terraform/helper
James Nugent f49583d25a core: support native list variables in config
This commit adds support for native list variables and outputs, building
up on the previous change to state. Interpolation functions now return
native lists in preference to StringList.

List variables are defined like this:

variable "test" {
    # This can also be inferred
    type = "list"
    default = ["Hello", "World"]
}

output "test_out" {
    value = "${var.a_list}"
}
This results in the following state:

```
...
            "outputs": {
                "test_out": [
                    "hello",
                    "world"
                ]
            },
...
```

And the result of terraform output is as follows:

```
$ terraform output
test_out = [
  hello
  world
]
```

Using the output name, an xargs-friendly representation is output:

```
$ terraform output test_out
hello
world
```

The output command also supports indexing into the list (with
appropriate range checking and no wrapping):

```
$ terraform output test_out 1
world
```

Along with maps, list outputs from one module may be passed as variables
into another, removing the need for the `join(",", var.list_as_string)`
and `split(",", var.list_as_string)` which was previously necessary in
Terraform configuration.

This commit also updates the tests and implementations of built-in
interpolation functions to take and return native lists where
appropriate.

A backwards compatibility note: previously the concat interpolation
function was capable of concatenating either strings or lists. The
strings use case was deprectated a long time ago but still remained.
Because we cannot return `ast.TypeAny` from an interpolation function,
this use case is no longer supported for strings - `concat` is only
capable of concatenating lists. This should not be a huge issue - the
type checker picks up incorrect parameters, and the native HIL string
concatenation - or the `join` function - can be used to replicate the
missing behaviour.
2016-05-10 14:49:14 -04:00
..
acctest tests: allow opt-out of remote tests via env var 2016-01-21 15:44:18 -06:00
config Fix failing tests 2014-10-09 21:29:21 -07:00
diff helper/diff: replace ocnfig/lang 2016-02-03 13:24:04 -05:00
hashcode formatting, cleanups 2015-02-11 11:40:49 -08:00
logging provider/aws: log HTTP req/resp at DEBUG level 2016-03-14 12:26:37 -05:00
mutexkv provider/aws: serialize SG rule access to fix race condition 2015-11-18 12:39:59 -06:00
pathorcontents ssh: accept private key contents instead of path 2015-11-12 14:59:14 -06:00
resource core: Add terraform_version to state 2016-05-10 14:40:11 -04:00
schema core: support native list variables in config 2016-05-10 14:49:14 -04:00
README.md dos2unix 2014-07-28 10:43:00 -07:00

README.md

Helper Libraries

This folder contains helper libraries for Terraform plugins. A running joke is that this is "Terraform standard library" for plugins. The goal of the packages in this directory are to provide high-level helpers to make it easier to implement the various aspects of writing a plugin for Terraform.