seastar::logger Class Reference

Detailed Description

Logger class for ostream or syslog.

Java style api for logging.

static seastar::logger logger("lsa-api");
logger.info("Triggering compaction");

The output format is: (depending on level) DEBUG Y-m-d T,%03d [shard 0] - "your msg"
It is possible to rate-limit log messages, see logger::rate_limit.

#include <seastar/util/log.hh>

Classes
class	lambda_log_writer
class	log_writer

Public Member Functions
template<typename... Args>
void	error (format_info fmt, Args &&... args) noexcept
template<typename... Args>
void	warn (format_info fmt, Args &&... args) noexcept
template<typename... Args>
void	info (format_info fmt, Args &&... args) noexcept
template<typename... Args>
void	info0 (format_info fmt, Args &&... args) noexcept
template<typename... Args>
void	debug (format_info fmt, Args &&... args) noexcept
template<typename... Args>
void	trace (format_info fmt, Args &&... args) noexcept
const sstring &	name () const noexcept
log_level	level () const noexcept
void	set_level (log_level level) noexcept

Static Public Member Functions
static void	set_ostream (std::ostream &out) noexcept
	Set output stream, default is std::cerr.
static void	set_ostream_enabled (bool enabled) noexcept
	Also output to ostream. default is true.
static void	set_stdout_enabled (bool enabled) noexcept
	Also output to stdout. default is true.
static void	set_syslog_enabled (bool enabled) noexcept
static void	set_shard_field_width (unsigned width) noexcept
static void	set_with_color (bool enabled) noexcept

Member Function Documentation

debug()

template<typename... Args>

void seastar::logger::debug ( format_info  fmt, Args &&...  args  )

inlinenoexcept

Log with debug tag: DEBUG Y-m-d T,%03d [shard 0] - "your msg"

Parameters

fmt	- {fmt} style format string (implictly converted to struct logger::format_info) or a logger::format_info passed down the call chain.
args	- args to print string

error()

template<typename... Args>

void seastar::logger::error ( format_info  fmt, Args &&...  args  )

inlinenoexcept

Log with error tag: ERROR Y-m-d T,%03d [shard 0] - "your msg"

Parameters

fmt	- {fmt} style format string (implictly converted to struct logger::format_info) or a logger::format_info passed down the call chain.
args	- args to print string

info()

template<typename... Args>

void seastar::logger::info ( format_info  fmt, Args &&...  args  )

inlinenoexcept

Log with info tag: INFO Y-m-d T,%03d [shard 0] - "your msg"

Parameters

fmt	- {fmt} style format string (implictly converted to struct logger::format_info) or a logger::format_info passed down the call chain.
args	- args to print string

info0()

template<typename... Args>

void seastar::logger::info0 ( format_info  fmt, Args &&...  args  )

inlinenoexcept

Log with info tag on shard zero only: INFO Y-m-d T,%03d [shard 0] - "your msg"

Parameters

fmt	- {fmt} style format string (implictly converted to struct logger::format_info) or a logger::format_info passed down the call chain.
args	- args to print string

level()

log_level seastar::logger::level ( ) const

inlinenoexcept

Returns

current log level for this logger

name()

const sstring& seastar::logger::name ( ) const

inlinenoexcept

Returns

name of the logger. Usually one logger per module

set_level()

void seastar::logger::set_level ( log_level  level )

inlinenoexcept

Parameters

level

- set the log level

set_shard_field_width()

static void seastar::logger::set_shard_field_width ( unsigned  width )

staticnoexcept

Set the width of shard id field in log messages

this_shard_id() is printed as a part of the prefix in logging messages, like "[shard 42]", where 42 is the decimal number of the current shard id printed with a minimal width.

Parameters

width

the minimal width of the shard id field

set_syslog_enabled()

static void seastar::logger::set_syslog_enabled ( bool  enabled )

staticnoexcept

Also output to syslog. default is false

NOTE: syslog() can block, which will stall the reactor thread. this should be rare (will have to fill the pipe buffer before syslogd can clear it) but can happen.

set_with_color()

static void seastar::logger::set_with_color ( bool  enabled )

staticnoexcept

enable/disable the colored tag in ostream

Note

this is a noop if fmtlib's version is less than 6.0

trace()

template<typename... Args>

void seastar::logger::trace ( format_info  fmt, Args &&...  args  )

inlinenoexcept

Log with trace tag: TRACE Y-m-d T,%03d [shard 0] - "your msg"

Parameters

fmt	- {fmt} style format string (implictly converted to struct logger::format_info) or a logger::format_info passed down the call chain.
args	- args to print string

warn()

template<typename... Args>

void seastar::logger::warn ( format_info  fmt, Args &&...  args  )

inlinenoexcept

Log with warning tag: WARN Y-m-d T,%03d [shard 0] - "your msg"

Parameters

fmt	- {fmt} style format string (implictly converted to struct logger::format_info) or a logger::format_info passed down the call chain.
args	- args to print string

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The documentation for this class was generated from the following file:

• seastar/util/log.hh