Extract filebeat prospector 'fileds' used from all attributes definitions (ruby based) - ruby

Question

I'm currently adding filebeat support for services we provide;
For every service we have several log files I would like to track;
I have 1 common filebeat recipe and I'm distinguishing between the different services' logs in different attributes .rb files;
In those I have a separate definition per log;
All definitions have the same "fileds" configuration;
Can I add it to someplace to be used by all configurations?
My structure:
cookbooks
common
recipes
filebeat.rb
services
attributes
service1.rb
service2.rb
The content of servicesX.rb has the following definitions:
access_log = {
'paths' => ['TBD'],
'input_type' => 'log',
'fields' => {
'hostname' => node["opsworks"]["instance"]["hostname"],
'customer' => node["opsworks"]["instance"]["layers"][0],
'internal_ip' => node["opsworks"]["instance"]["private_ip"],
'ec2id' => node["opsworks"]["instance"]["aws_instance_id"],
'os' => node["opsworks"]["instance"]["os"],
'instance_type' => node["opsworks"]["instance"]["instance_type"] },
'fields_under_root' => true
}
audit_log = {
'paths' => ['TBD'],
'input_type' => 'log',
'fields' => {
'hostname' => node["opsworks"]["instance"]["hostname"],
'customer' => node["opsworks"]["instance"]["layers"][0],
'internal_ip' => node["opsworks"]["instance"]["private_ip"],
'ec2id' => node["opsworks"]["instance"]["aws_instance_id"],
'os' => node["opsworks"]["instance"]["os"],
'instance_type' => node["opsworks"]["instance"]["instance_type"]
},
'fields_under_root' => true
}
How can I extract
'fields' => {
'hostname' => node["opsworks"]["instance"]["hostname"],
'customer' => node["opsworks"]["instance"]["layers"][0],
'internal_ip' => node["opsworks"]["instance"]["private_ip"],
'ec2id' => node["opsworks"]["instance"]["aws_instance_id"],
'os' => node["opsworks"]["instance"]["os"],
'instance_type' => node["opsworks"]["instance"]["instance_type"]
Someplace in the same file (servicesX.rb) so to be used by all log files definitions?
Note: I'm a ruby novice :/
Thank you!!

Answer 1

After feedback and clarification in comments below, OP seems to want to DRY the code and re-use a fields definition.
Simplest is to store it in a variable and then use that:
fields = {
'hostname' => node["opsworks"]["instance"]["hostname"],
'customer' => node["opsworks"]["instance"]["layers"][0],
'internal_ip' => node["opsworks"]["instance"]["private_ip"],
'ec2id' => node["opsworks"]["instance"]["aws_instance_id"],
'os' => node["opsworks"]["instance"]["os"],
'instance_type' => node["opsworks"]["instance"]["instance_type"]
}
audit_log = {
'paths' => ['TBD'],
'input_type' => 'log',
'fields' => fields
}
This, however, may cause issues with how node is set. It really depends on the flow of the rest of your script. In chef (assuming this is about chef) a node is the context on which the script runs, so setting the fields too early might give issues when that node is used much later:
fields = { hostname: node["opsworks"]["instance"]["hostname"] }
# ... do lots of stuff, like fetching, preparing, connecting and whatnot.
fields # now contains the `node` values as set before connecting etc.
If this is an issue, a better option would be to define a method that returns the fields from a passed-in node:
def fields(node)
{
'hostname' => node["opsworks"]["instance"]["hostname"],
'customer' => node["opsworks"]["instance"]["layers"][0],
'internal_ip' => node["opsworks"]["instance"]["private_ip"],
'ec2id' => node["opsworks"]["instance"]["aws_instance_id"],
'os' => node["opsworks"]["instance"]["os"],
'instance_type' => node["opsworks"]["instance"]["instance_type"]
}
end
Or, cleaned up:
def fields(node)
instance = node["opsworks"]["instance"]
{
hostname: instance["hostname"],
customer: instance["layers"][0],
internal_ip: instance["private_ip"],
ec2id: instance["aws_instance_id"],
os: instance["os"],
instance_type: instance["instance_type"]
}
end
Then use that function:
audit_log = {
'paths' => ['TBD'],
'input_type' => 'log',
'fields' => fields(node)
}

Answer 2

After my research: The benefits of the implementation does not justify the time invested;
Leaving it;