Terraform Maven Plugin

The Terraform Maven Plugin brings Maven to Terraform, which greatly enhances Terraform’s project lifecycle and dependency management capability. Maven, in some form has been the standard for Java project management for over a decade. Now, all of that Maven goodness can be used with Terraform!

Integrate automtated tests (Spock, JUnit, TestNG) into your Terraform projects, use Maven's dependency management functionality with Terraform, combine Java and Terraform into the same project, and more!

Contents

• Artifacts in This Repository
• Repository Directory Structure
• Benefits of the Terraform Maven Plugin
• Maven Goals
  • tf:get
  • tf:init
  • tf:plan
  • tf:apply
  • tf:destroy
  • tf:package
  • tf:deploy
  • tf:clean
  • tf:wrapper
• How Commands Are Delegated to Terraform
  • *nix-based Operating Systems
  • Windows Operating Systems
• Getting Started
• Setting Up a Terraform Maven Project
• Setting Up a Terraform Maven Project Using an ArcheType
• How to Use Terraform Maven Projects
• Articles

Not finding what you are looking for? Try the Wiki!

Artifacts in This Repository

Artifact Name	Version	Latest Snapshot	Description
tf-maven-plugin			Terraform Maven Plugin
tf-cmd-api			Terraform Command API
tf-s3-archetype			Maven Terraform S3 Archetype

Repository Directory Structure

• examples - Terraform Maven example projects
  • tf-s3 - A Terraform Maven s3 example project
  • tf-s3-consumer - An example project that consumes the tf-s3 project as a dependency
• tf-build-tools - The parent project of the tf-maven-plugin and tf-cmd-api projects
  • tf-maven-plugin - The Terraform Maven Plugin project
  • tf-cmd-api - A Java API for Terraform project
  • tf-test-groovy - A Java library that assists with Testing Terraform using Groovy (e.g. Spock)
  • tf-s3-archetype - An Archetype for a S3 Terraform Project

Benefits of the Terraform Maven Plugin

• Dependency Management
  • Terraform really has no dependency management to speak of. Even when you use Terraform Cloud, Terraform Enterprise or some other private Terraform module registry, a version update to a module means editing the Terraform code in each and every place that module is sourced. The Terraform Maven Plugin allows you to specify your dependencies for Terraform the same way you specify your dependencies with Java: in an external Maven POM file. And because it's Maven, Terraform modules sourced from Maven repos can also take advantage of version ranges and Maven's SNAPSHOT functionality. It also resolves transitive dependencies. No more modifying code for version updates! No more sourcing obscure URLs! Hooray, Maven!
• Packaging as Part of the Build Lifecycle
  • The package goal can package a Terraform root module for deployment into a Maven repo or it can package that same Terraform root module with its dependencies for deployment into an isolated environment or Terraform Enterprise. It's all part of a single Maven goal/command.
• Deploying Terraform Artifacts to a Maven Repo with an Attached POM is a Snap
  • By default, the deploy goal deploys a zip artifact packaged by the package goal to a Maven repo along with the POM of the current Maven Terraform project. But if you want to point to a differnt POM or a different artifact for deployment, it can do that too. Easy peasy.
• Terraform support for Java testing frameworks
  • The tf-cmd-api artifact provides Java support for Terraform, which can be used to easily integrate mature Java testing frameworks, like Spock, JUnit or TestNG. One example of this is the [tf-s3 example in this repo].
• Simple Integration with CI Tools
  • Get rid of hundreds of lines of untested code in your CI tool and replace it with tested build lifecycle management using Maven! Most CI tools either have Maven included or have a Maven plugin available. Less Terraform build logic in your CI tool means more reliable builds and less CI code to maintain.
• Build Terraform Maven Projects or Standalone Terraform Configurations and Anything In Between
  • You can use the Terraform Maven plugin for building any Terraform, not just Terraform Maven projects! The default configuration is opinionated around the Maven project structure. But that's available to override. Do you have a different folder containing Terraform modules that you want packaged into a Fat Zip? No problem. What about just running a Terraform configuration in some directory that you specify? That works too. You don't lose anything with the Terraform Maven plugin. You just gain a whole lot of packaged functionality and the build lifecycle power of Maven with Terraform!

Maven Goals

tf:get

Description:

Downloads Maven artifacts into a common modules directory and extracts each artifacts contents into a folder named for the artifact (version agnostic).

Optional Parameters:

tf:init

Description:

Executes the terraform init command. See https://www.terraform.io/docs/commands/init.html.

Optional Parameters:

tf:plan

Description:

Executes the terraform plan command. See https://www.terraform.io/docs/commands/plan.html.

Optional Parameters:

tf:apply

Description:

Executes the terraform apply command. See https://www.terraform.io/docs/commands/apply.html.

Optional Parameters:

tf:destroy

Description:

Executes the terraform destroy command. See https://www.terraform.io/docs/commands/destroy.html.

Optional Parameters:

tf:package

Description:

Recursively packages the Terraform files from the root module directory as target/{artifact-id}-{version}.zip. Optionally, a fat compressed package can be created instead, which also includes the Terraform module dependencies if available; see the tf:get goal above.

Note: Within the fat compressed package, module source paths are updated accordingly so that the pacakge is a wholly contained working module that can be consumed as a module, extracted, initialized and applied as-is or submitted to Terraform Enterprise.

tf:deploy

Description:

Deploys a packaged Terraform zip artifact (see tf:package) with a POM to the specified Maven repo.

tf:clean

Description:

Deletes all 'terraform' files from terraform configurations along with the Terraform modules directory.

tf:wrapper

Description:

Binds the Maven project to a specific Terraform binary version (think Maven Wrapper, but for Terraform).

The format of the URL from which to fetch the Terraform binary is modeled after HashiCorp's distribution URL.

{distributionSite}/{releaseDir}/{releaseVer}/{releaseName}_{releaseVer}_{releaseOS}_{releaseSuffix}

The default location is

How Commands Are Delegated to Terraform

Terraform commands are executed in a forked shell that is joined to the Maven process. This has important implications based on the operating system being used.

*nix-based Operating Systems

Terraform commands executed on *nix-based systems are forked into a bash shell that is joined to the Maven process.

Windows Operating Systems

Terraform commands executed on Windows operating systems by default use the Windows default command line (cmd.exe), which is not strictly compatible with Terraform as of Terraform v0.12 (e.g. -var parameters fail).

However, Git Bash can be used in place of the default Windows command line to improve compatibility with Terraform commands. To enable Git Bash, either set a Java system property shellPath or an environment variable SHELL_PATH to the absolute path of the Git Bash executable.

Setting Up a Terraform Maven Project

Instead of doing all the above steps you can simply build the module/project by running the Maven Archetype Plugin which creates project from an archetype.

An example on how to generate the project using an archetype is shown below.

mvn archetype:generate -B -DarchetypeGroupId=com.deliveredtechnologies -DarchetypeArtifactId="tf-s3-archetype" -DarchetypeVersion=0.12 -DgroupId=<custom_group_name> -DartifactId=<custom-artifact_name>

Maven Non-Interactive mode creates a project with the name that you passed in under .

or

mvn archetype:generate -DarchetypeGroupId=com.deliveredtechnologies -DarchetypeArtifactId="tf-s3-archetype" -DarchetypeVersion=0.12

After running the above command mvn interactive console prompts for the required arguments (ex: groupId and artifactId) and creates the project accordingly.

How to Use Terraform Maven Projects

If you used the above configuration, the following Terraform Maven goals are mapped to the project's Maven phases.

Use the plugin or update the plugin configuration in the POM to call terraform specific commands (e.g. mvn tf:init tf:apply).

Articles

• Making Terraform Testing Groovy: Part 1 - Pre-provision Testing
• Unit Testing Terraform
• Maven Gives Terraform a Big Boost