lib/vlog.h

   1 /*
   2  * Copyright (c) 2008, 2009, 2010 Nicira Networks.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #ifndef VLOG_H
  18 #define VLOG_H 1
  19
  20 #include <limits.h>
  21 #include <stdarg.h>
  22 #include <stdbool.h>
  23 #include <time.h>
  24 #include "util.h"
  25
  26 #ifdef  __cplusplus
  27 extern "C" {
  28 #endif
  29
  30 /* Logging importance levels. */
  31 #define VLOG_LEVELS                             \
  32     VLOG_LEVEL(EMER, LOG_ALERT)                 \
  33     VLOG_LEVEL(ERR, LOG_ERR)                    \
  34     VLOG_LEVEL(WARN, LOG_WARNING)               \
  35     VLOG_LEVEL(INFO, LOG_NOTICE)                \
  36     VLOG_LEVEL(DBG, LOG_DEBUG)
  37 enum vlog_level {
  38 #define VLOG_LEVEL(NAME, SYSLOG_LEVEL) VLL_##NAME,
  39     VLOG_LEVELS
  40 #undef VLOG_LEVEL
  41     VLL_N_LEVELS
  42 };
  43
  44 const char *vlog_get_level_name(enum vlog_level);
  45 enum vlog_level vlog_get_level_val(const char *name);
  46
  47 /* Facilities that we can log to. */
  48 #define VLOG_FACILITIES                                         \
  49     VLOG_FACILITY(SYSLOG, "%05N|%c|%p|%m")                      \
  50     VLOG_FACILITY(CONSOLE, "%d{%b %d %H:%M:%S}|%05N|%c|%p|%m")  \
  51     VLOG_FACILITY(FILE, "%d{%b %d %H:%M:%S}|%05N|%c|%p|%m")
  52 enum vlog_facility {
  53 #define VLOG_FACILITY(NAME, PATTERN) VLF_##NAME,
  54     VLOG_FACILITIES
  55 #undef VLOG_FACILITY
  56     VLF_N_FACILITIES,
  57     VLF_ANY_FACILITY = -1
  58 };
  59
  60 const char *vlog_get_facility_name(enum vlog_facility);
  61 enum vlog_facility vlog_get_facility_val(const char *name);
  62
  63 /* VLM_ constant for each vlog module. */
  64 enum vlog_module {
  65 #define VLOG_MODULE(NAME) VLM_##NAME,
  66 #include "vlog-modules.def"
  67     VLM_N_MODULES,
  68     VLM_ANY_MODULE = -1
  69 };
  70
  71 const char *vlog_get_module_name(enum vlog_module);
  72 enum vlog_module vlog_get_module_val(const char *name);
  73
  74 /* Rate-limiter for log messages. */
  75 struct vlog_rate_limit {
  76     /* Configuration settings. */
  77     unsigned int rate;          /* Tokens per second. */
  78     unsigned int burst;         /* Max cumulative tokens credit. */
  79
  80     /* Current status. */
  81     unsigned int tokens;        /* Current number of tokens. */
  82     time_t last_fill;           /* Last time tokens added. */
  83     time_t first_dropped;       /* Time first message was dropped. */
  84     unsigned int n_dropped;     /* Number of messages dropped. */
  85 };
  86
  87 /* Number of tokens to emit a message.  We add 'rate' tokens per second, which
  88  * is 60 times the unit used for 'rate', thus 60 tokens are required to emit
  89  * one message. */
  90 #define VLOG_MSG_TOKENS 60
  91
  92 /* Initializer for a struct vlog_rate_limit, to set up a maximum rate of RATE
  93  * messages per minute and a maximum burst size of BURST messages. */
  94 #define VLOG_RATE_LIMIT_INIT(RATE, BURST)                   \
  95         {                                                   \
  96             RATE,                           /* rate */      \
  97             (MIN(BURST, UINT_MAX / VLOG_MSG_TOKENS)         \
  98              * VLOG_MSG_TOKENS),            /* burst */     \
  99             0,                              /* tokens */    \
 100             0,                              /* last_fill */ \
 101             0,                              /* first_dropped */ \
 102             0,                              /* n_dropped */ \
 103         }
 104
 105 /* Configuring how each module logs messages. */
 106 enum vlog_level vlog_get_level(enum vlog_module, enum vlog_facility);
 107 void vlog_set_levels(enum vlog_module, enum vlog_facility, enum vlog_level);
 108 char *vlog_set_levels_from_string(const char *);
 109 char *vlog_get_levels(void);
 110 bool vlog_is_enabled(enum vlog_module, enum vlog_level);
 111 bool vlog_should_drop(enum vlog_module, enum vlog_level,
 112                       struct vlog_rate_limit *);
 113 void vlog_set_verbosity(const char *arg);
 114
 115 /* Configuring log facilities. */
 116 void vlog_set_pattern(enum vlog_facility, const char *pattern);
 117 const char *vlog_get_log_file(void);
 118 int vlog_set_log_file(const char *file_name);
 119 int vlog_reopen_log_file(void);
 120
 121 /* Function for actual logging. */
 122 void vlog_init(void);
 123 void vlog_exit(void);
 124 void vlog(enum vlog_module, enum vlog_level, const char *format, ...)
 125     __attribute__((format(printf, 3, 4)));
 126 void vlog_valist(enum vlog_module, enum vlog_level, const char *, va_list)
 127     __attribute__((format(printf, 3, 0)));
 128 void vlog_rate_limit(enum vlog_module, enum vlog_level,
 129                      struct vlog_rate_limit *, const char *, ...)
 130     __attribute__((format(printf, 4, 5)));
 131
 132 /* Defines THIS_MODULE as MODULE, for use with the convenience macros below. */
 133 #define VLOG_DEFINE_THIS_MODULE(MODULE) enum { THIS_MODULE = VLM_##MODULE };
 134
 135 /* Convenience macros.  These assume that THIS_MODULE is defined as the current
 136  * module, as set up by e.g. the VLOG_DEFINE_MODULE macro above.
 137  *
 138  * Guaranteed to preserve errno.
 139  */
 140 #define VLOG_EMER(...) VLOG(VLL_EMER, __VA_ARGS__)
 141 #define VLOG_ERR(...) VLOG(VLL_ERR, __VA_ARGS__)
 142 #define VLOG_WARN(...) VLOG(VLL_WARN, __VA_ARGS__)
 143 #define VLOG_INFO(...) VLOG(VLL_INFO, __VA_ARGS__)
 144 #define VLOG_DBG(...) VLOG(VLL_DBG, __VA_ARGS__)
 145
 146 /* More convenience macros, for testing whether a given level is enabled in
 147  * THIS_MODULE.  When constructing a log message is expensive, this enables it
 148  * to be skipped. */
 149 #define VLOG_IS_EMER_ENABLED() true
 150 #define VLOG_IS_ERR_ENABLED() vlog_is_enabled(THIS_MODULE, VLL_EMER)
 151 #define VLOG_IS_WARN_ENABLED() vlog_is_enabled(THIS_MODULE, VLL_WARN)
 152 #define VLOG_IS_INFO_ENABLED() vlog_is_enabled(THIS_MODULE, VLL_INFO)
 153 #define VLOG_IS_DBG_ENABLED() vlog_is_enabled(THIS_MODULE, VLL_DBG)
 154
 155 /* Convenience macros for rate-limiting.
 156  * Guaranteed to preserve errno.
 157  */
 158 #define VLOG_ERR_RL(RL, ...) VLOG_RL(RL, VLL_ERR, __VA_ARGS__)
 159 #define VLOG_WARN_RL(RL, ...) VLOG_RL(RL, VLL_WARN, __VA_ARGS__)
 160 #define VLOG_INFO_RL(RL, ...) VLOG_RL(RL, VLL_INFO, __VA_ARGS__)
 161 #define VLOG_DBG_RL(RL, ...) VLOG_RL(RL, VLL_DBG, __VA_ARGS__)
 162
 163 #define VLOG_DROP_ERR(RL) vlog_should_drop(THIS_MODULE, VLL_ERR, RL)
 164 #define VLOG_DROP_WARN(RL) vlog_should_drop(THIS_MODULE, VLL_WARN, RL)
 165 #define VLOG_DROP_INFO(RL) vlog_should_drop(THIS_MODULE, VLL_INFO, RL)
 166 #define VLOG_DROP_DBG(RL) vlog_should_drop(THIS_MODULE, VLL_DBG, RL)
 167
 168 /* Command line processing. */
 169 #define VLOG_OPTION_ENUMS OPT_LOG_FILE
 170 #define VLOG_LONG_OPTIONS                                   \
 171         {"verbose",     optional_argument, 0, 'v'},         \
 172         {"log-file",    optional_argument, 0, OPT_LOG_FILE}
 173 #define VLOG_OPTION_HANDLERS                    \
 174         case 'v':                               \
 175             vlog_set_verbosity(optarg);         \
 176             break;                              \
 177         case OPT_LOG_FILE:                      \
 178             vlog_set_log_file(optarg);          \
 179             break;
 180 void vlog_usage(void);
 181
 182 /* Implementation details. */
 183 #define VLOG(LEVEL, ...)                                \
 184     do {                                                \
 185         if (min_vlog_levels[THIS_MODULE] >= LEVEL) {    \
 186             vlog(THIS_MODULE, LEVEL, __VA_ARGS__);      \
 187         }                                               \
 188     } while (0)
 189 #define VLOG_RL(RL, LEVEL, ...)                                     \
 190     do {                                                            \
 191         if (min_vlog_levels[THIS_MODULE] >= LEVEL) {                \
 192             vlog_rate_limit(THIS_MODULE, LEVEL, RL, __VA_ARGS__);   \
 193         }                                                           \
 194     } while (0)
 195 extern enum vlog_level min_vlog_levels[VLM_N_MODULES];
 196
 197 #ifdef  __cplusplus
 198 }
 199 #endif
 200
 201
 202 #endif /* vlog.h */