Looking for a tool to help you format your CFEngine policy? Have you heard of cffmt?
You might recall that we had a chat with the author, Miek Gieben in The agent is in - Episode 24.1 In case you missed it, cffmt is a command line tool for formatting CFEngine policy files, like gofmt for .cf files.2 Let’s take a look.
Consistent formatting can really ease reading of policy, but sometimes editors are configured differently and you can end up with inconsistently formatted policy. For example, here is a contrived policy file with some irregular formatting:
bundle agent __main__
{
vars: "String1"
string => "Hello String1";
"list" slist => { "one", "two", "three", "four", "five" };
files:
"/tmp/hello-world.txt" content => "$(String1)",
perms => mog( "600",
"root",
"root"),
comment => "Important stuff";
classes:
"Some_class"
expression => "any";
reports:
Some_class:: "Some_class is defined.";
@if minium_version(3.21)
any::
"Running 3.21 or later $(sys.cf_version)";
@endif
}Let’s use cffmt to clean it up. First, we need to install cffmt which we can do using go install:
go install github.com/miekg/cf/cmd/cffmt@maingo: downloading github.com/miekg/cf v0.1.25
go: downloading github.com/shivamMg/ppds v0.0.1
go: downloading github.com/alecthomas/chroma/v2 v2.12.0
go: downloading github.com/dlclark/regexp2 v1.10.0Once installed you should find cffmt in ~/go/bin/. Simply run cffmt with the path to the policy file as an argument.
~/go/bin/cffmt /tmp/feature-friday-36-0.cfWe can see it emits a much more nicely formatted policy file:
bundle agent __main__
{
vars:
"String1" string => "Hello String1";
"list" slist => { "one", "two", "three", "four", "five" };
files:
"/tmp/hello-world.txt"
content => "$(String1)",
perms => mog("600", "root", "root"),
comment => "Important stuff";
classes:
"Some_class" expression => "any";
reports:
Some_class::
"Some_class is defined.";
@if minium_version(3.21)
any::
"Running 3.21 or later $(sys.cf_version)";
@endif
}While cffmt is quite opinionated, it does provide the capability to skip formatting a file if there is a top-level comment # cffmt:no which is useful if you are auto-formatting many policy files. You can also instruct it to format slist vars with an entry on each line by placing a # cffmt:list comment preceding the definition.
Happy Friday! 🎉
