Parse error using 'use' in Google Cloud - php

Question

I am trying to post some form data to Google Datastore, using this documentation here and here. I am struggling with knowing how to post the form data to the datastore, but I thought I had cracked it when I got the following error.
Parse error: syntax error, unexpected 'use' (T_USE) in record-usage.php on line 23
So my question is in two parts:
how do I post data to the Datastore from my form? (the examples in the documentation seem to offer two different ways of posting to the store)
how do I fix this syntax error?
Here is my code (it's actually line 7 in the sample below):
if(isset($_POST['submit'])) {
# Includes the autoloader for libraries installed with composer
require __DIR__ . '/vendor/autoload.php';
# Imports the Google Cloud client library
use Google\Cloud\Datastore\DatastoreClient;
# Your Google Cloud Platform project ID
$projectId = 'room-usage';
# Instantiates a client
$datastore = new DatastoreClient([
'projectId' => $projectId
]);
# The kind for the new entity
$kind = 'RoomUsage';
# The name/ID for the new entity
$name = $roomname + $_POST('timestamp');
# The Cloud Datastore key for the new entity
$taskKey = $datastore->key($kind, $name);
if($_POST('countinput') == '') {
$formdata->Headcount = $_POST('countslider');
} else {
$formdata->Headcount = $_POST('countinput');
}
$formdata->Timestamp = $_POST('timestamp');
$formdata->EnteredBy = $_POST('userid');
$formdata->RoomID = $_POST('roomid');
$formdata->Activity = $_POST('activity');
$formdata->Estimate = $_POST('estimate');
$formdata->NotAudited = $_POST('notaudited');
$formdata->Reason = $_POST('reason');
function save_room_usage(DatastoreClient $datastore, $formdata) {
$RoomUsage = $datastore->RoomUsage();
$transaction->updateBatch([$formdata]);
$transaction->commit();
}
# Prepares the new entity
$task = $datastore->entity($taskKey,
['Timestamp' => $_POST('timestamp'),
'Headcount' => $formdata->Headcount,
'EnteredBy' => $_POST('userid'),
'RoomID' => $_POST('roomid'),
'Activity' => $_POST('activity'),
'Estimate' => $_POST('estimate'),
'NotAudited' => $_POST('notaudited'),
'Reason' => $_POST('reason')]);
# Saves the entity
$datastore->upsert($task);
$status = 'Saved ' . $task->key() . ': ' . $task['description'];
}

Answer 1

Use
You can't have use inside a function. Think of it like an import.
Instead, move it outside of the method but inside your namespace. Simplest way to get going is just move it to the top of your file.
Writing data
Looking at this code:
$transaction->updateBatch([$formdata]);
$transaction->commit();
I think you've misinterpreted the transaction documentation. In the code example it presents, it first reads entities from Datastore via a Batch Lookup, then writes them back as a batch with:
$transaction->updateBatch([$fromAccount, $toAccount]);
In that example $fromAccount and $toAccount are proper entities with keys.
In your example, you are trying to batch write just a bunch of random data. Since you are only writing one record, you should delete that code.
The second part of your code where you create an entity and then upsert it should work. If you did end up needing to write more than one entity in a transaction, it is $task that you would use in the updateBatch method rather than the raw data.