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openvswitch/lib/vlog.h
Ben Pfaff e2eed6a758 vlog: Add a little more detail to ratelimit messages
When a message is suppressed by vlog ratelimiting, and then that message
occurs again much later, sometimes we get messages like this:

   Dropped 4 log messages in last 8695 seconds due to excessive rate

It seems pretty clear in this case that in fact we just didn't get that
kind of message for most of that 8695 seconds.  This commit improves the
message by adding a little more detail, e.g.:

   Dropped 4 log messages in last 8695 seconds (most recently, 6697 seconds
   ago) due to excessive rate.

Bug #2144.
2011-06-21 15:09:08 -07:00

278 lines
11 KiB
C

/*
* Copyright (c) 2008, 2009, 2010, 2011 Nicira Networks.
*
* Licensed 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.
*/
#ifndef VLOG_H
#define VLOG_H 1
#include <limits.h>
#include <stdarg.h>
#include <stdbool.h>
#include <time.h>
#include "compiler.h"
#include "util.h"
#ifdef __cplusplus
extern "C" {
#endif
/* Logging importance levels.
*
* The following log levels, in descending order of importance, are enabled by
* default:
*
* - EMER: Not currently used.
*
* - ERR: A high-level operation or a subsystem failed. Attention is
* warranted.
*
* - WARN: A low-level operation failed, but higher-level subsystems may be
* able to recover.
*
* - INFO: Information that may be useful in retrospect when investigating
* a problem.
*
* The lowest log level is not enabled by default:
*
* - DBG: Information useful only to someone with intricate knowledge of the
* system, or that would commonly cause too-voluminous log output.
*/
#define VLOG_LEVELS \
VLOG_LEVEL(EMER, LOG_ALERT) \
VLOG_LEVEL(ERR, LOG_ERR) \
VLOG_LEVEL(WARN, LOG_WARNING) \
VLOG_LEVEL(INFO, LOG_NOTICE) \
VLOG_LEVEL(DBG, LOG_DEBUG)
enum vlog_level {
#define VLOG_LEVEL(NAME, SYSLOG_LEVEL) VLL_##NAME,
VLOG_LEVELS
#undef VLOG_LEVEL
VLL_N_LEVELS
};
const char *vlog_get_level_name(enum vlog_level);
enum vlog_level vlog_get_level_val(const char *name);
/* Facilities that we can log to. */
#define VLOG_FACILITIES \
VLOG_FACILITY(SYSLOG, "%05N|%c|%p|%m") \
VLOG_FACILITY(CONSOLE, "%d{%b %d %H:%M:%S}|%05N|%c|%p|%m") \
VLOG_FACILITY(FILE, "%d{%b %d %H:%M:%S}|%05N|%c|%p|%m")
enum vlog_facility {
#define VLOG_FACILITY(NAME, PATTERN) VLF_##NAME,
VLOG_FACILITIES
#undef VLOG_FACILITY
VLF_N_FACILITIES,
VLF_ANY_FACILITY = -1
};
const char *vlog_get_facility_name(enum vlog_facility);
enum vlog_facility vlog_get_facility_val(const char *name);
/* A log module. */
struct vlog_module {
const char *name; /* User-visible name. */
int levels[VLF_N_FACILITIES]; /* Minimum log level for each facility. */
int min_level; /* Minimum log level for any facility. */
};
/* Creates and initializes a global instance of a module named MODULE. */
#if USE_LINKER_SECTIONS
#define VLOG_DEFINE_MODULE(MODULE) \
VLOG_DEFINE_MODULE__(MODULE) \
extern struct vlog_module *vlog_module_ptr_##MODULE; \
struct vlog_module *vlog_module_ptr_##MODULE \
__attribute__((section("vlog_modules"))) = &VLM_##MODULE
#else
#define VLOG_DEFINE_MODULE(MODULE) extern struct vlog_module VLM_##MODULE
#endif
const char *vlog_get_module_name(const struct vlog_module *);
struct vlog_module *vlog_module_from_name(const char *name);
/* Rate-limiter for log messages. */
struct vlog_rate_limit {
/* Configuration settings. */
unsigned int rate; /* Tokens per second. */
unsigned int burst; /* Max cumulative tokens credit. */
/* Current status. */
unsigned int tokens; /* Current number of tokens. */
time_t last_fill; /* Last time tokens added. */
time_t first_dropped; /* Time first message was dropped. */
time_t last_dropped; /* Time of most recent message drop. */
unsigned int n_dropped; /* Number of messages dropped. */
};
/* Number of tokens to emit a message. We add 'rate' tokens per second, which
* is 60 times the unit used for 'rate', thus 60 tokens are required to emit
* one message. */
#define VLOG_MSG_TOKENS 60
/* Initializer for a struct vlog_rate_limit, to set up a maximum rate of RATE
* messages per minute and a maximum burst size of BURST messages. */
#define VLOG_RATE_LIMIT_INIT(RATE, BURST) \
{ \
RATE, /* rate */ \
(MIN(BURST, UINT_MAX / VLOG_MSG_TOKENS) \
* VLOG_MSG_TOKENS), /* burst */ \
0, /* tokens */ \
0, /* last_fill */ \
0, /* first_dropped */ \
0, /* last_dropped */ \
0, /* n_dropped */ \
}
/* Configuring how each module logs messages. */
enum vlog_level vlog_get_level(const struct vlog_module *, enum vlog_facility);
void vlog_set_levels(struct vlog_module *,
enum vlog_facility, enum vlog_level);
char *vlog_set_levels_from_string(const char *);
char *vlog_get_levels(void);
bool vlog_is_enabled(const struct vlog_module *, enum vlog_level);
bool vlog_should_drop(const struct vlog_module *, enum vlog_level,
struct vlog_rate_limit *);
void vlog_set_verbosity(const char *arg);
/* Configuring log facilities. */
void vlog_set_pattern(enum vlog_facility, const char *pattern);
const char *vlog_get_log_file(void);
int vlog_set_log_file(const char *file_name);
int vlog_reopen_log_file(void);
/* Initialization. */
void vlog_init(void);
void vlog_exit(void);
/* Functions for actual logging. */
void vlog(const struct vlog_module *, enum vlog_level, const char *format, ...)
PRINTF_FORMAT (3, 4);
void vlog_valist(const struct vlog_module *, enum vlog_level,
const char *, va_list)
PRINTF_FORMAT (3, 0);
void vlog_fatal(const struct vlog_module *, enum vlog_level,
const char *format, ...)
PRINTF_FORMAT (3, 4) NO_RETURN;
void vlog_fatal_valist(const struct vlog_module *, enum vlog_level,
const char *, va_list)
PRINTF_FORMAT (3, 0) NO_RETURN;
void vlog_rate_limit(const struct vlog_module *, enum vlog_level,
struct vlog_rate_limit *, const char *, ...)
PRINTF_FORMAT (4, 5);
/* Creates and initializes a global instance of a module named MODULE, and
* defines a static variable named THIS_MODULE that points to it, for use with
* the convenience macros below. */
#define VLOG_DEFINE_THIS_MODULE(MODULE) \
VLOG_DEFINE_MODULE(MODULE); \
static struct vlog_module *const THIS_MODULE = &VLM_##MODULE
/* Convenience macros. These assume that THIS_MODULE points to a "struct
* vlog_module" for the current module, as set up by e.g. the
* VLOG_DEFINE_MODULE macro above.
*
* Guaranteed to preserve errno.
*/
#define VLOG_FATAL(...) vlog_fatal(THIS_MODULE, VLL_ERR, __VA_ARGS__)
#define VLOG_EMER(...) VLOG(VLL_EMER, __VA_ARGS__)
#define VLOG_ERR(...) VLOG(VLL_ERR, __VA_ARGS__)
#define VLOG_WARN(...) VLOG(VLL_WARN, __VA_ARGS__)
#define VLOG_INFO(...) VLOG(VLL_INFO, __VA_ARGS__)
#define VLOG_DBG(...) VLOG(VLL_DBG, __VA_ARGS__)
/* More convenience macros, for testing whether a given level is enabled in
* THIS_MODULE. When constructing a log message is expensive, this enables it
* to be skipped. */
#define VLOG_IS_EMER_ENABLED() true
#define VLOG_IS_ERR_ENABLED() vlog_is_enabled(THIS_MODULE, VLL_EMER)
#define VLOG_IS_WARN_ENABLED() vlog_is_enabled(THIS_MODULE, VLL_WARN)
#define VLOG_IS_INFO_ENABLED() vlog_is_enabled(THIS_MODULE, VLL_INFO)
#define VLOG_IS_DBG_ENABLED() vlog_is_enabled(THIS_MODULE, VLL_DBG)
/* Convenience macros for rate-limiting.
* Guaranteed to preserve errno.
*/
#define VLOG_ERR_RL(RL, ...) VLOG_RL(RL, VLL_ERR, __VA_ARGS__)
#define VLOG_WARN_RL(RL, ...) VLOG_RL(RL, VLL_WARN, __VA_ARGS__)
#define VLOG_INFO_RL(RL, ...) VLOG_RL(RL, VLL_INFO, __VA_ARGS__)
#define VLOG_DBG_RL(RL, ...) VLOG_RL(RL, VLL_DBG, __VA_ARGS__)
#define VLOG_DROP_ERR(RL) vlog_should_drop(THIS_MODULE, VLL_ERR, RL)
#define VLOG_DROP_WARN(RL) vlog_should_drop(THIS_MODULE, VLL_WARN, RL)
#define VLOG_DROP_INFO(RL) vlog_should_drop(THIS_MODULE, VLL_INFO, RL)
#define VLOG_DROP_DBG(RL) vlog_should_drop(THIS_MODULE, VLL_DBG, RL)
/* Macros for logging at most once per execution. */
#define VLOG_ERR_ONCE(...) VLOG_ONCE(VLL_ERR, __VA_ARGS__)
#define VLOG_WARN_ONCE(...) VLOG_ONCE(VLL_WARN, __VA_ARGS__)
#define VLOG_INFO_ONCE(...) VLOG_ONCE(VLL_INFO, __VA_ARGS__)
#define VLOG_DBG_ONCE(...) VLOG_ONCE(VLL_DBG, __VA_ARGS__)
/* Command line processing. */
#define VLOG_OPTION_ENUMS OPT_LOG_FILE
#define VLOG_LONG_OPTIONS \
{"verbose", optional_argument, NULL, 'v'}, \
{"log-file", optional_argument, NULL, OPT_LOG_FILE}
#define VLOG_OPTION_HANDLERS \
case 'v': \
vlog_set_verbosity(optarg); \
break; \
case OPT_LOG_FILE: \
vlog_set_log_file(optarg); \
break;
void vlog_usage(void);
/* Implementation details. */
#define VLOG(LEVEL, ...) \
do { \
enum vlog_level level__ = LEVEL; \
if (THIS_MODULE->min_level >= level__) { \
vlog(THIS_MODULE, level__, __VA_ARGS__); \
} \
} while (0)
#define VLOG_RL(RL, LEVEL, ...) \
do { \
enum vlog_level level__ = LEVEL; \
if (THIS_MODULE->min_level >= level__) { \
vlog_rate_limit(THIS_MODULE, level__, RL, __VA_ARGS__); \
} \
} while (0)
#define VLOG_ONCE(LEVEL, ...) \
do { \
static bool already_logged; \
if (!already_logged) { \
already_logged = true; \
vlog(THIS_MODULE, LEVEL, __VA_ARGS__); \
} \
} while (0)
#define VLOG_DEFINE_MODULE__(MODULE) \
extern struct vlog_module VLM_##MODULE; \
struct vlog_module VLM_##MODULE = \
{ \
#MODULE, /* name */ \
{ [ 0 ... VLF_N_FACILITIES - 1] = VLL_INFO }, /* levels */ \
VLL_INFO, /* min_level */ \
};
#ifdef __cplusplus
}
#endif
#endif /* vlog.h */