mtail是一个可以从应用程序日志中提取指标，并将其导出到时间序列数据库或时间序列计算器中，以便配置警报和仪表盘的工具。

它的目的在于填补没有导出自己内部状态的应用程序和已有监控系统之间的空白，由于有自定义抽取粘合代码，无修改应用程序或重写相同的框架。

提取由定义了模式和动作的mtail程序来控制。

安装方法

预编译的二进制文件

推荐使用最新的生产版本二进制文件安装mtail。可按需选择对应Windows，OSX和Linux等系统版本。

源码编译

需要安装运行版本不低于1.9的Go环境。如果不想在本地环境中安装Go，也可以选择Dockerfile。

下载编译好的二进制文件后运行即可

# nohup ./mtail -progs /path/to/mtailprograms -logs /path/to/logfile &
# cat /path/to/mtailprograms
counter nginx_line_count
#正则统计访问日志的行数，可以在grafana中配置视图观察访问量趋势
/$/ {
  nginx_line_count++
}
# ./mtail -h
mtail version v3.0.0-rc12 git revision 936050df9856da258f13e5df71a5a0c7f8f6acdc go version go1.10.1

Usage:
  -address string
        Host or IP address on which to bind HTTP listener
  -alsologtostderr
        log to standard error as well as files
  -block_profile_rate int
        Nanoseconds of block time before goroutine blocking events reported. 0 turns off.  See https://golang.org/pkg/runtime/#SetBlockProfileRate
  -collectd_prefix string
        Prefix to use for collectd metrics.
  -collectd_socketpath string
        Path to collectd unixsock to write metrics to.
  -compile_only
        Compile programs only, do not load the virtual machine.
  -dump_ast
        Dump AST of programs after parse (to INFO log).
  -dump_ast_types
        Dump AST of programs with type annotation after typecheck (to INFO log).
  -dump_bytecode
        Dump bytecode of programs (to INFO log).
  -emit_prog_label
        Emit the 'prog' label in variable exports. (default true)
  -graphite_host_port string
        Host:port to graphite carbon server to write metrics to.
  -graphite_prefix string
        Prefix to use for graphite metrics.
  -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
  -logfds value
        List of file descriptor numbers to monitor, separated by commas.  This flag may be specified multiple times.
  -logs value
        List of log files to monitor, separated by commas.  This flag may be specified multiple times.
  -logtostderr
        log to standard error instead of files
  -metric_push_interval_seconds int
        Interval between metric pushes, in seconds. (default 60)
  -metric_push_write_deadline duration
        Time to wait for a push to succeed before exiting with an error. (default 10s)
  -mtailDebug int
        Set parser debug level.
  -mutex_profile_fraction int
        Fraction of mutex contention events reported.  0 turns off.  See http://golang.org/pkg/runtime/#SetMutexProfileFraction
  -one_shot
        Compile the programs, then read the contents of the provided logs from start until EOF, print the values of the metrics store and exit. This is a debugging flag only, not for production use.
  -one_shot_metrics
        DEPRECATED: Dump metrics (to stdout) after one shot mode.
  -override_timezone string
        If set, use the provided timezone in timestamp conversion, instead of UTC.
  -port string
        HTTP port to listen on. (default "3903")
  -progs string
        Name of the directory containing mtail programs
  -statsd_hostport string
        Host:port to statsd server to write metrics to.
  -statsd_prefix string
        Prefix to use for statsd metrics.
  -stderrthreshold value
        logs at or above this threshold go to stderr
  -syslog_use_current_year
        Patch yearless timestamps with the present year. (default true)
  -v value
        log level for V logs
  -version
        Print mtail version information.
  -vmodule value
        comma-separated list of pattern=N settings for file-filtered logging