Header Match - Support notContains and other modes

[ksauce]

What should we add or change to make your life better?

There are scenarios to route based on a Header match modes:

NotContains
notContains: this is a modified NOT version of contains. This is not a strict NOT logic of contains rule because we want to maintains the AND relationships between items in the dictionary.

It will match only if the following are satisfied:

Header key does not exist.
For all header keys that exist, the value substrings are not found in header value.
In the example below, if request contains fooHeader: fooValue, barHeader: badValue, it would not be considered as match since foo is a substring of fooValue.

{
  "headers": {
    "notContains": {
      "fooHeader": "foo",
      "barHeader": "bar",
    }
  }
}

Psedocode would be

bool match = (!(headers?["fooHeader"].hasSubString("foo") ?? true) &&
              !(headers?["barHeader"].hasSubString("bar") ?? true))

AnyContains
anyContains: ALL header keys must be present. ANY one of the values for each of the header keys must be present as substring. All keys must have a substring matched.

{
  "headers": {
    "anyContains": {
      "fooHeader": [
        "foo1",
        "foo2"
        ],
      "barHeader": [
        "bar1",
        "bar2"
        ]
    }
  }
}

AnyValues
anyValues: ALL header keys must be present. ANY one of the values for each of the header keys must be present. All keys must have a value matched.

{
  "headers": {
    "anyValues": {
      "fooHeader": [
        "foo1Value",
        "foo2Values"
        ],
      "barHeader": [
        "bar1Value",
        "bar2Value"
        ]
    }
  }
}

Why is this important to you?

fairly common rules that teams would use when making routing decisions

[karelz]

Triage:

• NotContains - this seems highly specialized. It brings OR into the routing logic, which does not exist there. It feels like very specific case, not much general. Unless we see more interest, we will likely not support it from config. It should be achievable via RouteConstraint. We should add small doc/example how to do these type of things.
• AnyContains - we can extend our HeaderMatchMode with 'contains'. Adding 2 rules, one for each header should then solve this scenario.
• AnyValues - we already have it with HeaderMatchMode.ExactHeader - this should be achievable today.

@ksauce can you please confirm the Any* solutions would be acceptable for you? (mainly we are trying to confirm if we understand correctly your AND/OR semantics requirements)

[ksauce]

NotContains - Yes please provide example to use RouteConstraint.

AnyContains - sounds good

AnyValues - yes it does exist. thank you

[ksauce]

Regarding NotContains, it has been determined we don't need to bring the OR into the routing logic. We only need the simple NotContains for the single header and value

[adityamandaleeka]

Triage: Marking this "backlog" to indicate it's not 1.0.