Table of Contents
webapp-config — manage installs of web-based applications for virtual hosting
webapp-config
[
--bug-report
]
-I
[
-dghusDE
--soft
--secure
] {
app-name
} {
app-version
}
webapp-config
[
--bug-report
]
-U
[
-dghusDE
] {
app-name
} {
app-version
}
webapp-config
[
--bug-report
]
-C
{
-d
directory
}
webapp-config
--list-installs
[[
app-name
]] [[
app-version
]]
webapp-config
--list-unused-installs
[[
app-name
]] [[
app-version
]]
webapp-config
--show-installed
[[
-d
directory
]]
webapp-config
--show-postinst
app-name
app-version
webapp-config
[--list-servers] | [-v] | [--version] | [-h] | [--help]
webapp-config is a powerful tool that allows you to install, upgrade, and remove web-based applications in a virtual-hosting environment.
webapp-config is aimed at providing the package management functionality that you need if you are running multiple web sites off of the same computer (virtual hosting).
Package managers such as rpm and emerge are designed to install one copy of a package, and to install it onto one fixed location. This conflicts with the needs of a virtual hosting environment, where you need to be able to install a package in multiple places, so that it can be part of more than just the one website. But package managers are essential for maintaining a computer over time - so how can we have both?
The answer is a two-stage install. The traditional package manager installs a master copy into /usr/share/webapps/
. This master copy isn't fit to run - but it is ready to then be used by webapp-config to install the package multiple times in multiple places.
webapp-config allows you to install multiple copies of the same package on the same computer at the same time. You choose which directory to install each separate copy into.
We call these multiple installations "virtual copies".
You can also have different versions of the same package installed at the same time. This allows you to gradually roll out a new version of a package across your sites; you are not forced to upgrade every single website at once.
webapp-config minimises the number of duplicated files to the absolute minimum possible, to keep disk space usage low. The majority of files are hard linked to the master copy; only configuration files, and any files that the package needs to write to, are copied into the virtual copy.
If you are used to installing web-based applications by hand, you'll appreciate that it can be a pain to get every file owned by the correct user, and with the correct permissions. Some files need to be owned by the user that the webserver runs as. Others need to be owned by specific shell accounts, so that those users can login and edit the configuration files. If your Linux distribution offers you a choice of web servers - each running under a different user - even the installers can struggle to get it right.
With webapp-config, you tell the installer which web server you are going to be using, and which shell account needs to be able to edit the configuration files. webapp-config then installs your files with the correct ownership and permissions.
webapp-config automatically ensures that your configuration files are never overwritten during an upgrade - even if you have not edited the files at all. Additionally, webapp-config will never overwrite any file that it did not install, or that has been changed since it was installed by webapp-config. webapp-config uses md5 checksums to determine whether a file has been changed or not. In the case of symbolic links, webapp-config will not replace a symlink that points to a different file.
When an upgrade does attempt to overwrite a protected file, webapp-config creates a ._cfg file with the new file inside. You can use etc-update to complete the install, just as you would with the regular emerge.
A virtual copy is built mostly by creating hard links to files under /usr/share/webapps
. If a hard link cannot be created, the file is copied from /usr/share/webapps
instead.
Hard links can only be created to files on the same filesystem. If you keep /usr/share/webapps
and /var/www
on different filesystems, webapp-config cannot use hard links, and will be forced to copy the files instead.
There are two ways to get around the hard link problem.
The easiest way is to make /usr/share/webapps
a symlink to a directory under /var/www
. For most people, this will ensure that everything is on the same filesystem.
However, if you keep the websites you host on separate filesystems (like I do), then webapp-config is never going to be able to hard-link files for you.
You can choose to use the --soft
command-line switch instead. This switch tells webapp-config to create symbolic links instead of hard links. Symbolic links work across filesystems.
The problem with using symbolic links is that some packages do not work when the virtual copy is made from symbolic links. Many users - and system administrators alas - have also complained that they find directories full of symbolic links confusing. For these reasons, symbolic links are not used by default in webapp-config any more.
By default, the master copy contains the metadata that decides which files get linked into a virtual copy and which files do not. Files are either owned by the web server (server-owned), are configuration files (config-owned), or are linked in (virtual). Directories can be server-ownedor config-owned, but most of the time they need to be just plain directories (default-owned) created inside the installation directory (set with the -d
switch). webapp-config provides a number of switches which allows you to override the master copy's metadata - if you ever find that you need to.
The --default-dirs
and --virtual-files
switches allow you to decide what webapp-config will do if (respectively) a directory or a file is marked as being default or virtual. You can tell webapp-config to make the directory or file any of the other choices - server-owned or config-owned - instead.
-I
, --install
Activate install mode.
-U
, --upgrade
Activate upgrade mode.
-C
, --clean
Activate remove mode.
--list-installs
app-name
app-version
, --li
app-name
app-version
Outputs a list of all the virtual copies of the app-name
-app-version
package.
If you omit app-name
or app-version
webapp-config will display all available packages/versions.
--list-unused-installs
app-name
app-version
, --lui
app-name
app-version
Outputs a list of all the master copies of the app-name
-app-version
package that have not been installed using webapp-config -I
.
Both app-name
or app-version
can be * to search for multiple packages or versions.
--show-installed
, --si
Outputs the app-name and app-version of the application installed in directory
.
Use the -d
switch to tell webapp-config which directory
to look in. directory
is a directory under the htdocs dir.
--show-postinst
app-name
app-version
, --spi
app-name
app-version
Displays the post-installation instructions of the app-name
-app-version
package. Very handy if you didn't see them displayed when the package was installed.
--show-postupgrade
app-name
app-version
, --spu
app-name
app-version
Displays the post-upgrade instructions of the app-name
-app-version
package. Very handy if you didn't see them displayed when the package was upgraded.
--list-servers
, --ls
Outputs a list of the web servers that webapp-config currently supports.
Use the -s
server
switch to change which web-server an install or upgrade should use.
-?
, --help
Provide a list of supported switches. Also lists all the default values for each switch.
-v
, --version
Displays the current version number of webapp-config
List of the remaining switches that webapp-config accepts. To see the default values that webapp-config will use when a switch is omitted, use webapp-config --help
.
app-name
app-version
Together, these two parameters tell webapp-config which package to install (-I
mode), upgrade to (-U
mode), or to search for (--list-installs
mode).
They must be the last two parameters passed to webapp-config.
These parameters are not optional.
--bug-report
, --pretend
, -p
Provide output to include inside a bug-report.
Use this switch if you're having problems with the install (-I
mode), upgrade (-U
mode), or clean (-C
mode) operations. Add this switch to the command-line that's not working, and make sure you paste the output into your bug report.
If you need to use this switch, make sure it's the first switch you use to call webapp-config.
-s
server
, --server
server
Set which web-server to install (-I
mode) or upgrade (-U
mode) for.
webapp-config needs to know which web server you are going to use to access your virtual copy. If you don't provide the correct switch, your virtual copy may not work correctly.
Use webapp-config --list-servers
to see a list of valid server
settings.
-u
user
, --user
user
Set which user will own any installed configuration files.
When webapp-apache creates a virtual copy (-I
mode), the virtual copy creates local copies of any configuration files that the package needs to use. By using the -u
switch, you can specify which user
owns these configuration files.
If you give shell accounts out to the users who host websites on your computer, the -u
allows you to give ownership of the configuration file (and therefore write permission) to the shell account associated with the website.
user
can be a username or a numerical user id.
-g
group
, --group
group
Set which group will own any installed configuration files.
When webapp-apache creates a virtual copy (-I
mode), the virtual copy creates local copies of any configuration files that the package needs to use. By using the -g
switch, you can specify which group
owns these configuration files.
If you give shell accounts out to groups of users who host websites on your computer, the -g
allows you to give ownership of the configuration file (and therefore write permission) to the group associated with the website.
group
can be a group name or a numerical group id.
-d
directory
, --dir
directory
Specify where to create the virtual copy.
The webapp-config tool allows you to create a virtual copy anywhere you want. You are no longer limited to installing a web-based app in /home/httpd/htdocs/<package-name>/! Simply use the -d
switch to tell webapp-config where you want to create your virtual copy.
directory
is a directory under your htdocs dir. If you do not set the hostname
correctly (by using the -h
switch), webapp-config will look under the wrong htdocs directory!
This option is required by the -C
switch.
-h
host
, --host
host
Specify the fully-qualified domain name of the virtual host.
Some web-based applications - whether through genuine need or bad design - need to know the hostname of the website that they are part of.
Some web-based applications need to install files (such as cgi scripts) that do not belong under the htdocs directory. To make sure that these files go in the right place, you need to use the -h
switch to tell webapp-config the hostname of the website.
host
must be a fully-qualified domain name.
If you do not use the -h
switch, your virtual copy may not work correctly.
-D
KEY=VALUE
, --define
KEY=VALUE
Define a configuration variable for webapp-config.
Allows to name a KEY=VALUE
pair that will be imported into the configuration
variables of webapp-config. This allows you to provide
customized variables which can be used in the
configuration file. This can also be used to
temporarily overwrite variables from the configuration
file.
-E
variable name
, --envvar
variable name
Define an environment variable that will be picked up by webapp-config.
Allows to name single environment variable that will be imported by webapp-config. This allows you to provide customized variables which can be used in the configuration file. This can also be used to temporarily overwrite variables from the configuration file.
--envall
Imports all environment variables into the configuration process of webapp-config.
-V
, --verbose
Use this option to increase the amount of output from the --list-installs
switch.
--soft
Use this option to create the virtual copy using symbolic links instead of hard links.
You may find this option useful if /usr/share/webapps
is on a different filesystem to your htdocs directories. However, it has been discovered that some packages do not work with this option, which is why it is no longer the default behaviour. You are always better off making /usr/share/webapps
a symlink to a directory on the same filesystem as your htdocs directories.
--secure
Use this option to install into the htdocs-secure
directory rather than into the htdocs
directory.
This option is useful if you keep separate directories for your http: and https: sites.
You can change 'htdocs-secure' by editing the config file /etc/vhosts/webapp-config
.
--default-dirs
type
, --vd
type
, --virtual-files
type
, --vf
type
type
must be one of:
Directories or files are owned by the user that the web server runs as. Use the -s
switch to specify which web server to use.
Directories or files are owned by the user and group specified with the -u
and -g
switches.
Directories or files are shared; no local copy is created.
All of these examples are aimed at Gentoo Linux. If you are using webapp-config on a different Linux distribution, they may not work out of the box for you.
To install a copy of phpmyadmin-2.5.6, so that it is available from http://www.example.com/databases/admin/, you would do this:
webapp-config -I -h www.example.com -d /databases/admin/ phpmyadmin 2.5.6
To make sure that the shell account 'dbadmin' could edit the configuration files of phpmyadmin, you'd add the -u
switch like this:
webapp-config -I -h www.example.com -d /databases/admin -u dbadmin phpmyadmin 2.5.6
To upgrade the copy of phpmyadmin-2.5.6 to version 2.5.7, you would do this:
webapp-config -U -d /databases/admin/ phpmyadmin 2.5.7
To upgrade all the virtual copies of phpmyadmin-2.5.6, you would do this:
for x in `webapp-config --li phpmyadmin 2.5.6`;do . ${x}/.webapp && webapp-config -U -h ${WEB_HOSTNAME} -d ${WEB_INSTALLDIR} phpmyadmin 2.5.7; done
To remove the copy of phpmyadmin-2.5.7, you would do this:
webapp-config -C -h www.example.com -d /databases/admin/
To remove all the virtual copies of phpmyadmin-2.5.7, you would do this:
for x in `webapp-config --li phpmyadmin 2.5.7`;do . ${x}/.webapp && webapp-config -C -h ${WEB_HOSTNAME} -d ${WEB_INSTALLDIR}; done
/etc/vhosts/webapp-config
Configuration file, holding the defaults for webapp-config
/var/db/webapps
This directory tree holds information about the location of each virtual copy on the computer.
webapp.eclass(5), webapp-config(5), emerge(1)
webapp-config is based on the design for an installer for web-based application installers first defined in GLEP #11 for the Gentoo Linux project.