6b8735bb18
Refactor validator main function to avoid 'interface' symbol clash. Add get_mtu() for interfaces, returns the sub-int's MTU or its parent's MTU, defaulting to 1500. Ensure MTU for all bridge-domain members is set to the same value. Ensure all bridge-domain members are L2 (have no LCP, have no address)
Design
YAML Configuration
The main file that is handled by this program is the Configuration File.
Validation
There are three types of validation: schema which ensures that the input YAML has the correct fields of well known types, semantic which ensures that the configuration doesn't violate semantic constraints and runtime which ensures that the configuration can be applied to the VPP daemon.
Schema Validators
First the configuration file is held against a structural validator, provided by Yamale.
Based on a validation schema in schema.yaml, the input file is checked for syntax correctness.
For example, a dot1q field must be an integer between 1 and 4095, wile an lcp string must
match a certain regular expression. After this first pass of syntax validation, I'm certain that
if a field is set, it is of the right type (ie. string, int, enum).
Semantic Validators
A set of semantic validators, each with a unique name, ensure that the semantics of the YAML are correct. For example, a physical interface cannot have an LCP, addresses or sub-interfaces, if it is to be a member of a BondEthernet.
Validators are expected to return a tuple of (bool,[string]) where the boolean signals success (False meaning the validator rejected the configuration file, True meaning it is known to be correct), and a list of zero or more strings which contain messages meant for human consumption.
Runtime Validators
After the configuration file is considered syntax and semanticly valid, there is one more set of
checks to perform -- runtime validators ensure that the configuration elements such as physical
network devices (ie. HundredGigabitEthernet12/0/0 or plugin lcpng are present on the system.
It does this by connecting to VPP and querying the runtime state to ensure that what is modeled
in the configuration file is able to be committed.