kubectl-filter-output

README

kubectl-filter-output

Plugin for kubectl to filter uninteresting metadata fields for humans from JSON or YAML output.

Installation

Compile From Source

These instructions assume you have go installed and a $GOPATH set. Just run

make install

The binary is installed in $GOPATH/bin. If this directory is on your $PATH, you are done. Otherwise you have to copy the binary in a directory of your $PATH.

Usage

The plugin can be used whenever kubectl is used with YAML or JSON output.

kubectl fo [--filter <expr1>,<expr2>] ...

Command line examples:

kubectl fo get svc kubernetes -o yaml
kubectl fo get pod -o json
kubectl fo --filter metadata,-metadata.label,status get svc kubernetes -oyaml

It can also be used via pipe:

kubectl get svc kubernetes -o yaml | kubectl-fo -i
kubectl get pod -o json | kubectl-fo -i -o json
kubectl get svc kubernetes -oyaml | kubectl-fo -i --filter metadata,-metadata.label,status

If no --filter is specified, only the default filters are applied. These fields are always removed from the output:

• metadata.managedFields

• metadata.selfLink

• metadata.annotations.'kubectl.kubernetes.io/last-applied-configuration'

--filter / -f option

With the --filter <filter-expression> or -f <filter-expression> option additional fields can be filtered. This is simple alternative for using the advanced -o jsonpath output.

The filter expression is a comma separated list of simple JSON path field expressions. Each item can be prefixed with + or - optionally to keep or remove the fields respectively. Keeping (+) is the default if not specified.

Filter expression examples:

1. --filter metadata.name,metadata.namespace only keeps metadata.name and metadata.namespace. It is the same as --filter +metadata.name,+metadata.namespace

2. --filter -status drops the status field of on object

3. --filter metadata,-metadata.labels,-metadata.annotations keeps the metadata field but drops labels and annotations

Examples

Before

$ kubectl get svc kubernetes -oyaml
apiVersion: v1
kind: Service
metadata:
  creationTimestamp: "2021-01-07T10:33:32Z"
  labels:
    component: apiserver
    provider: kubernetes
  managedFields:
    - apiVersion: v1
      fieldsType: FieldsV1
      fieldsV1:
        f:metadata:
          f:labels:
            .: {}
            f:component: {}
            f:provider: {}
        f:spec:
          f:clusterIP: {}
          f:ports:
            .: {}
            k:{"port":443,"protocol":"TCP"}:
              .: {}
              f:name: {}
              f:port: {}
              f:protocol: {}
              f:targetPort: {}
          f:sessionAffinity: {}
          f:type: {}
      manager: kube-apiserver
      operation: Update
      time: "2021-01-07T10:33:32Z"
  name: kubernetes
  namespace: default
  resourceVersion: "154"
  selfLink: /api/v1/namespaces/default/services/kubernetes
  uid: e25e7b7f-1d86-4f3d-aabd-9ab373dfa958
spec:
  clusterIP: 100.64.0.1
  ports:
    - name: https
      port: 443
      protocol: TCP
      targetPort: 443
  sessionAffinity: None
  type: ClusterIP
status:
  loadBalancer: {}

With default filters

$ kubectl fo get svc kubernetes -oyaml
apiVersion: v1
kind: Service
metadata:
  creationTimestamp: "2021-01-07T10:33:32Z"
  labels:
    component: apiserver
    provider: kubernetes
  name: kubernetes
  namespace: default
  resourceVersion: "154"
  uid: e25e7b7f-1d86-4f3d-aabd-9ab373dfa958
spec:
  clusterIP: 100.64.0.1
  ports:
    - name: https
      port: 443
      protocol: TCP
      targetPort: 443
  sessionAffinity: None
  type: ClusterIP
status:
  loadBalancer: {}

With additional filters

$ kubectl fo --filter metadata,-metadata.label,status get svc kubernetes -oyaml
metadata:
  creationTimestamp: "2021-01-07T10:33:32Z"
  labels:
    component: apiserver
    provider: kubernetes
  name: kubernetes
  namespace: default
  resourceVersion: "154"
  uid: e25e7b7f-1d86-4f3d-aabd-9ab373dfa958
status:
  loadBalancer: {}

Note that the filters always work on the items of a List

$ kubectl fo --filter metadata,-metadata.labels,-metadata.annotations,spec get node -oyaml
apiVersion: v1
items:
- metadata:
    creationTimestamp: "2021-01-07T10:35:34Z"
    name: my-node-1234
    resourceVersion: "716271"
    uid: 4f424ebb-8e2c-42b4-9e80-c7f15bbc4fb9
  spec:
    podCIDR: 100.96.0.0/24
    podCIDRs:
    - 100.96.0.0/24
    providerID: vsphere://42070914-70ac-7214-0886-69104a2dc946
kind: List
metadata:
  resourceVersion: ""
  selfLink: ""