src/server/server.h

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 *
 */

#pragma once

#include <inttypes.h>
#include <tbb/concurrent_vector.h>

#include <array>
#include <atomic>
#include <cstddef>
#include <cstdint>
#include <list>
#include <map>
#include <memory>
#include <set>
#include <shared_mutex>
#include <string>
#include <type_traits>
#include <unordered_map>
#include <utility>
#include <vector>

#include "cluster/cluster.h"
#include "cluster/replication.h"
#include "cluster/slot_import.h"
#include "cluster/slot_migrate.h"
#include "commands/commander.h"
#include "lua.hpp"
#include "memory_profiler.h"
#include "namespace.h"
#include "search/index_manager.h"
#include "search/indexer.h"
#include "server/redis_connection.h"
#include "stats/log_collector.h"
#include "stats/stats.h"
#include "storage/redis_metadata.h"
#include "storage/storage.h"
#include "task_runner.h"
#include "tls_util.h"
#include "worker.h"

constexpr const char *REDIS_VERSION = "4.0.0";

struct DBScanInfo {
  // Last scan system clock in seconds
  int64_t last_scan_time_secs = 0;
  KeyNumStats key_num_stats;
  bool is_scanning = false;
};

struct ConnContext {
  Worker *owner;
  int fd;

  ConnContext(Worker *w, int fd) : owner(w), fd(fd) {}

  bool operator<(const ConnContext &c) const {
    if (owner == c.owner) {
      return fd < c.fd;
    }

    return owner < c.owner;
  }

  bool operator==(const ConnContext &c) const { return owner == c.owner && fd == c.fd; }
};

struct StreamConsumer {
  Worker *owner;
  int fd;
  std::string ns;
  redis::StreamEntryID last_consumed_id;
  StreamConsumer(Worker *w, int fd, std::string ns, redis::StreamEntryID id)
      : owner(w), fd(fd), ns(std::move(ns)), last_consumed_id(id) {}
};

struct ChannelSubscribeNum {
  std::string channel;
  size_t subscribe_num;
};

// CURSOR_DICT_SIZE must be 2^n where n <= 16
constexpr const size_t CURSOR_DICT_SIZE = 1024 * 16;
static_assert((CURSOR_DICT_SIZE & (CURSOR_DICT_SIZE - 1)) == 0, "CURSOR_DICT_SIZE must be 2^n");
static_assert(CURSOR_DICT_SIZE <= (1 << 16), "CURSOR_DICT_SIZE must be less than or equal to 2^16");

enum class CursorType : uint8_t {
  kTypeNone = 0,  // none
  kTypeBase = 1,  // cursor for SCAN
  kTypeHash = 2,  // cursor for HSCAN
  kTypeSet = 3,   // cursor for SSCAN
  kTypeZSet = 4,  // cursor for ZSCAN
};
struct CursorDictElement;

class NumberCursor {
 public:
  NumberCursor() = default;
  explicit NumberCursor(CursorType cursor_type, uint16_t counter, const std::string &key_name);
  explicit NumberCursor(uint64_t number_cursor) : cursor_(number_cursor) {}
  size_t GetIndex() const { return cursor_ % CURSOR_DICT_SIZE; }
  bool IsMatch(const CursorDictElement &element, CursorType cursor_type) const;
  std::string ToString() const { return std::to_string(cursor_); }

 private:
  CursorType getCursorType() const { return static_cast<CursorType>(cursor_ >> 61); }
  uint64_t cursor_;
};

struct CursorDictElement {
  NumberCursor cursor;
  std::string key_name;
};

enum SlowLog {
  kSlowLogMaxArgc = 32,
  kSlowLogMaxString = 128,
};

enum ClientType {
  kTypeNormal = (1ULL << 0),  // normal client
  kTypePubsub = (1ULL << 1),  // pubsub client
  kTypeMaster = (1ULL << 2),  // master client
  kTypeSlave = (1ULL << 3),   // slave client
};

enum ServerLogType { kServerLogNone, kReplIdLog };

enum class AuthResult {
  IS_USER,
  IS_ADMIN,
  INVALID_PASSWORD,
  NO_REQUIRE_PASS,
};

class ServerLogData {
 public:
  // Redis::WriteBatchLogData always starts with digit ascii, we use alphabetic to
  // distinguish ServerLogData with Redis::WriteBatchLogData.
  static const char kReplIdTag = 'r';
  static bool IsServerLogData(const char *header) {
    if (header) return *header == kReplIdTag;
    return false;
  }

  ServerLogData() = default;
  explicit ServerLogData(ServerLogType type, std::string content) : type_(type), content_(std::move(content)) {}

  ServerLogType GetType() const { return type_; }
  std::string GetContent() const { return content_; }
  std::string Encode() const;
  Status Decode(const rocksdb::Slice &blob);

 private:
  ServerLogType type_ = kServerLogNone;
  std::string content_;
};

class SlotImport;
class SlotMigrator;

class Server {
 public:
  explicit Server(engine::Storage *storage, Config *config);
  ~Server();

  Server(const Server &) = delete;
  Server &operator=(const Server &) = delete;

  Status Start();
  void Stop();
  void Join();
  bool IsStopped() const { return stop_; }
  bool IsLoading() const { return is_loading_; }
  Config *GetConfig() { return config_; }
  static StatusOr<std::unique_ptr<redis::Commander>> LookupAndCreateCommand(const std::string &cmd_name);
  void AdjustOpenFilesLimit();
  void AdjustWorkerThreads();

  Status AddMaster(const std::string &host, uint32_t port, bool force_reconnect);
  Status RemoveMaster();
  Status AddSlave(redis::Connection *conn, rocksdb::SequenceNumber next_repl_seq);
  void DisconnectSlaves();
  void CleanupExitedSlaves();
  bool IsSlave() const { return !master_host_.empty(); }
  void FeedMonitorConns(redis::Connection *conn, const std::vector<std::string> &tokens);
  void IncrFetchFileThread() { fetch_file_threads_num_++; }
  void DecrFetchFileThread() { fetch_file_threads_num_--; }
  int GetFetchFileThreadNum() const { return fetch_file_threads_num_; }

  int PublishMessage(const std::string &channel, const std::string &msg);
  void SubscribeChannel(const std::string &channel, redis::Connection *conn);
  void UnsubscribeChannel(const std::string &channel, redis::Connection *conn);
  void GetChannelsByPattern(const std::string &pattern, std::vector<std::string> *channels);
  void ListChannelSubscribeNum(const std::vector<std::string> &channels,
                               std::vector<ChannelSubscribeNum> *channel_subscribe_nums);
  void PSubscribeChannel(const std::string &pattern, redis::Connection *conn);
  void PUnsubscribeChannel(const std::string &pattern, redis::Connection *conn);
  size_t GetPubSubPatternSize() const { return pubsub_patterns_.size(); }
  void SSubscribeChannel(const std::string &channel, redis::Connection *conn, uint16_t slot);
  void SUnsubscribeChannel(const std::string &channel, redis::Connection *conn, uint16_t slot);
  void GetSChannelsByPattern(const std::string &pattern, std::vector<std::string> *channels);
  void ListSChannelSubscribeNum(const std::vector<std::string> &channels,
                                std::vector<ChannelSubscribeNum> *channel_subscribe_nums);

  void BlockOnKey(const std::string &key, redis::Connection *conn);
  void UnblockOnKey(const std::string &key, redis::Connection *conn);
  void BlockOnStreams(const std::vector<std::string> &keys, const std::vector<redis::StreamEntryID> &entry_ids,
                      redis::Connection *conn);
  void UnblockOnStreams(const std::vector<std::string> &keys, redis::Connection *conn);
  void WakeupBlockingConns(const std::string &key, size_t n_conns);
  void OnEntryAddedToStream(const std::string &ns, const std::string &key, const redis::StreamEntryID &entry_id);

  size_t GetReplicaCount() {
    slave_threads_mu_.lock();
    auto replica_count = slave_threads_.size();
    slave_threads_mu_.unlock();
    return replica_count;
  }

  std::string GetLastRandomKeyCursor();
  void SetLastRandomKeyCursor(const std::string &cursor);

  static int64_t GetCachedUnixTime();
  int64_t GetLastBgsaveTime();
  std::string GetRoleInfo();

  struct InfoEntry {
    std::string name;
    std::string val;

    InfoEntry(std::string name, std::string val) : name(std::move(name)), val(std::move(val)) {}
    InfoEntry(std::string name, std::string_view val) : name(std::move(name)), val(val.begin(), val.end()) {}
    InfoEntry(std::string name, const char *val) : name(std::move(name)), val(val) {}
    template <typename T, std::enable_if_t<std::is_integral_v<T> || std::is_floating_point_v<T>, int> = 0>
    InfoEntry(std::string name, T v) : name(std::move(name)), val(std::to_string(v)) {}
  };
  using InfoEntries = std::vector<InfoEntry>;

  InfoEntries GetStatsInfo();
  InfoEntries GetServerInfo();
  InfoEntries GetMemoryInfo();
  InfoEntries GetRocksDBInfo();
  InfoEntries GetClientsInfo();
  InfoEntries GetReplicationInfo();
  InfoEntries GetCommandsStatsInfo();
  InfoEntries GetClusterInfo();
  InfoEntries GetPersistenceInfo();
  InfoEntries GetCpuInfo();
  InfoEntries GetKeyspaceInfo(const std::string &ns);

  std::string GetInfo(const std::string &ns, const std::vector<std::string> &sections);
  std::string GetRocksDBStatsJson() const;
  ReplState GetReplicationState();

  bool PrepareRestoreDB();
  void WaitNoMigrateProcessing();
  Status AsyncCompactDB(const std::string &begin_key = "", const std::string &end_key = "");
  Status AsyncBgSaveDB();
  Status AsyncPurgeOldBackups(uint32_t num_backups_to_keep, uint32_t backup_max_keep_hours);
  Status AsyncScanDBSize(const std::string &ns);
  void GetLatestKeyNumStats(const std::string &ns, KeyNumStats *stats);
  int64_t GetLastScanTime(const std::string &ns) const;
  StatusOr<std::vector<rocksdb::BatchResult>> PollUpdates(uint64_t next_sequence, int64_t count, bool is_strict) const;

  std::string GenerateCursorFromKeyName(const std::string &key_name, CursorType cursor_type, const char *prefix = "");
  std::string GetKeyNameFromCursor(const std::string &cursor, CursorType cursor_type);

  int DecrClientNum();
  int IncrClientNum();
  int IncrMonitorClientNum();
  int DecrMonitorClientNum();
  int IncrBlockedClientNum();
  int DecrBlockedClientNum();
  std::string GetClientsStr();
  uint64_t GetClientID();
  void KillClient(int64_t *killed, const std::string &addr, uint64_t id, uint64_t type, bool skipme,
                  redis::Connection *conn);

  Status ScriptExists(const std::string &sha) const;
  Status ScriptGet(const std::string &sha, std::string *body) const;
  Status ScriptSet(const std::string &sha, const std::string &body) const;
  void ScriptReset();
  Status ScriptFlush();

  Status FunctionGetCode(const std::string &lib, std::string *code) const;
  Status FunctionGetLib(const std::string &func, std::string *lib) const;
  Status FunctionSetCode(const std::string &lib, const std::string &code) const;
  Status FunctionSetLib(const std::string &func, const std::string &lib) const;

  Status Propagate(const std::string &channel, const std::vector<std::string> &tokens) const;
  Status ExecPropagatedCommand(const std::vector<std::string> &tokens);
  Status ExecPropagateScriptCommand(const std::vector<std::string> &tokens);

  LogCollector<PerfEntry> *GetPerfLog() { return &perf_log_; }
  LogCollector<SlowEntry> *GetSlowLog() { return &slow_log_; }
  void SlowlogPushEntryIfNeeded(const std::vector<std::string> *args, uint64_t duration, const redis::Connection *conn);

  std::shared_lock<std::shared_mutex> WorkConcurrencyGuard();
  std::unique_lock<std::shared_mutex> WorkExclusivityGuard();

  Stats stats;
  engine::Storage *storage;
  MemoryProfiler memory_profiler;
  std::unique_ptr<Cluster> cluster;
  static inline std::atomic<int64_t> unix_time_secs = 0;
  std::unique_ptr<SlotMigrator> slot_migrator;
  std::unique_ptr<SlotImport> slot_import;

  void UpdateWatchedKeysFromArgs(const std::vector<std::string> &args, const redis::CommandAttributes &attr);
  void UpdateWatchedKeysManually(const std::vector<std::string> &keys);
  void WatchKey(redis::Connection *conn, const std::vector<std::string> &keys);
  static bool IsWatchedKeysModified(redis::Connection *conn);
  void ResetWatchedKeys(redis::Connection *conn);
  std::list<std::pair<std::string, uint32_t>> GetSlaveHostAndPort();
  Namespace *GetNamespace() { return &namespace_; }

  AuthResult AuthenticateUser(const std::string &user_password, std::string *ns);

#ifdef ENABLE_OPENSSL
  UniqueSSLContext ssl_ctx;
#endif

  // search
  redis::GlobalIndexer indexer;
  redis::IndexManager index_mgr;

 private:
  void cron();
  void recordInstantaneousMetrics();
  static void updateCachedTime();
  Status autoResizeBlockAndSST();
  void updateWatchedKeysFromRange(const std::vector<std::string> &args, const redis::CommandKeyRange &range);
  void updateAllWatchedKeys();
  void increaseWorkerThreads(size_t delta);
  void decreaseWorkerThreads(size_t delta);
  void cleanupExitedWorkerThreads(bool force);

  std::atomic<bool> stop_ = false;
  std::atomic<bool> is_loading_ = false;
  int64_t start_time_secs_;
  std::mutex slaveof_mu_;
  std::string master_host_;
  uint32_t master_port_ = 0;
  Config *config_ = nullptr;
  std::string last_random_key_cursor_;
  std::mutex last_random_key_cursor_mu_;

  // client counters
  std::atomic<uint64_t> client_id_{1};
  std::atomic<int> connected_clients_{0};
  std::atomic<int> monitor_clients_{0};
  std::atomic<uint64_t> total_clients_{0};

  // slave
  std::mutex slave_threads_mu_;
  std::list<std::unique_ptr<FeedSlaveThread>> slave_threads_;
  std::atomic<int> fetch_file_threads_num_ = 0;

  // namespace
  Namespace namespace_;

  // Some jobs to operate DB should be unique
  std::mutex db_job_mu_;
  bool db_compacting_ = false;
  bool is_bgsave_in_progress_ = false;
  int64_t last_bgsave_timestamp_secs_ = -1;
  std::string last_bgsave_status_ = "ok";
  int64_t last_bgsave_duration_secs_ = -1;

  std::map<std::string, DBScanInfo> db_scan_infos_;

  LogCollector<SlowEntry> slow_log_;
  LogCollector<PerfEntry> perf_log_;

  std::map<std::string, std::list<ConnContext>> pubsub_channels_;
  std::map<std::string, std::list<ConnContext>> pubsub_patterns_;
  std::mutex pubsub_channels_mu_;
  std::vector<std::map<std::string, std::list<ConnContext>>> pubsub_shard_channels_;
  std::mutex pubsub_shard_channels_mu_;
  std::map<std::string, std::list<ConnContext>> blocking_keys_;
  std::mutex blocking_keys_mu_;

  std::atomic<int> blocked_clients_{0};

  std::mutex blocked_stream_consumers_mu_;
  std::map<std::string, std::set<std::shared_ptr<StreamConsumer>>> blocked_stream_consumers_;

  // threads
  std::shared_mutex works_concurrency_rw_lock_;
  std::thread cron_thread_;
  std::thread compaction_checker_thread_;
  TaskRunner task_runner_;
  std::vector<std::unique_ptr<WorkerThread>> worker_threads_;
  std::unique_ptr<ReplicationThread> replication_thread_;
  tbb::concurrent_queue<std::unique_ptr<WorkerThread>> recycle_worker_threads_;

  // memory
  std::atomic<int64_t> memory_startup_use_ = 0;

  // transaction
  std::atomic<size_t> watched_key_size_ = 0;
  std::map<std::string, std::set<redis::Connection *>> watched_key_map_;
  std::shared_mutex watched_key_mutex_;

  // SCAN ring buffer
  std::atomic<uint16_t> cursor_counter_ = {0};
  using CursorDictType = std::array<CursorDictElement, CURSOR_DICT_SIZE>;
  std::unique_ptr<CursorDictType> cursor_dict_;
};