template with multiple arguments

[daniel-torok]

I found that we can have custom templates: https://docs.gomplate.ca/functions/tmpl/
The documentation also says that we can pass a context object to it, referenced as {{ . }} in the template.

Can we provide multiple arguments to a template?
For example:

{{ define "Default" -}}
{{ if has .0 .1 }}{{ .0..1 }}{{ else }}{{ .2 }}{{ end }}
{{ end }}

{{ $ds := datasource "ds" }}
foo:
  bar: {{ template "Default" $ds keyToCheck defaultValue }}

In the example .0 , .1, .2 would refer to the indexed arguments the template received.

[hairyhenderson]

(I've converted this to a discussion as this is more of a question than an issue)

The context must be a single item, however that item can be a list (slice) or a map (dict). You can construct your own inline with the slice and dict functions:

{{ define "foo" }}
{{ if has .ds .key }}{{ index .ds .key }}{{ else }}{{ .default }}{{ end }}
{{ end }}

{{ $ds := datasource "ds" }}
foo:
  bar: {{ template "foo" dict "ds" $ds "key" $keyToCheck "default" $defaultValue }}

(See the docs for more about why index is necessary)

For more complex slices and maps it can be awkward to use the slice and dict functions extensively, so one pattern I've used a few times is to convert from inline YAML or JSON with the yaml or json functions. For example:

{{ $ipRanges := `
internal:
- 10.0.0.0/8
- 172.16.0.0/12
- 192.168.0.0/24
external:
- 1.0.0.0/8
- 123.234.5.0/24
` | yaml }}

{{ template "someTemplate" $ipRanges }}

[daniel-torok]

Thank you, I didn't notice the dict and slice functions for this purpose.