feat: Support logical operators for route expressions

[huhamhire]

Description

APISIX supports logical operators to combine multiple expressions.

e.g.

[
    "AND",
    ["arg_version", "==", "v2"],
    [
        "OR",
        ["arg_action", "==", "signup"],
        ["arg_action", "==", "subscribe"]
    ]
]

https://docs.api7.ai/apisix/reference/apisix-expressions#logical-operators

However, the ApisixRoute CRD only supports selecting route when "one of the expression is matched".

There is no clue about how to use logical operators by declarative ways. Neither from the document, nor from source code.

[kayx23]

This seems to translate to an AND:

apiVersion: apisix.apache.org/v2
kind: ApisixRoute
metadata:
  name: httpbin-route
spec:
  http:
    - name: httpbin-route
      match:
        paths:
          - /anything
        methods:
          - GET
        exprs:
        - subject:
            scope: Header
            name: X-Foo
          op: Equal
          value: bar
        - subject:
            scope: Header
            name: X-Foo-1
          op: Equal
          value: bar1
      backends:
        - serviceName: httpbin
          servicePort: 80

"vars": [
  ["http_x_foo","==","bar"],
  ["http_x_foo_1","==","bar1"]
]

But not sure how to make it an OR; or create a more complex composite logic. I checked the test cases and don't see anything relevant.

[huhamhire]

From what I've learned from lua-resty-expr, which is used by lua-resty-expr. The default operator for combining multiple expressions is AND, which is not how it says from the document.

https://github.com/api7/lua-resty-expr/blob/e91910500cfda40a7c976b832d59df5efab970c5/lib/resty/expr/v1.lua#L244