[Feature] something like `{{-` and `-}}` but that trims newlines only

[ItalyPaleAle]

Consider this template:

      ports:
      {{ with (datasource "values").bind }}
        - containerPort: 80
          hostPort: 80
          hostIP: {{ .ip | toYAML }}
        - containerPort: 8081
          hostPort: 8081
          hostIP: {{ .ip | toYAML }}
      {{ end }}

When running, the output is:

      ports:
        
        # Expose HTTP port and API on the Tailscale interface only
        - containerPort: 80
          hostPort: 80
          hostIP: 127.0.0.1

        - containerPort: 8081
          hostPort: 8081
          hostIP: 127.0.0.1

        

I understand that I can use {{- and -}} to trim the whitespace. For example:

      ports:
      {{ with (datasource "values").bind -}}
        - containerPort: 80
          hostPort: 80
          hostIP: {{ .ip | toYAML -}}
        - containerPort: 8081
          hostPort: 8081
          hostIP: {{ .ip | toYAML -}}
      {{ end }}

However, that follows how Go templates work, and they remove any whitespace characters, not just newlines. So, the result is something similar to:

      ports:
        - containerPort: 80
          hostPort: 80
          hostIP: 127.0.0.1
- containerPort: 8081
          hostPort: 8081
          hostIP: 127.0.0.1

As you can see, this removes also the spaces before the next item in the array, so this breaks my YAML.

Is there a way gomplate could be configured to behave more like Helm in this specific case, where using {{- for example only removes until the previous newline?

[hairyhenderson]

more like Helm in this specific case, where using {{- for example only removes until the previous newline?

Interesting - if {{- behaves differently in Helm, I guess they've diverged from Go's text/template parsing?

I haven't used Helm in a few years, but from what I recall, it suffered the same issue. However, to get around that, I remember using Helm's nindent function.

A few ways you could work around this particular issue:

1. output as JSON instead - it shouldn't (in theory?) have a trailing newline, and in this particular case the output will be valid in YAML as well: {{ .ip | toJSON }}
2. remove the trailing newline that toYAML introduces - using strings.TrimSpace makes sense in this case: {{ .ip | toYAML | strings.TrimSpace }}
3. use strings.Indent - {{ .ip | toYAML | strings.Indent 6 -}}

The behaviour of {{-/-}} is from Go's text/template package, and so its behaviour can't be changed for gomplate (at least, without diverging from the standard template language, which I don't want to do).

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[xxxcoltxxx]

@ItalyPaleAle You can use trims at left only:

      ports:
      {{- with (datasource "values").bind }}
        - containerPort: 80
          hostPort: 80
          hostIP: {{ .ip | toYAML }}
        - containerPort: 8081
          hostPort: 8081
          hostIP: {{ .ip | toYAML }}
      {{- end }}

Output is:

      ports:
        - containerPort: 80
          hostPort: 80
          hostIP: {{ .ip | toYAML }}
        - containerPort: 8081
          hostPort: 8081
          hostIP: {{ .ip | toYAML }}

[hairyhenderson]

Thanks @xxxcoltxxx - I think that answers the issue. I'm going to close this now.