Previously the templatefile function would permit any arbitrary string as
a variable name, but due to the HCL template syntax it would be impossible
to refer to one that isn't a valid HCL identifier without causing an
HCL syntax error.
The HCL syntax errors are correct, but don't really point to the root
cause of the problem. Instead, we'll pre-verify that the variable names
are valid before we even try to render the template, and given a
specialized error message that refers to the vars argument expression as
the problematic part, which will hopefully make the resolution path
clearer for a user encountering this situation.
The syntax error still remains for situations where all of the variable
names are correct but e.g. the user made a typo referring to one, which
makes sense because in that case the problem _is_ inside the template.
* add TencentCloud COS backend for remote state
* add vendor of dependence
* fixed error not handle and remove default value for prefix argument
* get appid from TF_COS_APPID environment variables
* add setdifference and setsubtract functions and docs
* remove setdifference as it is not implemented correct in underlying lib
* Update setintersection.html.md
* Update setproduct.html.md
* Update setunion.html.md
This guide now lives at:
- https://learn.hashicorp.com/terraform#getting-started
...and terraform.io has been redirecting to there for quite a while. This commit
removes the extra copy so that the text of the two versions doesn't drift, and
updates existing links to point to the new location.
This document now lives at:
- https://learn.hashicorp.com/terraform/development/running-terraform-in-automation
...and terraform.io has been redirecting to there for quite a while. This commit
removes the extra copy so that the text of the two versions doesn't drift, and
updates existing links to point to the new location.
The existing "type" argument allows specifying a type constraint that
allows for some basic validation, but often there are more constraints on
a variable value than just its type.
This new feature (requiring an experiment opt-in for now, while we refine
it) allows specifying arbitrary validation rules for any variable which
can then cause custom error messages to be returned when a caller provides
an inappropriate value.
variable "example" {
validation {
condition = var.example != "nope"
error_message = "Example value must not be \"nope\"."
}
}
The core parts of this are designed to do as little new work as possible
when no validations are specified, and thus the main new checking codepath
here can therefore only run when the experiment is enabled in order to
permit having validations.
These are intended to make it easier to work with arbitrary data
structures whose shape might not be known statically, such as the result
of jsondecode(...) or yamldecode(...) of data from a separate system.
For example, in an object value which has attributes that may or may not
be set we can concisely provide a fallback value to use when the attribute
isn't set:
try(local.example.foo, "fallback-foo")
Using a "try to evaluate" model rather than explicit testing fits better
with the usual programming model of the Terraform language where values
are normally automatically converted to the necessary type where possible:
the given expression is subject to all of the same normal type conversions,
which avoids inadvertently creating a more restrictive evaluation model
as might happen if this were handled using checks like a hypothetical
isobject(...) function, etc.
In earlier versions of Terraform the result of terraform state show was
in the pre-0.12 "flatmap" structure that was unable to reflect nested
data structures. That was fixed in Terraform 0.12, but as a consequence
this statement about the output being machine-parseable (which was
debateable even in older versions) is incorrect.
Fortunately, we now have "terraform show -json" to get output that is
intentionally machine-parseable, so we'll recommend to use that instead
here. The JSON output of that command is a superset of what's produced by
"terraform state show", so should be usable to meet any use-case that
might previously have been met by parsing the "terraform state show"
output.
Chris Griggs