#113245 Tim's demo code to check dup ports

gistfile1.txt

// You can edit this code!
// Click here and start typing.
package main

import "fmt"

type ContainerPort struct {
	Port     int32
	Protocol string
	HostPort int32
	HostIP   string
}

func warn(index int, ports []ContainerPort) []string {
	type portBlock struct {
		index int
		port  ContainerPort
	}
	allPorts := map[string][]portBlock{}
	var errs []string

	// This would need to visit all containers
	for i, port := range ports {
		if port.HostIP != "" && port.HostPort == 0 {
			errs = append(errs, fmt.Sprintf("case %d:: Warning: [%d] hostIP set without hostPort: %+v", index, i, port))
		}

		k := fmt.Sprintf("%d/%s", port.Port, port.Protocol)
		if others, found := allPorts[k]; found {
			// keys collided, but may be OK
			for _, other := range others {
				if port.HostPort == other.port.HostPort && port.HostIP == other.port.HostIP {
					// Exactly-equal is obvious.  Validation should already filter for this except when these are unspecified.
					errs = append(errs, fmt.Sprintf("case %d:: Warning: duplicate ports: [%d] and [%d]: %+v", index, other.index, i, other.port))
				} else if port.HostPort == 0 || other.port.HostPort == 0 {
					// HostPort = 0 is redundant with any other value, which is odd but not really dangerous.  HostIP doesn't matter here.
					errs = append(errs, fmt.Sprintf("case %d:: Warning: overlapping ports: [%d] and [%d]: %+v", index, other.index, i, other.port))
				} else if a, b := port.HostIP == "", other.port.HostIP == ""; port.HostPort == other.port.HostPort && ((a || b) && !(a && b)) {
					// If the HostPorts are the same and either HostIP is not specified while the other is not, the behavior is undefined.
					errs = append(errs, fmt.Sprintf("case %d:: Warning: dangerously ambiguous ports: [%d] and [%d]: %+v", index, other.index, i, other.port))
				}
			}
		}
		allPorts[k] = append(allPorts[k], portBlock{i, port})
	}
	return errs
}

func main() {
	cases := []struct {
		input []ContainerPort
		fail  bool
	}{{
		input: []ContainerPort{
			{9376, "TCP", 0, ""}}, // OK
		fail: false,
	}, {
		input: []ContainerPort{
			{9376, "TCP", 93, ""}}, // OK
		fail: false,
	}, {
		input: []ContainerPort{
			{9376, "TCP", 93, "1.2.3.4"}}, // OK
		fail: false,
	}, {
		input: []ContainerPort{
			{9376, "TCP", 93, ""}, // OK
			{9376, "TCP", 76, ""},
		},
		fail: false,
	}, {
		input: []ContainerPort{
			{9376, "TCP", 93, "1.2.3.4"}, // OK
			{9376, "TCP", 93, "5.6.7.8"},
		},
		fail: false,
	}, {
		input: []ContainerPort{
			{9376, "TCP", 93, "1.2.3.4"}, // OK
			{9376, "TCP", 76, "1.2.3.4"},
		},
		fail: false,
	}, {
		input: []ContainerPort{
			{9376, "TCP", 93, "1.2.3.4"}, // OK
			{9376, "TCP", 76, ""},
		},
		fail: false,
	}, {
		input: []ContainerPort{
			{9376, "TCP", 0, "1.2.3.4"}, // IP without Port
		},
		fail: true,
	}, {

		input: []ContainerPort{
			{9376, "TCP", 0, ""}, // DUP
			{9376, "TCP", 0, ""},
		},
		fail: true,
	}, {
		input: []ContainerPort{
			{9376, "TCP", 93, ""}, // DUP
			{9376, "TCP", 93, ""},
		},
		fail: true,
	}, {
		input: []ContainerPort{
			{9376, "TCP", 93, "1.2.3.4"}, // DUP
			{9376, "TCP", 93, "1.2.3.4"},
		},
		fail: true,
	}, {
		input: []ContainerPort{
			{9376, "TCP", 0, ""}, // OVERLAP
			{9376, "TCP", 93, ""},
		},
		fail: true,
	}, {
		input: []ContainerPort{
			{9376, "TCP", 93, ""}, // OVERLAP
			{9376, "TCP", 0, ""},
		},
		fail: true,
	}, {
		input: []ContainerPort{
			{9376, "TCP", 93, ""}, // OVERLAP
			{9376, "TCP", 0, ""},
			{9376, "TCP", 76, ""},
		},
		fail: true,
	}, {
		input: []ContainerPort{
			{9376, "TCP", 93, "1.2.3.4"}, // AMBIGUOUS
			{9376, "TCP", 93, ""},
		},
		fail: true,
	}, {
		input: []ContainerPort{
			{9376, "TCP", 93, ""}, // AMBIGUOUS
			{9376, "TCP", 93, "1.2.3.4"},
		},
		fail: true,
	}}
	for i, input := range cases {
		errs := warn(i, input.input)
		if (len(errs) > 0) != input.fail {
			fmt.Println("TEST FAILED for case", i)
		} else if len(errs) > 0 {
			fmt.Println(errs)
		}
	}
}