New properties API completion

[boeboe]

Ported the work done in WASM plugins to expose the properties API.

• Added all of the Getters in separate files
• Added marshaling and marshaling functions in serialization.go
• Added Istio and Envoy specific types in types.go
• Added GetProperty functions in utils.go
• Ported all documentation over
• Adopted unit test input data reflecting real data (from an Istio based setup)

TBD with @mathetake @jcchavezs @nacx

• The marshaling and unmarshaling functions should not be exclusive to properties api, as they are essential for the shared data API between different plugins as well
• Some consideration might need to be taken on Envoy vs Istio specific logic, although this is now already cleanly separated in different files

[mathetake]

The marshaling and unmarshaling functions should not be exclusive to properties api, as they are essential for the shared data API between different plugins as well

no we don't need for shared data as here we are having them only because it's the serialization format for properties vs shared data API doesn't have any format at the ABI level.

[mathetake]

please prefix the global "enum" by its type name as I suggested ^ to have clean namespace in the pkg

Suggested change

	const (
	// InterceptionNone indicates that the workload is not using IPtables for traffic interception
	None IstioTrafficInterceptionMode = iota
	// InterceptionTproxy implies traffic intercepted by IPtables with TPROXY mode
	Tproxy
	// InterceptionRedirect implies traffic intercepted by IPtables with REDIRECT mode. This is our default mode
	Redirect
	)
	const (
	// IstioTrafficInterceptionModeNone indicates that the workload is not using IPtables for traffic interception
	IstioTrafficInterceptionModeNone IstioTrafficInterceptionMode = iota
	// IstioTrafficInterceptionModeTproxy implies traffic intercepted by IPtables with TPROXY mode
	IstioTrafficInterceptionModeTproxy
	// IstioTrafficInterceptionModeRedirect implies traffic intercepted by IPtables with REDIRECT mode. This is our default mode
	IstioTrafficInterceptionModeRedirect
	)

[mathetake]

talked offline - let's move the serde functions after landing this PR and place it under internal/serde directory so that we could reuse it later on for shared data API wrapper

[boeboe]

@mathetake fixed the final linter warnings as well. if you give it a go with the changes I made based on your good feedback, we can merge.

[mathetake]

Suggested change

	type EnvoyTrafficDirection int
	const (
	// Unspecified means that the direction is not specified.
	Unspecified EnvoyTrafficDirection = iota
	// Inbound means that the transport is used for incoming traffic.
	Inbound
	// Outbound means that the transport is used for outgoing traffic.
	Outbound
	)
	type EnvoyTrafficDirection int
	const (
	// EnvoyTrafficDirectionUnspecified means that the direction is not specified.
	EnvoyTrafficDirectionUnspecified EnvoyTrafficDirection = iota
	// EnvoyTrafficDirectionInbound means that the transport is used for incoming traffic.
	EnvoyTrafficDirectionInbound
	// EnvoyTrafficDirectionOutbound means that the transport is used for outgoing traffic.
	EnvoyTrafficDirectionOutbound
	)

[boeboe]

Cfr #403 (comment)

[mathetake]

@boeboe you didn't resolve all my comments. I found a few places to fix, but all good

[mathetake]

Suggested change

	type IstioTrafficInterceptionMode int
	const (
	// None indicates that the workload is not using IPtables for traffic interception.
	None IstioTrafficInterceptionMode = iota
	// Tproxy implies traffic intercepted by IPtables with TPROXY mode.
	Tproxy
	// Redirect implies traffic intercepted by IPtables with REDIRECT mode. This is our default mode.
	Redirect
	)
	type IstioTrafficInterceptionMode int
	const (
	// IstioTrafficInterceptionModeNone indicates that the workload is not using IPtables for traffic interception.
	IstioTrafficInterceptionModeNone IstioTrafficInterceptionMode = iota
	// IstioTrafficInterceptionModeTproxy implies traffic intercepted by IPtables with TPROXY mode.
	IstioTrafficInterceptionModeTproxy
	// IstioTrafficInterceptionModeRedirect implies traffic intercepted by IPtables with REDIRECT mode. This is our default mode.
	IstioTrafficInterceptionModeRedirect
	)

[boeboe]

The most idiomatic Go comments are those that are clear, concise, and directly above the item they're describing. The Go community values clarity and simplicity, and the official Go documentation often uses the style seen in the first example.

Therefore, the first example is the most idiomatic:

const (
	// None indicates that the workload is not using IPtables for traffic interception.
	None IstioTrafficInterceptionMode = iota
	// Tproxy implies traffic intercepted by IPtables with TPROXY mode.
	Tproxy
	// Redirect implies traffic intercepted by IPtables with REDIRECT mode. This is our default mode.
	Redirect
)

The comments are directly above the constants they describe, and they don't repeat the constant's name, which is redundant and not necessary. The other examples are more verbose and less idiomatic.

Online examples can be found in plenty upstream well adopted modules. An example of the net/http package

https://cs.opensource.google/go/go/+/refs/tags/go1.21.3:src/net/http/server.go;l=2873

PS: IstioTrafficInterceptionModeRedirect does not make any sense, as this string would not even be useful in code nor documents (where does the type name start and end?). IstioTrafficInterceptionMode.Redirect (with the dot) would make a bit more sense, but is not as golang idiomatic as mentioned in the initial argument.

[mathetake]

After the prefix nits are resolved, will merge it