Merge pull request #948 from DavidS/iac-1190-ignore_foreign

(IAC-1190) add `ignore_foreign` when purging firewallchains

Author: daianamezdrea

README.md

@@ -127,7 +127,28 @@ The rules you create here are helpful if you don’t have any existing rules; th
 
 Rules are persisted automatically between reboots, although there are known issues with ip6tables on older Debian/Ubuntu distributions. There are also known issues with ebtables.
 
-1. In site.pp or another top-scope file, add the following code to set up a metatype to purge unmanaged firewall resources. This will clear any existing rules and make sure that only rules defined in Puppet exist on the machine.
+1. Use the following code to set up the default parameters for all of the firewall rules that you will establish later. These defaults will ensure that the `pre` and `post` classes are run in the correct order and avoid locking you out of your box during the first Puppet run.
+
+```puppet
+Firewall {
+  before  => Class['my_fw::post'],
+  require => Class['my_fw::pre'],
+}
+```
+
+2. Declare the `my_fw::pre` and `my_fw::post` classes to satisfy dependencies. You can declare these classes using an external node classifier or the following code:
+
+```puppet
+class { ['my_fw::pre', 'my_fw::post']: }
+```
+
+3. Include the `firewall` class to ensure the correct packages are installed:
+
+```puppet
+class { 'firewall': }
+```
+
+4. If you want to remove unmanaged firewall rules, add the following code to set up a metatype to purge unmanaged firewall resources in your site.pp or another top-scope file. This will clear any existing rules and make sure that only rules defined in Puppet exist on the machine.
 
 ```puppet
 resources { 'firewall':
@@ -168,28 +189,9 @@ resources { 'firewallchain':
 }
 ```
 
-  **Note** - If there are unmanaged rules in unmanaged chains, it will take two Puppet runs for the firewall chain to be purged. This is different than the `purge` parameter available in `firewallchain`.
+> **Note:** If there are unmanaged rules in unmanaged chains, it will take a second Puppet run for the firewall chain to be purged.
 
-2.  Use the following code to set up the default parameters for all of the firewall rules that you will establish later. These defaults will ensure that the `pre` and `post` classes are run in the correct order and avoid locking you out of your box during the first Puppet run.
-
-```puppet
-Firewall {
-  before  => Class['my_fw::post'],
-  require => Class['my_fw::pre'],
-}
-```
-
-3. Declare the `my_fw::pre` and `my_fw::post` classes to satisfy dependencies. You can declare these classes using an external node classifier or the following code:
-
-```puppet
-class { ['my_fw::pre', 'my_fw::post']: }
-```
-
-4. Include the `firewall` class to ensure the correct packages are installed:
-
-```puppet
-class { 'firewall': }
-```
+> **Note:** If you need more fine-grained control about which unmananged rules get removed, investigate the `purge` and `ignore_foreign` parameters available in `firewallchain`.
 
 ### Upgrading
 

lib/puppet/type/firewallchain.rb

@@ -163,6 +163,15 @@
     end
   end
 
+  newparam(:ignore_foreign, boolean: true) do
+    desc <<-PUPPETCODE
+      Ignore rules that do not match the puppet title pattern "^\d+[[:graph:][:space:]]" when purging unmanaged firewall rules in this chain.
+      This can be used to ignore rules that were not put in by puppet. Beware that nothing keeps other systems from configuring firewall rules with a comment that starts with digits, and is indistinguishable from puppet-configured rules.
+    PUPPETCODE
+    newvalues(false, true)
+    defaultto false
+  end
+
   # Classes would be a better abstraction, pending:
   # http://projects.puppetlabs.com/issues/19001
   autorequire(:package) do
@@ -240,6 +249,9 @@ def generate
     # Remove rules which match our ignore filter
     rules_resources.delete_if { |res| value(:ignore).find_index { |f| res.provider.properties[:line].match(f) } } if value(:ignore)
 
+    # Remove rules that were (presumably) not put in by puppet
+    rules_resources.delete_if { |res| res.provider.properties[:name].match(%r{^(\d+)[[:graph:][:space:]]})[1].to_i >= 9000 } if value(:ignore_foreign) == :true
+
     # We mark all remaining rules for deletion, and then let the catalog override us on rules which should be present
     rules_resources.each { |res| res[:ensure] = :absent }