update NetConf.DNS's json tag to omitempty

[cyclinder]

Fixes #1006

[dcbw]

@cyclinder could you add your Signed-off-by: to the commit? That will fix the DCO check. Thanks!

[coveralls]

coverage: 72.477%. remained the same when pulling 5241e42 on cyclinder:dns_omitempty into e255525 on containernetworking:main.

[cyclinder]

Thanks for the tip. Updated.

[cyclinder]

Hi @dcbw, I found IPAM and DNS fields are also tagged with omitempty, but this has no effect.

type NetConf struct {
	CNIVersion string `json:"cniVersion,omitempty"`
	IPAM         IPAM            `json:"ipam,omitempty"`
	DNS          DNS             `json:"dns,omitempty"`
}

type IPAM struct {
	Type string `json:"type,omitempty"`
}

type Test struct {
	Name string `json:"name,omitempty"`
}

func main(){
     	t := &test{
	    CNIVersion: "test",
	}

	bytes,err := json.Marshal(t)
	if err != nil {
		log.Fatalln(err)
	}

	log.Println(string(bytes))
}

#cyclinder~ go run main.go
2023/07/11 11:19:00 {"ipam":{},"dns":{},"cniVersion":"test"}

We should make struct to a pointer. Pointers have obvious "empty" values: nil.

type NetConf struct {
	CNIVersion string `json:"cniVersion,omitempty"`
	IPAM         *IPAM            `json:"ipam,omitempty"`
	DNS          *DNS             `json:"dns,omitempty"`
}

type IPAM struct {
	Type string `json:"type,omitempty"`
}

type Test struct {
	Name string `json:"name,omitempty"`
}

func main(){
     	t := &test{
	    CNIVersion: "test",
	}

	bytes,err := json.Marshal(t)
	if err != nil {
		log.Fatalln(err)
	}

	log.Println(string(bytes))
}

#cyclinder~ go run main.go
2023/07/11 11:21:00 {"cniVersion":"test"}

Can we set IPAM and DNS as pointers?

[cyclinder]

@dcbw Hi, Could you take a look? Can we set IPAM and DNS as pointers?

[cyclinder]

Hey @squeed, Could you please take a look? Thanks.

[s1061123]

I suppose we also need to change DNS in Result (at least 1.0.0) to pointer as well as NetConf if we change NetConf's DNS type. What do you think about that?

[s1061123]

I will cherry-pick your change and create another PR to care about both (NetConf + Result). Please let me know if you mind it. Thanks!

[s1061123]

Files #1035 with your commit (as cherry-pick).

[cyclinder]

Sorry for the delay @s1061123 due to busy with working :>

Please let me know if you mind it. Thanks!

It doesn't matter, you are welcome.

[s1061123]

Closed because #1039 fixes this issue.