yamldecode Function
yamldecode
parses a string as a subset of YAML, and produces a representation
of its value.
This function supports a subset of YAML 1.2, as described below.
This function maps YAML values to Terraform language values in the following way:
YAML type | Terraform type |
---|---|
!!str | string |
!!float | number |
!!int | number |
!!bool | bool |
!!map | object(...) with attribute types determined per this table |
!!seq | tuple(...) with element types determined per this table |
!!null | The Terraform language null value |
!!timestamp | string in RFC 3339 format |
!!binary | string containing base64-encoded representation |
The Terraform language automatic type conversion rules mean that you don't usually need to worry about exactly what type is produced for a given value, and can just use the result in an intuitive way.
Note though that the mapping above is ambiguous -- several different source
types map to the same target type -- and so round-tripping through yamldecode
and then yamlencode
cannot produce an identical result.
YAML is a complex language and it supports a number of possibilities that the Terraform language's type system cannot represent. Therefore this YAML decoder supports only a subset of YAML 1.2, with restrictions including the following:
Although aliases to earlier anchors are supported, cyclic data structures (where a reference to a collection appears inside that collection) are not. If
yamldecode
detects such a structure then it will return an error.Only the type tags shown in the above table (or equivalent alternative representations of those same tags) are supported. Any other tags will result in an error.
Only one YAML document is permitted. If multiple documents are present in the given string then this function will return an error.
Examples
Related Functions
jsondecode
is a similar operation using JSON instead of YAML.yamlencode
performs the opposite operation, encoding a value as YAML.