Add a FarmMetricsBlock that includes asset and log record counts by type.

modules/ui/metrics/config/install/block.block.farm_metrics.yml

@@ -0,0 +1,19 @@
+langcode: en
+status: false
+dependencies:
+  module:
+    - farm_ui_metrics
+  theme:
+    - gin
+id: farm_metrics
+theme: gin
+region: content
+weight: 0
+provider: null
+plugin: farm_metrics_block
+settings:
+  id: farm_metrics_block
+  label: 'Metrics'
+  provider: farm_ui_metrics
+  label_display: '0'
+visibility: {  }

modules/ui/metrics/css/metrics_block.css

@@ -0,0 +1,4 @@
+.metrics-container {
+  display: flex;
+  flex-flow: row wrap;
+}

modules/ui/metrics/farm_ui_metrics.libraries.yml

@@ -0,0 +1,4 @@
+metrics_block:
+  css:
+    theme:
+      css/metrics_block.css: { }

modules/ui/metrics/src/Plugin/Block/FarmMetricsBlock.php

@@ -0,0 +1,141 @@
+<?php
+
+namespace Drupal\farm_ui_metrics\Plugin\Block;
+
+use Drupal\Core\Block\BlockBase;
+use Drupal\Core\Database\Connection;
+use Drupal\Core\Entity\EntityTypeBundleInfoInterface;
+use Drupal\Core\Link;
+use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Provides a 'Metrics' block.
+ *
+ * @Block(
+ *   id = "farm_metrics_block",
+ *   admin_label = @Translation("Farm Metrics")
+ * )
+ */
+class FarmMetricsBlock extends BlockBase implements ContainerFactoryPluginInterface {
+
+  /**
+   * The database service.
+   *
+   * @var \Drupal\Core\Database\Connection
+   */
+  protected $database;
+
+  /**
+   * The bundle info service.
+   *
+   * @var \Drupal\Core\Entity\EntityTypeBundleInfoInterface
+   */
+  protected $bundleInfo;
+
+  /**
+   * Constructs a \Drupal\Component\Plugin\PluginBase object.
+   *
+   * @param array $configuration
+   *   A configuration array containing information about the plugin instance.
+   * @param string $plugin_id
+   *   The plugin_id for the plugin instance.
+   * @param mixed $plugin_definition
+   *   The plugin implementation definition.
+   * @param \Drupal\Core\Database\Connection $database
+   *   The database service.
+   * @param \Drupal\Core\Entity\EntityTypeBundleInfoInterface $bundle_info
+   *   The bundle info service.
+   */
+  public function __construct(array $configuration, $plugin_id, $plugin_definition, Connection $database, EntityTypeBundleInfoInterface $bundle_info) {
+    parent::__construct($configuration, $plugin_id, $plugin_definition);
+    $this->database = $database;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
+    return new static(
+      $configuration,
+      $plugin_id,
+      $plugin_definition,
+      $container->get('database'),
+      $container->get('entity_type.bundle.info')
+    );
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function build() {
+    $output = [];
+
+    // Create a container for asset metrics.
+    $output['asset'] = [
+      '#markup' => '<strong>' . Link::createFromRoute('Assets', 'view.farm_asset.page')->toString() . '</strong>',
+      'metrics' => [
+        '#type' => 'container',
+        '#attributes' => [
+          'class' => 'assets metrics-container',
+        ],
+      ],
+    ];
+    $metrics = $this->getEntityMetrics('asset');
+    foreach ($metrics as $metric) {
+      $output['asset']['metrics'][] = [
+        '#markup' => $metric,
+      ];
+    }
+    $output['#cache']['tags'] = ['asset_list'];
+
+    // Create a section for log metrics.
+    $output['log'] = [
+      '#markup' => '<strong>' . Link::createFromRoute('Logs', 'view.farm_log.page')->toString() . '</strong>',
+      'metrics' => [
+        '#type' => 'container',
+        '#attributes' => [
+          'class' => 'logs metrics-container',
+        ],
+      ],
+    ];
+    $metrics = $this->getEntityMetrics('log');
+    foreach ($metrics as $metric) {
+      $output['log']['metrics'][] = [
+        '#markup' => $metric,
+      ];
+    }
+    $output['#cache']['tags'] = ['log_list'];
+
+    // Attach CSS.
+    $output['#attached']['library'][] = 'farm_ui_metrics/metrics_block';
+
+    // Return the output.
+    return $output;
+  }
+
+  /**
+   * Gather metrics for rendering in the block.
+   *
+   * @param string $entity_type
+   *   The entity type machine name.
+   *
+   * @return array
+   *   Returns an array of metric information.
+   */
+  protected function getEntityMetrics($entity_type) {
+    $metrics = [];
+
+    // Load bundles.
+    $bundles = $this->bundleInfo->getBundleInfo($entity_type);
+
+    // Count records by type.
+    foreach ($bundles as $bundle => $bundle_info) {
+      $count = $this->database->query('SELECT COUNT(*) FROM {' . $entity_type . '_field_data} WHERE type=:type', [':type' => $bundle])->fetchField();
+      $metrics[] = Link::createFromRoute($bundle_info['label'] . ': ' . $count, 'view.farm_asset.page_type', ['arg_0' => $bundle], ['attributes' => ['class' => 'metric button']])->toString();
+    }
+
+    return $metrics;
+  }
+
+}