Terraform
yamlencode Function
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 type | YAML type |
|---|---|
string | !!str |
number | !!float or !!int |
bool | !!bool |
list(...) | !!seq |
set(...) | !!seq |
tuple(...) | !!seq |
map(...) | !!map |
object(...) | !!map |
| Null value | !!null |
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 Terraform language
types, passing the yamlencode result to 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 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.
Examples
> yamlencode({"a":"b", "c":"d"})
"a": "b"
"c": "d"
> yamlencode({"foo":[1, 2, 3], "bar": "baz"})
"bar": "baz"
"foo":
- 1
- 2
- 3
> yamlencode({"foo":[1, {"a":"b","c":"d"}, 3], "bar": "baz"})
"bar": "baz"
"foo":
- 1
- "a": "b"
"c": "d"
- 3
yamlencode always uses YAML's "block style" for mappings and sequences, unless
the mapping or sequence is empty. To generate flow-style YAML, use
jsonencode instead: YAML flow-style is a superset
of JSON syntax.
Related Functions
jsonencodeis a similar operation using JSON instead of YAML.yamldecodeperforms the opposite operation, decoding a YAML string to obtain its represented value.