mirror of https://gitee.com/bigwinds/arangodb
237 lines
8.7 KiB
C++
237 lines
8.7 KiB
C++
////////////////////////////////////////////////////////////////////////////////
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/// @brief Class to get and cache information about the cluster state
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///
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/// @file ClusterInfo.h
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///
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/// DISCLAIMER
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///
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/// Copyright 2010-2013 triagens GmbH, Cologne, Germany
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///
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/// Licensed under the Apache License, Version 2.0 (the "License");
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/// you may not use this file except in compliance with the License.
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/// You may obtain a copy of the License at
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///
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/// http://www.apache.org/licenses/LICENSE-2.0
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///
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/// Unless required by applicable law or agreed to in writing, software
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/// distributed under the License is distributed on an "AS IS" BASIS,
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/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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/// See the License for the specific language governing permissions and
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/// limitations under the License.
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///
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/// Copyright holder is triAGENS GmbH, Cologne, Germany
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///
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/// @author Max Neunhoeffer
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/// @author Copyright 2013, triagens GmbH, Cologne, Germany
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////////////////////////////////////////////////////////////////////////////////
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#ifndef TRIAGENS_CLUSTER_STATE_H
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#define TRIAGENS_CLUSTER_STATE_H 1
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#include "Basics/Common.h"
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#include "Cluster/AgencyComm.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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namespace triagens {
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namespace arango {
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// -----------------------------------------------------------------------------
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// --SECTION-- some types for ClusterInfo
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// -----------------------------------------------------------------------------
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typedef string ServerID; // ID of a server
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typedef string DatabaseID; // ID/name of a database
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typedef string CollectionID; // ID of a collection
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typedef string ShardID; // ID of a shard
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// -----------------------------------------------------------------------------
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// --SECTION-- class CollectionInfo
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// -----------------------------------------------------------------------------
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struct CollectionInfo {
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enum Status {
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LOADED = 1,
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UNLOADED = 2
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};
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enum Type {
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NORMAL = 1,
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EDGES = 2
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};
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DatabaseID database;
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string id;
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string name;
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Status status;
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Type type;
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vector<string> shards;
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CollectionInfo () : id(""), name(""), status(LOADED), type(NORMAL) {
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}
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~CollectionInfo () {
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}
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};
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// -----------------------------------------------------------------------------
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// --SECTION-- class ClusterInfo
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// -----------------------------------------------------------------------------
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class ClusterInfo {
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// -----------------------------------------------------------------------------
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// --SECTION-- constructors and destructors
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// -----------------------------------------------------------------------------
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////////////////////////////////////////////////////////////////////////////////
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/// @brief initialises library
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///
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/// We are a singleton class, therefore nobody is allowed to create
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/// new instances or copy them, except we ourselves.
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////////////////////////////////////////////////////////////////////////////////
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ClusterInfo ();
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ClusterInfo (ClusterInfo const&); // not implemented
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void operator= (ClusterInfo const&); // not implemented
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static ClusterInfo* _theinstance;
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public:
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////////////////////////////////////////////////////////////////////////////////
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/// @brief shuts down library
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////////////////////////////////////////////////////////////////////////////////
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~ClusterInfo ();
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// -----------------------------------------------------------------------------
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// --SECTION-- public methods
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// -----------------------------------------------------------------------------
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////////////////////////////////////////////////////////////////////////////////
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/// @brief get the unique instance
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////////////////////////////////////////////////////////////////////////////////
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static ClusterInfo* instance ();
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////////////////////////////////////////////////////////////////////////////////
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/// @brief initialise function to call once when still single-threaded
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////////////////////////////////////////////////////////////////////////////////
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static void initialise ();
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////////////////////////////////////////////////////////////////////////////////
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/// @brief cleanup function to call once when shutting down
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////////////////////////////////////////////////////////////////////////////////
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static void cleanup () {
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delete _theinstance;
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_theinstance = 0;
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}
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////////////////////////////////////////////////////////////////////////////////
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/// @brief find the endpoint of a server from its ID.
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///
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/// If it is not found in the cache, the cache is reloaded once, if
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/// it is still not there an empty string is returned as an error.
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////////////////////////////////////////////////////////////////////////////////
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string getServerEndpoint(ServerID const& serverID);
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////////////////////////////////////////////////////////////////////////////////
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/// @brief (re-)load the information about servers from the agency
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///
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/// Usually one does not have to call this directly.
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////////////////////////////////////////////////////////////////////////////////
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void loadServerInformation ();
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////////////////////////////////////////////////////////////////////////////////
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/// @brief find the server who is responsible for a shard
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///
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/// If it is not found in the cache, the cache is reloaded once, if
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/// it is still not there an empty string is returned as an error.
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////////////////////////////////////////////////////////////////////////////////
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ServerID getResponsibleServer(ShardID const& shardID);
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////////////////////////////////////////////////////////////////////////////////
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/// @brief (re-)load the information about shards from the agency
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///
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/// Usually one does not have to call this directly.
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////////////////////////////////////////////////////////////////////////////////
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void loadShardInformation ();
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////////////////////////////////////////////////////////////////////////////////
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/// @brief ask whether a cluster database exists
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////////////////////////////////////////////////////////////////////////////////
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bool doesDatabaseExist (DatabaseID const& databaseID);
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////////////////////////////////////////////////////////////////////////////////
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/// @brief (re-)load the information about databases from the agency
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///
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/// Usually one does not have to call this directly.
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////////////////////////////////////////////////////////////////////////////////
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void loadDatabaseInformation ();
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////////////////////////////////////////////////////////////////////////////////
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/// @brief ask about a collection
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///
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/// If it is not found in the cache, the cache is reloaded once, if
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/// it is still not there an empty 0 pointer is returned. The caller
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/// must not delete the pointer.
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////////////////////////////////////////////////////////////////////////////////
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CollectionInfo const* getCollectionInfo(
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DatabaseID const& databaseID,
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CollectionID const& collectionID);
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////////////////////////////////////////////////////////////////////////////////
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/// @brief (re-)load the information about collections from the agency
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///
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/// Usually one does not have to call this directly.
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////////////////////////////////////////////////////////////////////////////////
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void loadCollectionsInformation ();
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////////////////////////////////////////////////////////////////////////////////
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/// @brief get a number of cluster-wide unique IDs, returns the first
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/// one and guarantees that <number> are reserved for the caller.
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////////////////////////////////////////////////////////////////////////////////
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uint64_t fetchIDs (uint64_t number);
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private:
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AgencyComm _agency;
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// Cached data from the agency, we reload whenever necessary:
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map<ServerID,string> serverAddresses; // from Current/ServersRegistered
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map<ShardID,ServerID> shards; // from Current/ShardLocation
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map<CollectionID,CollectionInfo*> collections;
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// from Current/Collections/
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triagens::basics::ReadWriteLock lock;
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};
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} // end namespace arango
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} // end namespace triagens
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#ifdef __cplusplus
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}
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#endif
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#endif
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// Local Variables:
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// mode: outline-minor
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// outline-regexp: "^\\(/// @brief\\|/// {@inheritDoc}\\|/// @addtogroup\\|// --SECTION--\\|/// @\\}\\)"
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// End:
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