2D array in YAML

user_9548061 0
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I've a helm chart with attribute 2darrayIPs. This attribute takes value from values.yaml file which inturn is given via helm installation command

helm-chart/templates/main.yaml

2darrayIPs: {{ .Values.2darrayIPs }}

helm-chart/values.yaml

2darrayIPs: [[]]  -- empty array, this value is given via installation command

I'm passing 2d array via helm command while installing helm chart.

helm install ..... -f val.yaml

val.yaml

2darrayIPs:
  - - 1.1.1.1
    - 2.2.2.2
  - - 3.3.3.3
    - 4.4.4.4

I'm getting this error while installing helm chart:

Error: YAML parse error on templates/main.yaml: error converting YAML to JSON: yaml: did not find expected ',' or ']'

If I give one array as given below, the installation is successful but in my logs I get a single array with only one value instead of two:

[[1.1.1.1 2.2.2.2]]

val.yaml

2darrayIPs:
  - - 1.1.1.1
    - 2.2.2.2

Where am I going wrong?

helm3 kubernetes-helm yaml arrays
2 Answers

If your templates are trying to write out something more complex than a simple string, the default {{ .Values.name }} serialization is something Go-native that's not especially useful. Helm includes a toJson template function, and also an undocumented toYaml, which can write these out in more useful formats.

# as an array of arrays, in JSON syntax
2darrayIPs: {{ .Values.2darrayIPs | toJson }}

# as an array of arrays, in expanded YAML syntax
# (identical to the previous, but `helm template` output will be
# easier to read)
2darrayIPs: {{- .Values.2darrayIPs | toYaml | nindent 2 }}

# as a YAML-encoded string; for example in a ConfigMap
2darrayIPs: |-
{{ .Values.2darrayIPs | toYaml | indent 2 }}
user_100081730

This is valid yaml. If possible, you should raise an issue on the repository of the yaml parser used here. In the meantime, Yaml is a superset of JSON, so you can use plain JSON 2D arrays:

2darrayIPs: [["1.1.1.1","2.2.2.2"]]
user_81868980
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