Improve Experience of Renaming / Moving Constructs

[skorfmann]

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Description

Given the following Construct

  const api = new AppsyncGraphqlApi(this, 'GraphQL', {
      authenticationType: 'AMAZON_COGNITO_USER_POOLS',
      name: 'cdk.dev',
      schema,
      userPoolConfig: [{
        defaultAction: 'DENY',
        userPoolId: userPool.id!
      }]
    })

When renaming its Construct id from GraphQL to GraphQL1 the resource gets recreated by Terraform since the Terraform resource name changes from cdkdev_GraphQL_E4BC4DB4 to cdkdev_GraphQL1_A79E37DD. This applies not only to renaming, but also when refactoring and moving a Construct into another Construct and therefore changing its position in the Construct tree.

Terraform Plan excerpt

    {
      "address": "aws_appsync_graphql_api.cdkdev_GraphQL1_A79E37DD",
      "mode": "managed",
      "type": "aws_appsync_graphql_api",
      "name": "cdkdev_GraphQL1_A79E37DD",
      "provider_name": "aws",
      "change": {
        "actions": [
          "create"
        ],
        "before": null,
        "after": {
          "additional_authentication_provider": [],
          "authentication_type": "AMAZON_COGNITO_USER_POOLS",
          "log_config": [],
          "name": "cdk.dev",
          "openid_connect_config": [],
          "schema": "\n      schema {\n        query: Query\n      }\n\n      type Query {\n        test: Int,\n        snippet: Snippet!\n      }\n\n      type Snippet {\n        id: ID!\n        author: String!\n        title: String!\n        content: String!\n      }\n  ",
          "tags": null,
          "user_pool_config": [
            {
              "app_id_client_regex": null,
              "default_action": "DENY",
              "user_pool_id": "eu-central-1_Uieh1GWj0"
            }
          ],
          "xray_enabled": null
        },
        "after_unknown": {
          "additional_authentication_provider": [],
          "arn": true,
          "id": true,
          "log_config": [],
          "openid_connect_config": [],
          "uris": true,
          "user_pool_config": [
            {
              "aws_region": true
            }
          ]
        }
      }
    },
    {
      "address": "aws_appsync_graphql_api.cdkdev_GraphQL_E4BC4DB4",
      "mode": "managed",
      "type": "aws_appsync_graphql_api",
      "name": "cdkdev_GraphQL_E4BC4DB4",
      "provider_name": "aws",
      "change": {
        "actions": [
          "delete"
        ],
        "before": {
          "additional_authentication_provider": [],
          "arn": "arn:aws:appsync:eu-central-1:412153864843:apis/xxx",
          "authentication_type": "AMAZON_COGNITO_USER_POOLS",
          "id": "xxx",
          "log_config": [],
          "name": "cdk.dev",
          "openid_connect_config": [],
          "schema": "\n      schema {\n        query: Query\n      }\n\n      type Query {\n        test: Int,\n        snippet: Snippet!\n      }\n\n      type Snippet {\n        id: ID!\n        author: String!\n        title: String!\n        content: String!\n      }\n  ",
          "tags": {},
          "uris": {
            "GRAPHQL": "https://xxx.appsync-api.eu-central-1.amazonaws.com/graphql",
            "REALTIME": "wss://xxx.appsync-realtime-api.eu-central-1.amazonaws.com/graphql"
          },
          "user_pool_config": [
            {
              "app_id_client_regex": "",
              "aws_region": "eu-central-1",
              "default_action": "DENY",
              "user_pool_id": "eu-central-1_Uieh1GWj0"
            }
          ],
          "xray_enabled": false
        },
        "after": null,
        "after_unknown": {}
      }
    },

I think it would desirable to make this a smoother experience. There are various approaches to this, here are two which came to my mind:

• Provide a helper to rename resources easily
• Autodetect moved resources (similar to what Git does with renamed files)

[sam-goodwin]

For the git algorithm, what would you be comparing to?

[skorfmann]

For the git algorithm, what would you be comparing to?

I think a plan file contains all the information which is required, so there shouldn't be a need to pull the entire state from remote backends.

[DJAlPee]

There is something available directly in Terraform: https://www.terraform.io/language/modules/develop/refactoring
Would be great, if moved could be added to CDKTF as well (which would solve this issue?!).

[ansgarm]

Yep! That one will probably help with implementing this feature.
Here are two other related issues tracking specifically the moved block: #1292, #1102

[ansgarm]

Idea: To make simple renaming easier we could add a helper that creates a moved block:

const api = new AppsyncGraphqlApi(this, 'GraphQL', {
      authenticationType: 'AMAZON_COGNITO_USER_POOLS',
      name: 'cdk.dev',
      schema,
      userPoolConfig: [{
        defaultAction: 'DENY',
        userPoolId: userPool.id!
      }]
    })

rename(api, "GraphQL1")
// or
api.rename("GraphQL1") // beware name collisions with a potential rename argument/attribute
// or
oldNameWas(api, "GraphQL0")

[dr0l3]

That would solve all my problems.

oldNameWas either as method or function looks significantly superior because the resources current name doesn't change location. rename(construct, "newname"), and construct.rename("new-name") all have the problem that the name of the resource is effectively moved to after the resources. This means that when you read a resource the only way to know if that is still the resources actual name is by checking current usages of the resource. With the oldNameWas its always clear what the current name is.

Alternatively could just call it by its tf name

const api = new AppsyncGraphqlApi(this, 'GraphQL1', {
      ...
    }).moved("GraphQL")

or

const api = new AppsyncGraphqlApi(this, 'GraphQL1', {
      ...
    }).movedFrom("GraphQL")

[github-actions]

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