4bc1696fd1
The graph walking mechanism is specified as requiring a graph with a single root, which in practice means there's exactly one node in the graph which doesn't have any dependencies. However, we previously weren't verifying that invariant is true for subgraphs returned from DynamicExpand. It was working anyway, but it's not ideal to be relying on a behavior that isn't guaranteed by our underlying infrastructure. We also previously had the RootTransformer being a bit clever and trying to avoid adding a new node if there is already only a single graph with no dependencies. That special case isn't particularly valuable since there's no harm in turning a one-node graph into a two-node graph with an explicit separate root node, and doing that allows us to assume that the root node is always present and is always exactly terraform.rootNode. Many existing DynamicExpand implementations were not producing valid graphs and were previously getting away with it. All of them now produce properly-rooted graphs that should pass validation, and we will guarantee that with an explicit check of the DynamicExpand return value before we try to walk that subgraph. For good measure we also verify that the root node is exactly terraform.rootNode, even though that isn't strictly required by our graph walker, just to help us catch potential future bugs where a DynamicExpand implementation neglects to add our singleton root node. |
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| version | ||
| website | ||
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| BUGPROCESS.md | ||
| CHANGELOG.md | ||
| checkpoint.go | ||
| codecov.yml | ||
| CODEOWNERS | ||
| commands.go | ||
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| experiments.go | ||
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| help.go | ||
| LICENSE | ||
| main_test.go | ||
| main.go | ||
| Makefile | ||
| plugins.go | ||
| provider_source.go | ||
| README.md | ||
| signal_unix.go | ||
| signal_windows.go | ||
| tools.go | ||
| version.go | ||
| working_dir.go | ||
Terraform
- Website: https://www.terraform.io
- Forums: HashiCorp Discuss
- Documentation: https://www.terraform.io/docs/
- Tutorials: HashiCorp's Learn Platform
- Certification Exam: HashiCorp Certified: Terraform Associate
Terraform is a tool for building, changing, and versioning infrastructure safely and efficiently. Terraform can manage existing and popular service providers as well as custom in-house solutions.
The key features of Terraform are:
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Infrastructure as Code: Infrastructure is described using a high-level configuration syntax. This allows a blueprint of your datacenter to be versioned and treated as you would any other code. Additionally, infrastructure can be shared and re-used.
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Execution Plans: Terraform has a "planning" step where it generates an execution plan. The execution plan shows what Terraform will do when you call apply. This lets you avoid any surprises when Terraform manipulates infrastructure.
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Resource Graph: Terraform builds a graph of all your resources, and parallelizes the creation and modification of any non-dependent resources. Because of this, Terraform builds infrastructure as efficiently as possible, and operators get insight into dependencies in their infrastructure.
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Change Automation: Complex changesets can be applied to your infrastructure with minimal human interaction. With the previously mentioned execution plan and resource graph, you know exactly what Terraform will change and in what order, avoiding many possible human errors.
For more information, refer to the What is Terraform? page on the Terraform website.
Getting Started & Documentation
Documentation is available on the Terraform website:
If you're new to Terraform and want to get started creating infrastructure, please check out our Getting Started guides on HashiCorp's learning platform. There are also additional guides to continue your learning.
Show off your Terraform knowledge by passing a certification exam. Visit the certification page for information about exams and find study materials on HashiCorp's learning platform.
Developing Terraform
This repository contains only Terraform core, which includes the command line interface and the main graph engine. Providers are implemented as plugins, and Terraform can automatically download providers that are published on the Terraform Registry. HashiCorp develops some providers, and others are developed by other organizations. For more information, see Extending Terraform.
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To learn more about compiling Terraform and contributing suggested changes, refer to the contributing guide.
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To learn more about how we handle bug reports, refer to the bug triage guide.
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To learn how to contribute to the Terraform documentation in this repository, refer to the Terraform Documentation README.