the following files generated by makepkg:


* The binary files to install.
==A suitable problem - example==
* {{ic|.PKGINFO}}: contains all the metadata needed by pacman to deal with packages, dependencies, etc.
* {{ic|.MTREE}}: contains hashes and timestamps of the files, which are included in the local database so that pacman can verify the integrity of the package.
* {{ic|.INSTALL}}: an optional file used to execute commands after the install/upgrade/remove stage. (This file is present only if specified in the {{ic|PKGBUILD}}.)
* {{ic|.Changelog}}: an optional file kept by the package maintainer documenting the changes of the package. (It is not present in all packages.)


== Preparation ==
I have a ReadyNAS Duo v1. which is connected to my LAN. These days I quite often turn it off as it doesn't need to run perpetually.


===Prerequisite software===
A problem that this causes is that if I forget to comment out the NFS share(s) that I'm using from the /etc/fstab file, I have to wait for a minute or two during the boot process whilst the system repetitively tries to make a connection.


First ensure that the necessary tools are installed. The package group '''base-devel''' should be sufficient; it includes '''make''' and additional tools needed for compiling from source.
I attempted to get AutoFS to work for me. I got close but I just wasn't allowed to see the files on the NFS NAS share.


# pacman -S base-devel
So then I looked at the following extremely simple & effective solution. (Wish I had of done this one first, as it would have saved me a couple of hours of a loosing battle!)


One of the key tools for building packages is [[makepkg]] (provided by [[pacman]]) which does the following:
#Checks if package dependencies are installed.
#Downloads the source file(s) from the specified server(s).
#Unpacks the source file(s).
#Compiles the software and installs it under a fakeroot environment.
#Strips symbols from binaries and libraries.
#Generates the package meta file which is included with each package.
#Compresses the fakeroot environment into a package file.
#Stores the package file in the configured destination directory, which is the present working directory by default.


=== Download and test the installation ===
==How do you do use it?==


Download the source tarball of the software you want to package, extract it, and follow the author's steps to install the program.  Make a note of all commands and/or steps needed to compile and install it. You will be repeating those same commands in the ''PKGBUILD'' file.
Add the following to the beginning of the options section in your /etc/fstab the numbers at the end are a time limit for how long it should try to make a connection before giving up & moving on:


Most software authors stick to the 3-step build cycle:
noauto,x-systemd.automount,x-systemd.device-timeout=10


./configure
After I added the above to the following line in my fstab:
make
make install


This is a good time to make sure the program is working correctly.
192.168.1.15:/media-2  /mnt/NAS-media-2 nfs    noauto,x-systemd.automount,x-systemd.device-timeout=10,timeo=14,hard,intr,noatime 0 0


== Creating a PKGBUILD ==
I could boot Manjaro whilst the ReadyNAS' Cat-6 network cable was unplugged, & there was NO noticeable delay. After the system was booted, I plugged the cable in & then called the NFS share /media-2 in Worker & it read the drive & listed the contents.


When you run {{ic|makepkg}}, it will look for a {{ic|PKGBUILD}} file in the present working directory. If a {{ic|PKGBUILD}} file is found it will download the software's source code and compile it according to the instructions specified in the {{ic|PKGBUILD}} file. The instructions must be fully interpretable by the [[Wikipedia:Bash_(Unix_shell)|Bash]] shell. After successful completion, the resulting binaries and metadata of the package, i.e. package version and dependencies, are packed in a {{ic|pkgname.pkg.tar.xz}} package file that can be installed with {{ic|pacman -U ''<package file>''}}.
After that I unplugged the drive, which had Worker (my file manager of choice) looking for it as I hadn't changed out of the the media-2 directory. When I plugged the cable back in, it took ~10 seconds or so & then Worker automatically re-listed the contents or this very large partition that has well over 2000 directories, each holding multiple files.


To begin with a new package, you should first create an empty working directory, (preferably {{ic|~/abs/'''pkgname'''}}), change into that directory, and create a {{ic|PKGBUILD}} file.  You can either copy the prototype PKGBUILD {{ic|/usr/share/pacman/PKGBUILD.proto}} to your working directory or copy a {{ic|PKGBUILD}} from a similar package. The latter may be useful if you only need to change a few options.


=== Defining PKGBUILD variables ===
===Speed up your boot===


Example PKGBUILDs are located in {{Ic|/usr/share/pacman/}}. An explanation of possible {{ic|PKGBUILD}} variables can be found in the [[PKGBUILD]] article.
If you have a very large /home & the boot process is held up when a scheduled fsck takes place (really not a big problem if you are using ext4), you can add the '''x-systemd.automount''' section to the options section of the line in your fstab for /home like so:


''makepkg'' defines three variables that you should use as part of the build and install process:
UUID=<id.number> /home noauto,x-systemd.automount,ext4 defaults 0 1
; {{ic|startdir}}: This contains the absolute path to the directory where the {{ic|PKGBUILD}} file is located. This variable used to be used in combination with {{ic|/src}} or {{ic|/pkg}} postfixes, but the use of {{ic|srcdir}} and {{ic|pkgdir}} variables is the modern method. {{ic|$startdir/src}} is '''not''' guaranteed to be the same as {{ic|$srcdir}}, and likewise for {{ic|$pkgdir}}. Use of this variable is deprecated and strongly discouraged.
; {{ic|srcdir}}: This points to the directory where ''makepkg'' extracts or copies all source files.
; {{ic|pkgdir}}: This points to the directory where ''makepkg'' bundles the installed package, which becomes the root directory of your built package.
All of them contain ''absolute'' paths, which means, you don't have to worry about your working directory if you use these variables properly.


{{Note|''makepkg'', and thus the {{ic|build()}} and {{ic|package()}} functions, are intended to be non-interactive.  Interactive utilities or scripts called in those functions may break ''makepkg'', particularly if it is invoked with build-logging enabled ({{ic|-l}}). (See [https://bugs.archlinux.org/task/13214 FS13214].)}}
This will allow services that do not depend on /home to start while /home is checked by fsck, mounting /home when it is first accessed; the kernel will buffer all file access to /home until it is ready.


{{Note|Apart from the current package Maintainer, there may be previous maintainers listed above as Contributors.}}


=== PKGBUILD Functions ===
=Support=


There are 5 functions, listed here in the order they are executed if all of them exist. If one does not exist, it is simply skipped.
Following is a link to this page's forum counterpart where you can post any related feedback: [http://forum.manjaro.org/index.php?topic=4942.0]
 
{{Note|This does not apply to the {{ic|package()}} function, as it is required in every PKGBUILD}}
 
==== The {{ic|pkgver()}} function ====
 
Beginning with pacman 4.1, you can update the pkgver variable during a makepkg. {{ic|pkgver()}} is run right after the sources are fetched and extracted.
 
This is particularly useful if you are [[VCS PKGBUILD Guidelines|making git/svn/hg/etc. packages]], where the build process may remain the same, but the source could be updated every day, even every hour. The old way of doing this was to put the date into the pkgver field which, if the software was not updated, makepkg would still rebuild it thinking the version had changed. Some useful commands for this are {{ic|git describe}}, {{ic|hg identify -ni}}, etc. Please test these before submitting a PKGBUILD, as a failure in the {{ic|pkgver()}} function can stop a build in its tracks.
{{Note|pkgver cannot contain spaces or hyphens ({{ic|-}}). Using sed to correct this is common.}}
 
==== The {{ic|prepare()}} function ====
 
Pacman 4.1 introduces the {{ic|prepare()}} function. In this function, commands that are used to prepare sources for building are run, such as patching. This function is run before the build function and after package extraction. If extraction is skipped ({{ic|makepkg -e}}), then {{ic|prepare()}} is not run.
 
{{Note| (From {{ic|man PKGBUILD}}) The function is run in {{ic|bash -e}} mode, meaning any command that exits with a non-zero status will cause the function to exit.}}
 
==== The {{ic|build()}} function ====
 
Now you need to implement the {{ic|build()}} function in the {{ic|PKGBUILD}} file. This function uses common shell commands in [[Wikipedia:Bash_(Unix_shell)|Bash]] syntax to automatically compile software and create a {{ic|pkg}} directory to install the software to.  This allows ''makepkg'' to package files without having to sift through your filesystem.
 
The first step in the {{ic|build()}} function is to change into the directory created by uncompressing the source tarball. ''makepkg'' will change the current directory to {{ic|srcdir}} before executing the {{ic|build()}}, thus in most common cases the first command will look like this:
 
cd "$pkgname-$pkgver"
 
The {{ic|/usr/share/pacman/PKGBUILD.proto}} file suggests doing
 
cd "$srcdir/$pkgname-$pkgver"
 
instead. Again, as {{ic|$srcdir}} is an absolute path, this does not make any difference.
 
Now, you need to list the same commands you used when you manually compiled the software. The {{ic|build()}} function in essence automates everything you did by hand and compiles the software in the fakeroot build environment. If the software you are packaging uses a configure script, it is good practice to use {{ic|1=--prefix=/usr}} when building packages for pacman. A lot of software installs files relative to the {{ic|/usr/local}} directory, which should only be done if you are manually building from source. All Arch Linux packages should use the {{ic|/usr}} directory. As seen in the {{ic|/usr/share/pacman/PKGBUILD.proto}} file, the next two lines often look like this:
 
./configure --prefix=/usr
make
 
{{Note|If your software does not need to build anything, DO NOT use the {{ic|build()}} function. The {{ic|build()}} function is not required, but the {{ic|package()}} function is.}}
 
==== The {{ic|check()}} function ====
 
Place for calls to {{Ic|make check}} and similar testing routines. It is highly recommended to have {{ic|check()}} as it helps to make sure software has been built correctly and works fine with its dependencies.
 
Users who don't need it (and occasionally maintainers who can not fix a package for this to pass) can disable it using {{Ic|!check}} in PKGBUILD/makepkg options or call {{ic|makepkg}} with {{ic|--nocheck}} flag.
 
==== The {{ic|package()}} function ====
 
The final step is to put the compiled files in a directory where ''makepkg'' can retrieve them to create a package.  This by default is the {{ic|pkg}} directory—a simple fakeroot environment.  The {{ic|pkg}} directory replicates the hierarchy of the root file system of the software's installation paths.  If you have to manually place files under the root of your filesystem, you should install them in the {{ic|pkg}} directory under the same directory structure.  For example, if you want to install a file to {{ic|/usr/bin}}, it should instead be placed under {{ic|$pkgdir/usr/bin}}.  Very few install procedures require the user to copy dozens of files manually.  Instead, for most software, calling {{ic|make install}} will do so.  The final line should look like the following in order to correctly install the software in the {{ic|pkg}} directory:
 
make DESTDIR="$pkgdir/" install
 
{{Note|It is sometimes the case where {{ic|DESTDIR}} is not used in the {{ic|Makefile}}; you may need to use {{ic|prefix}} instead. If the package is built with ''autoconf''/''automake'', use {{ic|DESTDIR}}; this is what is [https://www.gnu.org/software/automake/manual/automake.html#Install documented] in the manuals. If {{ic|DESTDIR}} does not work, try building with {{ic|1=make prefix="$pkgdir/usr/" install}}. If that does not work, you will have to look further into the install commands that are executed by "{{ic|make <...> install}}".}}
 
In some odd cases, the software expects to be run from a single directory. In such cases, it is wise to simply copy these to {{ic|$pkgdir/opt}}.
 
More often than not, the installation process of the software will create any sub-directories below the {{ic|pkg}} directory. If it does not, however, ''makepkg'' will generate a lot of errors and you will need to manually create sub-directories by adding the appropriate {{ic|mkdir -p}} commands in the {{ic|build()}} function before the installation procedure is run.
 
In old packages, there was no {{ic|package()}} function. So, files were put into the ''pkg'' directory at the end of the {{ic|build()}} function. If {{ic|package()}} is not present, {{ic|build()}} runs via ''fakeroot''. In new packages, {{ic|package()}} is required and runs via ''fakeroot'' instead, and {{ic|build()}} runs without any special privileges.
 
{{ic|makepkg --repackage}} runs only the {{ic|package()}} function, so it creates a {{ic|*.pkg.*}} file without compiling the package. This may save time e.g. if you just have changed the {{ic|depends}} variable of the package.
 
{{Note|The {{ic|package()}} function is the only required function in a PKGBUILD. If you must only copy files into their respective directories to install a program, do not put it in the {{ic|build()}} function, put that in the {{ic|package()}} function.}}
 
== Testing the PKGBUILD and package ==
 
As you are writing the {{ic|build()}} function, you will want to test your changes frequently to ensure there are no bugs. You can do this using the {{ic|makepkg}} command in the directory containing the {{ic|PKGBUILD}} file. With a properly formatted {{ic|PKGBUILD}}, makepkg will create a package; with a broken or unfinished {{ic|PKGBUILD}}, it will raise an error.
 
If makepkg finishes successfully, it will place a file named {{ic|pkgname-pkgver.pkg.tar.xz}} in your working directory. This package can be installed with the {{ic|pacman -U}} command. However, just because a package file was built does not imply that it is fully functional. It might conceivably contain only the directory and no files whatsoever if, for example, a prefix was specified improperly. You can use pacman's query functions to display a list of files contained in the package and the dependencies it requires with {{ic|pacman -Qlp [package file]}} and {{ic|pacman -Qip [package file]}} respectively.
 
If the package looks sane, then you are done! However, if you plan on releasing the {{ic|PKGBUILD}} file, it is imperative that you check and double-check the contents of the {{ic|depends}} array.
 
Also ensure that the package binaries actually ''run'' flawlessly! It is annoying to release a package that contains all necessary files, but crashes because of some obscure configuration option that does not quite work well with the rest of the system. If you are only going to compile packages for your own system, though, you do not need to worry too much about this quality assurance step, as you are the only person suffering from mistakes, after all.
 
=== Checking package sanity ===
 
After testing package functionality check it for errors using [[namcap]]:
$ namcap PKGBUILD
$ namcap ''<package file name>''.pkg.tar.xz
 
Namcap will:
# Check PKGBUILD contents for common errors and package file hierarchy for unnecessary/misplaced files
# Scan all ELF files in package using {{ic|ldd}}, automatically reporting which packages with required shared libraries are missing from {{Ic|depends}} and which can be omitted as transitive dependencies
# Heuristically search for missing and redundant dependencies
and much more.
Get into the habit of checking your packages with namcap to avoid having to fix the simplest mistakes after package submission.
 
== Submitting packages to the AUR ==
 
Please read [https://wiki.archlinux.org/index.php/AUR_User_Guidelines#Submitting_packages AUR User Guidelines#Submitting packages] for a detailed description of the submission process.
 
== Summary ==
 
#Download the source tarball of the software you want to package.
#Try compiling the package and installing it into an arbitrary directory.
#Copy over the prototype {{ic|/usr/share/pacman/PKGBUILD.proto}} and rename it to {{ic|PKGBUILD}} in a temporary working directory -- preferably {{ic|~/abs/}}.
#Edit the {{ic|PKGBUILD}} according to the needs of your package.
#Run {{ic|makepkg}} and see whether the resulting package is built correctly.
#If not, repeat the last two steps.
 
=== Warnings ===
 
* Before you can automate the package building process, you should have done it manually at least once unless you know ''exactly'' what you are doing ''in advance'', in which case you would not be reading this in the first place. Unfortunately, although a good bunch of program authors stick to the 3-step build cycle of "{{ic|./configure}}; {{ic|make}}; {{ic|make install}}", this is not always the case, and things can get real ugly if you have to apply patches to make everything work at all. Rule of thumb: If you cannot get the program to compile from the source tarball, and make it install itself to a defined, temporary subdirectory, you do not even need to try packaging it. There is not any magic pixie dust in {{ic|makepkg}} that makes source problems go away.
* In a few cases, the packages are not even available as source and you have to use something like {{ic|sh installer.run}} to get it to work. You will have to do quite a bit of research (read READMEs, INSTALL instructions, man pages, perhaps ebuilds from Gentoo or other package installers, possibly even the MAKEFILEs or source code) to get it working. In some really bad cases, you have to edit the source files to get it to work at all. However, {{ic|makepkg}} needs to be completely autonomous, with no user input. Therefore if you need to edit the makefiles, you may have to bundle a custom patch with the {{ic|PKGBUILD}} and install it from inside the {{ic|prepare()}} function, or you might have to issue some {{ic|sed}} commands from inside the {{ic|prepare()}} function.
 
==Create a patch file==
 
Example for individual file
 
  $ diff -Naur filename.ext.old filename.ext > filename-patchname.diff
 
  # PKGBUILD
  cd "${srcdir}/${pkgname}-${pkgver}"
  patch -uN filename.ext ../filename-patchname.diff || return 1
 
Example for multiple files
 
  $ diff -Naur package-ver.old package-ver > package-patchname.diff
 
  # PKGBUILD
  cd "${srcdir}/${pkgname}-${pkgver}"
  patch -uNp1 -i ../${pkgname}-patchname.diff || return 1




[[Category:Contents Page]]
[[Category:Contents Page]]

Revision as of 02:42, 12 February 2014

Introduction

I found a combination of systemd options (on the ArchWiki [1] that can be used in the /etc/fstab when mounting storage devices - be they internal external or network shares.

The magic these mount options bring (to me) is that if a network share or an external drive that is being called via /etc/fstab is not present, they save your machine from hanging for a minute or two during the boot process.

A device called this way via /etc/fstab is mounted the first time data is attempted to be accessed from it. Only on this first mount is there any (minor) noticeable delay, when compared to having the device mounted the "old" way.


A suitable problem - example

I have a ReadyNAS Duo v1. which is connected to my LAN. These days I quite often turn it off as it doesn't need to run perpetually.

A problem that this causes is that if I forget to comment out the NFS share(s) that I'm using from the /etc/fstab file, I have to wait for a minute or two during the boot process whilst the system repetitively tries to make a connection.

I attempted to get AutoFS to work for me. I got close but I just wasn't allowed to see the files on the NFS NAS share.

So then I looked at the following extremely simple & effective solution. (Wish I had of done this one first, as it would have saved me a couple of hours of a loosing battle!)


How do you do use it?

Add the following to the beginning of the options section in your /etc/fstab the numbers at the end are a time limit for how long it should try to make a connection before giving up & moving on:

noauto,x-systemd.automount,x-systemd.device-timeout=10

After I added the above to the following line in my fstab:

192.168.1.15:/media-2   /mnt/NAS-media-2 nfs    noauto,x-systemd.automount,x-systemd.device-timeout=10,timeo=14,hard,intr,noatime 0 0

I could boot Manjaro whilst the ReadyNAS' Cat-6 network cable was unplugged, & there was NO noticeable delay. After the system was booted, I plugged the cable in & then called the NFS share /media-2 in Worker & it read the drive & listed the contents.

After that I unplugged the drive, which had Worker (my file manager of choice) looking for it as I hadn't changed out of the the media-2 directory. When I plugged the cable back in, it took ~10 seconds or so & then Worker automatically re-listed the contents or this very large partition that has well over 2000 directories, each holding multiple files.


Speed up your boot

If you have a very large /home & the boot process is held up when a scheduled fsck takes place (really not a big problem if you are using ext4), you can add the x-systemd.automount section to the options section of the line in your fstab for /home like so:

UUID=<id.number> /home noauto,x-systemd.automount,ext4 defaults 0 1

This will allow services that do not depend on /home to start while /home is checked by fsck, mounting /home when it is first accessed; the kernel will buffer all file access to /home until it is ready.


Support

Following is a link to this page's forum counterpart where you can post any related feedback: [2]

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