夜莺初探四·mtail插件采集日志指标

前言

上一篇介绍了Categraf的配置，这篇我们尝试通过使用google开源的mtail工具来作为Categraf的插件，从应用日志中提取指标数据。

mtail项目介绍和配置文件说明

通过mtail -h可以很方便看到参数详细，也推荐乔克-从日志中提取指标的瑞士军刀或者Dream运维梦工厂-categraf-mtail日志收集插件详解来了解更多,我就不再班门弄斧了。
当然也可以通过官方来了解详情新手村介绍 和高手入门

Categraf采集插件

categraf-mtail插件地址

https://github.com/flashcatcloud/categraf/tree/main/inputs/mtail

源码解读

package mtail
...

//常量值
const inputName = `mtail`
const description = ` extract internal monitoring data from application logs`

//配置
// MTail holds the configuration for the plugin.
type MTail struct {
    config.PluginConfig
    Instances []*Instance `toml:"instances"`
}
//配置文件中instances对象需要参数结构体
type Instance struct {
	config.InstanceConfig


	/**
		type InternalConfig struct {
			// append labels
			Labels map[string]string `toml:"labels"`

			// metrics drop and pass filter
			MetricsDrop       []string `toml:"metrics_drop"`
			MetricsPass       []string `toml:"metrics_pass"`
			MetricsDropFilter filter.Filter
			MetricsPassFilter filter.Filter

			// metric name prefix
			MetricsNamePrefix string `toml:"metrics_name_prefix"`

			// mapping value
			ProcessorEnum []*ProcessorEnum `toml:"processor_enum"`

			// whether instance initial success
			inited bool `toml:"-"`
		}
		type InstanceConfig struct {
			InternalConfig
			IntervalTimes int64 `toml:"interval_times"`
		}
	**/


	NamePrefix           string        `toml:"name_prefix"`
	Progs                string        `toml:"progs"` 							//规则文件（xxx.mtail）的目录
	Logs                 []string      `toml:"logs"` 							//要监控的日志文件
	IgnoreFileRegPattern string        `toml:"ignore_filename_regex_pattern"`
	OverrideTimeZone     string        `toml:"override_timezone"`				//指定时区
	EmitProgLabel        string        `toml:"emit_prog_label"`					//是否导出label标签 string类型的bool值 
	emitProgLabel        bool          `toml:"-"`
	EmitMetricTimestamp  string        `toml:"emit_metric_timestamp"`			//metrics是否带时间戳 string类型的bool值
	emitMetricTimestamp  bool          `toml:"-"`
	PollInterval         time.Duration `toml:"poll_interval"`
	PollLogInterval      time.Duration `toml:"poll_log_interval"`
	MetricPushInterval   time.Duration `toml:"metric_push_interval"`
	MaxRegexpLen         int           `toml:"max_regexp_length"`
	MaxRecursionDepth    int           `toml:"max_recursion_depth"`

	SyslogUseCurrentYear string `toml:"syslog_use_current_year"` // true
	sysLogUseCurrentYear bool   `toml:"-"`
	LogRuntimeErrors     string `toml:"vm_logs_runtime_errors"` // true
	logRuntimeErrors     bool   `toml:"-"`
	//
	ctx    context.Context    `toml:"-"`
	cancel context.CancelFunc `toml:"-"`
	m      *mtail.Server
}
//配置文件中instances对象的Init函数，调用mtail
func (ins *Instance) Init() error {

	//初始化检查，设置默认值

	if len(ins.Progs) == 0 || len(ins.Logs) == 0 {
		return types.ErrInstancesEmpty
	}

	// set default value
	ins.sysLogUseCurrentYear = ins.SyslogUseCurrentYear == "true"
	ins.logRuntimeErrors = ins.LogRuntimeErrors == "true"
	ins.emitProgLabel = ins.EmitProgLabel == "true"
	ins.emitMetricTimestamp = ins.EmitMetricTimestamp == "true"

	if