src/kudu/tools/tool_action_common.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 <cstdint>
#include <memory>
#include <ostream>
#include <string>
#include <vector>

#include "kudu/client/shared_ptr.h"
#include "kudu/gutil/macros.h"
#include "kudu/gutil/port.h"
#include "kudu/gutil/ref_counted.h"
#include "kudu/util/status.h"

namespace boost {
template <typename Signature>
class function;
} // namespace boost

namespace kudu {

class MonoDelta;
class faststring;

namespace client {
class KuduClient;
} // namespace client

namespace master {
class MasterServiceProxy;
} // namespace master

namespace rpc {
class RpcController;
} // namespace rpc

namespace log {
class ReadableLogSegment;
} // namespace log

namespace server {
class GetFlagsResponsePB_Flag;
class ServerStatusPB;
} // namespace server

namespace tools {

struct RunnerContext;

// Constants for parameters and descriptions.
extern const char* const kMasterAddressesArg;
extern const char* const kMasterAddressesArgDesc;
extern const char* const kTabletIdArg;
extern const char* const kTabletIdArgDesc;

// Utility methods used by multiple actions across different modes.

// Builds a proxy to a Kudu server running at 'address', returning it in
// 'proxy'.
//
// If 'address' does not contain a port, 'default_port' is used instead.
template<class ProxyClass>
Status BuildProxy(const std::string& address,
                  uint16_t default_port,
                  std::unique_ptr<ProxyClass>* proxy);

// Get the current status of the Kudu server running at 'address', storing it
// in 'status'.
//
// If 'address' does not contain a port, 'default_port' is used instead.
Status GetServerStatus(const std::string& address, uint16_t default_port,
                       server::ServerStatusPB* status);

// Prints the contents of a WAL segment to stdout.
//
// The following gflags affect the output:
// - print_entries: in what style entries should be printed.
// - print_meta: whether or not headers/footers are printed.
// - truncate_data: how many bytes to print for each data field.
Status PrintSegment(const scoped_refptr<log::ReadableLogSegment>& segment);

// Print the current status of the Kudu server running at 'address'.
//
// If 'address' does not contain a port, 'default_port' is used instead.
Status PrintServerStatus(const std::string& address, uint16_t default_port);

// Print the current timestamp of the Kudu server running at 'address'.
//
// If 'address' does not contain a port, 'default_port' is used instead.
Status PrintServerTimestamp(const std::string& address, uint16_t default_port);

// Retrieve flags from a remote server.
//
// If 'address' does not contain a port, 'default_port' is used instead.
//
// 'all_flags' controls whether all flags are returned, or only flags which are
// explicitly set.
//
// 'flag_tags' is a comma-separated list of tags used to restrict which flags
// are returned. An empty value matches all tags.
Status GetServerFlags(const std::string& address,
                      uint16_t default_port,
                      bool all_flags,
                      const std::string& flag_tags,
                      std::vector<server::GetFlagsResponsePB_Flag>* flags) WARN_UNUSED_RESULT;

// Prints the values of the gflags set for the Kudu server running at 'address'.
//
// If 'address' does not contain a port, 'default_port' is used instead.
Status PrintServerFlags(const std::string& address, uint16_t default_port);

// Changes the value of the gflag given by 'flag' to the value in 'value' on
// the Kudu server running at 'address'.
//
// If 'address' does not contain a port, 'default_port' is used instead.
Status SetServerFlag(const std::string& address, uint16_t default_port,
                     const std::string& flag, const std::string& value);

// Get the configured master addresses on the most recently connected to leader master.
std::string GetMasterAddresses(const client::KuduClient& client);

// Return true if 'str' matches any of the patterns in 'patterns', or if
// 'patterns' is empty.
bool MatchesAnyPattern(const std::vector<std::string>& patterns, const std::string& str);

// A table of data to present to the user.
//
// Supports formatting based on the --format flag.
// All data is buffered in memory before being output.
//
// Example usage:
//    DataTable table({"person", "favorite color"});
//    vector<string> cols(2);
//    AddTableRow({"joe", "red"}, &cols);
//    AddTableRow({"bob", "green"}, &cols);
//    AddTableRow({"alice", "yellow"}, &cols);
//    PrintTable(headers, cols, cout);
class DataTable {
 public:
  // Construct a table with the given column names.
  explicit DataTable(std::vector<std::string> col_names);

  // Add a row of data to the table.
  //
  // REQUIRES: 'row.size()' matches the number of column names specified
  // in the constructor.
  void AddRow(std::vector<std::string> row);

  // Add a column of data to the right side of the table.
  //
  // REQUIRES: if any rows have been added already, the length of this column
  // must match the length of all existing columns.
  void AddColumn(std::string name, std::vector<std::string> column);

  // Print the table to 'out'.
  Status PrintTo(std::ostream& out) const WARN_UNUSED_RESULT;
 private:
  std::vector<std::string> column_names_;
  std::vector<std::vector<std::string>> columns_;
};

// Wrapper around a Kudu client which allows calling proxy methods on the leader
// master.
class LeaderMasterProxy {
 public:
  LeaderMasterProxy() = default;
  explicit LeaderMasterProxy(client::sp::shared_ptr<client::KuduClient> client);

  // Initializes the leader master proxy with the given master addresses and timeout.
  Status Init(const std::vector<std::string>& master_addrs, const MonoDelta& timeout);

  // Initialize the leader master proxy given the provided tool context.
  //
  // Uses the required 'master_addresses' option for the master addresses, and
  // the optional 'timeout_ms' flag to control admin and operation timeouts.
  Status Init(const RunnerContext& context);

  // Calls a master RPC service method on the current leader master.
  template<typename Req, typename Resp>
  Status SyncRpc(const Req& req,
                 Resp* resp,
                 const char* func_name,
                 const boost::function<Status(master::MasterServiceProxy*,
                                              const Req&, Resp*,
                                              rpc::RpcController*)>& func);

 private:
  client::sp::shared_ptr<client::KuduClient> client_;
};

// Facilitates sending and receiving messages with the tool control shell.
//
// May be used by a subprocess communicating with the shell via pipe, or by the
// shell itself to read/write messages via stdin/stdout respectively.
class ControlShellProtocol {
 public:
  enum class SerializationMode {
    // Each message is serialized as a four byte big-endian size followed by
    // the protobuf-encoded message itself.
    PB,

    // Each message is serialized into a protobuf-like JSON representation
    // terminated with a newline character.
    JSON,
  };

  // Whether the provided fds are closed at class destruction time.
  enum class CloseMode {
    CLOSE_ON_DESTROY,
    NO_CLOSE_ON_DESTROY,
  };

  // Constructs a new protocol instance.
  //
  // If 'close_mode' is CLOSE_ON_DESTROY, the instance has effectively taken
  // control of 'read_fd' and 'write_fd' and the caller shouldn't use them.
  ControlShellProtocol(SerializationMode serialization_mode,
                       CloseMode close_mode,
                       int read_fd,
                       int write_fd);

  ~ControlShellProtocol();

  // Receives a protobuf message, blocking if the pipe is empty.
  //
  // Returns EndOfFile if the writer on the other end of the pipe was closed.
  //
  // Returns an error if serialization_mode_ is PB and the received message
  // sizes exceeds kMaxMessageBytes.
  template <class M>
  Status ReceiveMessage(M* message);

  // Sends a protobuf message, blocking if the pipe is full.
  //
  // Returns EndOfFile if the reader on the other end of the pipe was closed.
  template <class M>
  Status SendMessage(const M& message);

 private:
  // Private helpers to drive actual pipe reading and writing.
  Status DoRead(faststring* buf);
  Status DoWrite(const faststring& buf);

  static const int kMaxMessageBytes;

  const SerializationMode serialization_mode_;
  const CloseMode close_mode_;
  const int read_fd_;
  const int write_fd_;

  DISALLOW_COPY_AND_ASSIGN(ControlShellProtocol);
};

} // namespace tools
} // namespace kudu