pdns/dolog.hh

   1 /*
   2  * This file is part of PowerDNS or dnsdist.
   3  * Copyright -- PowerDNS.COM B.V. and its contributors
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of version 2 of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * In addition, for the avoidance of any doubt, permission is granted to
  10  * link this program with OpenSSL and to (re)distribute the binaries
  11  * produced as the result of such linking.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21  */
  22 #pragma once
  23 #include <fstream>
  24 #include <iostream>
  25 #include <optional>
  26 #include <sstream>
  27 #include "config.h"
  28 #if !defined(RECURSOR)
  29 #include <syslog.h>
  30 #else
  31 #include "logger.hh"
  32 #endif // RECURSOR
  33
  34
  35 /* This file is intended not to be metronome specific, and is simple example of C++2011
  36    variadic templates in action.
  37
  38    The goal is rapid easy to use logging to console & syslog.
  39
  40    Usage:
  41           string address="localhost";
  42           vinfolog("Got TCP connection from %s", remote);
  43           infolog("Bound to %s port %d", address, port);
  44           warnlog("Query took %d milliseconds", 1232.4); // yes, %d
  45           errlog("Unable to bind to %s: %s", ca.toStringWithPort(), strerr(errno));
  46
  47    Will log to stdout. Will syslog in any case with LOG_INFO,
  48    LOG_WARNING, LOG_ERR respectively. If g_verbose=false, vinfolog is a noop.
  49    More generically, dolog(someiostream, "Hello %s", stream) will log to someiostream
  50
  51    This will happily print a string to %d! Doesn't do further format processing.
  52 */
  53
  54 #if !defined(RECURSOR)
  55 inline void dolog(std::ostream& os, const char*s)
  56 {
  57   os<<s;
  58 }
  59
  60 template<typename T, typename... Args>
  61 void dolog(std::ostream& os, const char* s, T value, Args... args)
  62 {
  63   while (*s) {
  64     if (*s == '%') {
  65       if (*(s + 1) == '%') {
  66         ++s;
  67       }
  68       else {
  69         os << value;
  70         s += 2;
  71         dolog(os, s, args...);
  72         return;
  73       }
  74     }
  75     os << *s++;
  76   }
  77 }
  78
  79 extern bool g_verbose;
  80 extern bool g_syslog;
  81 #ifdef DNSDIST
  82 extern bool g_logtimestamps;
  83 extern std::optional<std::ofstream> g_verboseStream;
  84 #endif
  85
  86 inline void setSyslogFacility(int facility)
  87 {
  88   /* we always call openlog() right away at startup */
  89   closelog();
  90   openlog("dnsdist", LOG_PID|LOG_NDELAY, facility);
  91 }
  92
  93 template<typename... Args>
  94 void genlog(std::ostream& stream, int level, bool doSyslog, const char* s, Args... args)
  95 {
  96   std::ostringstream str;
  97   dolog(str, s, args...);
  98
  99   auto output = str.str();
 100
 101   if (doSyslog) {
 102     syslog(level, "%s", output.c_str());
 103   }
 104
 105 #ifdef DNSDIST
 106   if (g_logtimestamps) {
 107     char buffer[50] = "";
 108     struct tm tm;
 109     time_t t;
 110     time(&t);
 111     localtime_r(&t, &tm);
 112     if (strftime(buffer, sizeof(buffer), "%b %d %H:%M:%S ", &tm) == 0) {
 113       buffer[0] = '\0';
 114     }
 115     stream<<buffer;
 116   }
 117 #endif
 118
 119   stream<<output<<std::endl;
 120 }
 121
 122 template<typename... Args>
 123 void verboselog(const char* s, Args... args)
 124 {
 125 #ifdef DNSDIST
 126   if (g_verboseStream) {
 127     genlog(*g_verboseStream, LOG_DEBUG, false, s, args...);
 128   }
 129   else {
 130 #endif /* DNSDIST */
 131     genlog(std::cout, LOG_DEBUG, g_syslog, s, args...);
 132 #ifdef DNSDIST
 133   }
 134 #endif /* DNSDIST */
 135 }
 136
 137 #define vinfolog if (g_verbose) verboselog
 138
 139 template<typename... Args>
 140 void infolog(const char* s, Args... args)
 141 {
 142   genlog(std::cout, LOG_INFO, g_syslog, s, args...);
 143 }
 144
 145 template<typename... Args>
 146 void warnlog(const char* s, Args... args)
 147 {
 148   genlog(std::cout, LOG_WARNING, g_syslog, s, args...);
 149 }
 150
 151 template<typename... Args>
 152 void errlog(const char* s, Args... args)
 153 {
 154   genlog(std::cout, LOG_ERR, g_syslog, s, args...);
 155 }
 156
 157 #else // RECURSOR
 158
 159 #define g_verbose 0
 160
 161 inline void dolog(Logger::Urgency u, const char* s)
 162 {
 163   g_log << u << s << std::endl;
 164 }
 165
 166 inline void dolog(const char* s)
 167 {
 168   g_log << s << std::endl;
 169 }
 170
 171 template<typename T, typename... Args>
 172 void dolog(Logger::Urgency u, const char* s, T value, Args... args)
 173 {
 174   g_log << u;
 175   while (*s) {
 176     if (*s == '%') {
 177       if (*(s + 1) == '%') {
 178         ++s;
 179       }
 180       else {
 181         g_log << value;
 182         s += 2;
 183         dolog(s, args...);
 184         return;
 185       }
 186     }
 187     g_log << *s++;
 188   }
 189 }
 190
 191 #define vinfolog if(g_verbose)infolog
 192
 193 template<typename... Args>
 194 void infolog(const char* s, Args... args)
 195 {
 196   dolog(Logger::Info, s, args...);
 197 }
 198
 199 template<typename... Args>
 200 void warnlog(const char* s, Args... args)
 201 {
 202   dolog(Logger::Warning, s, args...);
 203 }
 204
 205 template<typename... Args>
 206 void errlog(const char* s, Args... args)
 207 {
 208   dolog(Logger::Error, s, args...);
 209 }
 210
 211 #endif
 212