Here are the slides from Nick Fagerlund's PuppetConf 2016 presentation called PuppetConf 2016: Puppet 4.x: The Low WAT-tage Edition. Watch the videos at https://www.youtube.com/playlist?list=PLV86BgbREluVjwwt-9UL8u2Uy8xnzpIqa

1. Puppet 4: The Low WAT-tage
Edition
Nick Fagerlund, Puppet

2. nickf@puppet.com
@nfagerlund
nfagerlund.net
2
Hi, I’m Nick Fagerlund!!!!

3. I’ve seen things you people wouldn’t believe
My 2013 talk: https://www.youtube.com/watch?v=aU7vjKYqMUo
My much smarter inspiration: https://www.destroyallsoftware.com/talks/wat
3

4. Agenda
4

5. Agenda
1. Fundamental Chaos
2. Slapstick
3. Elegance
5

6. 1. Fundamental Chaos
6

7. Relative Namespacing
class profile::apache {
include apache
}
7

8. Relative Namespacing
class profile::apache {
class {'apache':}
}
8

9. Relative Namespacing
include apache meant…
• <CURRENT NAMESPACE>::apache
• <PARENT OF CURRENT NAMESPACE>::apache
• etc. and so on
• Eventually, ::apache
https://projects.puppetlabs.com/issues/2053
https://tickets.puppetlabs.com/browse/PUP-121
9

10. Relative Namespacing
class profile::apache {
include ::apache
}
10

11. Is Truth Beauty, and Beauty Truth?
Facts:
architecture => x86_64
domain => local
facterversion => 2.4.2
fqdn => "treepie.local"
gid => staff
hardwareisa => i386
hardwaremodel => x86_64
hostname => treepie
11

12. Is Truth Beauty, and Beauty Truth?
if $::is_virtual {
# do something
}
12

13. Is Truth Beauty, and Beauty Truth?
“false”
13

14. Is Truth Beauty, and Beauty Truth?
if $::is_virtual == 'true' { ... }
# or:
if str2bool($::is_virtual) { ... }
# with the str2bool() function
from puppetlabs/stdlib
14

15. Is Truth Beauty, and Beauty Truth?
$interfaces =
lo0,gif0,stf0,en0,en1,en2,p2p0,awdl0,
bridge0,utun0
$macaddress_en0 = 72:00:04:eb:7a:93
...etc.
15

16. 2. Slapstick
16

17. Data Type Nonsense
$myvar = /^# @.*$/
notice($myvar)
# Error: …Syntax error at
'/' at /root/test.pp:1
17

18. Data Type Nonsense
$one = 1
# String
$one_times_one = 1*1
# Fixnum
$an_undef = undef
# NilClass
$multi_undefs = [undef, undef]
# Symbol (:undef)
18

19. Interpolation Shenanigans
notice("Twenty plus eighty is ${20 + 80}.")
# Error: left operand of + is not a number at
/root/test.pp:15
19

20. Interpolation Shenanigans
notice("Twenty plus eighty is ${'20' + 80}.")
# Notice: Scope(Class[main]): Twenty plus
eighty is 100.
20

21. Interpolation Shenanigans
• Single bare word:
• ${variable}
• Bare word plus chained function call:
• ${variable.split(‘,’)}
• That’s it. Otherwise it’s an expression.
21

22. Inconsistent Comparisons
notice( 'eat' == 'EAt' ) # true
notice( 'eat' in 'EAten' ) # false
22

23. The Great Escape
$greeting = 'How's it going?'
23

24. The Great Escape
$s32path = 'C:WindowsSystem32'
notice($s32path)
# Error: Unclosed quote after ''
in 'C:WindowsSystem32'
24

25. The Great Escape
$s32path = 'C:WindowsSystem32'
notice($s32path)
# Notice: Scope(Class[main]):
C:WindowsSystem32
>:c
25

26. The Great Escape
$gitconfig = @("GITCONFIG"/L)
[user]
name = ${displayname}
email = ${email}
[alias]
lg = "log —pretty=format:’%C(yellow)%h
%C(reset) %s%C(cyan)%cr%C(reset) %C(blue)%an
%C(reset) %C(green)%d%C(reset)’ --graph"
| GITCONFIG
26

27. The Great Escape
$s32path = @(MYPATH)
C:WindowsSystem32
-MYPATH
notice($s32path)
# Notice: Scope(Class[main]):
C:WindowsSystem32
27

28. Class Class
class class {
notify {'hey it worked':}
}
include class
# Error: Syntax error at 'class' at
/root/test.pp:5
28

29. Class Class
class class {
notify {'hey it worked':}
}
include "class"
# Notice: hey it worked
# Notice: /Stage[main]/Class/Notify[hey it
worked]/message: defined 'message' as 'hey it
worked'
29

30. Class Class
class class {
notify {'hey it worked':}
}
include "class"
# Error: 'class' is not a valid classname
at /Users/nick/Desktop/test.pp:1:7
30

31. 3. Elegance
31

32. Data Type Annotations
class ntp (
$autoupdate = $ntp::params::autoupdate,
$config = $ntp::params::config,
$config_template = $ntp::params::config_template,
$disable_monitor = $ntp::params::disable_monitor,
$driftfile = $ntp::params::driftfile,
$logfile = $ntp::params::logfile,
$iburst_enable = $ntp::params::iburst_enable,
$keys_enable = $ntp::params::keys_enable,
$keys_file = $ntp::params::keys_file,
$keys_controlkey = $ntp::params::keys_controlkey,
$keys_requestkey = $ntp::params::keys_requestkey,
$keys_trusted = $ntp::params::keys_trusted,
$package_ensure = $ntp::params::package_ensure,
$package_name = $ntp::params::package_name,
$panic = $ntp::params::panic,
$preferred_servers = $ntp::params::preferred_servers,
$restrict = $ntp::params::restrict,
$interfaces = $ntp::params::interfaces,
$servers = $ntp::params::servers,
$service_enable = $ntp::params::service_enable,
$service_ensure = $ntp::params::service_ensure,
$service_manage = $ntp::params::service_manage,
$service_name = $ntp::params::service_name,
$udlc = $ntp::params::udlc
) inherits ntp::params {
...
32
...
validate_absolute_path($config)
validate_string($config_template)
validate_bool($disable_monitor)
validate_absolute_path($driftfile)
if $logfile { validate_absolute_path($logfile) }
validate_bool($iburst_enable)
validate_bool($keys_enable)
validate_re($keys_controlkey, ['^d+$', ''])
validate_re($keys_requestkey, ['^d+$', ''])
validate_array($keys_trusted)
validate_string($package_ensure)
validate_array($package_name)
validate_bool($panic)
validate_array($preferred_servers)
validate_array($restrict)
validate_array($interfaces)
validate_array($servers)
validate_bool($service_enable)
validate_string($service_ensure)
validate_bool($service_manage)
validate_string($service_name)
validate_bool($udlc)

33. Data Type Annotations
~~~~ 👀 ZOOM AND ENHANCE 👀 ~~~~
class ntp (
$config_template = $ntp::params::config_template,
$disable_monitor = $ntp::params::disable_monitor,
...
) inherits ntp::params {
...
validate_string($config_template)
validate_bool($disable_monitor)
33

34. Data Type Annotations
class ntp (
Boolean $disable_monitor =
$ntp::params::disable_monitor,
Pattern[/^d+$/] $keys_controlkey =
$ntp::params::keys_controlkey,
Integer $keys_requestkey =
$ntp::params::keys_requestkey,
Array $keys_trusted =
$ntp::params::keys_trusted,
String $package_ensure =
$ntp::params::package_ensure,
34

35. Iteration
•Old Ruby DSL?
•Do-nothing defined types?
•create_resources function?
35

36. Data Type Annotations
# in Hiera data:
admin_users:
casey:
uid: '1330'
gid: allstaff
shell: zsh
groups:
- developers
- release
leslie:
uid: '1308'
gid: allstaff
groups:
- prosvc
36
# in Puppet manifest:
class puppet_ops::users::virtual {
create_resources(
'@user',
lookup('admin_users'),
{ # defaults
ensure => present,
purge_ssh_keys => true,
}
)
}

37. Iteration
$binaries = ['facter', 'hiera', 'mco', ‘puppet',
'puppetserver']
$binaries.each |String $binary| {
file { "/usr/bin/${binary}":
ensure => link,
target => "/opt/puppetlabs/bin/${binary}",
}
}
37

38. EPP Templates
<%- | Boolean $keys_enable,
String $keys_file,
Array $keys_trusted,
String $keys_requestkey,
String $keys_controlkey
| -%>
<%# Parameter tag ↑ -%>
<%# Non-printing tag ↓ -%>
<% if $keys_enable { -%>
<%# Expression-printing tag ↓ -%>
keys <%= $keys_file %>
38
<% unless $keys_trusted =~ Array[Data,0,0]
{ -%>
trustedkey <%= $keys_trusted.join(' ') %>
<% } -%>
<% if $keys_requestkey =~ String[1] { -%>
requestkey <%= $keys_requestkey %>
<% } -%>
<% if $keys_controlkey =~ String[1] { -%>
controlkey <%= $keys_controlkey %>
<% } -%>
<% } -%>

39. Thanks
39

40. Questions?
nickf@puppet.com
@nfagerlund
nfagerlund.net
40