Added Database Maintenance Mode.

Author: galli-leo

app/Console/Commands/DBDown.php

@@ -0,0 +1,200 @@
+<?php
+
+namespace App\Console\Commands;
+
+use Illuminate\Console\Command;
+use Illuminate\Support\Facades\DB;
+use Illuminate\Support\Facades\Storage;
+use Illuminate\Support\Facades\Config;
+
+class DBDown extends Command
+{
+    /**
+     * The name and signature of the console command.
+     *
+     * @var string
+     */
+    protected $signature = 'db:down {maintenance_to_use?}';
+
+    /**
+     * The console command description.
+     *
+     * @var string
+     */
+    protected $description = 'Start Database Maintenance mode';
+
+    /**
+     * Create a new command instance.
+     *
+     * @return void
+     */
+    public function __construct()
+    {
+        parent::__construct();
+    }
+
+    /**
+     * Execute the console command.
+     *
+     * @return mixed
+     */
+    public function handle()
+    {
+        //
+        $info = $this->get_maintenance_info();
+        if ($info === false)
+        {
+            $this->info("Starting maintenance mode!");
+            $config = $this->argument('maintenance_to_use');
+            if ($config == "")
+            {
+                $config = "maintenance";
+            }
+            $this->start_maintenance_mode($config);
+        }
+        else
+        {
+            $this->error("Maintenance mode already on the way. Currently on stage: {$info['stage_name']}");
+        }
+    }
+
+    protected function get_maintenance_info()
+    {
+        if (Storage::disk()->exists("db.down"))
+        {
+            $contents = Storage::get("db.down");
+            return json_decode($contents, true);
+        }
+
+        return false;
+    }
+
+    protected function start_maintenance_mode($config = "tmdb_maintenance")
+    {
+        $this->replicate_tables($config);
+
+        $this->finish_preparations();
+    }
+
+    protected function replicate_tables($config)
+    {
+        $info = array(
+            "stage" => "db.replication",
+            "stage_name" => "Database Replication",
+            "progress" => 0.0
+        );
+
+        $this->set_maintenance_info($info);
+        //Replicating database
+        $from_db = Config::get("database.$config.from_database");
+        $to_db = Config::get("database.$config.to_database");
+        $connection = Config::get("database.$config.db_connection");
+        if ($from_db == "" || $to_db == "")
+        {
+            $this->error("Please check your configuration!");
+            $this->free_maintenance_info();
+            return;
+        }
+
+        $this->info("Replicating database from $from_db to $to_db");
+
+        $conf_tables = Config::get("database.$config.tables");
+        $tables = $conf_tables;
+        if ($conf_tables == "all" || $conf_tables == "")
+        {
+          $tables = DB::select("SHOW TABLES FROM $from_db");
+          $real_tables = array();
+          foreach ($tables as $dict) {
+              foreach ($dict as $key => $value) {
+                  $real_tables[] = $value;
+              }
+          }
+          $tables = $real_tables;
+        }
+
+        $this->info("Replicating tables ".join(", ", $tables));
+
+        $first_tables = Config::get("database.$config.tables_before");
+
+        if (is_array($first_tables) && count($first_tables) > 0)
+        {
+            $this->info("Starting with table(s) ".join(",", $first_tables));
+
+            foreach ($first_tables as $value) {
+                if (($key = array_search($value, $tables)) !== false) {
+                    unset($tables[$key]);
+                }
+            }
+
+            foreach ($first_tables as $value) {
+                array_unshift($tables, $value);
+            }
+
+            $this->info("Order of replication: ".join(", ", $tables));
+        }
+
+        $current = 0;
+        $total = count($tables);
+
+        DB::connection($connection)->statement("SET foreign_key_checks = 0;");
+        foreach ($tables as $value) {
+            try {
+                DB::connection($connection)->statement("DROP TABLE $to_db.$value");
+            } catch (Exception $e) {
+                //Ignore since maybe table does not exist yet.
+            }
+
+            $create_syntax = DB::select("SHOW CREATE TABLE $from_db.$value");
+            $actual_syntax = "";
+            foreach ($create_syntax as $syntax) {
+                //dd($syntax);
+                foreach ($syntax as $key => $val) {
+                    if ($key == "Create Table")
+                    {
+                        $actual_syntax = $val;
+                    }
+                }
+
+            }
+
+            $actual_syntax = str_replace("`$value`", "`$to_db`.`$value`", $actual_syntax);
+            DB::connection($connection)->statement($actual_syntax);
+            //DB::connection($connection)->getPdo()->query($actual_syntax);
+            DB::connection($connection)->statement("INSERT INTO $to_db.$value SELECT * FROM $from_db.$value");
+            $current += 1;
+            $this->info("Replicated table $value. ($current/$total)");
+            $info = array(
+                "stage" => "db.replication",
+                "stage_name" => "Database Replication",
+                "progress" => $current / (float)$total
+            );
+
+            $this->set_maintenance_info($info);
+        }
+        DB::connection($connection)->statement("SET foreign_key_checks = 1;");
+
+        $this->info("Finished Replicating Database.");
+    }
+
+    protected function finish_preparations()
+    {
+      $info = array(
+          "stage" => "finished",
+          "stage_name" => "Database Maintenance!",
+          "progress" => 1.0
+      );
+
+      $this->set_maintenance_info($info);
+      $this->info("Finished preparing Database Maintenance. You can now safely manipulate production database!");
+    }
+
+    protected function set_maintenance_info($info)
+    {
+        Storage::put("db.down", json_encode($info));
+    }
+
+    protected function free_maintenance_info()
+    {
+        Storage::delete("db.down");
+    }
+}