nonsensitive Function
Note: This function is only available in Terraform v0.15 and later.
nonsensitive
takes a sensitive value and returns a copy of that value with
the sensitive marking removed, thereby exposing the sensitive value.
Warning: Using this function indiscriminately will cause values that Terraform would normally have considered as sensitive to be treated as normal values and shown clearly in Terraform's output. Use this function only when you've derived a new value from a sensitive value in a way that eliminates the sensitive portions of the value.
Normally Terraform tracks when you use expressions to derive a new value from a value that is marked as sensitive, so that the result can also be marked as sensitive.
However, you may wish to write expressions that derive non-sensitive results
from sensitive values. For example, if you know based on details of your
particular system and its threat model that a SHA256 hash of a particular
sensitive value is safe to include clearly in Terraform output, you could use
the nonsensitive
function to indicate that, overriding Terraform's normal
conservative behavior:
output "sensitive_example_hash" { value = nonsensitive(sha256(var.sensitive_example))}
Another example might be if the original value is only partially sensitive and you've written expressions to separate the sensitive and non-sensitive parts:
variable "mixed_content_json" { description = "A JSON string containing a mixture of sensitive and non-sensitive values." type = string sensitive = true} locals { # mixed_content is derived from var.mixed_content_json, so it # is also considered to be sensitive. mixed_content = jsondecode(var.mixed_content_json) # password_from_json is derived from mixed_content, so it's # also considered to be sensitive. password_from_json = local.mixed_content["password"] # username_from_json would normally be considered to be # sensitive too, but system-specific knowledge tells us # that the username is a non-sensitive fragment of the # original document, and so we can override Terraform's # determination. username_from_json = nonsensitive(local.mixed_content["username"])}
When you use this function, it's your responsibility to ensure that the
expression passed as its argument will remove all sensitive content from
the sensitive value it depends on. By passing a value to nonsensitive
you are
declaring to Terraform that you have done all that is necessary to ensure that
the resulting value has no sensitive content, even though it was derived
from sensitive content. If a sensitive value appears in Terraform's output
due to an inappropriate call to nonsensitive
in your module, that's a bug in
your module and not a bug in Terraform itself.
Use this function sparingly and only with due care.
nonsensitive
will return an error if you pass a value that isn't marked
as sensitive, because such a call would be redundant and potentially confusing
or misleading to a future maintainer of your module. Use nonsensitive
only
after careful consideration and with definite intent.
Consider including a comment adjacent to your call to explain to future maintainers what makes the usage safe and thus what invariants they must take care to preserve under future modifications.
Examples
The following examples are from terraform console
when running in the
context of the example above with variable "mixed_content_json"
and
the local value mixed_content
, with a valid JSON string assigned to
var.mixed_content_json
.
> var.mixed_content_json(sensitive value)> local.mixed_content(sensitive value)> local.mixed_content["password"](sensitive value)> nonsensitive(local.mixed_content["username"])"zqb"> nonsensitive("clear") Error: Invalid function argument Invalid value for "value" parameter: the given value is not sensitive, so thiscall is redundant.
Note though that it's always your responsibility to use nonsensitive
only
when it's safe to do so. If you use nonsensitive
with content that
ought to be considered sensitive then that content will be disclosed:
> nonsensitive(var.mixed_content_json)<<EOT{ "username": "zqb", "password": "p4ssw0rd"}EOT> nonsensitive(local.mixed_content){ "password" = "p4ssw0rd" "username" = "zqb"}> nonsensitive(local.mixed_content["password"])"p4ssw0rd"