migrate-to-plugin-framework

Terraform SDK v2 to Plugin Framework Migration

Migrate Terraform provider data sources and resources from terraform-plugin-sdk/v2 to terraform-plugin-framework, following patterns established by completed migrations in the target codebase.

Migration Workflow

Phase 0: Codebase Discovery

Before writing any code, understand how the target provider is structured. This determines whether you follow existing conventions or fall back to the templates in references/.

1. Find existing framework code — search for imports of terraform-plugin-framework to locate already-migrated data sources and resources. Note their file structure, naming conventions, and patterns.
2. Identify the provider registration files — find where DataSources() and Resources() are returned from the framework provider, and where DataSourcesMap/ResourcesMap are defined in the SDK provider.
3. Check for codegen or shared tooling — some providers use code generation (e.g. tfplugindocs, custom generators). Look for go:generate directives, Makefile targets, or tools/ directories.
4. Locate test infrastructure — find how existing tests set up protoV5ProviderFactories or equivalent. Note the test package conventions and any shared test helpers.
5. Check for a muxed server — look for tf5muxserver or tf6muxserver usage. This determines whether the protocol v5 block constraint applies (see references/gotchas.md #1).

Phase 1: Analyse the SDK v2 Source

1. Read the existing SDK v2 file to understand:
   • Schema fields: types, Optional/Required/Computed, validation, defaults
   • CRUD operations: which API calls are made
   • Helper functions: filter logic, flatten functions, state waiting
   • CustomizeDiff: any custom validation logic
2. Identify the API client methods and response types used
3. Check for nested blocks (TypeSet/TypeList with Elem: &schema.Resource{})
4. Note any ForceNew, DiffSuppressFunc, or DefaultFunc usage

Phase 2: Create Package Structure

If Phase 0 found existing framework code: match those conventions exactly (directory layout, file naming, import organisation).

Otherwise, use the 3-file pattern as a fallback:

Data sources:

internal/<package>/
├── datasource_<name>.go         # Schema, interfaces, Metadata, Configure
├── datasource_<name>_model.go   # Model struct with tfsdk tags
├── datasource_<name>_read.go    # Read implementation + helpers
└── helpers.go                   # Shared utilities (if needed)

Resources:

internal/<package>/
├── resource_<name>.go           # Schema, interfaces, Metadata, Configure
├── resource_<name>_model.go     # Model struct(s) with tfsdk tags
├── resource_<name>_crud.go      # Create, Read, Update, Delete implementations
└── helpers.go                   # Shared utilities (if needed)

Phase 3: Write the Model

Create the model struct:

• id is always types.String — even if SDK v2 used TypeInt (see references/gotchas.md #5)
• Use types.String, types.Bool, types.Int64, types.Float64 for scalars
• Use types.Set, types.List, types.Map for collections
• Every field needs a tfsdk:"field_name" tag matching the schema attribute name

Consult references/schema-mapping.md for the full type mapping table.

Phase 4: Write the Schema

Create the schema definition with: interface checks, struct, constructor, Metadata, Configure, and Schema methods.

Key rules:

• Protocol v5 nested blocks — if the provider uses tf5muxserver, SDK v2 TypeSet/TypeList with Elem: &schema.Resource{} MUST become blocks, not attributes. See references/gotchas.md #1.
• MaxItems: 1 nested objects become SingleNestedBlock. See references/gotchas.md #6.
• Explicit id — declare as schema.StringAttribute{Computed: true}. See references/gotchas.md #5.
• ForceNew becomes planmodifier.RequiresReplace().
• DefaultFunc becomes Default (e.g., stringdefault.StaticString("value")).
• DiffSuppressFunc becomes a custom planmodifier.
• CustomizeDiff becomes ModifyPlan (implement ResourceWithModifyPlan).

For code templates, see references/data-source-template.md or references/resource-template.md.

Phase 5: Write the Read/CRUD Implementation

Implement the operations following these patterns:

1. Nil safety — defensive client check at the start of every operation. See references/gotchas.md #4.
2. Read config/state via req.Config.Get(ctx, &state) (data sources) or req.Plan.Get(ctx, &plan) (resources).
3. API pointer dereference — dereference safely. See references/gotchas.md #2.
4. Filter pattern for data sources: list all items, apply filters, expect exactly 1 result.
5. Flatten pattern for nested sets: use types.ObjectValueFrom with model structs. See references/gotchas.md #3.
6. Set state via resp.State.Set(ctx, &state).
7. Concurrency control — replicate any mutex patterns from the SDK v2 implementation.
8. State waiting for resources: wait for stable state after mutations if the API is asynchronous.

Phase 6: Register and Remove

Three changes required:

1. Add to the framework provider: import the new package, add to DataSources() or Resources() return slice.
2. Remove from the SDK provider: delete the entry from DataSourcesMap or ResourcesMap.
3. Delete the old SDK v2 file.

Use the registration files identified in Phase 0. Look for how existing framework data sources/resources are registered.

Phase 7: Verify Build Iteratively

Run the build and fix errors in a loop:

1. Run go build ./...
2. If compilation errors occur:
   • Fix the reported errors
   • Run go build ./... again
3. Run go vet ./... to catch additional issues
4. Repeat until clean

Common build errors during migration:

• Missing imports (framework packages have different import paths than SDK v2)
• Type mismatches between model fields and API types (pointer vs value)
• Interface compliance failures (missing methods on the struct)

Phase 8: Tests

Leverage the test infrastructure discovered in Phase 0:

1. Check if existing tests still pass — if tests were in a separate package using the muxed provider factories, they may work without changes after registration is updated.
2. If tests need migration, follow the same test patterns found in Phase 0:
   • Use the same protoV5ProviderFactories setup
   • Match the existing test naming and structure conventions
   • Use the same testAccPreCheck pattern
3. Provide the test command for the user to run (do not run tests yourself):

   go test ./internal/<package>/... -v 2>&1 | tee test-output.log
   

Phase 9: Documentation

Update the corresponding docs/data-sources/ or docs/resources/ markdown file if the schema changed (e.g., id type change from int to string).

Quick Reference

Need	File
Type mapping (SDK v2 → Framework)	references/schema-mapping.md
Common failure modes	references/gotchas.md
Data source code template	references/data-source-template.md
Resource code template	references/resource-template.md