Assign list to a key within a chart - templates

Question

Deployment.yaml
...
env: {{ .Values.env}}
...
Values.yaml:
env:
- name: "DELFI_DB_USER"
value: "yyy"
- name: "DELFI_DB_PASSWORD"
value: "xxx"
- name: "DELFI_DB_CLASS"
value: "com.mysql.jdbc.Driver"
- name: "DELFI_DB_URL"
value: "jdbc:sqlserver://dockersqlserver:1433;databaseName=ddbeta;sendStringParametersAsUnicode=false"
feels like I'm missing something obvious.
linter says: ok
template says:
env: [map[name:DELFI_DB_USER value:yyy] map[name:DELFI_DB_PASSWORD
value:xxx] map[name:DELFI_DB_CLASS value:com.mysql.jdbc.Driver]
map[value:jdbc:mysql://dockersqlserver.{{ .Release.Namespace
}}.svc.cluster.local:3306/ddbeta\?\&amp\;useSSL=true\&amp\;requireSSL=false
name:DELFI_DB_URL]]
upgrade says:
Error: UPGRADE FAILED: YAML parse error on
xxx/templates/deployment.yaml: error converting YAML to JSON: yaml:
line 35: found unexpected ':'
solution:
env:
{{- range .Values.env }}
- name: {{ .name | quote }}
value: {{ .value | quote }}
{{- end }}

Answer 1

The current Go template expansion will give output which is not YAML:
env: {{ .Values.env}}
becomes:
env: env: [Some Go type stuff that isn't YAML]...
The Helm Go template needs to loop over the keys of the source YAML dictionary.
This is described in the Helm docs.
The correct Deployment.yaml is:
...
env:
{{- range .Values.env }}
- name: {{ .name | quote }}
value: {{ .value | quote }}
{{- end }}
...

Answer 2

Helm includes undocumented toYaml and toJson template functions; either will work here (because valid JSON is valid YAML). A shorter path could be
env: {{- .Values.env | toYaml | nindent 2 }}
Note that you need to be a little careful with the indentation, particularly if you're setting any additional environment variables that aren't in that list. In this example I've asked Helm to indent the YAML list two steps more, so additional environment values need to follow that too
env: {{- .Values.env | toYaml | nindent 2 }}
- name: OTHER_SERVICE_URL
value: "http://other-service.default.svc.cluster.local"