Fixes#7607
An empty list is a valid value for formatlist which means to just return
an empty list as a result. The logic was somewhat convoluted here so I
cleaned that up a bit too. The function overall can definitely be
cleaned up a lot more but I left it mostly as-is to fix the bug.
This commit adds a new interpolation function, zipmap, which produces a
map given a list of string keys and a list of values of the same length
as the list of keys.
The name comes from the same operation in Clojure (and likely other
functional langauges).
The concat interpolation function now only accepts list arguments.
Strings are no longer supported, for concatenation or appending to
lists. All arguments must be a list, and single elements can be promoted
with the `list` interpolation function.
* `map(key, value, ...)` - Returns a map consisting of the key/value pairs
specified as arguments. Every odd argument must be a string key, and every
even argument must have the same type as the other values specified.
Duplicate keys are not allowed. Examples:
* `map("hello", "world")`
* `map("us-east", list("a", "b", "c"), "us-west", list("b", "c", "d"))`
This will allow the concat interpolation function to accept lists of
lists, and lists of maps as well as strings. We still allow bare strings
for backwards compatibility, but remove some of the old comment wording
as it could cause confusion of this function with actual string
concatenation.
Since maps are now supported in the config, this removes the superfluous
(and failing) TestInterpolationFuncConcatListOfMaps.
Allow lists and maps within the list interpolation function via variable
interpolation. Since this requires setting the variadic type to TypeAny,
we check for non-heterogeneous lists in the callback.
The list() interpolation function provides a way to add support for list
literals (of strings) to HIL without having to invent new syntax for it
and modify the HIL parser.
It presents as a function, thus:
- list() -> []
- list("a") -> ["a"]
- list("a", "b") -> ["a", "b"]
Thanks to @wr0ngway for the idea of this approach, fixes#7460.
The `concat()` interpolation function does not yet support types other
than strings / lists of strings. Make it an error message instead of a
panic when a list of non-primitives is supplied.
Fixes the panic in #7030
Fixes#4474, where lookup() calls fail out the entire interpolation when
the provided key value is not found in the map. This will allow using
coalesce() along with lookup() to greatly improve module flexibility.
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.
This changes the representation of maps in the interpolator from the
dotted flatmap form of a string variable named "var.variablename.key"
per map element to use native HIL maps instead.
This involves porting some of the interpolation functions in order to
keep the tests green, and adding support for map outputs.
There is one backwards incompatibility: as a result of an implementation
detail of maps, one could access an indexed map variable using the
syntax "${var.variablename.key}".
This is no longer possible - instead HIL native syntax -
"${var.variablename["key"]}" must be used. This was previously
documented, (though not heavily used) so it must be noted as a backward
compatibility issue for Terraform 0.7.
hil.Eval() now returns (hil.EvaluationResult, error) instead of (value,
type, error). This commit updates the call sites, but retains all
previous behaviour. Tests are also updated.
This function returns -1 for negative numbers, 0 for 0 and 1 for positive numbers.
Useful when you need to set a value for the first resource and a different value for the rest of the resources.
Example: `${element(split(",", var.r53_failover_policy), signum(count.index))}`
These new functions allow Terraform to be used for network address space
planning tasks, and make it easier to produce reusable modules that
contain or depend on network infrastructure.
For example:
- cidrsubnet allows an aws_subnet to derive its
CIDR prefix from its parent aws_vpc.
- cidrhost allows a fixed IP address for a resource to be assigned within
an address range defined elsewhere.
- cidrnetmask provides the dotted-decimal form of a prefix length that is
accepted by some systems such as routing tables and static network
interface configuration files.
The bulk of the work here is done by an external library I authored called
go-cidr. It is MIT licensed and was implemented primarily for the purpose
of using it within Terraform. It has its own unit tests and so the unit
tests within this change focus on simple success cases and on the correct
handling of the various error cases.
There isn't any precedent for abbreviating words in the interpolation
function names, and it may not be clear to all users what "enc" and "dec"
are short for, so instead we'll prefer to spell out the whole words for
improved readability.
Mitchell Hashimoto