Serial port datasource (#3247) (#1860)

* Add serial port datasource

* Add doc for serial port ds

* Serial port test

* Formatting

* Markdown fixes

* Remove pagination, we should always be able to retrieve 1MB

Signed-off-by: Modular Magician <magic-modules@google.com>

.changelog/3247.txt

@@ -0,0 +1,3 @@
+```release-note:new-datasource
+`google_compute_instance_serial_port`
+```

google-beta/data_source_google_compute_instance_serial_port.go

@@ -0,0 +1,59 @@
+package google
+
+import (
+	"github.com/hashicorp/terraform-plugin-sdk/helper/schema"
+)
+
+func dataSourceGoogleComputeInstanceSerialPort() *schema.Resource {
+	return &schema.Resource{
+		Read: computeInstanceSerialPortRead,
+		Schema: map[string]*schema.Schema{
+			"port": {
+				Type:     schema.TypeInt,
+				Required: true,
+			},
+			"instance": {
+				Type:     schema.TypeString,
+				Required: true,
+			},
+			"zone": {
+				Type:     schema.TypeString,
+				Optional: true,
+				Computed: true,
+			},
+			"project": {
+				Type:     schema.TypeString,
+				Optional: true,
+				Computed: true,
+			},
+			"contents": {
+				Type:     schema.TypeString,
+				Computed: true,
+			},
+		},
+	}
+}
+
+func computeInstanceSerialPortRead(d *schema.ResourceData, meta interface{}) error {
+	config := meta.(*Config)
+	project, err := getProject(d, config)
+	if err != nil {
+		return err
+	}
+	d.Set("project", project)
+	zone, err := getZone(d, config)
+	if err != nil {
+		return err
+	}
+	d.Set("zone", zone)
+
+	port := int64(d.Get("port").(int))
+	output, err := config.clientCompute.Instances.GetSerialPortOutput(project, zone, d.Get("instance").(string)).Port(port).Do()
+	if err != nil {
+		return err
+	}
+
+	d.Set("contents", output.Contents)
+	d.SetId(output.SelfLink)
+	return nil
+}

google-beta/data_source_google_compute_instance_serial_port_test.go

@@ -0,0 +1,81 @@
+package google
+
+import (
+	"fmt"
+	"regexp"
+	"testing"
+
+	"github.com/hashicorp/terraform-plugin-sdk/helper/acctest"
+	"github.com/hashicorp/terraform-plugin-sdk/helper/resource"
+)
+
+func TestAccDataSourceComputeInstanceSerialPort_basic(t *testing.T) {
+	instanceName := fmt.Sprintf("tf-test-serial-data-%s", acctest.RandString(10))
+	resource.Test(t, resource.TestCase{
+		PreCheck:  func() { testAccPreCheck(t) },
+		Providers: testAccProviders,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccComputeInstanceSerialPort(instanceName),
+				Check: resource.ComposeTestCheckFunc(
+					// Contents of serial port output include lots of initialization logging
+					resource.TestMatchResourceAttr("data.google_compute_instance_serial_port.serial", "contents",
+						regexp.MustCompile("Initializing cgroup subsys")),
+				),
+			},
+		},
+	})
+}
+
+func testAccComputeInstanceSerialPort(instanceName string) string {
+	return fmt.Sprintf(`
+resource "google_compute_instance" "default" {
+	name				 = "%s"
+	machine_type = "n1-standard-1"
+	zone				 = "us-central1-a"
+
+	boot_disk {
+		initialize_params {
+			image = "debian-8-jessie-v20160803"
+		}
+	}
+
+	// Local SSD disk
+	scratch_disk {
+		interface = "SCSI"
+	}
+
+	network_interface {
+		network = "default"
+
+		access_config {
+			// Ephemeral IP
+		}
+	}
+
+	metadata = {
+		foo = "bar"
+		serial-port-logging-enable = "TRUE"
+		windows-keys = jsonencode(
+			{
+				email		 = "example.user@example.com"
+				expireOn = "2020-04-14T01:37:19Z"
+				exponent = "AQAB"
+				modulus	 = "wgsquN4IBNPqIUnu+h/5Za1kujb2YRhX1vCQVQAkBwnWigcCqOBVfRa5JoZfx6KIvEXjWqa77jPvlsxM4WPqnDIM2qiK36up3SKkYwFjff6F2ni/ry8vrwXCX3sGZ1hbIHlK0O012HpA3ISeEswVZmX2X67naOvJXfY5v0hGPWqCADao+xVxrmxsZD4IWnKl1UaZzI5lhAzr8fw6utHwx1EZ/MSgsEki6tujcZfN+GUDRnmJGQSnPTXmsf7Q4DKreTZk49cuyB3prV91S0x3DYjCUpSXrkVy1Ha5XicGD/q+ystuFsJnrrhbNXJbpSjM6sjo/aduAkZJl4FmOt0R7Q=="
+				userName = "example-user"
+			}
+		)
+	}
+
+	service_account {
+		scopes = ["userinfo-email", "compute-ro", "storage-ro"]
+	}
+}
+
+data "google_compute_instance_serial_port" "serial" {
+	instance = google_compute_instance.default.name
+	zone		 = google_compute_instance.default.zone
+	port		 = 1
+}
+`, instanceName)
+}

google-beta/provider.go

@@ -506,6 +506,7 @@ func Provider() terraform.ResourceProvider {
 			"google_compute_global_address":                   dataSourceGoogleComputeGlobalAddress(),
 			"google_compute_image":                            dataSourceGoogleComputeImage(),
 			"google_compute_instance":                         dataSourceGoogleComputeInstance(),
+			"google_compute_instance_serial_port":             dataSourceGoogleComputeInstanceSerialPort(),
 			"google_compute_instance_group":                   dataSourceGoogleComputeInstanceGroup(),
 			"google_compute_lb_ip_ranges":                     dataSourceGoogleComputeLbIpRanges(),
 			"google_compute_network":                          dataSourceGoogleComputeNetwork(),

website/docs/d/datasource_compute_instance_serial_port.html.markdown

@@ -0,0 +1,102 @@
+---
+subcategory: "Compute Engine"
+layout: "google"
+page_title: "Google: google_compute_instance_serial_port"
+sidebar_current: "docs-google-datasource-compute-instance-serial-port"
+description: |-
+  Get the serial port output from a Compute Instance.
+---
+
+# google\_compute\_instance\_serial\_port
+
+Get the serial port output from a Compute Instance. For more information see
+the official [API](https://cloud.google.com/compute/docs/instances/viewing-serial-port-output) documentation.
+
+## Example Usage
+
+```hcl
+data "google_compute_instance_serial_port" "serial" {
+  instance = "my-instance"
+  zone = "us-central1-a"
+  port = 1
+}
+
+output "serial_out" {
+  value = data.google_compute_instance_serial_port.serial.contents
+}
+```
+
+Using the serial port output to generate a windows password, derived from the [official guide](https://cloud.google.com/compute/docs/instances/windows/automate-pw-generation):
+
+```hcl
+resource "google_compute_instance" "windows" {
+  name         = "windows-instance"
+  machine_type = "n1-standard-1"
+  zone         = "us-central1-a"
+
+  boot_disk {
+    initialize_params {
+      image = "gce-uefi-images/windows-2019"
+    }
+  }
+
+  network_interface {
+    network = "default"
+
+    access_config {
+      // Ephemeral IP
+    }
+  }
+
+  metadata = {
+    serial-port-logging-enable = "TRUE"
+    // Derived from https://cloud.google.com/compute/docs/instances/windows/automate-pw-generation
+    windows-keys = jsonencode(
+      {
+        email    = "example.user@example.com"
+        expireOn = "2020-04-14T01:37:19Z"
+        exponent = "AQAB"
+        modulus  = "wgsquN4IBNPqIUnu+h/5Za1kujb2YRhX1vCQVQAkBwnWigcCqOBVfRa5JoZfx6KIvEXjWqa77jPvlsxM4WPqnDIM2qiK36up3SKkYwFjff6F2ni/ry8vrwXCX3sGZ1hbIHlK0O012HpA3ISeEswVZmX2X67naOvJXfY5v0hGPWqCADao+xVxrmxsZD4IWnKl1UaZzI5lhAzr8fw6utHwx1EZ/MSgsEki6tujcZfN+GUDRnmJGQSnPTXmsf7Q4DKreTZk49cuyB3prV91S0x3DYjCUpSXrkVy1Ha5XicGD/q+ystuFsJnrrhbNXJbpSjM6sjo/aduAkZJl4FmOt0R7Q=="
+        userName = "example-user"
+      }
+    )
+  }
+
+  service_account {
+    scopes = ["userinfo-email", "compute-ro", "storage-ro"]
+  }
+}
+
+data "google_compute_instance_serial_port" "serial" {
+  instance = google_compute_instance.windows.name
+  zone     = google_compute_instance.windows.zone
+  port     = 4
+}
+
+output "serial_out" {
+  value = data.google_compute_instance_serial_port.serial.contents
+}
+```
+
+## Argument Reference
+
+The following arguments are supported:
+
+* `instance` - (Required) The name of the Compute Instance to read output from.
+
+* `port` - (Required) The number of the serial port to read output from. Possible values are 1-4.
+
+- - -
+
+* `project` - (Optional) The project in which the Compute Instance exists. If it
+    is not provided, the provider project is used.
+
+* `zone` - (Optional) The zone in which the Compute Instance exists.
+    If it is not provided, the provider zone is used.
+
+## Attributes Reference
+
+In addition to the arguments listed above, the following computed attributes are
+exported:
+
+* `contents` - The output of the serial port. Serial port output is available only when the VM instance is running, and logs are limited to the most recent 1 MB of output per port.