![The tree can be queried using XPath
augtool> print /files/etc/passwd/*[uid='0'][1]
/files/etc/passwd/root
/files/etc/passwd/root/password = "x"
/files/etc/passwd/root/uid = "0"
/files/etc/passwd/root/gid = "0"
/files/etc/passwd/root/name = "root"
/files/etc/passwd/root/home = "/root"
/files/etc/passwd/root/shell = "/bin/bash"
OggCamp | 8 | Dominic Cleal](https://image.slidesharecdn.com/augeas-oggcamp-2012-120820175919-phpapp01/85/Configuration-surgery-with-Augeas-OggCamp-12-8-320.jpg)
![But also modified
$ grep root /etc/fstab
/dev/mapper/vgiridium-lvroot / ext4 defaults 1 1
$ augtool
augtool> match /files/etc/fstab/*[file='/']/opt
/files/etc/fstab/1/opt = defaults
augtool> set /files/etc/fstab/*[file='/']/opt noatime
augtool> match /files/etc/fstab/*[file='/']/opt
/files/etc/fstab/1/opt = noatime
augtool> save
Saved 1 file(s)
augtool> exit
$ grep root /etc/fstab
/dev/mapper/vgiridium-lvroot / ext4 noatime 1 1
OggCamp | 9 | Dominic Cleal](https://image.slidesharecdn.com/augeas-oggcamp-2012-120820175919-phpapp01/85/Configuration-surgery-with-Augeas-OggCamp-12-9-320.jpg)
![Bindings include Perl, Python, Java, PHP, Ruby...
...OCaml, Haskell, Lua, Vala...
#!/usr/bin/env ruby
require 'augeas'
aug = Augeas.open
# Print each mount
aug.match("/files/etc/fstab/*[file]").each do |m|
mount = aug.get("#{m}/file")
dev = aug.get("#{m}/spec")
puts "#{dev} is mounted at #{mount}"
end
# Edit / mount option
aug.set("/files/etc/fstab/*[file='/']/opt",
"noatime")
aug.save!
OggCamp | 10 | Dominic Cleal](https://image.slidesharecdn.com/augeas-oggcamp-2012-120820175919-phpapp01/85/Configuration-surgery-with-Augeas-OggCamp-12-10-320.jpg)
![Puppet has a native provider
augeas { 'export /foo':
context => '/files/etc/exports',
changes => [
"set dir[. = '/foo'] /foo",
"set dir[. = '/foo']/client weeble",
"set dir[. = '/foo']/client/option[1] ro",
"set dir[. = '/foo']/client/option[2] all_squash",
],
}
$ cat /etc/exports
/foo weeble(ro,all_squash)
OggCamp | 11 | Dominic Cleal](https://image.slidesharecdn.com/augeas-oggcamp-2012-120820175919-phpapp01/85/Configuration-surgery-with-Augeas-OggCamp-12-11-320.jpg)
Configuration surgery with Augeas (OggCamp 12)
- 1. Configuration surgery with Augeas Dominic Cleal dcleal@redhat.com OggCamp 12, Liverpool 19th August 2012 Presentation forked from Rapha?l Pinson's at RMLL 2012
- 2. Tired of ugly sed and awk one liners? or of using tons of different parsing libraries or brittle tricks? OggCamp | 2 | Dominic Cleal
- 3. Become a configuration surgeon with Augeas OggCamp | 3 | Dominic Cleal
- 4. What is the need? ¡ñ Many different syntaxes ¡ñ Securely editing configuration files with a unified API OggCamp | 4 | Dominic Cleal
- 5. A tree, its branches and leaves Augeas turns configuration files into a tree structure: /etc/hosts -> /files/etc/hosts ... and their parameters into branches and leaves: augtool> print /files/etc/hosts /files/etc/hosts /files/etc/hosts/1 /files/etc/hosts/1/ipaddr = "127.0.0.1" /files/etc/hosts/1/canonical = "localhost" OggCamp | 5 | Dominic Cleal
- 6. Augeas provides many stock parsers They are called lenses: Access Cron Host_Conf Aliases Crypttab Hostname Anacron debctrl Hosts_Access Approx Desktop IniFile AptConf Dhcpd Inputrc Automaster Dpkg Iptables Automounter Exports Kdump BackupPCHosts FAI_DiskConfig Keepalived cgconfig Fonts Keepalived cgrules Fuse Login_defs Channels Grub Mke2fs ... $ augtool print /augeas//path | wc -l 788 OggCamp | 6 | Dominic Cleal
- 7. augtool lets you inspect the tree $ augtool augtool> ls / augeas/ = (none) files/ = (none) augtool> print /files/etc/passwd/root/ /files/etc/passwd/root /files/etc/passwd/root/password = "x" /files/etc/passwd/root/uid = "0" /files/etc/passwd/root/gid = "0" /files/etc/passwd/root/name = "root" /files/etc/passwd/root/home = "/root" /files/etc/passwd/root/shell = "/bin/bash" OggCamp | 7 | Dominic Cleal
- 8. The tree can be queried using XPath augtool> print /files/etc/passwd/*[uid='0'][1] /files/etc/passwd/root /files/etc/passwd/root/password = "x" /files/etc/passwd/root/uid = "0" /files/etc/passwd/root/gid = "0" /files/etc/passwd/root/name = "root" /files/etc/passwd/root/home = "/root" /files/etc/passwd/root/shell = "/bin/bash" OggCamp | 8 | Dominic Cleal
- 9. But also modified $ grep root /etc/fstab /dev/mapper/vgiridium-lvroot / ext4 defaults 1 1 $ augtool augtool> match /files/etc/fstab/*[file='/']/opt /files/etc/fstab/1/opt = defaults augtool> set /files/etc/fstab/*[file='/']/opt noatime augtool> match /files/etc/fstab/*[file='/']/opt /files/etc/fstab/1/opt = noatime augtool> save Saved 1 file(s) augtool> exit $ grep root /etc/fstab /dev/mapper/vgiridium-lvroot / ext4 noatime 1 1 OggCamp | 9 | Dominic Cleal
- 10. Bindings include Perl, Python, Java, PHP, Ruby... ...OCaml, Haskell, Lua, Vala... #!/usr/bin/env ruby require 'augeas' aug = Augeas.open # Print each mount aug.match("/files/etc/fstab/*[file]").each do |m| mount = aug.get("#{m}/file") dev = aug.get("#{m}/spec") puts "#{dev} is mounted at #{mount}" end # Edit / mount option aug.set("/files/etc/fstab/*[file='/']/opt", "noatime") aug.save! OggCamp | 10 | Dominic Cleal
- 11. Puppet has a native provider augeas { 'export /foo': context => '/files/etc/exports', changes => [ "set dir[. = '/foo'] /foo", "set dir[. = '/foo']/client weeble", "set dir[. = '/foo']/client/option[1] ro", "set dir[. = '/foo']/client/option[2] all_squash", ], } $ cat /etc/exports /foo weeble(ro,all_squash) OggCamp | 11 | Dominic Cleal
- 12. Other projects using Augeas ¡ñ libguestfs ¡ñ virt-tools, e.g. p2v, v2v ¡ñ NUT ¡ñ ZYpp ¡ñ Config::Model ¡ñ Augeas::Validator OggCamp | 13 | Dominic Cleal
- 13. Questions? http://augeas.net augeas-devel@redhat.com freenode: #augeas OggCamp | 14 | Dominic Cleal