provider-framework-migration

Files (2)

• SKILL.md
• schema-mapping.md · references/

SKILL.md (first lines)

# Migrating from Plugin SDKv2 to the Plugin Framework

The Plugin Framework is required for net-new resources and data sources;
SDKv2 is maintenance-only. Migration is **per-resource and incremental**: a
muxed provider serves SDKv2 and Framework implementations side by side, so
you never need a big-bang rewrite. This skill covers the mux setup, the
per-resource workflow, and the behavioral traps that turn a mechanical
translation into a silent breaking change.

**Reference** (load when needed):
- `references/schema-mapping.md` — the full SDKv2 → Framework translation
  table with code pairs

Official guide: [Framework migration](https://developer.hashicorp.com/terraform/plugin/framework/migrating).

## Decide Whether to Migrate at All

Migration has real risk and little user-visible payoff, so triage first:

- **Do not migrate complex or heavily-used resources** without a driving
  need (a Framework-only feature, a bug that SDKv2 cannot fix). The two
  SDKs differ behaviorally — most importantly around null versus zero
  values — and those differences surface as breaking changes for existing
  users. This is the standing policy in large providers like
  terraform-provider-aws.
- **Simple resources migrate safely**: flat schemas, no `DiffSuppressFunc`,
  no `CustomizeDiff`, no `StateFunc`, no complex nested blocks.
- New capabilities never require migrating old code — mux and write the new
  resource in the Framework alongside the old ones.

To tell what mode a provider is in, check `go.mod`: `terraform-plugin-mux`
present means it already serves both; only `terraform-plugin-sdk/v2` means
SDKv2-only (mux setup is your first step); only
`terraform-plugin-framework` means the migration is done.

## Step 1: Mux the Provider

Combine both plugin servers in `main.go`. Serving protocol version 6
requires upgrading the SDKv2 server with `tf5to6server` (protocol 6 needs
Terraform CLI >= 1.0; if you must support 0.12+, mux at protocol 5 with
`tf6to5server`/`tf5muxserver` instead — but the Framework provider then
cannot use protocol-6-only features like nested attributes):

```go
package main

import (
    "context"
    "flag"
    "log"

    "github.com/hashicorp/terraform-plugin-framework/providerserver"
    "github.com/hashicorp/terraform-plugin-go/tfprotov6"
    "github.com/hashicorp/terraform-plugin-go/tfprotov6/tf6server"
    "github.com/hashicorp/terraform-plugin-mux/tf5to6server"
    "github.com/hashicorp/terraform-plugin-mux/tf6muxserver"

    "example.org/terraform-provider-examplecloud/internal/provider"
    sdkprovider "example.org/terraform-provider-examplecloud/internal/sdkprovider"
)

func main() {
    var debug bool
    flag.BoolVar(&debug, "debug", false, "run with support for debuggers")
    flag.Parse()

    ctx := context.Background()

    upgradedSDKServer, err := tf5to6server.UpgradeServer(
        ctx,
        sdkprovider.Provider().GRPCProvider,
    )
    if err != nil {
        log.Fatal(err)
    }

    providers := []func() tfprotov6.ProviderServer{
        providerserver.NewProtocol6(provider.New(version)()),
        func() tfprotov6.ProviderServer { return upgradedSDKServer },
    }

    muxServer, err := tf6muxserver.NewMuxServer(ctx, providers...)
    if err != nil {
        log.Fatal(err)
    }

    var serveOpts []tf6server.ServeOpt
    if debug {
        serveOpts = append(serveOpts, tf6server.WithManagedDebug())
    }

    err = tf6server.Serve("registry.terraform.io/example/examplecloud",
        muxServer.ProviderServer, serveOpts...)
    if err != nil {
        log.Fatal(err)
    }
}
```

Mux requirements that bite in practice:

- **Provider schemas must match exactly** across both plugins — same
  provider-level attributes, same types, same descriptions. Keep one source
  of truth for the provider configuration and mirror it.
- **Each resource and data source may exist in only one** of the two
  plugins. Migration's final step is deleting the SDKv2 registration.
- If publishing to the Registry with protocol 6, set
  `"metadata": {"protocol_versions": ["6.0"]}` in
  `terraform-registry-manifest.json`.

## Step 2: Baseline Before You Touch Anything

The migrated resource must be indistinguishable to users. Prove it with
tests that exist *before* the migration:

1. Ensure the resource has passing acceptance coverage: `_basic` with an
   import step (`ImportStateVerify: true`), `_disappears`, and per-attribute
   update tests. If coverage is missing, write it against the SDKv2
   implementation first — these tests are the migration's acceptance

From hashicorp/agent-skills, MPL-2.0.

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