metering.php.tmpl

<?php
/*
 * Copyright 2018 Google LLC
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * @package marketplace_metering
 * @version 1.0
 */
/*
Plugin Name: Usage Metering
Plugin URI: https://cloud.google.com/launcher
Description: Wordpress usage metering.
Author: Google LLC
Version: 1.0
Author URI: https://cloud.google.com/
*/

const AGENT_PORT = %%AGENT_LOCAL_PORT%%;

/**
 * Returns the current time in ISO8601 format with microsecond resolution.
 */
function now() {
    list($usec, $sec) = explode(" ", microtime());
    return date("Y-m-d\TH:i:s", $sec) . substr($usec, 1, 8) . date("P", $sec);
}

/**
 * Returns the metering agent url with an optional path component.
 */
function agent_url($path) {
  $port = AGENT_PORT;
  return esc_url_raw( "http://localhost:$port/$path" );
}

/**
 * Returns the metering agent report url.
 */
function report_url() {
  return agent_url('report');
}

/**
 * Returns the metering agent status url.
 */
function status_url() {
  return agent_url('status');
}

/*
 * Reports a single request to the metering agent.
 */
function report_request() {
  $now = now();
  $body = array(
    'name' => 'requests',
    'startTime' => $now,
    'endTime' => $now,
    'value' => array( 'int64Value' => 1 )
  );
  $args = array(
    'headers' => array( 'Content-Type' => 'application/json' ),
    'body' => json_encode( $body )
  );

  $response = wp_remote_post( report_url(), $args);
  $response_code = wp_remote_retrieve_response_code( $response );

  return $response_code == 200;
}

/**
 * A 'wp' action that reports requests for singular post/page views.
 */
function handle_view() {
  if (is_singular()) {
    report_request();
  }
}

/**
 * Renders the Metering Status widget.
 */
function usage_metering_status_widget_display() {
  $response = wp_remote_get(status_url());
  $error = '';
  $status = NULL;
  if (is_wp_error($request)) {
    $error = 'Cannot reach agent';
  } else {
    $body = wp_remote_retrieve_body($response);
    $status = json_decode($body, true);
    if ($status["currentFailureCount"] > 0) {
      $error = 'Agent is failing to report usage';
    }
    $lastSuccess = DateTime::createFromFormat('Y-m-d\TH:i:s+', $status['lastReportSuccess']);
    $now = new DateTime();
    $successInterval = $now->diff($lastSuccess)->format('%ad %hh %im %ss');
  }

  if ($error == '') {
    $current_status = '<font color="green">SUCCESS</font>';
  } else {
    $current_status = "<font color=\"red\">FAILURE: $error</font>";
  }

  // Widget HTML
  ?>
  <h3>Reporting Health</h3>
  <p><?= $current_status ?></p>

  <? if ($status != null) : ?>
  <h3>Status Data</h3>
  <table>
    <tr>
      <td><b>Last report success</b></td>
      <td><?= $successInterval ?> ago</td>
    </tr>
    <tr>
      <td><b>Current failures</b></td>
      <td><?= $status['currentFailureCount'] ?></td>
    </tr>
    <tr>
      <td><b>Total failures</b></td>
      <td><?= $status['totalFailureCount'] ?></td>
    </tr>
  </table>
  <? endif; ?>
  <?
}

/**
 * Registers the Metering Status widget.
 */
function register_usage_metering_status_widget() {
  wp_add_dashboard_widget(
    'usage_metering_status_widget',
    'Usage Metering Status',
    'usage_metering_status_widget_display'
  );
}

// Action registrations.
add_action('wp', 'handle_view');
add_action('wp_dashboard_setup', 'register_usage_metering_status_widget');

?>