Difference between pages "Funtoo:Metro" and "The Gentoo.org Redesign, Part 2"

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[[Metro]] is the build system for [[Funtoo Linux]] and [[Gentoo Linux]] stages. It automates the bootstrapping process.
{{Article
|Summary=Have you ever woken up in the morning to the realization that your personal development Web site isn't really that great? If so, you're in good company. In this series, Daniel Robbins shares his experiences as he redesigns the www.gentoo.org Web site using technologies like XML, XSLT, and Python. Along the way, you may find some excellent approaches to use in your next Web site redesign. In this, the second installment, Daniel shows off the new documentation system and sets up a daily CVS-log mailing list.
|Author=Drobbins
|Previous in Series=The Gentoo.org Redesign, Part 1
|Next in Series=The Gentoo.org Redesign, Part 3
}}
== The doc system ==


This tutorial will take you through installing, setting up and running [[Metro]].
If you've read the first installment of my series on the gentoo.org redesign, then you know that I'm the Chief Architect of Gentoo Linux, making me responsible for the Gentoo Linux Web site. And right now, the site leaves a lot to be desired. Yes, it does look somewhat attractive, but when you look beyond the cute graphics you will see that it really doesn't serve the needs of its primary target audience: Gentoo Linux developers, users, and potential users.


= Preface =
Last time, I used a user-centric design approach to create a set of priorities for the site, and then used these priorities to create an action plan for revamping gentoo.org. Two things were at the top of the priority list: new developer documentation and a new mailing list to communicate to developers changes made to our CVS repository. While adding the new CVS mailing list was relatively easy (though, as you will see, it was more difficult than I thought), the new developer documentation required a lot of planning and work.


== How Metro Works ==
Not only did I need to create some actual documentation (a task that I had been ignoring for too long), but I also had to choose an official XML syntax that our new master documentation would use. You see, until a few weeks ago, I was creating the documentation in raw HTML. This was definitely a naughty thing to do, because by doing this content was being mixed (the actual information) with presentation (the display-related HTML tags). And what did I end up with? An inflexible mess, that's what. It was hard to edit the actual documentation and extremely difficult to make site-wide HTML improvements.


You may be wondering how [[Metro]] creates its first stage tarball. As you may have guessed, [[Metro]] cannot create a stage tarball out of thin air. To build a new stage tarball, [[Metro]] must use an existing, older stage tarball called a "seed" stage. This "seed" stage typically is used as the ''build environment'' for creating the stage we want.
In this article, I'll proudly demonstrate the site's new flexible XML documentation solution. But first, I'll recap my experiences in adding the CVS log mailing list to our site.


[[Metro]] can use two kinds of seed stages. Traditionally, [[Metro]] has used a stage3 as a seed stage. This stage3 is then used to build a new stage1, which in turn is used to build a new stage2, and then a new stage3. This is generally the most reliable way to build [[Gentoo Linux]] or [[Funtoo Linux]], so it's the recommended approach.
== Adding the CVS log mailing list ==
{{fancyimportant|'''After switching metro builds to Funtoo profile, Gentoo stages are no longer provided'''!}}


== Seeds and Build Isolation ==
The goal of the CVS log mailing list is to inform developers of new commits made to our CVS repository. Since I already had the mailman mailing list manager (see Resources) installed, I thought that creating this new list would be easy. First, I would simply create the mailing list, then add the proper "hook" to the CVS repository so that e-mails would be automatically generated and sent out, describing the changes to our sources as they happened.


Another important concept to mention here is something called ''build isolation''. Because [[Metro]] creates an isolated build environment, and the build environment is explicitly defined using existing, tangible entities -- a seed stage and a portage snapshot -- you will get consistent, repeatable results. In other words, the same seed stage, portage snapshot and build instructions will generate an essentially identical result, even if you perform the build a month later on someone else's workstation.
I first started researching a special file in my repository's CVSROOT called "loginfo." Theoretically, by modifying this file, I could instruct CVS to execute a script when any commit (and thus, modification) was made to the repository. So I created a special loginfo script and plugged it into my existing repository. And it did indeed send out e-mails to the new "gentoo-cvs" mailing list whenever modifications were made to our sources.


== Local Build ==
Unfortunately, this solution wasn't all I'd hoped it would be. First of all, it generated lots of e-mail messages -- one for each modified file -- and secondly, the messages were cryptic and sometimes even empty! I quickly removed my loginfo script and put the gentoo-cvs mailing list project on hold. It was clear that CVS's loginfo hook wasn't appropriate for my needs, and I had a hard time tracking down any loginfo-related documentation that could help me solve my problem.


Say you wanted to build a new <tt>pentium4</tt> stage3 tarball. The recommended method of doing this would be to grab an existing <tt>pentium4</tt> stage3 tarball to use as your seed stage. [[Metro]] will be told to use this existing <tt>pentium4</tt> stage3 to build a new stage1 for the same <tt>pentium4</tt>. For this process, the generic <tt>pentium4</tt> stage3 would provide the ''build environment'' for creating our new stage1. Then, the new stage1 would serve as the build environment for creating the new <tt>pentium4</tt> stage2. And the new <tt>pentium4</tt> stage2 would serve as the build environment for creating the new <tt>pentium4</tt> stage3.
== cvs2cl.pl ==


In the [[Metro]] terminology this is called a '''local build''', which means a stage3 of a given architecture is used to seed a brand new build of the same architecture. Incidentally this will be the first exercise we are going to perform in this tutorial.
Several weeks later I started looking for an alternative to loginfo. This time I did the smart thing and headed over to http://freshmeat.net. There I quickly found just what I was looking for: the incredibly wonderful cvs2cl.pl perl script available from http://red-bean.com (see Resources). Instead of using the loginfo hook, cvs2cl.pl uses the cvs log command to connect directly to the repository and extract the appropriate relevant log information. Also, rather than spitting out relatively cryptic CVS log messages, it does a great job of reformatting everything into a readable ChangeLog format:


A week later, you may want to build a brand new <tt>pentium4</tt> stage3 tarball. Rather than starting from the original <tt>pentium4</tt> stage3 again, you'd probably configure [[Metro]] to use the most-recently-built <tt>pentium4</tt> stage3 as the seed. [[Metro]] has built-in functionality to make this easy, allowing it to easily find and track the most recent stage3 seed available.
{{file|desc=Output generated by cvs2cl.pl|body=
 
2001-04-09 20:58  drobbins
== Remote Build ==
      * app-doc/gentoo-web/files/xml/dev.xml: new fixes
 
2001-04-09 20:47  drobbins
[[Metro]] can also perform '''remote build''', where a stage3 of a different, but binary compatible, architecture is used as a seed to build a different architecture stage3. Consequentiality the second exercise we are going to perform in this tutorial will be to build a <tt>core2 32bit</tt> stage3 tarball from the <tt>pentium4</tt> stage3 tarball we have just built.
      * app-doc/gentoo-web/: gentoo-web-1.0.ebuild,  
 
      files/pyhtml/index.pyhtml, files/xml/gentoo-howto.xml: new gentoo-howto
TODO: add caveats about what archs can be seeded and what can be not (maybe a table?)
      fixes
 
2001-04-09 20:03  drobbins
== Tailored Build ==
      * app-doc/gentoo-web/files/xml/dev.xml: typo fix
 
2001-04-09 20:02  drobbins
Last, it's also worthy noting that both in <tt>local</tt> and <tt>remote builds</tt>, [[Metro]] can be configured to add and/or remove individual packages to the final tarball.
      * app-doc/gentoo-web/files/pyhtml/index.pyhtml: little update
Let's say you can't live without <tt>app-misc/screen</tt>, at the end of this tutorial, we will show how to have your tailored stage3 to include it.
}}
 
== Installing Metro ==
 
'''The recommended and supported method''' is to use the Git repository of [[Metro]].  First, ensure you remove the {{Package|dev-util/metro}} package if you had installed it:
 
<console>
# ##i##emerge -aC dev-util/metro
</console>
 
Then ensure that {{Package|dev-vcs/git}} and {{Package|dev-python/boto}} are installed on your system:
 
<console>
# ##i##emerge dev-vcs/git
# ##i##emerge dev-python/boto
</console>
 
Next, clone the master git repository as follows:
 
<console>
# ##i##cd /root
# ##i##git clone git://github.com/funtoo/metro.git
# ##i##ln -s /root/metro/metro /usr/bin/metro
# ##i##cp /root/metro/metro.conf ~/.metro
</console>
 
You will now have a directory called <tt>/root/metro</tt> that contains all the [[Metro]] source code.
 
Metro is now installed. It's time to customize it for your local system.
 
= Configuring Metro =
 
{{Note|Metro is not currently able to build Gentoo stages. See {{Bug|FL-901}}.}}
 
[[User:Drobbins|Daniel Robbins]] maintains [[Metro]], so it comes pre-configured to successfully build [[Funtoo Linux]] releases. Before reading further, you might want to customize some basic settings like the number of concurrent jobs to fit your hardware's capabilities or the directory to use for produced stage archives. This is accomplished by editing <tt>~/.metro</tt> which is the [[Metro]]'s master configuration file.
 
Please note that <code>path/install</code> must point to where metro was installed. Point <code>path/distfiles</code> to where your distfiles reside. Also set <code>path/mirror/owner</code> and <code>path/mirror/group</code> to the owner and group of all the files that will be written to the build repository directory, which by default (as per the configuration file) is at <code>/home/mirror/funtoo</code>.
 
{{file|name=.metro|desc=Metro configuration|body=
# Main metro configuration file - these settings need to be tailored to your install:
 
[section path]
install: /root/metro
tmp: /var/tmp/metro
distfiles: /var/src/distfiles
work: $[path/tmp]/work/$[target/build]/$[target/name]
 
[section path/mirror]
 
: /home/mirror/funtoo
owner: root
group: repomgr
dirmode: 775


[section portage]
cvs2cl.pl can also be instructed to generate output in XML format, and in my next article I'll take advantage of this by incorporating an up-to-date ChangeLog into the new developer section of our site.


MAKEOPTS: auto
== The cvslog.sh script ==


[section emerge]
Here's the script I now use to generate the daily ChangeLog e-mails. First, it changes the current working directory to the location of my checked-out CVS repository. Then, it creates $yesterday and $today environment variables that contain the appropriate dates in RFC 822 format. Notice that both date variables have the time set to either "00:00" or midnight. These variables are, in turn, used to create a $cvsdate variable that is then passed to cvs2cl.pl to specify the date range that I'm interested in -- the span of time from yesterday at midnight to today at midnight. Thus, the $cvsdate variable contains a datespec that informs cvs2cl.pl to log only changes made yesterday, but not others.


options: --jobs=4 --load-average=4 --keep-going=n
In addition, I also created a $nicedate variable (used in the mail subject line) and use the mutt mailer (in mailx compatibility mode [see Resources]) to send the e-mail to the gentoo-cvs mailing list:


# This line should not be modified:
{{file|name=cvslog.sh|body=
[collect $[path/install]/etc/master.conf]
#!/bin/bash
cd /usr/portage
cvs -q update -dP
yesterday=`date -d "1 day ago 00:00" -R`
today=`date -d "00:00" -R`
cvsdate=-d\'${yesterday}\<${today}\'
nicedate=`date -d yesterday +"%d %b %Y %Z (%z)"`
/home/drobbins/gentoo/cvs2cl.pl -f /home/drobbins/gentoo/cvslog.txt -l "${cvsdate}"
mutt -x gentoo-cvs -s "cvs log for $nicedate" <\
/home/drobbins/gentoo/cvslog.txt
}}
}}


== Arch and Subarch ==
Using cron, I run this script every night at midnight. Thanks to cvs2cl.pl, my developers now get accurate and readable daily CVS updates.
 
In the following example we are creating a pentium4 stage 3 compiled for x86-32bit binary compatibility. Pentium4 is a subarch of the x86-32bit architecture. Once you have metro installed you may find a full list of each subarch in your <tt>/root/metro/subarch</tt> directory each subarch will have the file extension .spec
Example:
<console>
###i## ls /root/metro/subarch
# ls subarch/
amd64-bulldozer-pure64.spec  armv7a.spec          core-avx-i.spec        i686.spec        pentium.spec
amd64-bulldozer.spec        armv7a_hardfp.spec  core2_32.spec          k6-2.spec        pentium2.spec
amd64-k10-pure64.spec        athlon-4.spec        core2_64-pure64.spec    k6-3.spec        pentium3.spec
amd64-k10.spec              athlon-mp.spec      core2_64.spec          k6.spec          pentium4.spec
amd64-k8+sse3.spec          athlon-tbird.spec    corei7-pure64.spec      native_32.spec    pentiumpro.spec
amd64-k8+sse3_32.spec        athlon-xp.spec      corei7.spec            native_64.spec    prescott.spec
amd64-k8-pure64.spec        athlon.spec          generic_32.spec        niagara.spec      ultrasparc.spec
amd64-k8.spec                atom_32.spec        generic_64-pure64.spec  niagara2.spec    ultrasparc3.spec
amd64-k8_32.spec            atom_64-pure64.spec  generic_64.spec        nocona.spec      xen-pentium4+sse3.spec
armv5te.spec                atom_64.spec        generic_sparcv9.spec    opteron_64.spec  xen-pentium4+sse3_64.spec
armv6j.spec                  btver1.spec          geode.spec              pentium-m.spec
armv6j_hardfp.spec          btver1_64.spec      i486.spec              pentium-mmx.spec
</console>


= First stages build (local build) =
== The documentation project ==


To get this all started, we need to bootstrap the process by downloading an initial seed stage3 to use for building and place it in its proper location in <tt>/home/mirror/funtoo</tt>, so that [[Metro]] can find it. We will also need to create some special &quot;control&quot; files in <tt>/home/mirror/funtoo</tt>, which will allow [[Metro]] to understand how it is supposed to proceed.
Now, for the Gentoo Linux documentation project. Our new documentation system involves two groups of people or target audiences: the documentation creators and the documentation readers. The creators need a well-designed XML syntax that doesn't get in their way; the readers, who couldn't care less about the XML, want generated HTML documentation that is both functional and attractive. The implementation challenge is to put together a complete system that addresses the needs of both audiences. Oh, and I suppose there is a third "audience" -- me, the webmaster and the person designing the new system. Since I'm going to be interacting with the new doc system whenever the site is upgraded, I need it to be reliable and flexible.


== Step 0: Optional Quick Copy of Portage Tree ==
== The Web-ready HTML ==


There is a quick step you can perform to avoid having Metro re-clone the entire Portage tree. Perform this as root:
First, let's talk a bit about the Web-ready HTML that'll be generated from my master XML files. To make great, readable documentation, I'll need to have support for the proper XML tags. For example, the ability to insert notes, important messages, and warnings into the body of the document (and have them prominently displayed in the resultant HTML) is a must. Also, I must be able to insert blocks of code, and it would be great if actual user input could somehow be offset from program output. I could even add tags that highlight the source code comments in an alternate color so that the code blocks are more readable.


<console>
The documents should have a table of contents (with hyperlinks to the appropriate chapters), a synopsis, a revision date, version, and an authors list at the top of the document. And, of course, every document should have a header at the extreme top of the page containing a small Gentoo Linux logo. Clicking on this logo should bring you back to the main Gentoo Linux page. Last but not least, every document should have a footer that contains copyright information, along with a contact e-mail address.
# ##i##install -d /var/tmp/metro/cache/cloned-repositories
# ##i##cat /root/metro/etc/builds/funtoo-current/build.conf  | grep name
# ##i##name: ports-2012
# ##i##cp -a /usr/portage /var/tmp/metro/cache/cloned-repositories/ports-2012
# ##i##cd /usr/portage; git checkout funtoo.org
</console>


== Step 1: Set up pentium4 repository (local build) ==
== The spiffy new logo ==


Assuming we're following the basic steps outlined in the previous section, and building an unstable funtoo (<tt>funtoo-current</tt>) build for the <tt>pentium4</tt>, using a generic <tt>pentium4</tt> stage3 as a seed stage, then here the first set of steps we'd perform:
This was a hefty list of requirements, and I decided to focus on the most entertaining part first, the new Gentoo Linux logo that would appear in the upper-left corner of every Gentoo Linux document. I used the "g" from the "gentoo" graphic (created using the excellent and free Blender 3D program) on our main page as the basis for the new smaller logo. I tweaked the extrusion settings a bit and then added a chrome environment map. Finally, I positioned the lights and camera just so, and the new logo was complete. After importing it into Xara X (see Resources) and adding some text, this was the result:


<console>
[[File:L-redesign-02.gif|frame|class=img-responsive|caption=The new Gentoo Linux logo]]
# ##i##install -d "${METRO_MIRROR}/funtoo-current/x86-32bit/pentium4"
# ##i##cd "${METRO_MIRROR}/funtoo-current/x86-32bit/pentium4"
# ##i##install -d 2011-12-13
# ##i##cd 2011-12-13
# ##i##wget -c http://ftp.osuosl.org/pub/funtoo/funtoo-current/x86-32bit/pentium4/2011-12-13/stage3-pentium4-funtoo-current-2011-12-13.tar.xz
# ##i##cd ..
# ##i##install -d .control/version
# ##i##echo &quot;2011-12-13&quot; &gt; .control/version/stage3
# ##i##install -d .control/strategy
# ##i##echo &quot;local&quot; &gt; .control/strategy/build
# ##i##echo &quot;stage3&quot; &gt; .control/strategy/seed
</console>


OK, let's review the steps above. First, we create the directory <tt>"${METRO_MIRROR}/funtoo-current/x86-32bit/pentium4"</tt>, which is where Metro will expect to find unstable <tt>funtoo-current</tt> pentium4 builds -- it is configured to look here by default. Then we create a specially-named directory to house our seed x86 stage3. Again, by default, Metro expects the directory to be named this way. We enter this directory, and download our seed x86 stage3 from funtoo.org. Note that the <tt>2010-12-24</tt> version stamp matches. Make sure that your directory name matches the stage3 name too. Everything has been set up to match Metro's default filesystem layout.
I used this new logo as inspiration for the rest of the HTML color scheme, using a purplish theme throughout. I made heavy use of cascading style sheets (CSS) to control font attributes and spacing. Once I had a decent HTML prototype in place, I started focusing on the guts of the new documentation -- the new XML syntax. I wanted the syntax to be as simple as possible, so I created just enough XML tags to allow for the proper organization of the document, but no more. Then I started working on the XSLT to transform the XML into the target HTML.


Next, we go back to the <tt>"${METRO_MIRROR}/funtoo-current/x86-32bit/pentium4"</tt> directory, and inside it, we create a <tt>.control</tt> directory. This directory and its subdirectories contain special files that Metro references to determine certain aspects of its behavior. The <tt>.control/version/stage3</tt> file is used by Metro to track the most recently-built stage3 for this particular build and subarch. Metro will automatically update this file with a new version stamp after it successfully builds a new stage3. But because Metro didn't actually ''build'' this stage3, we need to set up the <tt>.control/version/stage3</tt> file manually. This will allow Metro to find our downloaded stage3 when we set up our pentium4 build to use it as a seed. Also note that Metro will create a similar <tt>.control/version/stage1</tt> file after it successfully builds an pentium4 funtoo-current stage1.
== The result! ==


We also set up <tt>.control/strategy/build</tt> and <tt>.control/strategy/seed</tt> files with values of <tt>local</tt> and <tt>stage3</tt> respectively. These files define the building strategy Metro will use when we build pentium4 funtoo-current stages. With a build strategy of <tt>local</tt>, Metro will source its seed stage from funtoo-current pentium4, the current directory. And with a seed strategy of <tt>stage3</tt>, Metro will use a stage3 as a seed, and use this seed to build a new stage1, stage2 and stage3.
After much tweaking and a good amount of feedback from one of my developers, the new documentation system reached the point where it was ready for use. I immediately began work on our first new development guide, "The Gentoo Linux Documentation Guide" (xml-guide.html), which contains a complete description of the new XML format. Not only did this allow other developers to begin work on the new-style documentation, but it also served as an excellent example of the new documentation system in action. Be sure to read this guide to get a complete understanding of our new XML syntax.


== Step 2: Building the pentium4 stages ==
== DocBook vs. Guide ==


Incidentally, if all you wanted to do at this point was to build a new pentium4 funtoo-current stage1/2/3 (plus openvz and vserver templates). You would begin the process by typing:
If you're working on your own documentation solution, you may also want to consider the DocBook XML and SGML formats (see Resources). DocBook is well-suited for large-scale technical documentation and book projects, is very flexible, and has many (maybe too many) features. In addition, there are a number of existing packages that can be used to convert DocBook XML/SGML to man pages, texinfo files, Postscript, PDF, and, of course, HTML formats.


<console>
I didn't choose DocBook because a lightweight XML syntax worked best for Gentoo's needs. Right now, our XML guide syntax has around 20 tags and about 10 attributes. The limited tagset makes guide XML easy to transform into other formats such as HTML, and also ensures a certain level of consistency throughout our entire documentation set, since the format is so simple. Because I have my own XML format, I'll be able to extend the format with new tags as needed. I like having that level of control. I view XML as a technology that should be used by people to structure their data in ways that they find most helpful. In other words, the ability to define our own elements and attributes is a precious thing, and I should take full advantage of it. After all, it's the defining feature of XML.
# ##i##cd /root/metro
# ##i##scripts/ezbuild.sh funtoo-current pentium4
</console>


If you have a slow machine, it could take several hours to be completed because several "heavy" components like gcc or glibc have to be recompiled in each stage. Once a stage has been successfully completed, it is placed in the <tt>"${METRO_MIRROR}/funtoo-current/x32-bit/pentium4/YYYY-MM-DD"</tt> subdirectory, where <tt>YYYY-MM-DD</tt> is today's date at the time the <tt>ezbuild.sh</tt> script was started or the date you put on the ezscript.sh command line.
Of course, creating your own XML syntax is not always the best solution, especially when data interchange is important to you. Amid all the XML hype, one thing that is often overlooked is that conversion to and from different XML formats can be extremely difficult. In many cases, the two formats won't be 100% compatible, and you'll have the unpleasant choice of either throwing away data and/or metadata, intentionally avoiding use of certain elements or attributes, or creating a "super-format" that will accommodate the data and metadata from both XML formats. In the documentation world, DocBook is a pretty good choice as a "super-format" because it's so flexible; it can easily accommodate documentation imported from a variety of sources.


== Step 3: The next build ==
However, DocBook's richness and flexibility can also create problems. For example, there may be hundreds of tags that you may never need, and supporting all these tags in your XSLT can make conversion to other formats more difficult. So, while DocBook is a great container for documentation converted from other formats, your own minimal XML syntax will almost always be easier to convert to other formats.


At this point, you now have a new pentium4 stage3. If you'd like, you can reconfigure Metro to use the most recently-built pentium4 stage3 as a seed for any pentium4 builds. To do this, simply type:
The most important thing is to carefully evaluate any potential solution while keeping the needs of your target audience(s) in mind.
 
<console> # ##i##echo &quot;local&quot; &gt; /home/mirror/funtoo/funtoo-current/x86-32bit/pentium4/.control/strategy/build</console>
Now, Metro will use the most recentpentium4 stage3 as a seed. The <tt>.control/remote</tt> files you created will be ignored by Metro, since it's no longer going to perform a remote build.
 
= Building for another binary compatible architecture (remote build) =
 
As written above, [[Metro]] is able to perform '''remote build''' building different architecture stage3 from a binary compatible seeding stage3 (e.g. using a pentium4 stage3 to seed a <tt>Intel Core2 32bits</tt> stage3).
 
In the Metro terminology this is called a '''remote build''' (a stage 3 of a different, but binary compatible, architecture is used as a seed).
What's not compatible? You can't use a <tt>Sparc</tt> architecture to generate an <tt>x86</tt> or <tt>ARM</tt> based stage and vice-versa. If you use a 32bit stage then you don't want to seed a 64bit build from it. Be sure that you are using a stage from the same architecture that you are trying to seed. Check [http://ftp.osuosl.org/pub/funtoo/funtoo-current/ Funtoo-current FTP Mirror] for a stage that is from the same Architecture that you will be building. 
 
{{Note|Often, one build (ie. funtoo-current) can be used as a seed for another build such as funtoo-stable. However, hardened builds require hardened stages as seeds in order for the build to complete successfully.}}
 
== Step 1: Set up Core_2 32bit repository ==
 
In this example, we're going to use this pentium4 funtoo-current stage3 to seed a new Core_2 32bit funtoo-current build. To get that done, we need to set up the pentium4 build directory as follows:
 
<console>
# ##i## cd "${METRO_MIRROR}/funtoo-current/x86-32bit"
# ##i##install -d core2_32
# ##i##cd core2_32
# ##i##install -d .control/strategy
# ##i##echo &quot;remote&quot; &gt; .control/strategy/build
# ##i##echo &quot;stage3&quot; &gt; .control/strategy/seed
# ##i##install -d .control/remote
# ##i##echo &quot;funtoo-current&quot; &gt; .control/remote/build
# ##i##echo &quot;x86-32bit&quot; &gt; .control/remote/arch_desc
# ##i##echo &quot;pentium4&quot; &gt; .control/remote/subarch
</console>
 
The steps we follow are similar to those we performed for a ''local build'' to set up our pentium4 directory for local build. However, note the differences. We didn't download a stage, because we are going to use the pentium4 stage to build a new Core_2 32bit stage. We also didn't create the <tt>.control/version/stage{1,3}</tt> files because Metro will create them for us after it successfully builds a new stage1 and stage3. We are still using a <tt>stage3</tt> seed strategy, but we've set the build strategy to <tt>remote</tt>, which means that we're going to use a seed stage that's not from this particular subdirectory. Where are we going to get it from? The <tt>.control/remote</tt> directory contains this information, and lets Metro know that it should look for its seed stage3 in the <tt>/home/mirror/funtoo/funtoo-current/x86-32bit/pentium4</tt> directory. Which one will it grab? You guessed it -- the most recently built ''stage3'' (since our seed strategy was set to <tt>stage3</tt>) that has the version stamp of <tt>2010-12-24</tt>, as recorded in <tt>/home/mirror/funtoo-current/x86-32bit/pentium4/.control/version/stage</tt>. Now you can see how all those control files come together to direct Metro to do the right thing.
 
{{Note|<code>arch_desc</code> should be set to one of: <code>x86-32bit</code>, <code>x86-64bit</code> or <code>pure64</code> for PC-compatible systems. You must use a 32-bit build as a seed for other 32-bit builds, and a 64-bit build as a seed for other 64-bit builds.}}
 
== Step 2: Building the Core_2 32bit stages ==
 
Now, you could start building your new Core_2 32bit stage1/2/3 (plus openvz and vserver templates) by typing the following:
 
<console>
# ##i##/root/metro/scripts/ezbuild.sh funtoo-current core2_32
</console>
 
In that case, the produced stages are placed in the <tt>/home/mirror/funtoo/funtoo-current/x32-bit/core2_32/YYYY-MM-DD</tt> subdirectory.
 
== Step 3: The Next Build ==
 
At this point, you now have a new Core_2 32bit stage3. If you'd like, you can reconfigure Metro to use the most recently-built Core_2 32bit stage3 as a seed for any new Core_2 32bit builds.
 
In the Metro terminology this is called a '''local build''' (a stage 3 of a a given architecture is used to seed a brand new build of the same architecture).
 
To do this, simply type:
 
<console>
# ##i##echo &quot;local&quot; &gt; /home/mirror/funtoo/funtoo-current/x86-32bit/core2_32/.control/strategy/build
</console>
 
Now, Metro will use the most recent Core_2 32bit stage3 as a seed. The <tt>.control/remote</tt> files you created will be ignored by Metro, since it's no longer going to perform a remote build.
 
= Build your own tailored stage3 =
 
Metro can be easily configured for building custom stage3 by including additional packages. Notice that including packages with heavy dependencies such as gnome, kde, xorg-server is not recommended (not tested so far). Well tested packages are <tt>app-misc/mc</tt>, <tt>app-misc/screen</tt>, <tt>sys-process/htop</tt>, <tt>sys-apps/dstat</tt>. An example for funtoo-current stage. Edit the following configuration file <tt>/root/metro/etc/builds/funtoo-current/build.conf</tt>:
{{file|name=funtoo-current/build.conf|body=
[collect ../../fslayouts/funtoo/layout.conf]
 
[section release]
 
author: Daniel Robbins <drobbins@funtoo.org>
 
[section target]
 
compression: xz
 
[section portage]
 
FEATURES:
SYNC: $[snapshot/source/remote]
USE:
 
[section profile]
 
format: new
path: gentoo:funtoo/1.0/linux-gnu
arch: $[:path]/arch/$[target/arch_desc]
build: $[:path]/build/current
flavor: $[:path]/flavor/core
mix-ins:
 
[section version]
 
python: 2.7
 
[section emerge]
 
 
[section snapshot]
 
type: live
compression: xz
 
[section snapshot/source]
 
type: git
branch: funtoo.org
# branch to have checked out for tarball:
branch/tar: origin/master
name: ports-2012
remote: git://github.com/funtoo/ports-2012.git
options: pull
 
[section metro]
 
options:
options/stage: cache/package
target: gentoo
 
[section baselayout]
 
services: sshd
 
[section multi]
 
snapshot: snapshot
 
[section files]
 
motd/trailer: [
 
>>> Send suggestions, improvements, bug reports relating to...
 
>>> This release:                  $[release/author]
>>> Funtoo Linux (general):        Funtoo Linux (http://www.funtoo.org)
>>> Gentoo Linux (general):        Gentoo Linux (http://www.gentoo.org)
]
 
[collect ../../multi-targets/$[multi/mode:zap]]
}}


= Building Gentoo stages =
== Wrapping it up ==


[[Category:HOWTO]]
With the new doc system in place, I converted all our docs to the new format and posted the new docs on our existing site. In addition, I created a link to the gentoo-cvs mailing list subscription page. The key point here is that I integrated these features into the existing site so that users could benefit from the improvements right away.
[[Category:Metro]]
{{ArticleFooter}}

Revision as of 05:00, January 1, 2015

Have you ever woken up in the morning to the realization that your personal development Web site isn't really that great? If so, you're in good company. In this series, Daniel Robbins shares his experiences as he redesigns the www.gentoo.org Web site using technologies like XML, XSLT, and Python. Along the way, you may find some excellent approaches to use in your next Web site redesign. In this, the second installment, Daniel shows off the new documentation system and sets up a daily CVS-log mailing list.
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The doc system

If you've read the first installment of my series on the gentoo.org redesign, then you know that I'm the Chief Architect of Gentoo Linux, making me responsible for the Gentoo Linux Web site. And right now, the site leaves a lot to be desired. Yes, it does look somewhat attractive, but when you look beyond the cute graphics you will see that it really doesn't serve the needs of its primary target audience: Gentoo Linux developers, users, and potential users.

Last time, I used a user-centric design approach to create a set of priorities for the site, and then used these priorities to create an action plan for revamping gentoo.org. Two things were at the top of the priority list: new developer documentation and a new mailing list to communicate to developers changes made to our CVS repository. While adding the new CVS mailing list was relatively easy (though, as you will see, it was more difficult than I thought), the new developer documentation required a lot of planning and work.

Not only did I need to create some actual documentation (a task that I had been ignoring for too long), but I also had to choose an official XML syntax that our new master documentation would use. You see, until a few weeks ago, I was creating the documentation in raw HTML. This was definitely a naughty thing to do, because by doing this content was being mixed (the actual information) with presentation (the display-related HTML tags). And what did I end up with? An inflexible mess, that's what. It was hard to edit the actual documentation and extremely difficult to make site-wide HTML improvements.

In this article, I'll proudly demonstrate the site's new flexible XML documentation solution. But first, I'll recap my experiences in adding the CVS log mailing list to our site.

Adding the CVS log mailing list

The goal of the CVS log mailing list is to inform developers of new commits made to our CVS repository. Since I already had the mailman mailing list manager (see Resources) installed, I thought that creating this new list would be easy. First, I would simply create the mailing list, then add the proper "hook" to the CVS repository so that e-mails would be automatically generated and sent out, describing the changes to our sources as they happened.

I first started researching a special file in my repository's CVSROOT called "loginfo." Theoretically, by modifying this file, I could instruct CVS to execute a script when any commit (and thus, modification) was made to the repository. So I created a special loginfo script and plugged it into my existing repository. And it did indeed send out e-mails to the new "gentoo-cvs" mailing list whenever modifications were made to our sources.

Unfortunately, this solution wasn't all I'd hoped it would be. First of all, it generated lots of e-mail messages -- one for each modified file -- and secondly, the messages were cryptic and sometimes even empty! I quickly removed my loginfo script and put the gentoo-cvs mailing list project on hold. It was clear that CVS's loginfo hook wasn't appropriate for my needs, and I had a hard time tracking down any loginfo-related documentation that could help me solve my problem.

cvs2cl.pl

Several weeks later I started looking for an alternative to loginfo. This time I did the smart thing and headed over to http://freshmeat.net. There I quickly found just what I was looking for: the incredibly wonderful cvs2cl.pl perl script available from http://red-bean.com (see Resources). Instead of using the loginfo hook, cvs2cl.pl uses the cvs log command to connect directly to the repository and extract the appropriate relevant log information. Also, rather than spitting out relatively cryptic CVS log messages, it does a great job of reformatting everything into a readable ChangeLog format:

    - Output generated by cvs2cl.pl
2001-04-09 20:58  drobbins
      * app-doc/gentoo-web/files/xml/dev.xml: new fixes
2001-04-09 20:47  drobbins
      * app-doc/gentoo-web/: gentoo-web-1.0.ebuild, 
      files/pyhtml/index.pyhtml, files/xml/gentoo-howto.xml: new gentoo-howto
      fixes
2001-04-09 20:03  drobbins
      * app-doc/gentoo-web/files/xml/dev.xml: typo fix
2001-04-09 20:02  drobbins
      * app-doc/gentoo-web/files/pyhtml/index.pyhtml: little update

cvs2cl.pl can also be instructed to generate output in XML format, and in my next article I'll take advantage of this by incorporating an up-to-date ChangeLog into the new developer section of our site.

The cvslog.sh script

Here's the script I now use to generate the daily ChangeLog e-mails. First, it changes the current working directory to the location of my checked-out CVS repository. Then, it creates $yesterday and $today environment variables that contain the appropriate dates in RFC 822 format. Notice that both date variables have the time set to either "00:00" or midnight. These variables are, in turn, used to create a $cvsdate variable that is then passed to cvs2cl.pl to specify the date range that I'm interested in -- the span of time from yesterday at midnight to today at midnight. Thus, the $cvsdate variable contains a datespec that informs cvs2cl.pl to log only changes made yesterday, but not others.

In addition, I also created a $nicedate variable (used in the mail subject line) and use the mutt mailer (in mailx compatibility mode [see Resources]) to send the e-mail to the gentoo-cvs mailing list:

   cvslog.sh
#!/bin/bash
cd /usr/portage
cvs -q update -dP
yesterday=`date -d "1 day ago 00:00" -R`
today=`date -d "00:00" -R`
cvsdate=-d\'${yesterday}\<${today}\'
nicedate=`date -d yesterday +"%d %b %Y %Z (%z)"`
/home/drobbins/gentoo/cvs2cl.pl -f /home/drobbins/gentoo/cvslog.txt -l "${cvsdate}" 
mutt -x gentoo-cvs -s "cvs log for $nicedate" <\
/home/drobbins/gentoo/cvslog.txt

Using cron, I run this script every night at midnight. Thanks to cvs2cl.pl, my developers now get accurate and readable daily CVS updates.

The documentation project

Now, for the Gentoo Linux documentation project. Our new documentation system involves two groups of people or target audiences: the documentation creators and the documentation readers. The creators need a well-designed XML syntax that doesn't get in their way; the readers, who couldn't care less about the XML, want generated HTML documentation that is both functional and attractive. The implementation challenge is to put together a complete system that addresses the needs of both audiences. Oh, and I suppose there is a third "audience" -- me, the webmaster and the person designing the new system. Since I'm going to be interacting with the new doc system whenever the site is upgraded, I need it to be reliable and flexible.

The Web-ready HTML

First, let's talk a bit about the Web-ready HTML that'll be generated from my master XML files. To make great, readable documentation, I'll need to have support for the proper XML tags. For example, the ability to insert notes, important messages, and warnings into the body of the document (and have them prominently displayed in the resultant HTML) is a must. Also, I must be able to insert blocks of code, and it would be great if actual user input could somehow be offset from program output. I could even add tags that highlight the source code comments in an alternate color so that the code blocks are more readable.

The documents should have a table of contents (with hyperlinks to the appropriate chapters), a synopsis, a revision date, version, and an authors list at the top of the document. And, of course, every document should have a header at the extreme top of the page containing a small Gentoo Linux logo. Clicking on this logo should bring you back to the main Gentoo Linux page. Last but not least, every document should have a footer that contains copyright information, along with a contact e-mail address.

This was a hefty list of requirements, and I decided to focus on the most entertaining part first, the new Gentoo Linux logo that would appear in the upper-left corner of every Gentoo Linux document. I used the "g" from the "gentoo" graphic (created using the excellent and free Blender 3D program) on our main page as the basis for the new smaller logo. I tweaked the extrusion settings a bit and then added a chrome environment map. Finally, I positioned the lights and camera just so, and the new logo was complete. After importing it into Xara X (see Resources) and adding some text, this was the result:

caption=The new Gentoo Linux logo

I used this new logo as inspiration for the rest of the HTML color scheme, using a purplish theme throughout. I made heavy use of cascading style sheets (CSS) to control font attributes and spacing. Once I had a decent HTML prototype in place, I started focusing on the guts of the new documentation -- the new XML syntax. I wanted the syntax to be as simple as possible, so I created just enough XML tags to allow for the proper organization of the document, but no more. Then I started working on the XSLT to transform the XML into the target HTML.

The result!

After much tweaking and a good amount of feedback from one of my developers, the new documentation system reached the point where it was ready for use. I immediately began work on our first new development guide, "The Gentoo Linux Documentation Guide" (xml-guide.html), which contains a complete description of the new XML format. Not only did this allow other developers to begin work on the new-style documentation, but it also served as an excellent example of the new documentation system in action. Be sure to read this guide to get a complete understanding of our new XML syntax.

DocBook vs. Guide

If you're working on your own documentation solution, you may also want to consider the DocBook XML and SGML formats (see Resources). DocBook is well-suited for large-scale technical documentation and book projects, is very flexible, and has many (maybe too many) features. In addition, there are a number of existing packages that can be used to convert DocBook XML/SGML to man pages, texinfo files, Postscript, PDF, and, of course, HTML formats.

I didn't choose DocBook because a lightweight XML syntax worked best for Gentoo's needs. Right now, our XML guide syntax has around 20 tags and about 10 attributes. The limited tagset makes guide XML easy to transform into other formats such as HTML, and also ensures a certain level of consistency throughout our entire documentation set, since the format is so simple. Because I have my own XML format, I'll be able to extend the format with new tags as needed. I like having that level of control. I view XML as a technology that should be used by people to structure their data in ways that they find most helpful. In other words, the ability to define our own elements and attributes is a precious thing, and I should take full advantage of it. After all, it's the defining feature of XML.

Of course, creating your own XML syntax is not always the best solution, especially when data interchange is important to you. Amid all the XML hype, one thing that is often overlooked is that conversion to and from different XML formats can be extremely difficult. In many cases, the two formats won't be 100% compatible, and you'll have the unpleasant choice of either throwing away data and/or metadata, intentionally avoiding use of certain elements or attributes, or creating a "super-format" that will accommodate the data and metadata from both XML formats. In the documentation world, DocBook is a pretty good choice as a "super-format" because it's so flexible; it can easily accommodate documentation imported from a variety of sources.

However, DocBook's richness and flexibility can also create problems. For example, there may be hundreds of tags that you may never need, and supporting all these tags in your XSLT can make conversion to other formats more difficult. So, while DocBook is a great container for documentation converted from other formats, your own minimal XML syntax will almost always be easier to convert to other formats.

The most important thing is to carefully evaluate any potential solution while keeping the needs of your target audience(s) in mind.

Wrapping it up

With the new doc system in place, I converted all our docs to the new format and posted the new docs on our existing site. In addition, I created a link to the gentoo-cvs mailing list subscription page. The key point here is that I integrated these features into the existing site so that users could benefit from the improvements right away.

   Tip

Read the next article in this series: The Gentoo.org Redesign, Part 3

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Awk by Example, Part 2 Records, loops, and arrays
Awk by Example, Part 3 String functions and ... checkbooks?
Bash by Example, Part 1 Fundamental programming in the Bourne again shell (bash)
Bash by Example, Part 2 More bash programming fundamentals
Bash by Example, Part 3 Exploring the ebuild system
BTRFS Fun
Funtoo Filesystem Guide, Part 1 Journaling and ReiserFS
Funtoo Filesystem Guide, Part 2 Using ReiserFS and Linux
Funtoo Filesystem Guide, Part 3 Tmpfs and Bind Mounts
Funtoo Filesystem Guide, Part 4 Introducing Ext3
Funtoo Filesystem Guide, Part 5 Ext3 in Action
GUID Booting Guide
Learning Linux LVM, Part 1 Storage management magic with Logical Volume Management
Learning Linux LVM, Part 2 The cvs.gentoo.org upgrade
Libvirt
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Linux Fundamentals, Part 2
Linux Fundamentals, Part 3
Linux Fundamentals, Part 4
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Making the Distribution, Part 1
Making the Distribution, Part 2
Making the Distribution, Part 3
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On screen annotation Write on top of apps on your screen
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OpenSSH Key Management, Part 2 Introducing ssh-agent and keychain
OpenSSH Key Management, Part 3 Agent Forwarding
Partition Planning Tips Keeping things organized on disk
Partitioning in Action, Part 1 Moving /home
Partitioning in Action, Part 2 Consolidating data
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POSIX Threads Explained, Part 2
POSIX Threads Explained, Part 3 Improve efficiency with condition variables
Sed by Example, Part 1
Sed by Example, Part 2
Sed by Example, Part 3
Successful booting with UUID Guide to use UUID for consistent booting.
The Gentoo.org Redesign, Part 1 A site reborn
The Gentoo.org Redesign, Part 2 The Documentation System
The Gentoo.org Redesign, Part 3 The New Main Pages
The Gentoo.org Redesign, Part 4 The Final Touch of XML
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