Add redis database backend

src/database-redis.cpp

@@ -0,0 +1,224 @@
+/*
+Minetest
+Copyright (C) 2014 celeron55, Perttu Ahola <celeron55@gmail.com>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#include "config.h"
+
+#if USE_REDIS
+/*
+	Redis databases
+*/
+
+
+#include "database-redis.h"
+#include <hiredis.h>
+
+#include "map.h"
+#include "mapsector.h"
+#include "mapblock.h"
+#include "serialization.h"
+#include "main.h"
+#include "settings.h"
+#include "log.h"
+
+Database_Redis::Database_Redis(ServerMap *map, std::string savedir)
+{
+	Settings conf;
+	conf.readConfigFile((std::string(savedir) + DIR_DELIM + "world.mt").c_str());
+	std::string tmp;
+	try {
+	tmp = conf.get("redis_address");
+	hash = conf.get("redis_hash");
+	} catch(SettingNotFoundException e) {
+		throw SettingNotFoundException("Set redis_address and redis_hash in world.mt to use the redis backend");
+	}
+	const char *addr = tmp.c_str();
+	int port = conf.exists("redis_port") ? conf.getU16("redis_port") : 6379;
+	ctx = redisConnect(addr, port);
+	if(!ctx)
+		throw FileNotGoodException("Cannot allocate redis context");
+	else if(ctx->err) {
+		std::string err = std::string("Connection error: ") + ctx->errstr;
+		redisFree(ctx);
+		throw FileNotGoodException(err);
+	}
+	srvmap = map;
+}
+
+int Database_Redis::Initialized(void)
+{
+	return 1;
+}
+
+void Database_Redis::beginSave() {
+	redisReply *reply;
+	reply = (redisReply*) redisCommand(ctx, "MULTI");
+	if(!reply)
+		throw FileNotGoodException(std::string("redis command 'MULTI' failed: ") + ctx->errstr);
+	freeReplyObject(reply);
+}
+
+void Database_Redis::endSave() {
+	redisReply *reply;
+	reply = (redisReply*) redisCommand(ctx, "EXEC");
+	if(!reply)
+		throw FileNotGoodException(std::string("redis command 'EXEC' failed: ") + ctx->errstr);
+	freeReplyObject(reply);
+}
+
+void Database_Redis::saveBlock(MapBlock *block)
+{
+	DSTACK(__FUNCTION_NAME);
+	/*
+		Dummy blocks are not written
+	*/
+	if(block->isDummy())
+	{
+		return;
+	}
+
+	// Format used for writing
+	u8 version = SER_FMT_VER_HIGHEST_WRITE;
+	// Get destination
+	v3s16 p3d = block->getPos();
+
+	/*
+		[0] u8 serialization version
+		[1] data
+	*/
+
+	std::ostringstream o(std::ios_base::binary);
+	o.write((char*)&version, 1);
+	// Write basic data
+	block->serialize(o, version, true);
+	// Write block to database
+	std::string tmp1 = o.str();
+	std::string tmp2 = i64tos(getBlockAsInteger(p3d));
+
+	redisReply *reply;
+	reply = (redisReply*) redisCommand(ctx, "HSET %s %s %b", hash.c_str(), tmp2.c_str(), tmp1.c_str(), tmp1.size());
+	if(!reply)
+		throw FileNotGoodException(std::string("redis command 'HSET %s %s %b' failed: ") + ctx->errstr);
+	if(reply->type == REDIS_REPLY_ERROR)
+		throw FileNotGoodException("Failed to store block in Database");
+
+	// We just wrote it to the disk so clear modified flag
+	block->resetModified();
+}
+
+MapBlock* Database_Redis::loadBlock(v3s16 blockpos)
+{
+	v2s16 p2d(blockpos.X, blockpos.Z);
+
+	std::string tmp = i64tos(getBlockAsInteger(blockpos));
+	redisReply *reply;
+	reply = (redisReply*) redisCommand(ctx, "HGET %s %s", hash.c_str(), tmp.c_str());
+	if(!reply)
+		throw FileNotGoodException(std::string("redis command 'HGET %s %s' failed: ") + ctx->errstr);
+
+	if (reply->type == REDIS_REPLY_STRING && reply->len == 0) {
+		freeReplyObject(reply);
+		errorstream << "Blank block data in database (reply->len == 0) ("
+			<< blockpos.X << "," << blockpos.Y << "," << blockpos.Z << ")" << std::endl;
+
+		if (g_settings->getBool("ignore_world_load_errors")) {
+			errorstream << "Ignoring block load error. Duck and cover! "
+				<< "(ignore_world_load_errors)" << std::endl;
+		} else {
+			throw SerializationError("Blank block data in database");
+		}
+		return NULL;
+	}
+
+	if (reply->type == REDIS_REPLY_STRING) {
+		/*
+			Make sure sector is loaded
+		*/
+		MapSector *sector = srvmap->createSector(p2d);
+
+		try {
+			std::istringstream is(std::string(reply->str, reply->len), std::ios_base::binary);
+			freeReplyObject(reply); // std::string copies the memory so we can already do this here
+			u8 version = SER_FMT_VER_INVALID;
+			is.read((char *)&version, 1);
+
+			if (is.fail())
+				throw SerializationError("ServerMap::loadBlock(): Failed"
+					" to read MapBlock version");
+
+			MapBlock *block = NULL;
+			bool created_new = false;
+			block = sector->getBlockNoCreateNoEx(blockpos.Y);
+			if (block == NULL)
+			{
+				block = sector->createBlankBlockNoInsert(blockpos.Y);
+				created_new = true;
+			}
+
+			// Read basic data
+			block->deSerialize(is, version, true);
+
+			// If it's a new block, insert it to the map
+			if (created_new)
+				sector->insertBlock(block);
+
+			// We just loaded it from, so it's up-to-date.
+			block->resetModified();
+		}
+		catch (SerializationError &e)
+		{
+			errorstream << "Invalid block data in database"
+				<< " (" << blockpos.X << "," << blockpos.Y << "," << blockpos.Z
+				<< ") (SerializationError): " << e.what() << std::endl;
+			// TODO: Block should be marked as invalid in memory so that it is
+			// not touched but the game can run
+
+			if (g_settings->getBool("ignore_world_load_errors")) {
+				errorstream << "Ignoring block load error. Duck and cover! "
+					<< "(ignore_world_load_errors)" << std::endl;
+			} else {
+				throw SerializationError("Invalid block data in database");
+			}
+		}
+
+		return srvmap->getBlockNoCreateNoEx(blockpos);  // should not be using this here
+	}
+	return NULL;
+}
+
+void Database_Redis::listAllLoadableBlocks(std::list<v3s16> &dst)
+{
+	redisReply *reply;
+	reply = (redisReply*) redisCommand(ctx, "HKEYS %s", hash.c_str());
+	if(!reply)
+		throw FileNotGoodException(std::string("redis command 'HKEYS %s' failed: ") + ctx->errstr);
+	if(reply->type != REDIS_REPLY_ARRAY)
+		throw FileNotGoodException("Failed to get keys from database");
+	for(size_t i = 0; i < reply->elements; i++)
+	{
+		assert(reply->element[i]->type == REDIS_REPLY_STRING);
+		dst.push_back(getIntegerAsBlock(stoi64(reply->element[i]->str)));
+	}
+	freeReplyObject(reply);
+}
+
+Database_Redis::~Database_Redis()
+{
+	redisFree(ctx);
+}
+#endif