Ansible jsonnet filter

example.yaml

  - name: Load kube-apiserver.yaml
    slurp:
      src: "{{tmpconfdir.path}}/etc/kubernetes/manifests/kube-apiserver.yaml"
    register: "apiserver_yaml"

  # Implement https://github.com/kubernetes/kubeadm/issues/1105#issuecomment-544887733
  - name: Patch apiserver healthcheck
    vars:
      mixin: |
        {spec+: {containers: [super.containers[0] + {
          livenessProbe+: { httpGet+: { httpHeaders: [
            { name: "Authorization",
              value: "Bearer {{healthcheck_token}}" }
          ]}}
        }] + super.containers[1:]}}
    copy:
      dest: "{{tmpconfdir.path}}/etc/kubernetes/manifests/kube-apiserver.yaml"
      content: | 
        {{ apiserver_yaml.content | b64decode | from_yaml | to_json | jsonnet_mixin(mixin) | from_json | to_yaml }}

jsonnet.py

# place me int filter_plugins dir next to your playbook

from __future__ import (absolute_import, division, print_function)
__metaclass__ = type

from ansible.errors import AnsibleError, AnsibleFilterError
from ansible.utils.display import Display

display = Display()

try:
    import _jsonnet
    HAS_LIB = True
except ImportError:
    HAS_LIB = False

def jsonnet_mixin(data, mixin):
    '''Evaluates Jsonnet '+ mixin' for a given input. 

    
    Example:
    - debug: msg="{{ '{a: 10}' | jsonnet_mixin('{b: self.a}') }}"
    '''
    if not HAS_LIB:
        raise AnsibleError('You need to install "jsonnet" from pypi')

    try:
        return _jsonnet.evaluate_snippet("filter_input", data + '+' + mixin)
    except Exception as e:
        # For older jmespath, we can get ValueError and TypeError without much info.
        raise AnsibleFilterError('Error in jsonnet_mixing filter plugin:\n%s' % e)


class FilterModule(object):
    ''' Query filter '''

    def filters(self):
        return {
            'jsonnet_mixin': jsonnet_mixin
        }