kubectl output formatted : looking for a specific column - kubernetes

Question

I'm looking to have a specific column, through my initial kubectl command
kubectl --context oam-ska-yo_jonnylee -n ebzz get -o json ingressroute zz-oamtoto
This give me the json below
{
"apiVersion":"traefik.containo.us/v1alpha1",
"kind":"IngressRoute",
"metadata":{
"annotations":{
"kubectl.kubernetes.io/last-applied-configuration":"{"sum-up"}\n"
},
"creationTimestamp":"2021-02-23T11:17:56Z",
"generation":1,
"labels":{
"instance":"webzz"
},
"managedFields":[
{
"apiVersion":"traefik.containo.us/v1alpha1",
"fieldsType":"FieldsV1",
"fieldsV1":{
"f:metadata":{
"f:annotations":{
".":{
},
"f:kubectl.kubernetes.io/last-applied-configuration":{
}
},
"f:labels":{
".":{
},
"f:instance":{
}
}
},
"f:spec":{
".":{
},
"f:entryPoints":{
},
"f:routes":{
}
}
},
"manager":"kubectl",
"operation":"Update",
"time":"2021-02-23T11:17:56Z"
}
],
"name":"zz-oamtoto",
"namespace":"ebzz",
"resourceVersion":"61112315",
"selfLink":"/apis/traefik.containo.us/v1alpha1/namespaces/ebzz/ingressroutes/zz-oamtoto",
"uid":"42727XXX-dd9e-45e4-9c7d-1225aea125"
},
"spec":{
"entryPoints":[
"http"
],
"routes":[
{
"kind":"Rule",
"match":"Host(`ebzz.acme.com`)",
"middlewares":[
{
"name":"ebzz-ebzz-basicauth"
}
],
"services":[
{
"kind":"Service",
"name":"zz-oamtoto",
"port":1234
}
]
}
]
}
}
What I'm looking at is to find a specific column, the routes one and most of all, one of its specific sub-column
"match":"Host('ebzz.acme.com')"
I tried the command below
kubectl --context oam-ska-yo_jonnylee -n ebzz get -o=custom-columns=svc:.spec.routes.-kind ingressroute zz-oamtoto
Which gives me this:
[map[kind:Rule match:Host(`ebzz.acme.com`) middlewares:[map[name:ebzz-ebzz-basicauth]] services:[map[kind:Service name:zz-oamtoto port:1234]]]]
What i've tried so far
kubectl --context oam-ska-yo_jonnylee -n ebzz get -o=custom-columns=svc:.spec.routes[kind] ingressroute zz-oamtoto
It gives me this
svc
error: invalid array index kind
I've tried this as well
kubectl --context oam-ska-yo_jonnylee -n ebzz get -o=custom-columns=svc:.spec.routes["kind"] ingressroute zz-oamtoto
But it gives me this
svc
error: invalid array index kind

Answer 1

After many trials, this one works
kubectl --context oam-ska-yo_jonnylee -n ebz get -o=custom-columns=.spec.routes[0].match ingressroute zz-oamtoto
The option custom-columns should give you the tuning if you are looking for a column.
For the first column, you are aiming to, you need to put a .spec followed by a dot and the column name, like this .spec.column_name
Once there, the routes column part, in this example, is an array. Therefore you need to put the [], followed by the number and then followed by the subname, here match. it gives you .spec.routes[0].match
Note: I use a svc in my initial kubectly query. It was a mistake, there is no use for that.

Answer 2

If I understood you correctly, you need
kubectl --context oam-ska-yo_jonnylee -n ebz get ingressroute zz-oamtoto --output=jsonpath={.spec.routes.match}
Here you can find more examples: kubectl Cheat Sheet