Terraform Strings. Interpolation, Multiline & Built-in… | by Jack Roper

Table of Contents

Toggle

Interpolation, Multiline & Built-in Functions

In this article, we will take a look at Strings in Terraform, firstly explaining what they are before looking at interpolation with some practical examples. There are lots of built-in functions provided by Terraform you can use with Strings, so we will then look at how you can use each to manipulate your Strings, again with a practical example of each. Lastly, we will look at String concatenation. This is the Terraform String 101!

In Terraform, a string is a sequence of characters used to represent text data. It’s one of the fundamental data types used to define configuration values. Strings in Terraform are typically used for configuration values, resource attributes, and variables.

There are two main ways to define strings:

1. Quoted Strings: These are enclosed in straight double-quote characters (e.g., "hello"). Quoted strings support escape sequences like \\n for newline, \\t for tab, and \\\" for a literal quote.
2. Heredoc Strings: Terraform also supports a special syntax called heredoc for defining multi-line strings or strings that contain special characters. Inspired by Unix shell languages, these are useful when you need to write more complex configurations.

<hello
world
EOT

What is interpolation?

Interpolation refers to the process of embedding expressions within strings to dynamically insert values from various sources. Interpolation allows you to create configurations that adapt based on variables or resource attributes. By using variables and interpolation, you can write reusable code snippets that can be applied to different scenarios with varying values.

What is Terraform string interpolation?

Terraform allows embedding expressions within strings using ${expression} syntax. This lets you dynamically insert values from variables, data sources, or function calls into your configurations. Well-written interpolation can make your Terraform code can reduce code duplication and make it…