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Functions Metadata

The opentf metadata functions command is used to print signatures for the functions available in the current OpenTF version.

Usage​

Usage: opentf metadata functions [options]

The following flags are available:

  • -json - Displays the function signatures in a machine-readable, JSON format.

Please note that, at this time, the -json flag is a required option. In future releases, this command will be extended to allow for additional options.

The output includes a format_version key, which has value "1.0". The semantics of this version are:

  • We will increment the minor version, e.g. "1.1", for backward-compatible changes or additions. Ignore any object properties with unrecognized names to remain forward-compatible with future minor versions.
  • We will increment the major version, e.g. "2.0", for changes that are not backward-compatible. Reject any input which reports an unsupported major version.

We will introduce new major versions only within the bounds of the OpenTF 1.0 Compatibility Promises.

Format Summary​

The following sections describe the JSON output format by example, using a pseudo-JSON notation. Important elements are described with comments, which are prefixed with //. To avoid excessive repetition, we've split the complete format into several discrete sub-objects, described under separate headers. References wrapped in angle brackets (like <block-representation>) are placeholders which, in the real output, would be replaced by an instance of the specified sub-object.

The JSON output format consists of the following objects and sub-objects:

Function Signature Representation​

{
  "format_version": "1.0",

  // "function_signatures" describes the signatures for all
  // available functions.
  "function_signatures": {
    // keys in this map are the function names, such as "abs"
    "example_function": {
      // "description" is an English-language description of
      // the purpose and usage of the function in Markdown.
      "description": "string",

      // "return_type" is a representation of a type specification
      // that the function returns.
      "return_type": "string",

      // "parameters" is an optional list of the positional parameters
      // that the function accepts.
      "parameters": [
        <parameter-representation>,
        …
      ],

      // "variadic_parameter" is an optional representation of the
      // additional arguments that the function accepts after those
      // matching with the fixed parameters.
      "variadic_parameter": <parameter-representation>
    },
    "example_function_two": { … }
  }
}

Parameter Representation​

A parameter representation describes a parameter to a function.

{
  // "name" is the internal name of the parameter
  "name": "string",

  // "description" is an optional English-language description of
  // the purpose and usage of the parameter in Markdown.
  "description": "string",

  // "type" is a representation of a type specification
  // that the parameter's value must conform to.
  "type": "string"
}