Add a datasource for google_compute_instance (hashicorp#1906)

* Add a compute datasource.

* Add provider changes.

* Add self_link support to google_compute_instance datasource.

* Error check complex d.Set calls.

Author: rileykarson

docs/d/datasource_compute_instance.html.markdown

@@ -0,0 +1,194 @@
+---
+layout: "google"
+page_title: "Google: google_compute_instance"
+sidebar_current: "docs-google-datasource-compute-instance-x"
+description: |-
+  Get a VM instance within GCE.
+---
+
+# google\_compute\_instance
+
+Get information about a VM instance resource within GCE. For more information see
+[the official documentation](https://cloud.google.com/compute/docs/instances)
+and
+[API](https://cloud.google.com/compute/docs/reference/latest/instances).
+
+
+## Example Usage
+
+```hcl
+data "google_compute_instance" "appserver" {
+	name = "primary-application-server"
+	zone = "us-central1-a"
+}
+```
+
+## Argument Reference
+
+The following arguments are supported:
+
+* `self_link` - (Optional) The self link of the instance. One of `name` or `self_link` must be provided.
+
+* `name` - (Optional) The name of the instance. One of `name` or `self_link` must be provided.
+
+---
+
+* `project` - (Optional) The ID of the project in which the resource belongs.
+    If `self_link` is provided, this value is ignored.  If neither `self_link`
+    nor `project` are provided, the provider project is used.
+
+* `zone` - (Optional) The zone of the instance. If `self_link` is provided, this
+    value is ignored.  If neither `self_link` nor `zone` are provided, the
+    provider zone is used.
+
+## Attributes Reference
+
+* `boot_disk` - The boot disk for the instance. Sructure is documented below.
+
+* `machine_type` - The machine type to create.
+
+* `network_interface` - The networks attached to the instance. Structure is documented below.
+
+* `attached_disk` - List of disks attached to the instance. Structure is documented below.
+
+* `can_ip_forward` - Whether sending and receiving of packets with non-matching source or destination IPs is allowed.
+
+* `description` - A brief description of the resource.
+
+* `deletion_protection` - Whether deletion protection is enabled on this instance.
+
+* `guest_accelerator` - List of the type and count of accelerator cards attached to the instance. Structure is documented below.
+
+* `labels` - A set of key/value label pairs assigned to the instance.
+
+* `metadata` - Metadata key/value pairs made available within the instance.
+
+* `min_cpu_platform` - The minimum CPU platform specified for the VM instance.
+
+* `scheduling` - The scheduling strategy being used by the instance.
+
+* `scratch_disk` - The scratch disks attached to the instance. Structure is documented below.
+
+* `service_account` - The service account to attach to the instance. Structure is documented below.
+
+* `tags` - The list of tags attached to the instance.
+
+* `instance_id` - The server-assigned unique identifier of this instance.
+
+* `metadata_fingerprint` - The unique fingerprint of the metadata.
+
+* `self_link` - The URI of the created resource.
+
+* `tags_fingerprint` - The unique fingerprint of the tags.
+
+* `label_fingerprint` - The unique fingerprint of the labels.
+
+* `cpu_platform` - The CPU platform used by this instance.
+
+* `network_interface.0.address` - The internal ip address of the instance, either manually or dynamically assigned.
+
+* `network_interface.0.access_config.0.assigned_nat_ip` - If the instance has an access config, either the given external ip (in the `nat_ip` field) or the ephemeral (generated) ip (if you didn't provide one).
+
+* `attached_disk.0.disk_encryption_key_sha256` - The [RFC 4648 base64](https://tools.ietf.org/html/rfc4648#section-4)
+    encoded SHA-256 hash of the [customer-supplied encryption key]
+    (https://cloud.google.com/compute/docs/disks/customer-supplied-encryption) that protects this resource.
+
+* `boot_disk.disk_encryption_key_sha256` - The [RFC 4648 base64](https://tools.ietf.org/html/rfc4648#section-4)
+    encoded SHA-256 hash of the [customer-supplied encryption key]
+    (https://cloud.google.com/compute/docs/disks/customer-supplied-encryption) that protects this resource.
+
+* `disk.0.disk_encryption_key_sha256` - The [RFC 4648 base64](https://tools.ietf.org/html/rfc4648#section-4)
+    encoded SHA-256 hash of the [customer-supplied encryption key]
+    (https://cloud.google.com/compute/docs/disks/customer-supplied-encryption) that protects this resource.
+
+---
+
+The `boot_disk` block supports:
+
+* `auto_delete` - Whether the disk will be auto-deleted when the instance is deleted.
+
+* `device_name` - Name with which attached disk will be accessible under `/dev/disk/by-id/`
+
+* `initialize_params` - Parameters with which a disk was created alongside the instance.
+    Structure is documented below.
+
+* `source` - The name or self_link of an existing disk (such as those managed by
+    `google_compute_disk`) that was attached to the instance.
+
+The `initialize_params` block supports:
+
+* `size` - The size of the image in gigabytes.
+
+* `type` - The GCE disk type. One of `pd-standard` or `pd-ssd`.
+
+* `image` - The image from which this disk was initialised.
+
+The `scratch_disk` block supports:
+
+* `interface` - The disk interface used for attaching this disk. One of `SCSI` or `NVME`.
+
+The `attached_disk` block supports:
+
+* `source` - The name or self_link of the disk attached to this instance.
+
+* `device_name` - Name with which the attached disk is accessible
+    under `/dev/disk/by-id/`
+
+* `mode` - Read/write mode for the disk. One of `"READ_ONLY"` or `"READ_WRITE"`.
+
+The `network_interface` block supports:
+
+* `network` - The name or self_link of the network attached to this interface.
+
+*  `subnetwork` - The name or self_link of the subnetwork attached to this interface.
+
+*  `subnetwork_project` - The project in which the subnetwork belongs.
+
+* `address` - The private IP address assigned to the instance.
+
+* `access_config` - Access configurations, i.e. IPs via which this
+    instance can be accessed via the Internet. Structure documented below.
+
+* `alias_ip_range` - An array of alias IP ranges for this network interface. Structure documented below.
+
+The `access_config` block supports:
+
+* `nat_ip` - The IP address that is be 1:1 mapped to the instance's
+    network ip.
+
+* `public_ptr_domain_name` - The DNS domain name for the public PTR record.
+
+* `network_tier` - The [networking tier][network-tier] used for configuring this instance. One of `PREMIUM` or `STANDARD`.
+
+The `alias_ip_range` block supports:
+
+* `ip_cidr_range` - The IP CIDR range represented by this alias IP range.
+
+* `subnetwork_range_name` - The subnetwork secondary range name specifying
+    the secondary range from which to allocate the IP CIDR range for this alias IP
+    range.
+
+The `service_account` block supports:
+
+* `email` - The service account e-mail address.
+
+* `scopes` - A list of service scopes.
+
+The `scheduling` block supports:
+
+* `preemptible` - Whether the instance is preemptible.
+
+* `on_host_maintenance` - Describes maintenance behavior for the
+    instance. One of `MIGRATE` or `TERMINATE`, for more info, read
+    [here](https://cloud.google.com/compute/docs/instances/setting-instance-scheduling-options)
+
+* `automatic_restart` - Specifies if the instance should be
+    restarted if it was terminated by Compute Engine (not a user).
+
+The `guest_accelerator` block supports:
+
+* `type` - The accelerator type resource exposed to this instance. E.g. `nvidia-tesla-k80`.
+
+* `count` - The number of the guest accelerator cards exposed to this instance.
+
+[network-tier]: https://cloud.google.com/network-tiers/docs/overview

docs/d/datasource_compute_region_instance_group.html.markdown

@@ -46,8 +46,9 @@ The following arguments are supported:
 
 - - -
 
-* `project` - (Optional) The project in which the resource belongs. If it
-    is not provided, the provider project is used.
+* `project` - (Optional) The ID of the project in which the resource belongs.
+    If `self_link` is provided, this value is ignored.  If neither `self_link`
+    nor `project` are provided, the provider project is used.
 
 * `region` - (Optional) The region in which the resource belongs.  If `self_link`
     is provided, this value is ignored.  If neither `self_link` nor `region` are