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Get device states

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Retrieve and list device states.

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For detailed documentation that includes this code sample, see the following:

Code sample

Go

For more information, see the Cloud IoT Core Go API reference documentation. 


// getDeviceStates retrieves and lists device states.
func getDeviceStates(w io.Writer, projectID string, region string, registryID string, device string) ([]*cloudiot.DeviceState, error) {
	// Authorize the client using Application Default Credentials.
	// See https://g.co/dv/identity/protocols/application-default-credentials
	ctx := context.Background()
	httpClient, err := google.DefaultClient(ctx, cloudiot.CloudPlatformScope)
	if err != nil {
		return nil, err
	}
	client, err := cloudiot.New(httpClient)
	if err != nil {
		return nil, err
	}

	path := fmt.Sprintf("projects/%s/locations/%s/registries/%s/devices/%s", projectID, region, registryID, device)
	response, err := client.Projects.Locations.Registries.Devices.States.List(path).Do()
	if err != nil {
		return nil, err
	}

	fmt.Fprintln(w, "Successfully retrieved device states!")

	for _, state := range response.DeviceStates {
		fmt.Fprintf(w, "%s : %s\n", state.UpdateTime, state.BinaryData)
	}

	return response.DeviceStates, nil
}

Java

For more information, see the Cloud IoT Core Java API reference documentation. 

/** Retrieves device metadata from a registry. * */
protected static List<DeviceState> getDeviceStates(
    String deviceId, String projectId, String cloudRegion, String registryName)
    throws GeneralSecurityException, IOException {
  GoogleCredentials credential =
      GoogleCredentials.getApplicationDefault().createScoped(CloudIotScopes.all());
  JsonFactory jsonFactory = JacksonFactory.getDefaultInstance();
  HttpRequestInitializer init = new HttpCredentialsAdapter(credential);
  final CloudIot service =
      new CloudIot.Builder(GoogleNetHttpTransport.newTrustedTransport(), jsonFactory, init)
          .setApplicationName(APP_NAME)
          .build();

  final String devicePath =
      String.format(
          "projects/%s/locations/%s/registries/%s/devices/%s",
          projectId, cloudRegion, registryName, deviceId);

  System.out.println("Retrieving device states " + devicePath);

  ListDeviceStatesResponse resp =
      service.projects().locations().registries().devices().states().list(devicePath).execute();

  return resp.getDeviceStates();
}

Node.js

For more information, see the Cloud IoT Core Node.js API reference documentation. 

// const cloudRegion = 'us-central1';
// const deviceId = 'my-device';
// const projectId = 'adjective-noun-123';
// const registryId = 'my-registry';
const iot = require('@google-cloud/iot');
const iotClient = new iot.v1.DeviceManagerClient({
  // optional auth parameters.
});

async function listDeviceStates() {
  const devicePath = iotClient.devicePath(
    projectId,
    cloudRegion,
    registryId,
    deviceId
  );

  const [response] = await iotClient.listDeviceStates({name: devicePath});
  const states = response.deviceStates;
  if (states.length === 0) {
    console.log(`No States for device: ${deviceId}`);
  } else {
    console.log(`States for device: ${deviceId}`);
  }

  for (let i = 0; i < states.length; i++) {
    const state = states[i];
    console.log(
      'State:',
      state,
      '\nData:\n',
      state.binaryData.toString('utf8')
    );
  }
}

listDeviceStates();

PHP

For more information, see the Cloud IoT Core PHP API reference documentation. 

use Google\Cloud\Iot\V1\DeviceManagerClient;

/**
 * Retrieve a device's state blobs.
 *
 * @param string $registryId IOT Device Registry ID
 * @param string $deviceId IOT Device ID
 * @param string $projectId Google Cloud project ID
 * @param string $location (Optional) Google Cloud region
 */
function get_device_state(
    $registryId,
    $deviceId,
    $projectId,
    $location = 'us-central1'
) {
    print('Getting device state' . PHP_EOL);

    // Instantiate a client.
    $deviceManager = new DeviceManagerClient();
    $deviceName = $deviceManager->deviceName($projectId, $location, $registryId, $deviceId);

    $response = $deviceManager->listDeviceStates($deviceName);

    foreach ($response->getDeviceStates() as $state) {
        print('State:' . PHP_EOL);
        printf('    Data: %s' . PHP_EOL, $state->getBinaryData());
        printf('    Update Time: %s' . PHP_EOL,
            $state->getUpdateTime()->toDateTime()->format('Y-m-d H:i:s'));
    }
}

Python

For more information, see the Cloud IoT Core Python API reference documentation. 

# project_id = 'YOUR_PROJECT_ID'
# cloud_region = 'us-central1'
# registry_id = 'your-registry-id'
# device_id = 'your-device-id'
client = iot_v1.DeviceManagerClient()
device_path = client.device_path(project_id, cloud_region, registry_id, device_id)

device = client.get_device(request={"name": device_path})
print("Last state: {}".format(device.state))

print("State history")
states = client.list_device_states(request={"name": device_path}).device_states
for state in states:
    print("State: {}".format(state))

return states

Ruby

For more information, see the Cloud IoT Core Ruby API reference documentation. 

# project_id  = "Your Google Cloud project ID"
# location_id = "The Cloud region the registry is located in"
# registry_id = "The registry to get device states from"
# device_id   = "The identifier of the device to get states for"

require "google/apis/cloudiot_v1"

# Initialize the client and authenticate with the specified scope
Cloudiot   = Google::Apis::CloudiotV1
iot_client = Cloudiot::CloudIotService.new
iot_client.authorization = Google::Auth.get_application_default(
  "https://www.googleapis.com/auth/cloud-platform"
)

# The resource name of the location associated with the project
parent   = "projects/#{project_id}/locations/#{location_id}"
resource = "#{parent}/registries/#{registry_id}/devices/#{device_id}"

# List the configurations for the provided device
result = iot_client.list_project_location_registry_device_states(
  resource
)
if result.device_states
  result.device_states.each do |state|
    puts "#{state.update_time}: #{state.binary_data}"
  end
else
  puts "No state messages"
end

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