Log: Should follow Java/Go/FFmpeg/NGINX log level specs.

[winlinvip]

The log level of SRS 1.0 to 4.0:

Verb > Debug > Trace > Warn > Error

The Java log4j specs, see apache/logging-log4j2

TRACE > DEBUG > INFO > WARN > ERROR > FATAL

The Go log specs, see golang/glog or kubernetes/klog:

Info > Warning > Error > Fatal

For Go, another defactor log specs is uber-go/zap

Debug > Info > Warn > Error > DPanic > Panic > Fatal

While FFmpeg has a more detail log level specs:

trace > debug > verbose > info > warning > error > fatal

The last one, NGXIN log level, see nginx:

DEBUG > INFO > NOTICE > WARN > ERR > CRIT > ALERT > EMERG

SRS 5.0+ should follow Java/Go/FFmpeg/Nginx log level specs.

Config

The config for log level:

# The log level for logging to console or file. It can be:
#       verbose, info, trace, warn, error
# If configure --log-level_v2=off, use SRS 4.0 level specs which is v1, the level text is:
#       Verb, Info, Trace, Warn, Error
# If configure --log-level_v2=on, use SRS 5.0 level specs which is v2, the level text is:
#       TRACE, DEBUG, INFO, WARN, ERROR
# Note: Do not support reloading, for SRS5+
# Overwrite by env SRS_SRS_LOG_LEVEL
# default: trace
srs_log_level trace;
# The log level v2, rewrite the config srs_log_level if not empty, it can be:
#       trace, debug, info, warn, error
# If configure --log-level_v2=off, use SRS 4.0 level specs which is v1, the level text is:
#       Verb, Info, Trace, Warn, Error
# If configure --log-level_v2=on, use SRS 5.0 level specs which is v2, the level text is:
#       TRACE, DEBUG, INFO, WARN, ERROR
# Overwrite by env SRS_SRS_LOG_LEVEL_V2
srs_log_level_v2 info;

The default level of SRS 4.0:

srs_log_level trace;

The default level of SRS 5.0:

srs_log_level trace;

srs_log_level_v2 info;

The default config should work well without any changes.

Configure

SRS 5.0 supports configure options to control the log text for level:

./configure --help |grep log-level
#  --log-level_v2=on|off     Whether use v2.0 log level definition, see log4j specs. Default: on

If ./configure --log-level_v2=off, use SRS 4.0 log level text, literally the same to srs_log_level, even though the config use srs_log_level_v2.

If ./configure srs_log_level_v2=on, use SRS 5.0 v2 log level text, apply both for the config srs_log_level and srs_log_level_v2.

The config file and configure is orthogonal:

• Config srs_log_level or srs_log_level_v2 control the converting from text to log level object.
• Configure --log-level_v2=on|off controls the log level text in each log line.

So you're able to use different log level for both new style and keep compability with old style.

Compare

If config with srs_log_level, the log text is described by bellow table:

Config srs_log_level	SRS 4.0	SRS 5.0 --log-level_v2=off	SRS 5.0 --log-level_v2=on
verbose	Verb	Verb	TRACE
info	Info	Info	DEBUG
trace	Trace	Trace	INFO
warn	Warn	Warn	WARN
error	Error	Error	ERROR

If config with srs_log_level_v2, the log text is described by bellow table:

Config srs_log_level_v2	SRS 5.0 ./configure --log-level_v2=off	SRS 5.0 ./configure --log-level_v2=on
trace	Verb	TRACE
debug	Info	DEBUG
info	Trace	INFO
warn	Warn	WARN
error	Error	ERROR

There is a full table about config and configure options:

Config srs_log_level	Config srs_log_level_v2	SRS 4.0	SRS 5.0 ./configure --log-level_v2=off	SRS 5.0 ./configure --log-level_v2=on
verbose	trace	Verb	Verb	TRACE
info	debug	Info	Info	DEBUG
trace	info	Trace	Trace	INFO
warn	warn	Warn	Warn	WARN
error	error	Error	Error	ERROR

The default config should work well, so you don't have to change it.

Example

The startup log of SRS 4.0:

[2022-10-26 11:46:47.991][Trace][6905][83h49oox] XCORE-SRS/4.0.265(Leo)

SRS. 5.0:

[2022-10-26 11:46:47.991][INFO][6905][83h49oox] XCORE-SRS/5.0.83(Bee)

Note: Please note that the level text is different.

[suzp1984]

srs/trunk/src/kernel/srs_kernel_log.hpp

Line 23 in 27f9db9

enum SrsLogLevel

Why not redefine the SrsLogLevel with SRS_LOG_LEVEL_V2 macro so that it can print the reasonable tags?

[2022-10-26 11:46:47.991][INFO][6905][83h49oox] XCORE-SRS/5.0.83(Bee)
The srs_trace() print INFO tag, it seems abnormal.

How about the below definition?

enum SrsLogLevel
{
    SrsLogLevelForbidden = 0x00,

    // Only used for very verbose debug, generally,
    // we compile without this level for high performance.
#ifdef SRS_LOG_LEVEL_V2
    SrsLogLevelVerbose = 0x01,
    SrsLogLevelInfo = 0x02,
    SrsLogLevelTrace = 0x04,
    SrsLogLevelWarn = 0x08,
    SrsLogLevelError = 0x10,
#else
    SrsLogLevelTrace = 0x01,
    SrsLogLevelInfo = 0x02,
    SrsLogLevelVerbose = 0x04,
    SrsLogLevelWarn = 0x08,
    SrsLogLevelError = 0x10,
#endif

    SrsLogLevelDisabled = 0x20,
};