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- Okay, so now I wanna talk about

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making HCL a little bit more useful.

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Obviously,

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choosing random names for your resources

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like buckets and so forth

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isn't gonna be terribly
useful in the real world.

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That's not generally what we want.

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So,

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and now, I'm using S3
buckets as an example

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for a couple of reasons.

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One, because they take no configuration

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to get started, there's
no required attributes.

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And two, they're very simple and they're,

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they don't cost anything if,

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if you don't store any data in them,

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if you just create them.

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So they make a good example
for configuring Terraform

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and doing demonstrations.

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But you should keep in mind that

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these techniques apply to any
resource in Terraform, okay?

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So what I'm about to show
you is called interpolation.

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This is simply

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evaluating string values and

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creating custom resource identifiers,

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and I'll show you the
syntax for doing that.

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Okay.

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So,

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you remember our previous example

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where we didn't have any attributes,

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and then we put in bucket
and we called it bucket one,

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and it wouldn't work because something was

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already named that.

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So,

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let's say we decide on a naming convention

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that we're gonna prefix our bucket names

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with the account ID that we saw

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in the caller identity before.

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This is how we would do that, okay?

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So, we're gonna call this one bucket two.

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And remember, this is just a
label internal to Terraform.

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And then we're gonna create
a quoted string, okay?

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And then within a quoted string,

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the syntax for this is
dollar sign, curly brace,

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and then the attribute that
you wanna place in that string

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and then the closing curly brace.

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Now, when Terraform runs,
it's gonna interpolate that,

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and it's gonna substitute in the value

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into this part, okay?

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So this is gonna resolve to
being the account ID string.

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And it's gonna create your bucket name

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that way.

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Prior to Terraform 12, interpolation was

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essentially the only
way to reference between

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objects in Terraform.

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Since Terraform 12,

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this syntax, you see
how this isn't quoted,

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it doesn't have the dollar sign,

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it doesn't have the curly
braces, it's just a raw value.

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So this was introduced in Terraform 12.

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Prior to Terraform 12, to do this,

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you would have to

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quote it and

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put the brackets, even
though there really is no

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interpolation here, it would
just interpolate that value.

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Now,

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this

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is valid, and this is the recommended way

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to reference variables within HCL.

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But if you need to,

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if you need to concatenate
it into a string,

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this is a good shortcut for doing that,

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because it doesn't require you to use

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a format,

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a function or anything like that.

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So it's a real simple way.

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It's a pretty self-explanatory code

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most of the time, so you can

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see what we get there,
the plan should tell us

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what the name of the bucket is going to be

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before we apply it.

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So you can see

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that it's already done the
interpolation within the plan,

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so that's already resolved.

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Okay.

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So we have our account ID, and
then a suffix of bucket two,

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which

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you saw in the code.

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So we'll just create that.