Cacher is the code snippet organizer for pro developers

<?php

/**
 * Implements hook_menu().
 */
function {my_module}_menu() {
  $items = array();

  $items['check-mandatory-fields'] = array(
    'title' => 'Mandatory content missing',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('{my_module}_mcm'),
    'access arguments' => array('access content'),
  );

  return $items;
}


function {my_module}_mcm() {
  $form = array();

  $form['submit'] = array(
    '#type' => 'submit',
    '#value' => 'Submit',
  );

  return $form;
}

function {my_module}_mcm_submit($form, &$form_state) {
  drupal_set_message('Gathering the empty fields');

  $mandatory_fields = array();
  $excluded_fields = array('group_content_access', 'og_group_ref');
  $instances = field_info_instances('node');
  foreach ($instances as $bundle_name => $bundle) {
    foreach ($bundle as $field_name => $field) {
      if ($field['required'] == TRUE && !in_array($field_name, $excluded_fields)) {
        $mandatory_fields[$bundle_name][] = $field_name;
      }
    }
  }

  $query = new EntityFieldQuery();
  $results = $query
    ->entityCondition('entity_type', 'node')
    ->entityCondition('bundle', array_keys($mandatory_fields), 'IN')
    ->propertyOrderBy('nid')
    ->execute();


  $batch = array(
    'operations' => array(
      array('{my_module}_mcm_process_batch', array($results['node'], $mandatory_fields)),
    ),
    'finished' => '{my_module}_mcm_process_batch_finished',
    'title' => t('Missing required content'),
    'init_message' => t('Batch is starting...'),
    'progress_message' => t('Processed @current out of @total.'),
    'error_message' => t('Batch has encountered an error.')
  );
  batch_set($batch);
  batch_process('check-mandatory-fields');
}

/**
 * The batch processor.
 */
function {my_module}_mcm_process_batch($nodes, $fields, &$context) {
  $limit = 1500;
  $context['finished'] = 0;

  if (!isset($context['sandbox']['file'])) {
    $field_labels = array(
      'Id',
      'Title',
      'Type',
      'Created date',
      'Operation(s)',
      'URL',
      'Author',
      'Empty fields',
    );
    // Create the file and print the labels in the header row.
    $filename = 'empty_required_fields.csv';
    $file_path = file_directory_temp() . '/' . $filename;
    $handle = fopen($file_path, 'w');
    fputcsv($handle, $field_labels);
    fclose($handle);

    $context['sandbox']['nodes'] = $nodes;
    $context['sandbox']['total_nodes'] = count($nodes);
    $context['sandbox']['file'] = $file_path;
    $context['results']['count'] = 0;
  }

  $handle = fopen($context['sandbox']['file'], 'a');

  if ($nodes_pending = count($context['sandbox']['nodes'])) {
    $actual_limit = min($nodes_pending, $limit);
    $node_info = array_slice(
      $context['sandbox']['nodes'],
      $context['results']['count'],
      $actual_limit,
      TRUE
    );
    $nodes = node_load_multiple(array_keys($node_info));
    foreach ($nodes as $node) {
      $empty_fields = array();
      foreach ($fields[$node->type] as $field_name) {
        $items = field_get_items('node', $node, $field_name);
        if (!$items) {
          $empty_fields[] = $field_name;
        }
      }

      if (!empty($empty_fields)) {
        $author = user_load($node->uid);
        $group_nodes = array();
        if ($space_items = field_get_items('node', $node, 'og_group_ref')) {
          foreach ($space_items as $item) {
            $group = node_load($item['target_id']);
            $group_nodes[] = $group->title;
          }
        }
        fputcsv(
          $handle,
          array(
            $node->nid,
            $node->title,
            $node->type,
            format_date($node->created, 'd/m/Y'),
            implode(', ', $group_nodes),
            'https://www.humanitarianresponse.info/' . drupal_get_path_alias(
              'node/' . $node->nid
            ),
            $author->name,
            implode(', ', $empty_fields)
          ),
          ';'
        );
      }
    }
    $context['results']['count'] += $actual_limit;
    $context['finished'] = $context['results']['count'] / $context['sandbox']['total_nodes'];
  }
  else {
    $context['finished'] = 1;
  }

  fclose($handle);

  $context['message'] = t(
    'Processed @count of @total nodes.',
    array(
      '@count' => $context['results']['count'],
      '@total' => $context['sandbox']['total_nodes'],
    )
  );
}

/**
 * The batch finish handler.
 */
function {my_module}_mcm_process_batch_finished($success, $results, $operations) {
  if ($success) {
    drupal_set_message('Batch is complete!');
  }
  else {
    $error_operation = reset($operations);
    $message = t('An error occurred while processing %error_operation with arguments: @arguments', array(
      '%error_operation' => $error_operation[0],
      '@arguments' => print_r($error_operation[1], TRUE)
    ));
    drupal_set_message($message, 'error');
  }
  drupal_set_message(l('Run again', 'check-mandatory-fields'));
}