convert function

convert evaluates an expression from the first argument, and converts the resulting value to the type constraint from the second argument. If the conversion is not possible, an error is returned. The type constraint argument uses convert evaluates an expression from the first argument, and converts the resulting value to the type constraint from the second argument. If the conversion is not possible, Terraform returns an error. The type constraint argument uses the same type expressions as variable and output type parameters.

Refer to the type constraint documentation for more information.

Examples

convert([], list(string))
// converts the empty tuple value to a list(string)
> convert([], list(string))
tolist([])
 
> convert({test = {}}, map(object({
  attr = optional(string)
  with_default = optional(string, "default")
})))
tomap({
  "test" = {
    "attr" = tostring(null)
    "with_default" = "default"
  }
})

The existing type conversion functions will remain for compatibility, and they function identically to the corresponding convert invocations. For collection types, we recommend you use convert to specify a more precise type to avoid the more ambiguous type inference behavior of any.

tostring(v) => convert(v, string)
tonumber(v) => convert(v, number)
tobool(v)   => convert(v, bool)
toset(v)    => convert(v, set(any))
tolist(v)   => convert(v, list(any))
tomap(v)    => convert(v, map(any))