Terraform object variable

Learn the Learn how Terraform fits into the. Note: This page is about Terraform 0. For Terraform 0. Expressions are used to refer to or compute values within a configuration. The simplest expressions are just literal values, like "hello" or 5but the Terraform language also allows more complex expressions such as references to data exported by resources, arithmetic, conditional evaluation, and a number of built-in functions.

Expressions can be used in a number of places in the Terraform language, but some contexts limit which expression constructs are allowed, such as requiring a literal value of a particular type or forbidding references to resource attributes. Each language feature's documentation describes any restrictions it places on expressions.

You can experiment with the behavior of Terraform's expressions from the Terraform expression console, by running the terraform console command. The result of an expression is a value. All values have a typewhich dictates where that value can be used and what transformations can be applied to it.

Strings, numbers, and bools are sometimes called primitive types. In most situations, lists and tuples behave identically, as do maps and objects. Whenever the distinction isn't relevant, the Terraform documentation uses each pair of terms interchangeably with a historical preference for "list" and "map". However, module authors and provider developers should understand the differences between these similar types and the related set typesince they offer different ways to restrict the allowed values for input variables and resource arguments.

For complete details about these types and an explanation of why the difference usually doesn't mattersee Type Constraints. Expressions are most often used to set values for the arguments of resources and child modules. In these cases, the argument has an expected type and the given expression must produce a value of that type. Where possible, Terraform automatically converts values from one type to another in order to produce the expected type.

If this isn't possible, Terraform will produce a type mismatch error and you must update the configuration with a more suitable expression. Terraform automatically converts number and bool values to strings when needed. It also converts strings to numbers or bools, as long as the string contains a valid representation of a number or bool value.

A literal expression is an expression that directly represents a particular constant value. Terraform has a literal expression syntax for each of the value types described above:. List literals can be split into multiple lines for readability, but always require a comma between values.

A comma after the final value is allowed, but not required. Values in a list can be arbitrary expressions. Values can be arbitrary expressions. Keys are strings; they can be left unquoted if they are a valid identifierbut must be quoted otherwise.

terraform object variable

You can use a non-literal expression as a key by wrapping it in parentheses, like var.Variables in Terraform are a great way to define centrally controlled reusable values.

The information in Terraform variables is saved independently from the deployment plans, which makes the values easy to read and edit from a single file.

You can use the general information about the variables as a quick cheat-sheet but the examples are a direct continuation to our Terraform beginners article. Terraform supports a few different variable formats. Depending on the usage, the variables are generally divided into inputs and outputs.

The input variables are used to define values that configure your infrastructure. Output variables, in contrast, are used to get information about the infrastructure after deployment. These can be useful for passing on information such as IP addresses for connecting to the server. Input variables are usually defined by stating a name, type and a default value. However, the type and default values are not strictly necessary. Terraform can deduct the type of the variable from the default or input value.

Variables can be predetermined in a file or included in the command line options. As such, the simplest variable is just a name while the type and value are selected based on the input. The input variables, like the one above, use a couple of different types: strings, lists, maps, and boolean. Here are some examples of how each type are defined and used. Strings mark a single value per structure and are commonly used to simplify and make complicated values more user-friendly.

Below is an example of a string variable definition. A string variable can then be used in resource plans.

Input Variables

Surrounded by double quotes, string variables are a simple substitution such as the example underneath. Another type of Terraform variables lists. They work much like a numbered catalogue of values. Each value can be called by their corresponding index in the list.

Here is an example of a list variable definition. Maps are a collection of string keys and string values. These can be useful for selecting values based on predefined parameters such as the server configuration by the monthly price. You can access the right value by using the matching key.

The values matching to their keys can also be used to look up information in other maps. For example, underneath is a short list of plans and their corresponding storage sizes.

How to use Terraform variables

These can then be used to find the right storage size based on the monthly price as defined in the previous example. They give the option to employ simple true or false values. For example, you might wish to have a variable that decides when to generate the root user password on a new deployment.Learn the Learn how Terraform fits into the. These two parameters are optional but linked; if you include one, you must include both.

Without a filter, this method lists variables for all workspaces you can access. Seven elements of the modern Application Lifecycle.

Create Account. Whether this is a Terraform or environment variable. Valid values are "terraform" or "env". Whether to evaluate the value of the variable as a string of HCL code.

Has no effect for environment variables. Whether the value is sensitive. If true then the variable is written once and not visible thereafter. The ID of the workspace that owns the variable. Obtain workspace IDs from the workspace settings or the Show Workspace endpoint. Optional The name of one workspace to list variables for.

If included, you must also include the organization name filter. Optional The name of the organization that owns the desired workspace. If included, you must also included the workspace name filter.

terraform object variable

New attributes for the variable. This object can include keyvaluedescriptioncategoryhcland sensitive properties, which are described above under create a variable.

All of these properties are optional; if omitted, a property will be left unchanged.You now have enough Terraform knowledge to create useful configurations, but we're still hard-coding access keys, AMIs, etc. To become truly shareable and version controlled, we need to parameterize the configurations. This page introduces input variables as a way to do this.

Let's first extract our region into a variable. Create another file variables. Note : The file can be named anything, since Terraform loads all files ending in. This defines the region variable within your Terraform configuration.

There is a default value which will be used if it is not set elsewhere. If no default is set in this block, the value is required and must be set using one of the methods shown later in this guide.

This uses the variable named regionprefixed with var. It tells Terraform that you're accessing a variable and that the value of the region variable should be used here. It configures the AWS provider with the given variable.

There are multiple ways to assign variables. The order below is also the order in which variable values are chosen. You can set variables directly on the command-line with the -var flag. Any command in Terraform that inspects the configuration accepts this flag, such as applyplanand refresh. Once again, setting variables this way will not save them, and they'll have to be entered repeatedly as commands are executed.

To persist variable values, create a file and assign variables within this file.

terraform object variable

Create a file named terraform. Terraform automatically loads all files in the current directory with the exact name of terraform.

If the file is named something else, you can use the -var-file flag to specify a file name.Learn the Learn how Terraform fits into the. Note: This page is about Terraform 0. For Terraform 0. Input variables serve as parameters for a Terraform module, allowing aspects of the module to be customized without altering the module's own source code, and allowing modules to be shared between different configurations.

When you declare variables in the root module of your configuration, you can set their values using CLI options and environment variables. When you declare them in child modulesthe calling module should pass values in the module block. Input variable usage is introduced in the Getting Started guide section Input Variables. Note: For brevity, input variables are often referred to as just "variables" or "Terraform variables" when it is clear from context what sort of variable is being discussed.

Other kinds of variables in Terraform include environment variables set by the shell where Terraform runs and expression variables used to indirectly represent a value in an expression. The label after the variable keyword is a name for the variable, which must be unique among all variables in the same module.

This name is used to assign a value to the variable from outside and to reference the variable's value from within the module. The name of a variable can be any valid identifier except the following:. These names are reserved for meta-arguments in module configuration blocksand cannot be declared as variable names. The variable declaration can optionally include a type argument to specify what value types are accepted for the variable, as described in the following section.

The variable declaration can also include a default argument. If present, the variable is considered to be optional and the default value will be used if no value is set when calling the module or running Terraform. The default argument requires a literal value and cannot reference other objects in the configuration.

Within the module that declared a variable, its value can be accessed from within expressions as var. The value assigned to a variable can be accessed only from expressions within the module where it was declared.

The type argument in a variable block allows you to restrict the type of value that will be accepted as the value for a variable. If no type constraint is set then a value of any type is accepted.

While type constraints are optional, we recommend specifying them; they serve as easy reminders for users of the module, and allow Terraform to return a helpful error message if the wrong type is used.

Type constraints are created from a mixture of type keywords and type constructors. The supported type keywords are:.

#1 Terraform tutorial for beginners - deep dive of terraform - Infrastructure as Code

The keyword any may be used to indicate that any type is acceptable. For more information on the meaning and behavior of these different types, as well as detailed information about automatic conversion of complex types, see Type Constraints. If both the type and default arguments are specified, the given default value must be convertible to the specified type. Because the input variables of a module are part of its user interface, you can briefly describe the purpose of each variable using the optional description argument:.

The description should concisely explain the purpose of the variable and what kind of value is expected. This description string might be included in documentation about the module, and so it should be written from the perspective of the user of the module rather than its maintainer.

For commentary for module maintainers, use comments.

Warning: This feature is currently experimental and is subject to breaking changes even in minor releases. We welcome your feedback, but cannot recommend using this feature in production modules yet. In addition to Type Constraints as described above, a module author can specify arbitrary custom validation rules for a particular variable using a validation block nested within the corresponding variable block:. The condition argument is an expression that must use the value of the variable to return true if the value is valid, or false if it is invalid.

The expression can refer only to the variable that the condition applies to, and must not produce errors. If the failure of an expression is the basis of the validation decision, use the can function to detect such errors.

For example:.GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together. Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Already on GitHub? Sign in to your account. I wanted to extract these to variables because i'm using the same values in a few places, including in the provider config where they work fine.

I am trying to do something like this; getting the same "configuration cannot contain interpolations" error. While it seems like this is being worked on, I wanted to also ask if this is the right way for me to use access and secret keys? Does it have to be placed here so that I don't have to check the access and secret keys to github.

I have the same problem i. Now that we have "environments" in terraform, I was hoping to have a single config. I can do this in "provider" blocks as the provider block allows interpolations so I can assume the relevant role for the environment I'm deploying to, however if I also rely on the role being set for the backend state management e.

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I managed to get it working by using AWS profiles instead of the access keys directly. What I did though was not optimal; but in my build steps, I ran a bash script that called AWS configure that ultimately set the default access key and secret. We want to archive something similar than antonosmond. Is there a workaround for this problem at the moment, documentation for backend configuration does not cover working with environments. Hi, I'm trying to the the same as NickMetzI'm running terraform 0.

All of the relevant variables are exported at the deployment pipeline level for me, so it's easy to init with the correct information for each environment. I don't find this ideal, but at least I can easily switch between environments and create new environments without having to edit any terraform.

NickMetz it's trying to do multiple environments with multiple backend buckets, not a single backend. You can't specify a different backend bucket in terraform environments.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. I just would like to use a variable as a block. I am using terraform 0. I know that I could set each parameter individually, but it would be far easier for me, to just set the complete block.

It isn't possible to populate the entire block in just one line. Instead, you must write out the block and assign each argument separately so that the transformation from an object value to a block is explicit and Terraform can validate the individual arguments:. This is an example of a Terraform design tradeoff that aims to make the configuration clearer to future readers at the expense of requiring a little more work on the part of the configuration author. In this case, the goal is to make it explicit which arguments are being set, rather than requring the reader to find and understand the declaration of var.

Learn more. How to use an object variable as a block? Ask Question. Asked 7 months ago. Active 6 months ago. Viewed times. Error: Unsupported argument on main. Carsten Carsten 1 1 gold badge 1 1 silver badge 5 5 bronze badges. Active Oldest Votes.

terraform object variable

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