One powerful feature of octocatalog-diff allows you to override ENC parameters when compiling the catalogs, to predict the effect of an ENC parameter change on the catalog. This is useful to simulate a change in agent node configuration without actually setting up an agent to do so.
To override an ENC parameter in both catalogs:
--enc-override parameters::some_class::some_param=value
To override an ENC parameter in the "to" catalog:
--to-enc-override parameters::some_class::some_param=value
To override an ENC parameter in the "from" catalog:
--from-enc-override parameters::some_class::some_param=value
You may use as many of these arguments as you wish to adjust as many ENC parameters as you wish.
As presently implemented, this only works on ENCs that supply their results as YAML.
Is your ENC doing something different? Please let us know so we can enhance octocatalog-diff to handle it!
Simulate a change to a top-level parameter named "role" only in the "to" catalog:
octocatalog-diff -n some-node.example.com -f master -t master \
--to-enc-override parameters::role=some_new_role
Simulate a change in a class parameter between the catalogs:
octocatalog-diff -n some-node.example.com -f master -t master \
--from-enc-override parameters::my_class::my_value=value_in_old \
--to-enc-override parameters::my_class::my_value=value_in_new
Note that each of the examples specified the from branch and to branch to be master. There is no requirement that you do this, but you can generally obtain the most accurate test results by changing only one variable at a time.
The format for declaring overrides with data types is the same as overriding facts.