Prior to Terraform 0.7, lists in Terraform were just a shallow abstraction
on top of strings with a magic delimiter between items. Wrapping a single
string in brackets in the configuration was Terraform's prompt that it
needed to split the string on that delimiter during interpolation.
In 0.7, when first-class lists were added, this convention was preserved
by flattening lists-of-lists by one level when they were encountered in
configuration. However, there was an oversight in that change where it
did not correctly handle the case where the inner list was unknown.
In #14135 we removed some code that was flattening partially-unknown lists
into fully-unknown (untyped) values. This inadvertently exposed the missed
case from the previous paragraph, causing issues for list-wrapped splat
expressions with unknown members. While this worked fine for resources,
due to some fixup done inside helper/schema, this did not work for other
interpolation contexts such as module blocks.
Various attempts to fix this up and restore the flattening behavior
selectively were unsuccessful, due to a proliferation of assumptions all
over the core code that would be too risky to change just to fix this bug.
This change, then, takes the different approach of removing the
requirement that splats be presented inside list brackets. This
requirement didn't make much sense anymore anyway, since no other
list-returning expression had this constraint and so the rest of Terraform
was already successfully dealing with both cases.
This leaves us with two different scenarios:
- For resource arguments, existing normalization code in helper/schema
does its own flattening that preserves compatibility with the common
practice of using bracketed splats. This change proves this with a test
within the "test" provider that exercises the whole Terraform core and
helper/schema stack that assigns bracketed splats to list and set
attributes.
- For arguments in other blocks, such as in module callsites, the
interpolator's own flattening behavior applies to known lists,
preserving compatibility with configurations from before
partially-computed splats were possible, but those wishing to use
partially-computed splats are required to drop the surrounding brackets.
This is less concerning because this scenario was introduced only in
0.9.5, so the scope for breakage is limited to those who adopted this
new feature quickly after upgrading.
As of this commit, the recommendation is to stop using brackets around
splats but the old form continues to be supported for backward
compatibility. In a future _major_ version of Terraform we will probably
phase out this legacy form to improve consistency, but for now both
forms are acceptable at the expense of some (pre-existing) weird behavior
when _actual_ lists-of-lists are used.
This addresses #14521 by officially adopting the suggested workaround of
dropping the brackets around the splat. However, it doesn't yet allow
passing of a partially-unknown list between modules: that still violates
assumptions in Terraform's core, so for the moment partially-unknown lists
work only within a _single_ interpolation expression, and cannot be
passed around between expressions. Until more holistic work is done to
improve Terraform's type handling, passing a partially-unknown splat
through to a module will result in a fully-unknown list emerging on
the other side, just as was the case before #14135; this change just
addresses the fact that this was failing with an error in 0.9.5.
We've been incorrectly validating (or not validating at all) the
requirement that certain blocks be followed by a name string, to prohibit
e.g. this:
variable {}
and:
variable = ""
Before this change we were catching this for most constructs only if
there were no _valid_ blocks of the same name in the same file. For
modules in particular, we were not catching this at all.
Now we detect this for all kinds of block (resources had a pre-existing
check, so aren't touched here) and produce a different error message
depending on which of the above incorrect forms are used.
This fixes#13575.
The variable validator assumes that any AST node it gets from an
interpolation walk is an indicator of an interpolation. Unfortunately,
back in f223be15 we changed the interpolation walker to emit a LiteralNode
as a way to signal that the result is a literal but not identical to the
input due to escapes.
The existence of this issue suggests a bit of a design smell in that the
interpolation walker interface at first glance appears to skip over all
literals, but it actually emits them in this one situation. In the long
run we should perhaps think about whether the abstraction is right here,
but this is a shallow, tactical change that fixes#13001.
When configuration is read out of JSON, HCL assumes that empty levels of
objects can be flattened, but this removes too much to decode into a
config.Terraform struct.
Reconstruct the appropriate AST to decode the config struct.
Fixes#11800
Type check the value of count so we don't panic on the conversion.
I wondered "why didn't we do this before?" There is no excuse for NOT
doing it at all but the reasoning was beacuse prior to the list/map work
in 0.7, the value couldn't be anything other than a string since any
primitive can turn into a string.
Regardless, we should've always done this.
Fixes#10597
This disallows any names for variables, modules, etc. starting with
ints. This causes parse errors with the new HIL parser and actually
causes long term ambiguities if we allow this.
I've also updated the upgrade guide to note this as a backwards
compatibility and how people can fix this going forward.
We allow variables to have descriptions specified, as additional context
for a module user as to what should be provided for a given variable.
We previously lacked a similar mechanism for outputs. Since they too are
part of a module's public interface, it makes sense to be able to add
descriptions for these for symmetry's sake.
This change makes a "description" attribute valid within an "output"
configuration block and stores it within the configuration data structure,
but doesn't yet do anything further with it. For now this is useful only
for third-party tools that might parse a module's config to generate
user documentation; later we could expose the descriptions as part of
the "apply" output, but that is left for a separate change.
Fixes#7846
This changes from using the HCL decoder to manually decoding the
`variable` blocks within the configuration. This gives us a lot more
power to catch validation errors. This PR retains the same tests and
fixes one additional issue (covered by a test) in the case where a
variable has no named assigned.
This is the limitation of all lifecycle attributes currently. Right now,
interpolations are allowed through and the user ends up thinking it
should work. We should give an error.
In the future it should be possible to support some minimal set of
interpolations (static variables, data sources even perhaps) but for now
let's validate that this doesn't work.
When a resource has only a single key set, the HCL parser treats that
key as part of the overall set of object keys. This isn't valid since
we expect resources to have exactly two keys. In this scenario, we have
to "unwrap" the keys back into a set of objects.
Dot indexing worked in the "regexps and strings" world of 0.6.x, but it
no longer works on the 0.7 series w/ proper List / Map types.
There is plenty of dot-indexed config out in the wild, so we need to do
what we can to point users to the new syntax.
Here is one place we can do it for user variables (`var.somemap`). We'll
also need to address Resource Variables and Module Variables in a
separate PR.
This fixes the panic in #7103 - a proper error message is now returned.
This commit changes config parsing from weak decoding lists and maps
into []string and map[string]string respectively to decode into
[]interface{} and map[string]interface{} respectively. This is in order
to take advantage of the work integrated in #7082 to defeat the backward
compatibility features of the mapstructure library.
Test coverage of loading empty variables and validating their default
types against expectation.
This allows the config loader to read "data" blocks from the config and
turn them into DataSource objects.
This just reads the data from the config file. It doesn't validate the
data nor do anything useful with it.
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.
Fixes an interpolation race that was occurring when a tainted destroy
node and a primary destroy node both tried to interpolate a computed
count in their config. Since they were sharing a pointer to the _same_
config, depending on how the race played out one of them could catch the
config uninterpolated and would then throw a syntax error.
The `Copy()` tree implemented for this fix can probably be used
elsewhere - basically we should copy the config whenever we drop nodes
into the graph - but for now I'm just applying it to the place that
fixes this bug.
Fixes#4982 - Includes a test covering that race condition.
This commit adds support for declaring variable types in Terraform
configuration. Historically, the type has been inferred from the default
value, defaulting to string if no default was supplied. This has caused
users to devise workarounds if they wanted to declare a map but provide
values from a .tfvars file (for example).
The new syntax adds the "type" key to variable blocks:
```
variable "i_am_a_string" {
type = "string"
}
variable "i_am_a_map" {
type = "map"
}
```
This commit does _not_ extend the type system to include bools, integers
or floats - the only two types available are maps and strings.
Validation is performed if a default value is provided in order to
ensure that the default value type matches the declared type.
In the case that a type is not declared, the old logic is used for
determining the type. This allows backwards compatiblity with previous
Terraform configuration.
This may be brittle as it makes use of .gitattributes to override the
autocrlf setting in order to have an input file with Windows line
endings across multiple platforms.
This was never intended to be valid syntax, but it worked in the old HCL
parser, and we've found a decent number of examples of it in the wild.
Fixed in https://github.com/hashicorp/hcl/pull/62 and we'll keep this
test in Terraform to cover the behavior.
Martin Atkins