K
Q

Question

ADD / REMOVE a backend block within k8s ingress manifest with JQ (YQ)

3/11/2019

I have a kubernetes ingress manifest YAML, looking like next:

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  annotations:
    certmanager.k8s.io/acme-http01-edit-in-place: "true"
    certmanager.k8s.io/cluster-issuer: letsencrypt
  name: staging
  namespace: dev
spec:
  rules:
  - host: staging.domain.com
    http:
      paths:
      - backend:
          serviceName: task-11111
          servicePort: 80
        path: /task-11111/*
      - backend:
          serviceName: task-22222
          servicePort: 80
        path: /task-22222/*
      - backend:
          serviceName: task-33333
          servicePort: 80
        path: /task-33333/*
  tls:
  - hosts:
    - staging.domain.com
    secretName: staging-domain-com

What I'm trying to achieve is to add (if not present) or remove (if present) a backend block. What I have now:

yq -y '.spec.rules[].http.paths += [{ "backend": { "serviceName": "'${CI_COMMIT_REF_NAME}'", "servicePort": 80}, "path": "/'${CI_COMMIT_REF_NAME}'/*"}]'

(adds a new block with variable value, but doesn't bother if it already exists)

yq -y 'del(.. | .paths? // empty | .[] | select(.path |contains("'${CI_COMMIT_REF_NAME}'")) )'

(fails with jq: error (at <stdin>:0): Invalid path expression with result {"backend":{"serviceName":...)

So rules may look like this after deletion (assume that CI_COMMIT_REF_NAME = task-33333):

spec:
  rules:
  - host: staging.domain.com
    http:
      paths:
      - backend:
          serviceName: task-11111
          servicePort: 80
        path: /task-11111/*
      - backend:
          serviceName: task-22222
          servicePort: 80
        path: /task-22222/*

or like this after adding (assume that CI_COMMIT_REF_NAME = task-44444):

spec:
  rules:
  - host: staging.domain.com
    http:
      paths:
      - backend:
          serviceName: task-11111
          servicePort: 80
        path: /task-11111/*
      - backend:
          serviceName: task-22222
          servicePort: 80
        path: /task-22222/*
      - backend:
          serviceName: task-33333
          servicePort: 80
        path: /task-33333/*
      - backend:
          serviceName: task-44444
          servicePort: 80
        path: /task-44444/*

Any help is greatly appreciated.

-- cardinal-gray

jq

json

kubernetes

yaml

1 Answer

3/11/2019

[The following has been revised to reflect the update to the question.]

Assuming CI_COMMIT_REF_NAME is available to jq as $CI_COMMIT_REF_NAME, which can be done using jq with the command-line argument:

--arg CI_COMMIT_REF_NAME "$CI_COMMIT_REF_NAME"

an appropriate jq filter would be along the following lines:

.spec.rules[0].http.paths |=
  (map(select(.path | index($CI_COMMIT_REF_NAME) | not)) as $new
   | if ($new | length) == length
     then . + [{ "backend": { "serviceName": $CI_COMMIT_REF_NAME, "servicePort": 80}, "path": ($CI_COMMIT_REF_NAME + "/*") }]
     else $new
     end )

You can test this with the following jq invocation:

jq --arg CI_COMMIT_REF_NAME task-4444 -f program.jq input.json

where of course input.json is the JSON version of your YAML.

(I'd use index in preference to contains if at all possible.)

-- peak

Source: StackOverflow

KQ

ADD / REMOVE a backend block within k8s ingress manifest with JQ (YQ)

Similar Questions

1 Answer

K
Q