apigee: add data source google_apigee_instance

[xuchenma]

Description

Adds a new google_apigee_instance data source, allowing users to look up an existing Apigee instance by org_id and name and retrieve its metadata (host, port, service_attachment, consumer_accept_list, etc.).

Use case: Retrieve the service_attachment URI of an Apigee instance to configure a PSC endpoint, without needing to manage the instance as a Terraform resource.

Example:

data "google_apigee_instance" "this" {
  org_id = "organizations/my_org"
  name   = "my-instance"
}

# Use service_attachment to configure a PSC endpoint
resource "google_compute_forwarding_rule" "psc" {
  target = data.google_apigee_instance.this.service_attachment
  ...
}

Fixes: hashicorp/terraform-provider-google#25911

Tests

--- PASS: TestAccDataSourceApigeeInstance_basic (2112.16s)
PASS
ok  github.com/hashicorp/terraform-provider-google/google/services/apigee  2112.934s

`google_apigee_instance` (data source)

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[roaks3]

You'll need to resolve some merge conflicts.

Also, did you consider generation from the resource with datasource:\ngenerate: true, or calling the resource Read?

[melinath]

We've moved over to using a registry for data sources instead of manually registering them. This means that provider_mmv1_resources no longer exists, which is what's causing the merge conflict.

You'll also need to add an init function so that the data sources are registered properly with the registry. See https://googlecloudplatform.github.io/magic-modules/develop/add-handwritten-datasource/ for an example.

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@xuchenma, this PR is being closed due to inactivity.

[xuchenma]

Obsolete — the google_apigee_instance data source was added and merged via #16230 and is present on main (data_source_apigee_instance.go). It looks up by org_id + name and exposes the full instance schema (including service_attachment), which covers this PR's use case. Leaving closed in favor of the merged #16230.