Severity Levels
ref: https://github.com/golang/glog/blob/23def4e6c14b4da8ac2ed8007337bc5eb5007998/glog.go#L100
"INFO" : 0
"WARNING" : 1
"ERROR" : 2
"FATAL" : 3
Flags
ref: https://github.com/golang/glog/blob/23def4e6c14b4da8ac2ed8007337bc5eb5007998/glog.go#L398
flag.BoolVar(&logging.toStderr, "logtostderr", false, "log to standard error instead of files")
flag.BoolVar(&logging.alsoToStderr, "alsologtostderr", false, "log to standard error as well as files")
flag.Var(&logging.verbosity, "v", "log level for V logs")
flag.Var(&logging.stderrThreshold, "stderrthreshold", "logs at or above this threshold go to stderr")
output
ref: https://github.com/golang/glog/blob/23def4e6c14b4da8ac2ed8007337bc5eb5007998/glog.go#L671
} else if l.toStderr {
os.Stderr.Write(data)
} else {
if alsoToStderr || l.alsoToStderr || s >= l.stderrThreshold.get() {
os.Stderr.Write(data)
}
V(x)
ref:
- https://github.com/golang/glog/blob/23def4e6c14b4da8ac2ed8007337bc5eb5007998/glog.go#L1004
- https://github.com/golang/glog/blob/23def4e6c14b4da8ac2ed8007337bc5eb5007998/glog.go#L1040
if logging.verbosity.get() >= level {
return Verbose(true)
}
Notes:
- V(x) are always output in
INFOseverity. - If
--logtostderris true, severity levels are not consulted. (this is default true with appscode/go/log) --stderrthresholdis 2, ie, ERROR. So, glog.Error() logs are alway written.
To control logging using severity (Not V levels), you need to set:
# only log ERROR / FATAL
glog-demo check --logtostderr=false --stderrthreshold=ERROR
# only log INFO at V=0 / WARN / ERROR / FATAL
glog-demo check --logtostderr=false --stderrthreshold=INFO
# only log INFO at V=0 / WARN / ERROR / FATAL
glog-demo check --logtostderr=true
# only log INFO at V=0,1,2 / WARN / ERROR / FATAL
glog-demo check --logtostderr=false --stderrthreshold=INFO --v=2
| func call | severity, V |
|---|---|
| appscode/go/log.Debug | INFO, V(4) |
| appscode/go/log.Info | INFO, V(3) |
| appscode/go/log.Warning | INFO, V(2) |
| appscode/go/log.Error | INFO, V(1) |
| appscode/go/log.Fatal | INFO, V(0) |
| glog.Info | INFO, V(0) |
| glog.Warning | WARN |
| glog.Error | ERROR |
| glog.Fatal | FATAL |
- https://github.com/tamalsaha/std-log-demo
- https://github.com/tamalsaha/glog-demo
- https://github.com/tamalsaha/kube-log-demo
- https://github.com/tamalsaha/ac-log-demo
$ glide up -v
$ go install -v
$ glog-demo check -h
Check restic backup
Usage:
check [flags]
Flags:
-h, --help help for check
Global Flags:
--alsologtostderr log to standard error as well as files
--analytics Send analytical events to Google Analytics (default true)
--log_backtrace_at traceLocation when logging hits line file:N, emit a stack trace (default :0)
--log_dir string If non-empty, write log files in this directory
--logtostderr log to standard error instead of files
--stderrthreshold severity logs at or above this threshold go to stderr (default 2)
-v, --v Level log level for V logs
--vmodule moduleSpec comma-separated list of pattern=N settings for file-filtered logging
# default settings
$ glog-demo check --stderrthreshold=ERROR
2018/01/09 07:58:14 FLAG: --alsologtostderr="false"
2018/01/09 07:58:14 FLAG: --analytics="true"
2018/01/09 07:58:14 FLAG: --help="false"
2018/01/09 07:58:14 FLAG: --log_backtrace_at=":0"
2018/01/09 07:58:14 FLAG: --log_dir=""
2018/01/09 07:58:14 FLAG: --logtostderr="false"
2018/01/09 07:58:14 FLAG: --stderrthreshold="2"
2018/01/09 07:58:14 FLAG: --v="0"
2018/01/09 07:58:14 FLAG: --vmodule=""
log.Println_____
2018/01/09 07:58:14 node.Name
glog.Infoln_____
glog.Warningln_____
glog.Errorln_____
E0109 07:58:14.796966 22837 main.go:53] node.Name
glog.V(0).Infoln_____
glog.V(1).Infoln_____
glog.V(2).Infoln_____
glog.V(3).Infoln_____
glog.V(4).Infoln_____
$ glog-demo check --stderrthreshold=INFO
2018/01/09 07:59:19 FLAG: --alsologtostderr="false"
2018/01/09 07:59:19 FLAG: --analytics="true"
2018/01/09 07:59:19 FLAG: --help="false"
2018/01/09 07:59:19 FLAG: --log_backtrace_at=":0"
2018/01/09 07:59:19 FLAG: --log_dir=""
2018/01/09 07:59:19 FLAG: --logtostderr="false"
2018/01/09 07:59:19 FLAG: --stderrthreshold="0"
2018/01/09 07:59:19 FLAG: --v="0"
2018/01/09 07:59:19 FLAG: --vmodule=""
log.Println_____
2018/01/09 07:59:19 node.Name
glog.Infoln_____
I0109 07:59:19.566625 23000 main.go:47] node.Name
glog.Warningln_____
W0109 07:59:19.566811 23000 main.go:50] node.Name
glog.Errorln_____
E0109 07:59:19.566928 23000 main.go:53] node.Name
glog.V(0).Infoln_____
I0109 07:59:19.567033 23000 main.go:58] node.Name
glog.V(1).Infoln_____
glog.V(2).Infoln_____
glog.V(3).Infoln_____
glog.V(4).Infoln_____
$ glog-demo check --stderrthreshold=INFO --v=2
2018/01/09 07:59:45 FLAG: --alsologtostderr="false"
2018/01/09 07:59:45 FLAG: --analytics="true"
2018/01/09 07:59:45 FLAG: --help="false"
2018/01/09 07:59:45 FLAG: --log_backtrace_at=":0"
2018/01/09 07:59:45 FLAG: --log_dir=""
2018/01/09 07:59:45 FLAG: --logtostderr="false"
2018/01/09 07:59:45 FLAG: --stderrthreshold="0"
2018/01/09 07:59:45 FLAG: --v="2"
2018/01/09 07:59:45 FLAG: --vmodule=""
log.Println_____
2018/01/09 07:59:45 node.Name
glog.Infoln_____
I0109 07:59:45.421904 23052 main.go:47] node.Name
glog.Warningln_____
W0109 07:59:45.422051 23052 main.go:50] node.Name
glog.Errorln_____
E0109 07:59:45.422123 23052 main.go:53] node.Name
glog.V(0).Infoln_____
I0109 07:59:45.422198 23052 main.go:58] node.Name
glog.V(1).Infoln_____
I0109 07:59:45.422211 23052 main.go:61] node.Name
glog.V(2).Infoln_____
I0109 07:59:45.422220 23052 main.go:64] node.Name
glog.V(3).Infoln_____
glog.V(4).Infoln_____
$ glog-demo check --logtostderr=true --v=-1
2018/01/08 19:48:53 FLAG: --alsologtostderr="false"
2018/01/08 19:48:53 FLAG: --analytics="true"
2018/01/08 19:48:53 FLAG: --help="false"
2018/01/08 19:48:53 FLAG: --log_backtrace_at=":0"
2018/01/08 19:48:53 FLAG: --log_dir=""
2018/01/08 19:48:53 FLAG: --logtostderr="true"
2018/01/08 19:48:53 FLAG: --stderrthreshold="2"
2018/01/08 19:48:53 FLAG: --v="-1"
2018/01/08 19:48:53 FLAG: --vmodule=""
log.Println_____
2018/01/08 19:48:53 node.Name
glog.Infoln_____
I0108 19:48:53.577603 29286 main.go:47] node.Name
glog.Warningln_____
W0108 19:48:53.577620 29286 main.go:50] node.Name
glog.Errorln_____
E0108 19:48:53.577631 29286 main.go:53] node.Name
glog.V(0).Infoln_____
glog.V(1).Infoln_____
glog.V(2).Infoln_____
glog.V(3).Infoln_____
glog.V(4).Infoln_____ -add_dir_header
If true, adds the file directory to the header of the log messages
-alsologtostderr
log to standard error as well as files
-log_backtrace_at value
when logging hits line file:N, emit a stack trace
-log_dir string
If non-empty, write log files in this directory
-log_file string
If non-empty, use this log file
-log_file_max_size uint
Defines the maximum size a log file can grow to. Unit is megabytes. If the value is 0, the maximum file size is unlimited. (default 1800)
-logtostderr
log to standard error instead of files (default true)
-one_output
If true, only write logs to their native severity level (vs also writing to each lower severity level)
-skip_headers
If true, avoid header prefixes in the log messages
-skip_log_headers
If true, avoid headers when opening log files
-stderrthreshold value
logs at or above this threshold go to stderr (default 2)
-v value
number for the log level verbosity
-vmodule value
comma-separated list of pattern=N settings for file-filtered logging
-alsologtostderr
log to standard error as well as files
-log_backtrace_at value
when logging hits line file:N, emit a stack trace
-log_dir string
If non-empty, write log files in this directory
-logtostderr
log to standard error instead of files
-stderrthreshold value
logs at or above this threshold go to stderr
-v value
log level for V logs
-vmodule value
comma-separated list of pattern=N settings for file-filtered logging