f0034beb33
Going back a long time we've had a special magic behavior which tries to recognize a situation where a module author either added or removed the "count" argument from a resource that already has instances, and to silently rename the zeroth or no-key instance so that we don't plan to destroy and recreate the associated object. Now we have a more general idea of "move statements", and specifically the idea of "implied" move statements which replicates the same heuristic we used to use for this behavior, we can treat this magic renaming rule as just another "move statement", special only in that Terraform generates it automatically rather than it being written out explicitly in the configuration. In return for wiring that in, we can now remove altogether the NodeCountBoundary graph node type and its associated graph transformer, CountBoundaryTransformer. We handle moves as a preprocessing step before building the plan graph, so we no longer need to include any special nodes in the graph to deal with that situation. The test updates here are mainly for the graph builders themselves, to acknowledge that indeed we're no longer inserting the NodeCountBoundary vertices. The vertices that NodeCountBoundary previously depended on now become dependencies of the special "root" vertex, although in many cases here we don't see that explicitly because of the transitive reduction algorithm, which notices when there's already an equivalent indirect dependency chain and removes the redundant edge. We already have plenty of test coverage for these "count boundary" cases in the context tests whose names start with TestContext2Plan_count and TestContext2Apply_resourceCount, all of which continued to pass here without any modification and so are not visible in the diff. The test functions particularly relevant to this situation are: - TestContext2Plan_countIncreaseFromNotSet - TestContext2Plan_countDecreaseToOne - TestContext2Plan_countOneIndex - TestContext2Apply_countDecreaseToOneCorrupted The last of those in particular deals with the situation where we have both a no-key instance _and_ a zero-key instance in the prior state, which is interesting here because to exercises an intentional interaction between refactoring.ImpliedMoveStatements and refactoring.ApplyMoves, where we intentionally generate an implied move statement that produces a collision and then expect ApplyMoves to deal with it in the same way as it would deal with all other collisions, and thus ensure we handle both the explicit and implied collisions in the same way. This does affect some UI-level tests, because a nice side-effect of this new treatment of this old feature is that we can now report explicitly in the UI that we're assigning new addresses to these objects, whereas before we just said nothing and hoped the user would just guess what had happened and why they therefore weren't seeing a diff. The backend/local plan tests actually had a pre-existing bug where they were using a state with a different instance key than the config called for but getting away with it because we'd previously silently fix it up. That's still fixed up, but now done with an explicit mention in the UI and so I made the state consistent with the configuration here so that the tests would be able to recognize _real_ differences where present, as opposed to the errant difference caused by that inconsistency. |
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| internal | ||
| scripts | ||
| tools | ||
| version | ||
| website | ||
| .gitignore | ||
| .go-version | ||
| .tfdev | ||
| BUGPROCESS.md | ||
| CHANGELOG.md | ||
| checkpoint.go | ||
| codecov.yml | ||
| CODEOWNERS | ||
| commands.go | ||
| Dockerfile | ||
| go.mod | ||
| go.sum | ||
| help.go | ||
| LICENSE | ||
| main_test.go | ||
| main.go | ||
| Makefile | ||
| plugins.go | ||
| provider_source.go | ||
| README.md | ||
| signal_unix.go | ||
| signal_windows.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:
-
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.
-
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.
-
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, see the introduction section of 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.
To learn more about compiling Terraform and contributing suggested changes, please refer to the contributing guide.
To learn more about how we handle bug reports, please read the bug triage guide.