Azure Verified Modules

Azure Verified Modules (AVM) Requirements

References: AVM Docs | Terraform Specs

Module Cross-Referencing (TFFR1)

• Reference other AVM modules via HashiCorp registry with pinned version: source = "Azure/xxx/azurerm" + version = "1.2.3"
• Use only AVM modules — no git references (git::, github.com/)

Azure Provider Requirements (TFFR3)

• Use required_providers block to enforce versions
• Prefer pessimistic version constraint (~>)

See references/code-examples.md for provider configuration example.

Code Style Standards

Naming (TFNFR4)

Use lower_snake_case for all locals, variables, outputs, resource symbolic names, and module symbolic names.

Resource Ordering (TFNFR6)

Place depended-on resources first. Keep resources with dependencies close to each other.

Count & for_each (TFNFR7)

• Use count for conditional resource creation
• Use map(xxx) or set(xxx) as for_each collection with static literal keys

Resource Block Internal Ordering (TFNFR8)

1. Top meta-arguments: provider, count, for_each
2. Arguments/blocks (alphabetical): required arguments → optional arguments → required nested blocks → optional nested blocks
3. Bottom meta-arguments: depends_on, lifecycle (sub-order: create_before_destroy, ignore_changes, prevent_destroy)

Separate sections with blank lines.

Module Block Ordering (TFNFR9)

1. Top: source, version, count, for_each
2. Arguments (alphabetical): required → optional
3. Bottom: depends_on, providers

Lifecycle ignore_changes (TFNFR10)

Use unquoted attributes: ignore_changes = [tags] (not ["tags"]). Quoted strings cause silent failures.

Conditional Creation (TFNFR11)

Wrap parameters requiring conditional creation with object type to avoid "known after apply" issues during plan.

Dynamic Blocks (TFNFR12)

Use for_each = <condition> ? [<item>] : [] pattern for optional nested blocks.

Default Values (TFNFR13)

Prefer coalesce() or try() over ternary expressions for default values — shorter and more readable.

Provider Declarations (TFNFR27)

• Declare provider blocks in modules only for configuration_aliases
• Provider configurations should be passed in by module users, because modules should remain provider-agnostic

Variable Requirements

Prohibited Variables (TFNFR14)

Avoid enabled or module_depends_on variables that control entire module operation. Feature toggles for specific resources are acceptable.

Definition Order (TFNFR15)

1. Required fields (alphabetical)
2. Optional fields (alphabetical)

Naming (TFNFR16)

Follow HashiCorp naming rules. Use positive statements for feature switches: xxx_enabled instead of xxx_disabled.

Descriptions (TFNFR17)

Write descriptions targeting module users (not developers). For object types, use HEREDOC format.

Types (TFNFR18)

• Define type for every variable, as precise as possible
• Use bool for true/false values (not string/number)
• Use concrete object instead of map(any)
• Reserve any for adequately justified cases only

Sensitive Data (TFNFR19)

For object variables with sensitive fields: either set sensitive = true on the entire variable, or extract sensitive fields into separate variables.

Non-Nullable Collections (TFNFR20)

Set nullable = false for collection values (sets, maps, lists) used in loops, because null collections cause runtime errors in for_each.

Nullability (TFNFR21)

Avoid nullable = true unless null carries specific semantic meaning.

Sensitive Defaults (TFNFR22, TFNFR23)

• Omit sensitive = false (it is the default)
• Do not set default values for sensitive inputs (e.g., passwords)

Deprecated Variables (TFNFR24)

• Move to deprecated_variables.tf
• Prefix description with DEPRECATED and declare the replacement name
• Clean up during major version releases

Output Requirements

Computed Outputs (TFFR2)

Output discrete computed attributes (anti-corruption layer pattern) rather than entire resource objects, because resource schemas change across provider versions.

• Avoid outputting values that are already inputs (except name)
• Use sensitive = true for sensitive attributes
• For for_each resources, output computed attributes in a map structure

Sensitive Outputs (TFNFR29)

Mark outputs containing confidential data with sensitive = true.

Deprecated Outputs (TFNFR30)

Move deprecated outputs to deprecated_outputs.tf. Define new outputs in outputs.tf. Clean up during major version releases.

Local Values (TFNFR31–33)

• Keep locals blocks in locals.tf (advanced: declare next to related resources)
• Arrange expressions alphabetically
• Use precise types (e.g., number for age, not string)

Terraform Configuration

Version Requirements (TFNFR25)

terraform.tf requirements:

• Single terraform block, required_version on first line
• Include min and max major version constraints
• Prefer ~> #.# or >= #.#.#, < #.#.# format

Providers in required_providers (TFNFR26)

• Each provider specifies source (format: namespace/name) and version
• Providers sorted alphabetically
• Include only directly required providers
• Version includes min and max major version constraints

Testing Requirements (TFNFR5, TFNFR36)

Required tools: terraform validate/fmt/test, terrafmt, Checkov, tflint (with azurerm ruleset), Go (optional).

Set prevent_deletion_if_contains_resources = false in test provider configs for clean teardown.

Documentation (TFNFR2)

Generate docs via terraform-docs. A .terraform-docs.yml file is required in the module root.

Feature Toggles (TFNFR34)

New resources in minor/patch versions require a toggle variable defaulting to false to avoid unexpected resource creation.

Breaking Changes (TFNFR35)

See references/breaking-changes.md for the full list of patterns that constitute breaking changes in resource, variable, and output blocks.

Contribution Standards (TFNFR3)

Set branch protection on the default branch: require PRs, approval, linear history, CODEOWNERS review. Prevent force pushes and branch deletion. No bypass for administrators.

References

• Code examples — HCL patterns for all requirements
• Compliance checklist — module review checklist
• Breaking changes — detailed breaking change patterns