docs: add example of using variables with count

closes #861
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Paul Hinze 2015-01-24 18:25:04 -06:00
parent 5dce9a9041
commit dec0c467e1
1 changed files with 32 additions and 3 deletions

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@ -44,9 +44,9 @@ resource type in the
There are **meta-parameters** available to all resources: There are **meta-parameters** available to all resources:
* `count` (int) - The number of identical resources to create. * `count` (int) - The number of identical resources to create.
This doesn't apply to all resources. You can use the `${count.index}` This doesn't apply to all resources. For details on using variables in
[interpolation](/docs/configuration/interpolation.html) to reference conjunction with count, see [Using Variables with
the current count index in your resource. `count`](#using-variables-with-count) below.
* `depends_on` (list of strings) - Explicit dependencies that this * `depends_on` (list of strings) - Explicit dependencies that this
resource has. These dependencies will be created before this resource has. These dependencies will be created before this
@ -94,6 +94,35 @@ provide more specific connection info for a specific provisioner.
An example use case might be to use a different user to log in An example use case might be to use a different user to log in
for a single provisioner. for a single provisioner.
<a id="using-variables-with-count"></a>
## Using Variables With `count`
When declaring multiple instances of a resource using [`count`](#count), it is
common to want each instance to have a different value for a given attribute.
You can use the `${count.index}`
[interpolation](/docs/configuration/interpolation.html) along with a mapping [variable](/docs/configuration/variables.html) to accomplish this.
For example, here's how you could create three [AWS Instances](/docs/providers/aws/r/instance.html) each with their own static IP
address:
```
variable "instance_ips" {
default = {
"0" = "10.11.12.100"
"1" = "10.11.12.101"
"2" = "10.11.12.102"
}
}
resource "aws_instance" "app" {
count = "3"
private_ip = "${lookup(instance_ips, count.index)}"
# ...
}
```
## Syntax ## Syntax
The full syntax is: The full syntax is: