Add support to run provider with debuggers

[williamhpark]

Overview

This PR adds support for debugging tools like Delve and Goland, which should improve the debugging experience for developers contributing to the provider.

Type of change

Enhancement

Related Issue(s)

• Resolves: Add debugging support #102

How To Test

1. Pull the branch locally: git pull && git checkout wpark/102-debugging-support
2. Configure a provider override in your ~/.terraformrc file, so that you use a local build of the provider rather than the published version. Refer to the documentation here for more details: https://developer.hashicorp.com/terraform/cli/config/config-file#development-overrides-for-provider-developers. Your .terraformrc file should look like this:

provider_installation {

  dev_overrides {
      "1Password/onepassword" = "<path to terraform-provider-onepassword repo root directory>"
  }

  # For all other providers, install them directly from their origin provider
  # registries as normal. If you omit this, Terraform will _only_ use
  # the dev_overrides block, and so no other providers will be available.
  direct {}
}

3. Install Delve on your system: https://github.com/go-delve/delve/tree/master/Documentation/installation
4. With either Delve or another debugging tool (e.g Goland), run a debugging session. Follow the instructions here, referring to the Compiling in debug mode section onward
5. Navigate to the examples directory in your terminal. Set the TF_REATTACH_PROVIDERS variable: export TF_REATTACH_PROVIDERS=<outputted value from debugging session>
6. Set breakpoints in your code
7. Test creating and destroying item resources. Follow the instructions here

• The breakpoints should be hit during the debugging session as expected

[volodymyrZotov]

Great improvement!