Pressflow

Merge lp://staging/~davidstrauss/pressflow/database-failover into lp://staging/pressflow

  1. database-failover
  2. Merge into 6
Proposed by David Strauss
Status: Rejected
Rejected by: David Strauss
Proposed branch: lp://staging/~davidstrauss/pressflow/database-failover
Merge into: lp://staging/pressflow
Diff against target: None lines
To merge this branch: bzr merge lp://staging/~davidstrauss/pressflow/database-failover
Reviewer Review Type Date Requested Status
David Strauss Pending
Review via email: mp+11606@code.staging.launchpad.net

Commit message

Built-in database failover, originally developed by David Rothstein and Acquia Hosting.

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lp://staging/~davidstrauss/pressflow/database-failover updated
50. By David Strauss

Add missing file

Unmerged revisions

50. By David Strauss

Add missing file

49. By David Strauss

Add changes from David Rothstein (Acquia Hosting).

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=== modified file 'includes/database.inc'
--- includes/database.inc 2009-07-01 22:36:49 +0000
+++ includes/database.inc 2009-09-11 15:02:34 +0000
@@ -130,6 +130,13 @@
130 install_goto('install.php');130 install_goto('install.php');
131 }131 }
132132
133 // If an array of possible databases (e.g., for a master-master setup) was
134 // specified and this is the first time we're trying to connect to them,
135 // choose the one we will connect to during this page request.
136 if (!isset($db_conns[$name]) && isset($db_url[$name]) && is_array($db_url[$name])) {
137 $db_conns[$name] = db_choose_active($db_url[$name], $name);
138 }
139
133 if (!isset($db_conns[$name])) {140 if (!isset($db_conns[$name])) {
134 // Initiate a new connection, using the named DB URL specified.141 // Initiate a new connection, using the named DB URL specified.
135 if (is_array($db_url)) {142 if (is_array($db_url)) {
@@ -163,9 +170,20 @@
163 _db_error_page("The database type '". $db_type ."' is unsupported. Please use either 'mysql' or 'mysqli' for MySQL, or 'pgsql' for PostgreSQL databases.");170 _db_error_page("The database type '". $db_type ."' is unsupported. Please use either 'mysql' or 'mysqli' for MySQL, or 'pgsql' for PostgreSQL databases.");
164 }171 }
165172
166 $db_conns[$name] = db_connect($connect_url);173 try {
174 $db_conns[$name] = db_connect($connect_url);
175 }
176 catch (Exception $e) {
177 _db_error_page($e->getMessage());
178 }
179
167 if (!empty($slave_connect_url)) {180 if (!empty($slave_connect_url)) {
168 $db_slave_conns[$name] = db_connect($slave_connect_url); 181 try {
182 $db_slave_conns[$name] = db_connect($slave_connect_url);
183 }
184 catch (Exception $e) {
185 _db_error_page($e->getMessage());
186 }
169 }187 }
170 }188 }
171189
@@ -184,6 +202,96 @@
184}202}
185203
186/**204/**
205 * Choose a database server to connect to during the current page request.
206 *
207 * This function will loop through a list of provided databases and attempt to
208 * connect to them in order, stopping when a successful connection is made.
209 * However, it also checks a (pluggable) cache to see if a different database
210 * server is preferred and moves that server to the front of the list so that
211 * it can be attempted before any of the others. If the database server that
212 * is eventually connected to is different from the one stored in the cache,
213 * it writes the new, preferred sever to the cache before exiting.
214 *
215 * @param $db_urls
216 * An ordered array of possible database servers to connect to. The keys
217 * should be unique identifiers for each server (e.g., "db1", "db2"), and
218 * the values should be database connection URLs. Once a database server
219 * has been chosen, the array will be replaced with a string containing the
220 * database connection URL that is actually being used.
221 * @param $name
222 * The name of the database that is being connected to. Usually this will be
223 * 'default', but alternate values can be specified if a separate, external
224 * set of database servers is being used for part of the page request (in
225 * addition to the main Drupal database).
226 * @return
227 * The new database connection.
228 */
229function db_choose_active(&$db_urls, $name) {
230 // Load the pluggable cache and check if it contains the name of a preferred
231 // database server. If so, move that server to the front of the list.
232 include_once variable_get('db_server_cache_inc', 'includes/db.server.cache.filesystem.inc');
233 if (function_exists('db_server_cache_get') && ($cached_db_server_id = db_server_cache_get($name))) {
234 if (isset($db_urls[$cached_db_server_id]) && $db_urls[$cached_db_server_id] != reset($db_urls)) {
235 $db_urls = array($cached_db_server_id => $db_urls[$cached_db_server_id]) + $db_urls;
236 }
237 }
238
239 // Loop through each database server and try to connect to it. Stop once a
240 // successful connection is made.
241 $error_message = '';
242 foreach ($db_urls as $id => $connect_url) {
243 $db_type = substr($connect_url, 0, strpos($connect_url, '://'));
244 $handler = "./includes/database.$db_type.inc";
245 if (is_file($handler)) {
246 include_once $handler;
247 // Try to connect to each server three times, with an increasing delay
248 // between each attempt.
249 $connection_attempt = 1;
250 $max_connection_attempts = 3;
251 while ($connection_attempt <= $max_connection_attempts) {
252 try {
253 // Quit the entire loop as soon as a successful connection is made.
254 $connection = db_connect($connect_url);
255 $preferred_db_server_id = $id;
256 break 2;
257 }
258 catch (Exception $e) {
259 if ($connection_attempt == $max_connection_attempts) {
260 $error_message .= ' Server '. $id .': '. $e->getMessage();
261 }
262 else {
263 // Wait 0.5 seconds before the second attempt, and 1 second before
264 // the third attempt.
265 usleep($connection_attempt * 500000);
266 }
267 }
268 $connection_attempt += 1;
269 }
270 }
271 else {
272 $error_message .= ' Server '. $id .": The database type '". $db_type ."' is unsupported. Please use either 'mysql' or 'mysqli' for MySQL, or 'pgsql' for PostgreSQL databases.";
273 }
274 }
275
276 // If no connection was made, show an error page and exit.
277 if (empty($connection)) {
278 _db_error_page($error_message);
279 }
280
281 // If the preferred database server changed, write this to the cache.
282 if (empty($cached_db_server_id) || $cached_db_server_id != $preferred_db_server_id) {
283 if (function_exists('db_server_cache_set')) {
284 db_server_cache_set($name, $preferred_db_server_id);
285 }
286 }
287
288 // Replace the list of database connection URLs with the one that is
289 // actually being used, and return the new database connection.
290 $db_urls = $db_urls[$preferred_db_server_id];
291 return $connection;
292}
293
294/**
187 * Helper function to show fatal database errors.295 * Helper function to show fatal database errors.
188 *296 *
189 * Prints a themed maintenance page with the 'Site off-line' text,297 * Prints a themed maintenance page with the 'Site off-line' text,
190298
=== modified file 'includes/database.mysql.inc'
--- includes/database.mysql.inc 2009-02-26 00:40:48 +0000
+++ includes/database.mysql.inc 2009-09-11 15:02:34 +0000
@@ -53,7 +53,10 @@
5353
54 // Check if MySQL support is present in PHP54 // Check if MySQL support is present in PHP
55 if (!function_exists('mysql_connect')) {55 if (!function_exists('mysql_connect')) {
56 throw new Exception('Unable to use the MySQL database because the MySQL extension for PHP is not installed. Check your <code>php.ini</code> to see how you can enable it.');
57 /* Original version (replaced with exception-based method above):
56 _db_error_page('Unable to use the MySQL database because the MySQL extension for PHP is not installed. Check your <code>php.ini</code> to see how you can enable it.');58 _db_error_page('Unable to use the MySQL database because the MySQL extension for PHP is not installed. Check your <code>php.ini</code> to see how you can enable it.');
59 */
57 }60 }
5861
59 // Decode url-encoded information in the db connection string62 // Decode url-encoded information in the db connection string
@@ -76,8 +79,11 @@
76 // (matched) rows, not the number of affected rows.79 // (matched) rows, not the number of affected rows.
77 $connection = @mysql_connect($url['host'], $url['user'], $url['pass'], TRUE, 2);80 $connection = @mysql_connect($url['host'], $url['user'], $url['pass'], TRUE, 2);
78 if (!$connection || !mysql_select_db(substr($url['path'], 1))) {81 if (!$connection || !mysql_select_db(substr($url['path'], 1))) {
82 throw new Exception(mysql_error());
83 /* Original version (replaced with exception-based method above):
79 // Show error screen otherwise84 // Show error screen otherwise
80 _db_error_page(mysql_error());85 _db_error_page(mysql_error());
86 */
81 }87 }
8288
83 // Force UTF-8.89 // Force UTF-8.
8490
=== modified file 'includes/database.mysqli.inc'
--- includes/database.mysqli.inc 2009-02-26 00:40:48 +0000
+++ includes/database.mysqli.inc 2009-09-11 15:02:34 +0000
@@ -57,7 +57,10 @@
57function db_connect($url) {57function db_connect($url) {
58 // Check if MySQLi support is present in PHP58 // Check if MySQLi support is present in PHP
59 if (!function_exists('mysqli_init') && !extension_loaded('mysqli')) {59 if (!function_exists('mysqli_init') && !extension_loaded('mysqli')) {
60 throw new Exception('Unable to use the MySQLi database because the MySQLi extension for PHP is not installed. Check your <code>php.ini</code> to see how you can enable it.');
61 /* Original version (replaced with exception-based method above):
60 _db_error_page('Unable to use the MySQLi database because the MySQLi extension for PHP is not installed. Check your <code>php.ini</code> to see how you can enable it.');62 _db_error_page('Unable to use the MySQLi database because the MySQLi extension for PHP is not installed. Check your <code>php.ini</code> to see how you can enable it.');
63 */
61 }64 }
6265
63 $url = parse_url($url);66 $url = parse_url($url);
@@ -76,7 +79,10 @@
76 @mysqli_real_connect($connection, $url['host'], $url['user'], $url['pass'], substr($url['path'], 1), $url['port'], NULL, MYSQLI_CLIENT_FOUND_ROWS);79 @mysqli_real_connect($connection, $url['host'], $url['user'], $url['pass'], substr($url['path'], 1), $url['port'], NULL, MYSQLI_CLIENT_FOUND_ROWS);
7780
78 if (mysqli_connect_errno() > 0) {81 if (mysqli_connect_errno() > 0) {
82 throw new Exception(mysqli_connect_error());
83 /* Original version (replaced with exception-based method above):
79 _db_error_page(mysqli_connect_error());84 _db_error_page(mysqli_connect_error());
85 */
80 }86 }
8187
82 // Force UTF-8.88 // Force UTF-8.
8389
=== modified file 'includes/database.pgsql.inc'
--- includes/database.pgsql.inc 2009-07-01 22:36:49 +0000
+++ includes/database.pgsql.inc 2009-09-11 15:02:34 +0000
@@ -47,7 +47,10 @@
47function db_connect($url) {47function db_connect($url) {
48 // Check if PostgreSQL support is present in PHP48 // Check if PostgreSQL support is present in PHP
49 if (!function_exists('pg_connect')) {49 if (!function_exists('pg_connect')) {
50 throw new Exception('Unable to use the PostgreSQL database because the PostgreSQL extension for PHP is not installed. Check your <code>php.ini</code> to see how you can enable it.');
51 /* Original version (replaced with exception-based method above):
50 _db_error_page('Unable to use the PostgreSQL database because the PostgreSQL extension for PHP is not installed. Check your <code>php.ini</code> to see how you can enable it.');52 _db_error_page('Unable to use the PostgreSQL database because the PostgreSQL extension for PHP is not installed. Check your <code>php.ini</code> to see how you can enable it.');
53 */
51 }54 }
5255
53 $url = parse_url($url);56 $url = parse_url($url);
@@ -79,7 +82,12 @@
79 $connection = @pg_connect($conn_string);82 $connection = @pg_connect($conn_string);
80 if (!$connection) {83 if (!$connection) {
81 require_once './includes/unicode.inc';84 require_once './includes/unicode.inc';
85 $error_message = decode_entities($php_errormsg);
86 ini_set('track_errors', $track_errors_previous);
87 throw new Exception($error_message);
88 /* Original version (replaced with exception-based method above):
82 _db_error_page(decode_entities($php_errormsg));89 _db_error_page(decode_entities($php_errormsg));
90 */
83 }91 }
8492
85 // Restore error tracking setting93 // Restore error tracking setting

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