As written the omitempty is allowing the YAML to parse without an error. Added a validate_config test to factor out the yaml:omitempty issue. Should we remove the omitempty annotations to catch these sorts of issues and check for null / empty after yaml.parse or is there another way?

I could see the matrix of property checks growing quite a bit as new properties get added over time - we'd need a check for each attribute or go down the reflect route which has it's own set of issues.

https://github.com/open-telemetry/opentelemetry-go-contrib/blob/main/config/v0.3.0/generated_config.go#L427

@mikeblum, I think that you need to implement func (j *AttributeNameValue) UnmarshalYAML(unmarshal func(interface{}) error) error and func (j *AttributeNameValue) MarshalJSON() ([]byte, error) methods. Look at config_json.go and config_yaml.go for examples.