How to get key from map

Question

I'm working on go template. Having some map in . I know how to get the value, as long as I know the key.

"Map value: {{ printf "%s" .key1 }}"

How to get key name from inside the template? I would expect maybe something like

"Map key: {{ printf "%s" (keys .)[0] }}"

You can `range` over a map to get *all* the keys and values, is that what you're looking for? There's no meaningful way to get a slice of the keys you can access by numeric index because slices are ordered and maps are not. — Adrian, Dec 21 '18 at 15:31
`range` is covered in the documentation under Actions: https://golang.org/pkg/text/template/#hdr-Actions — Adrian, Dec 21 '18 at 15:36
@Adrian Thanks, I can see it and it works indeed. Just don't want to put an answer when it is you who actually gave it. — BartBiczBoży, Dec 21 '18 at 15:39

score 2 · Accepted Answer · answered Dec 21 '18 at 17:26

2

As @Adrian commented:

{{ range $key, $val := . }}
key: {{ $key }}; value: {{ $val }}
{{ end }}

But it was hard to figure it out just from range documentation

answered Dec 21 '18 at 17:26

BartBiczBoży

WindyFields may be the answer to the title, but this is the technique I would actually use in a template. – Merchako Dec 14 '22 at 20:55
This saves my life. THANKS ! – M4kn4sh Mar 23 '23 at 15:38

score 0 · Answer 2 · answered May 27 '21 at 12:54

Since the question is tagged with consul-template... the syntax for Consul/Vault templates is (given .Data is the map):

{{ index .Data "complex.key.name" }}

This is useful, when the the key name is complex (say contains dots) and {{ .Data.complex.key.name }} is interpreted as accessing nested fields.

2 Answers2