Manipule helm chart yaml file having {{ }} as values

[ziomill]

Hello,

I should manipulate an helm chart file like this:

apiVersion: v1
kind: ConfigMap
metadata:
  name: myconfigmap
data:
  MY_PROP_1: {{ .Values.configuration.myFirstProp }}
  MY_PROP_2: {{ .Values.configuration.mySecondProp }}
  MY_PROP_3: {{ .Values.configuration.myThirdProp }}

I would replace the MY_PROP_1: {{ .Values.configuration.myFirstProp }} with MY_PROP_1: {{ .Values.deploy.myFirstProp }}.

Trying with the yq command:

yq '.data.MY_PROP_1 = "{{ .Values.deploy.myFirstProp }}"' YQ/configmap-env.yaml

I have this strange result:

apiVersion: v1
kind: ConfigMap
metadata:
  name: myconfigmap
data:
  MY_PROP_1: '{{ .Values.deploy.myFirstProp }}'
  MY_PROP_2: {? {.Values.configuration.mySecondProp: ''}: ''}
  MY_PROP_3: {? {.Values.configuration.myThirdProp: ''}: ''}

Problem 1: The MY_PROP_1 value is replaced by adding the single quotes.
Problem 2: Also other props MY_PROP_2 and MY_PROP_3 have been replaced with strange characters --> {? { the_value}: "}

The goal is to replace only the MY_PROP_1 property, avoiding single quotes. How to do that? Please note that normal yaml file with values without bracket works as expected.

Thank you

[mikefarah]

The problem is that the file is not valid yaml - it's a template file for generating yaml. When the underlying yaml parser reads it - it produces strange results :(

[ziomill]

Hi @mikefarah ,

So, it's impossible to use yq to manipulate helm chart "template" files. Is it right? :-(

[andry81]

So, it's impossible to use yq to manipulate helm chart "template" files. Is it right? :-(

You can't use any string as a value, you still must escape several specific characters, even in a double quotes string.
Why not change the template?

apiVersion: v1
kind: ConfigMap
metadata:
  name: myconfigmap
data:
  MY_PROP_1: "{{ .Values.configuration.myFirstProp }}"
  MY_PROP_2: "{{ .Values.configuration.mySecondProp }}"
  MY_PROP_3: "{{ .Values.configuration.myThirdProp }}"

[mikefarah]

Unless you can make the template a valid yaml file (like @andry81 has done) then the underlying parsers will not be able to interpret the template :(

[verliba]

I run this ed script after yq

{{'g/{\?? {\([^{}]*\): \'\'} *: *\'\'}/s//{{\\1}}/g'}}
wq

to fix the {? {stuff: ''}: ''} with {{stuff}}

PS: I hope some enjoys, it took me some time to login back here just to comment
PPS: my script is in template, feel free to remove {{' and }}' and replace \1 by \1 as well as ' by '

[sabreensalama]

@verliba , could you explain your answer as I have the same issue, and this will help me

[verliba]

@sabreensalama I am not quite certain anymore, about everything, it's been long time..
basically, I have this ed script within a cookiecutter template, so, the {{'whatever is here'}} are rendered, and the curly brackets and quotes are removed during that step, also I think things are un-escaped.. after passing cookiecutter, the actual .ed file might look like this

g/{\?? {\([^{}]*\): ''} *: *''}/s//{{\1}}/g
wq

what this does, I am not sure any more.. g/ is for global, and the s/ is for search and replace, I guess, the \1 refers to stuff inside of (..)
so it should come back to, what I said earlier.. fix the {? {stuff: ''}: ''} with {{stuff}}
there is some regex involved in it
I suppose that, those are, the ugly thing, yq does to all {{VARIABLES}} that were originally in the file