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tm_yamlencode Function

tm_yamlencode encodes a given value to a string using YAML 1.2 block syntax.

This function maps Terraform language values to YAML tags in the following way:

Terraform typeYAML type
number!!float or !!int
Null value!!null

tm_yamlencode uses the implied syntaxes for all of the above types, so it does not generate explicit YAML tags.

Because the YAML format cannot fully represent all of the Terramate language types, passing the tm_yamlencode result to tm_yamldecode will not produce an identical value, but the Terraform language automatic type conversion rules mean that this is rarely a problem in practice.

YAML is a superset of JSON, and so where possible we recommend generating JSON using tm_jsonencode instead, even if a remote system supports YAML. JSON syntax is equivalent to flow-style YAML and Terraform can present detailed structural change information for JSON values in plans, whereas Terraform will treat block-style YAML just as a normal multi-line string. However, generating YAML may improve readability if the resulting value will be directly read or modified in the remote system by humans.


tm_yamlencode({"a":"b", "c":"d"})
"a": "b"
"c": "d"

tm_yamlencode({"foo":[1, 2, 3], "bar": "baz"})
"bar": "baz"
- 1
- 2
- 3

tm_yamlencode({"foo":[1, {"a":"b","c":"d"}, 3], "bar": "baz"})
"bar": "baz"
- 1
- "a": "b"
  "c": "d"
- 3

tm_yamlencode always uses YAML's "block style" for mappings and sequences, unless the mapping or sequence is empty. To generate flow-style YAML, use tm_jsonencode instead: YAML flow-style is a superset of JSON syntax.

  • tm_jsonencode is a similar operation using JSON instead of YAML.
  • tm_yamldecode performs the opposite operation, decoding a YAML string to obtain its represented value.