Get value from list if list-item has key==value

Question

I have the following yaml

items:
   - itemName: a
     awesome: true
   - itemName: b
   - itemName: c
     awesome: false

I need a function that gets a as an output, since item a has the attribute awesome == true. How do I do that?

Approach that does not work:

{{- $result := "nope" }}
{{- range $i := $items }}
  {{- if and (and (hasKey $i. awesome) ($i.awesome)) !($result -eq "nope") }}
    {{- $result := $i.itemName }}
  {{- end }}
{{- end }}

Have not tried the above approach, but am confident that this does not work (see this post). What I'd need is a default function that works for lists. I could not find any in sprig. Any Idea?

score 1 · Accepted Answer · answered Oct 18 '21 at 12:48

The linked post, based on which you claim you know that the code doesn't work, does not, in the question snippet, pre-declare the variable.

In your code you do pre-declare the variable but you are making a different error. The error is that you are using := to assign the value to the pre-declared variable, however := in templates works the same as in Go itself, it initializes a new variable. You need to use = for assignment to an existing variable.

https://pkg.go.dev/text/template@go1.17.2#hdr-Variables

A pipeline inside an action may initialize a variable to capture the result. The initialization has syntax
$variable := pipeline
where $variable is the name of the variable. An action that declares a variable produces no output.

Variables previously declared can also be assigned, using the syntax
$variable = pipeline

So all you need to do is to change {{- $result := $i.itemName }} to {{- $result = $i.itemName }}.

{{- $result := "nope" }}
{{- range $i := $items }}
  {{- if and (and (hasKey $i. awesome) ($i.awesome)) !($result -eq "nope") }}
    {{- $result = $i.itemName }}
  {{- end }}
{{- end }}

An example to prove this is working: https://play.golang.org/p/A44yl7jo0v7

Get value from list if list-item has key==value

1 Answers1