refactor: DB Updates will now file level lock to stop duplicate updates (#6469)

* refactor: DB Updates will now file level lock to stop duplicate updates

* scrut fixes

* renamed function from clear_lock() to release_lock()

alerts.php

@@ -30,21 +30,7 @@ require __DIR__ . '/includes/init.php';
 
 $options = getopt('d::');
 
-$lock = false;
-if (file_exists($config['install_dir'].'/.alerts.lock')) {
-    $pids = explode("\n", trim(`ps -e | grep php | awk '{print $1}'`));
-    $lpid = trim(file_get_contents($config['install_dir'].'/.alerts.lock'));
-    if (in_array($lpid, $pids)) {
-        $lock = true;
-    }
-}
-
-if ($lock === true) {
-    exit(1);
-} else {
-    file_put_contents($config['install_dir'].'/.alerts.lock', getmypid());
-}
-
+set_lock('alerts');
 
 if (isset($options['d'])) {
     echo "DEBUG!\n";
@@ -74,7 +60,7 @@ if (!defined('TEST') && $config['alert']['disable'] != 'true') {
     echo 'End  : '.date('r')."\r\n";
 }
 
-unlink($config['install_dir'].'/.alerts.lock');
+release_lock('alerts');
 
 function ClearStaleAlerts()
 {

discovery.php

@@ -113,7 +113,9 @@ if (!$where) {
     exit;
 }
 
-require 'includes/sql-schema/update.php';
+if (get_lock('schema') === false) {
+    require 'includes/sql-schema/update.php';
+}
 
 $discovered_devices = 0;
 

doc/General/Updating.md

@@ -9,16 +9,32 @@ then you can do this by running the following command as the **librenms** user:
 This will update both the core LibreNMS files but also update the database
 structure if updates are available.
 
+#### Advanced users
+If you absolutely must update manually then you can do so by running the following commands:
+```bash
+cd /opt/librenms
+git pull
+php includes/sql-schema/update.php
+```
+
 ## Configuring the update channel ##
 LibreNMS follows the master branch on github for daily updates.
-You can change to the monthly releases by setting:
+
+#### Stable branch
+You can change to the stable monthly branch by setting:
 
 `$config['update_channel'] = 'release';`
 
+> Choose this branch if you want to have a stable release 
+
+#### Development branch
+You can change to the development branch by setting:
+
+`$config['update_channel'] = 'master';`
+
+> Choose this branch if you want the latest features at the cost that sometimes bugs are inadvertently introduced. 
+
 ## Disabling automatic updates ##
-LibreNMS by default performs updates on a daily basis. This can be disabled
-by ensuring:
+LibreNMS by default performs updates on a daily basis. This can be disabled by setting:
 
 `$config['update'] = 0;`
-
-is no longer commented out. 

html/index.php

@@ -57,7 +57,7 @@ $msg_box = array();
 // Check for install.inc.php
 if (!file_exists('../config.php') && $_SERVER['PATH_INFO'] != '/install.php') {
     // no config.php does so let's redirect to the install
-    header('Location: install.php');
+    header("Location: {$config['base_url']}/install.php");
     exit;
 }
 

html/install.php

@@ -22,7 +22,7 @@ if ($stage > 3) {
 require realpath(__DIR__ . '/..') . '/includes/init.php';
 
 // List of php modules we expect to see
-$modules = array('gd','mysqli','snmp','mcrypt');
+$modules = array('gd','mysqli','mcrypt');
 
 $dbhost = @$_POST['dbhost'] ?: 'localhost';
 $dbuser = @$_POST['dbuser'] ?: 'librenms';

includes/functions.php

@@ -2327,6 +2327,53 @@ function db_schema_is_current()
     return $current >= $latest;
 }
 
+/**
+ * Get the lock status for a given name
+ * @param $name
+ * @return bool
+ */
+function get_lock($name)
+{
+    global $config;
+    $lock_file = $config['install_dir']."/.$name.lock";
+    if (file_exists($lock_file)) {
+        $pids = explode("\n", trim(`ps -e | grep php | awk '{print $1}'`));
+        $lpid = trim(file_get_contents($lock_file));
+        if (in_array($lpid, $pids)) {
+            return true;
+        }
+    }
+    return false;
+}
+
+/**
+ * Set the lock status for a given name
+ * @param $name
+ */
+function set_lock($name)
+{
+    global $config;
+    $lock_file = $config['install_dir']."/.$name.lock";
+    $lock = get_lock($name);
+
+    if ($lock === true) {
+        echo "$lock_file exists, exiting\n";
+        exit(1);
+    } else {
+        file_put_contents($lock_file, getmypid());
+    }
+}
+
+/**
+ * Release lock file for a given name
+ * @param $name
+ */
+function release_lock($name)
+{
+    global $config;
+    unlink($config['install_dir']."/.$name.lock");
+}
+
 /**
  * @param $device
  * @return int|null

includes/sql-schema/update.php

@@ -15,6 +15,8 @@
  * See COPYING for more details.
  */
 
+set_lock('schema');
+
 if (!isset($debug)  && php_sapi_name() == 'cli') {
     // Not called from within discovery, let's load up the necessary stuff.
     $init_modules = array();
@@ -24,8 +26,11 @@ if (!isset($debug)  && php_sapi_name() == 'cli') {
     $debug = isset($options['d']);
 }
 
+d_echo("DB Schema update started....\n");
+
 if (db_schema_is_current()) {
     d_echo("DB Schema already up to date.\n");
+    release_lock('schema');
     return;
 }
 
@@ -91,3 +96,5 @@ if ($updating) {
         $_SESSION['build-ok'] = true;
     }
 }
+
+release_lock('schema');

sql-schema/107.sql

@@ -1,4 +1,3 @@
-UPDATE dbSchema SET version = 107;
 CREATE TABLE bill_port_counters_tmp(port_id int NOT NULL PRIMARY KEY, `timestamp` timestamp NOT NULL DEFAULT current_timestamp, in_counter bigint, in_delta bigint NOT NULL DEFAULT 0, out_counter bigint, out_delta bigint NOT NULL DEFAULT 0);
 INSERT INTO bill_port_counters_tmp(port_id, timestamp, in_counter, out_counter) SELECT q.port_id, q.max_timestamp, max(i.counter), max(o.counter) FROM (SELECT port_id, MAX(`timestamp`) AS max_timestamp FROM port_in_measurements GROUP BY port_id) q INNER JOIN port_in_measurements i ON q.port_id = i.port_id AND q.max_timestamp = i.timestamp INNER JOIN port_out_measurements o ON q.port_id = o.port_id AND q.max_timestamp = o.timestamp GROUP BY q.port_id, q.max_timestamp;
 RENAME TABLE bill_port_counters_tmp TO bill_port_counters;

sql-schema/118.sql

@@ -1,4 +1,3 @@
-UPDATE dbSchema SET version = 118;
 ALTER TABLE `eventlog` ADD `device_id` INT NOT NULL AFTER `host` ;
 ALTER TABLE `eventlog` ADD INDEX ( `device_id` ) ;
 UPDATE eventlog SET device_id=host WHERE device_id=0;

sql-schema/171.sql

@@ -1,4 +1,3 @@
-UPDATE `dbSchema` SET `version` = 171;
 ALTER TABLE `access_points` DEFAULT CHARSET=utf8 COLLATE utf8_unicode_ci;
 ALTER TABLE `alert_map` DEFAULT CHARSET=utf8 COLLATE utf8_unicode_ci;
 ALTER TABLE `alert_rules` DEFAULT CHARSET=utf8 COLLATE utf8_unicode_ci;