Upgrade to Terraform Plugin SDK v2

[trotttrotttrott]

Minimal changes to migrate to SDK v2. Closes #159. Additional SDK v2 feature integrations will be done in a separate changeset (#175).

tf-sdk-migrator was primary used for code changes. Minor changes had to be made manually to fix acceptance tests.

Support for Terraform 0.11 and Below is being dropped. The readme now includes a note about a Terraform 0.12+ requirement.

This will not incur breaking changes for existing codebases (assuming use of Terraform 0.12+).

[jvrplmlmn]

Reviewed it commit by commit. Most changes are basically using the new imports and some minor fixes. Without having too much context about the provider, looks good to me 👍 Also neat that the upgrade already helped fixing some minor issues (drift 😄 ).

[inkel]

Just curious about the reason behind this change.

[trotttrotttrott]

With SDKv2, the following acceptance test failure was occurring for both dashboard and folder permissions:

=== RUN   TestAccFolderPermission_basic
    resource_folder_permission_test.go:16: Step 1/2 error: After applying this test step and performing a `terraform refresh`, the plan was not empty.
        stdout


        An execution plan has been generated and is shown below.
        Resource actions are indicated with the following symbols:
          ~ update in-place

        Terraform will perform the following actions:

          # grafana_folder_permission.testPermission will be updated in-place
          ~ resource "grafana_folder_permission" "testPermission" {
                id         = "0XBNl58Gk"
                # (1 unchanged attribute hidden)

              + permissions {
                  + permission = "Admin"
                  + team_id    = -1
                  + user_id    = 3
                }
              - permissions {
                  - permission = "Admin" -> null
                  - team_id    = 0 -> null
                  - user_id    = 3 -> null
                }
              + permissions {
                  + permission = "Edit"
                  + role       = "Editor"
                  + team_id    = -1
                  + user_id    = -1
                }
              - permissions {
                  - permission = "Edit" -> null
                  - role       = "Editor" -> null
                  - team_id    = 0 -> null
                  - user_id    = 0 -> null
                }
              + permissions {
                  + permission = "View"
                  + team_id    = 2
                  + user_id    = -1
                }
              - permissions {
                  - permission = "View" -> null
                  - team_id    = 2 -> null
                  - user_id    = 0 -> null
                }
              + permissions {
                  + permission = "View"
                  + role       = "Viewer"
                  + team_id    = -1
                  + user_id    = -1
                }
              - permissions {
                  - permission = "View" -> null
                  - role       = "Viewer" -> null
                  - team_id    = 0 -> null
                  - user_id    = 0 -> null
                }
            }

        Plan: 0 to add, 1 to change, 0 to destroy.
--- FAIL: TestAccFolderPermission_basic (22.75s)

Terraform was writing -1 for default values, but terraform refresh showed that 0 is what Grafana uses for unset foreign key values. 0 makes sense given it's the default for int64 (DashboardAclUpdateItem).

It seems odd though that this did not cause drift without terraform refresh. Typically resources are refreshed as part of creating an execution plan. I suspect the answer is in the resources' read functions, but I'd have to investigate further.

[inkel]

Thanks for explaining. Definitely odd there wasn't drift. I wonder if this wouldn't be masquerading some obscure issue down the line 🤔