README: note level 4 heading issues

[pve-docs.git] / README.adoc

Proxmox VE Documentation
========================

We try to generate high quality documentation for
{website}[{pve}], and choose to use
http://www.methods.co.nz/asciidoc/[AsciiDoc] as base format.

The basic idea is to generate high quality manual pages, and assemble
them into a complete book, called link:pve-admin-guide.adoc[Proxmox VE
Administration Guide].  So we have one source, and generate several
documents from that. It is also possible to generate printable PDF
files, or ebook formats ('.epub').

When possible, we provide scripts to extract API definitions,
configuration or command line options from the source code.

To simplify the documentation task, we keep all Documentation within
this repository. It is possible to generate the docs without installing
any additional Proxmox packages with:

 make index

To update the auto-generate API definitions use:

 make update

NOTE: you need a fully installed development environment for that.


Debian Packages
---------------

We generate a development package called 'pve-doc-generator', which is
used by other Proxmox VE package to generate manual pages at package
build time.

Another package called 'pve-docs' is used to publish generated
'.html' and '.pdf' files on our web servers. You can generate
those Debian packages using:

 make deb


Common Macro definition in link:asciidoc/asciidoc-pve.conf[]
------------------------------------------------------------

'asciidoc' allows us to define common macros, which can then be
referred to using `{macro}`. We try to use this mechanism to improve
consistency. For example, we defined a macro called `pve`, which
expands to "Proxmox VE".

For URLs which are used more than once, two macros should be defined:

* `{name-url}`, which just contains the http(s) URL
* `{name}`, which contains the complete link including the canonical
description

For example, the macro `{forum-url}` expands to {forum-url}, and the macro
`{forum}` expands to {forum}.

The plan is to add more such definitions for terms which are used more
than once.

WARNING: When asciidoc encounters a misspelled macro name, it will
silently drop the containing line!


Autogenerated CLI Command Synopsis
----------------------------------

We generate the command line synopsis for all manual pages
automatically. We can do that, because we have a full declarative
definition of the {pve} API. I added those generated files
('*-synopsis.adoc') to the git repository, so that it is possible to
build the documentation without having a fully installed {pve}
development environment.

Style Guide
-----------

'asciidoc' uses a fairly simple markup syntax for formatting content.
The following basic principles should be followed throughout our
documentation.


Sections
~~~~~~~~

Sections are formatted using `two-line titles', by adding a line of
the appropriate characters and of the same length as the section title
below the title text:

 Level 0 (top level):     ======================
 Level 1:                 ----------------------
 Level 2:                 ~~~~~~~~~~~~~~~~~~~~~~
 Level 3:                 ^^^^^^^^^^^^^^^^^^^^^^
 Level 4 (bottom level):  ++++++++++++++++++++++

NOTE: Level 4 headings are currently not working for `manpage` outputs, you may
want to use `.SECTION' instead, which results in the same rendering, and this
level of Heading isn't displayed in any Index/TOC anyway.

Section titles should always be preceded by two empty lines. Each word
in a title should be capitalized except for ``articles, coordinating
conjunctions, prepositions, and the word to in infinitives unless they
appear as the first or last word of a title'' (see
http://web.mit.edu/course/21/21.guide/capitals.htm[Mayfield Electronic Handbook of Technical & Scientific Writing]).


Lists
~~~~~

Numbered Lists
^^^^^^^^^^^^^^

Numbered lists should be created using the implicit numbering format:

-----
. First level
.. Second level
. First level again
-----

. First level
.. Second level
. First level again


Bulleted Lists
^^^^^^^^^^^^^^

Bulleted lists should be created using the '*' symbol:

-----
* First level
** Second level
* First level again
-----

* First level
** Second level
* First level again


Labeled Lists
^^^^^^^^^^^^^

Labeled lists should be used to make lists of key-value style text
more readable, such as command line parameters or configuration options:

.Regular labeled lists
-----
First Label Text::

Element text paragraph

Second Label Text::

Another element text paragraph.
-----

First Label Text::

Element text paragraph

Second Label Text::

Another element text paragraph.

.Horizontal labeled lists
-----
[horizontal]
First Label Text:: Element text paragraph

Second Label Text:: Another element text paragraph.
-----

creates

[horizontal]
First Label Text:: Element text paragraph

Second Label Text:: Another element text paragraph.

The FAQ section uses a special questions and answers style for
labeled lists.


Text and Block Styles
~~~~~~~~~~~~~~~~~~~~~

'asciidoc' offers a wide range of default text styles:

* 'Emphasized text': created using \'text', used for emphasizing words
and phrases
* `Monospaced text`: created using \`text`, used for command / program
names, file paths, in-line commands, option names and values
* *Strong text*: created using \*text*, used for emphasizing concepts
or names when first introduced in a section.

There are also different built-in block styles that are used in
our documentation:

Complete paragraphs can be included literally by prepending each
of their lines with whitespace. Use this for formatting complete
commands on their own line, such as:

 pct set ID -option value

----
By surrounding a paragraph with lines containing at least four '-'
characters, its content is formatted as listing.

Use this for formatting file contents or command output.
----

Specially highlighted 'notes', 'warnings' and 'important' information
can be created by starting a paragraph with `NOTE:`, `WARNING:` or
`IMPORTANT:`:

NOTE: this is a note

WARNING: this is warning

IMPORTANT: this is important information

For each of these blocks (including lists and paragraphs), a block header
can be defined by prepending the block with a `.' character and the header
text:

-----
.Title of List
* First element
* Second element
* Third element
-----

.Title of List
* First element
* Second element
* Third element

For example, block headers can be used to add file names/paths to file
content listings.


Online Help
-----------
Each {pve} installation contains the full documentation in HTML format,
which is then used as the target of various help buttons in the GUI.

If after adding a specific entry in the documentation you want to
create a help button pointing to that, you need to do the
following:

* add a string id in double square brackets before your 
documentation entry,  like `[[qm_general_settings]]`
* rebuild the `asciidoc-pve` script and the HTML chapter file containing 
your entry
* add a property `onlineHelp` in the ExtJS panel you want to document,
using the above string, like `onlineHelp: qm_general_settings`
This panel has to be a child class of PVE.panel.InputPanel

On calling `make install` the asciidoc-pve script will populate
a JS object associating the string id and a link to the 
local HTML documentation, and the help button of your input panel 
will point to this link.


Screenshots
-----------

[thumbnail="screenshot/gui-datacenter-search.png"]

First, it should be noted that we can display screenshots on 'html'
and 'wiki' pages, and we can include them in printed documentation. But
it is not possible to render them inside manual pages. So screenshot
inside manual pages should be optional, i.e. the text should not
depend on the visibility of the screenshot. You can include a
screenshot by setting the 'thumbnail' attribute on a paragraph:

----
[thumbnail="screenshot/gui-datacenter-search.png"]
First, it should be noted ...
----

The corresponding file need to reside inside folder
`images/screenshot`, and should be in `.png` image format. We include
the screenshots in printed documentation, and 'pdftex' uses the
density (DPI) specified inside the file. So all screenshots should use
the same density. We currently require the density set to 146 DPI, so
that we can display a 1024 pixels wide image. You should not include
larger screenshots (although it is possible).

You can use the `./png-cleanup.pl` script to set the correct
density. Simply use the following command to import a screenshot
image:

----
# ./png-cleanup.pl screenshot.png images/screenshot/screenshot.png
----

TIP: You can use `identify -verbose screenshot.png` command to show
all image attributes (from debian package 'imagemagick')

.Default Screenshot Layout

[thumbnail="screenshot/gui-datacenter-search.png"]

We normally display screenshots as small thumbnail on the right side
of a paragraph. On printed documentation, we render the full sized
graphic just before the paragraph, or between the title and the text
if the paragraph has a title. It is usually a good idea to add a title
to paragraph with screenshots.

[thumbnail="screenshot/gui-datacenter-search.png", float="left"]

If you need to render many screenshots, it is possible to place them
on the left side, so you can alternate the thumbnail position using the
`float` attribute:

----
[thumbnail="screenshot/gui-datacenter-search.png", float="left"]
If you need to render many screenshots ...
----

Please avoid to many consecutive screenshots to avoid rendering
problems. Also verify the printed documentation to see if large
screenshots create layout problems.


Copyright
---------

Copyright (C) 2016-2017 Proxmox Server Solutions Gmbh

Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
any later version published by the Free Software Foundation; with no
Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A
copy of the license is included in the link:LICENSE[LICENSE] file.