This project contains the Chef Style Guide we use at SecondMarket. Some of these rules are enforced by FoodCritic; some others are not.
- Avoid punctuation ('_' or '-') in cookbook names. This is because any LWRPs you create will use the cookbook name as part of the LWRP name, so the method become very awkward. In particular, since '-' can't be part of a symbol in Ruby, you won't be able to use LWRPs in any cookbooks with '-' in them.
- All SecondMarket application cookbooks should be prefixed with 'sm' (e.g. 'smpostgresql')
- Use semantic versioning when numbering cookbooks. We also follow the same convention as Opscode, where the middle digit of a cookbook version is an odd number if unstable and even number if stable.
- Only upload stable cookbooks from master.
- Only upload unstable cookbooks from the dev branch. Merge to master and bump the version when stable.
- Always update CHANGELOG.md with any changes, with the JIRA ticket and a brief description.
Name things uniformly for their system and component. For the ganglia master,
- attributes:
node['ganglia']['master'] - recipe:
ganglia::master - role:
ganglia_master- Note: use of '-' in role names should be avoided use '_' instead - directories:
ganglia/master(if specific to component),ganglia(if not). For example:/var/log/ganglia/master
(The foregoing was shamelessly cribbed from Ironfan)
Name attributes after the recipe in which they are primarily used. e.g. node['postgresql']['server']
Don't use the default recipe (leave it blank). Instead, create recipes called server or client (or other).
Follow this order for information in each resource declaration:
- Source
- Cookbook
- Resource ownership
- Permissions
- Notifications
- Action
Example:
template "/tmp/foobar.txt" do
source "foobar.txt.erb"
owner "someuser"
group "somegroup"
mode 00644
variables(
:foo => 'bar'
)
notifies :reload, 'service[whatever]'
action :create
end
Always specify all five digits of the file mode, and not as a string.
Wrong:
mode "644"
Right:
mode 00644
In each resource declarations always specify the action to be taken:
Wrong:
package "monit"
Right:
package "monit" do
action :install
end
It goes without saying that all cookbooks should pass FoodCritic rules before being uploaded.
$ foodcritic -f all your-cookbook
should return nothing.
Even though the controversial FC001 Foodcritic rule has now been removed, we still prefer strings over symbols. Please retrofit old cookbooks as you come across them.
Wrong:
default[:foo][:bar] = 'baz'
Right:
default['foo']['bar'] = 'baz'
node.set_unless- Can lead to weird behavior if the node object had something set. Avoid unless altogether necessary (one example where it's necessary is innode['postgresql']['server']['password'])if node.run_list.include?("foo")i.e. branching in recipes based on what's in the node's run list. Better and more readable to use a feature flag and set its precedence appropriately.node['foo']['bar']i.e. setting normal attributes without specifying precedence. This is deprecated in Chef 11, so either usenode.set['foo']['bar']to replace its precedence in-place or choose the precedence to suit.
-
Author:: Julian Dunn (jdunn@secondmarket.com)
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Copyright:: 2012-2013, SecondMarket Labs, LLC.
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.