Sampler是一个用于shell命令执行，可视化和告警的工具。其配置使用的是一个简单的YAML文件。

为什么我需要它？

你可以直接从终端对任意动态进程进行采样 – 观察数据库中的更改，监控MQ动态消息（in-flight messages），触发部署脚本并在完成后获取通知。

如果有一种方法可以使用shell命令获取指标（metric），那么可以使用Sampler立即对其进行可视化。

安装

macOS

brew cask install sampler

或

sudo curl -Lo /usr/local/bin/sampler https://github.com/sqshq/sampler/releases/download/v1.0.3/sampler-1.0.3-darwin-amd64
sudo chmod +x /usr/local/bin/sampler

Linux

sudo wget https://github.com/sqshq/sampler/releases/download/v1.0.3/sampler-1.0.3-linux-amd64 -O /usr/local/bin/sampler
sudo chmod +x /usr/local/bin/sampler

注意：需要为Sampler安装libasound2-dev系统库用以播放触发器声音。通常库已安装在相应位置，但如果没有 – 你可以使用你习惯的包管理器进行安装，例如apt install libasound2-dev

Windows（实验）

建议在高级控制台模拟器下使用，如Cmder

Download .exe

使用

指定shell命令，Sampler会相应的速率执行这些命令。输出用于可视化。

使用Sampler基本上的三步过程：

在YAML配置文件中定义shell命令

运行sampler -c config.yml

在UI上调整组件大小和位置

市面早已有许多监控系统

Sampler绝不是监控系统的替代品，而是易于设置的开发工具。

如果spinning up和使用Grafana配置Prometheus是完全多余的任务，那么Sampler可能是正确的解决方案。没有服务器，没有数据库，不需要部署 – 你指定了shell命令，它就可以工作了。

我监控的每台服务器上都需要安装吗？

不，你可以在本地运行Sampler，但仍然可以从多台远程计算机上收集遥测数据。任何可视化都可能具有init命令，你可以在其中ssh到远程服务器。请参阅SSH example

组件

以下是每种组件类型的配置示例列表，其中包含与macOS兼容的采样脚本。

Runchart

runcharts:
  - title: Search engine response time
    rate-ms: 500        # sampling rate, default = 1000
    scale: 2            # number of digits after sample decimal point, default = 1
    legend:
      enabled: true     # enables item labels, default = true
      details: false    # enables item statistics: cur/min/max/dlt values, default = true
    items:
      - label: GOOGLE
        sample: curl -o /dev/null -s -w '%{time_total}'  https://www.google.com
        color: 178      # 8-bit color number, default one is chosen from a pre-defined palette
      - label: YAHOO
        sample: curl -o /dev/null -s -w '%{time_total}'  https://search.yahoo.com
      - label: BING
        sample: curl -o /dev/null -s -w '%{time_total}'  https://www.bing.com

Sparkline

sparklines:
  - title: CPU usage
    rate-ms: 200
    scale: 0
    sample: ps -A -o %cpu | awk '{s+=$1} END {print s}'
  - title: Free memory pages
    rate-ms: 200
    scale: 0
    sample: memory_pressure | grep 'Pages free' | awk '{print $3}'

Barchart

barcharts:
  - title: Local network activity
    rate-ms: 500        # sampling rate, default = 1000
    scale: 0            # number of digits after sample decimal point, default = 1
    items:
      - label: UDP bytes in
        sample: nettop -J bytes_in -l 1 -m udp | awk '{sum += $4} END {print sum}'
      - label: UDP bytes out
        sample: nettop -J bytes_out -l 1 -m udp | awk '{sum += $4} END {print sum}'
      - label: TCP bytes in
        sample: nettop -J bytes_in -l 1 -m tcp | awk '{sum += $4} END {print sum}'
      - label: TCP bytes out
        sample: nettop -J bytes_out -l 1 -m tcp | awk '{sum += $4} END {print sum}'

Gauge

gauges:
  - title: Minute progress
    rate-ms: 500        # sampling rate, default = 1000
    scale: 2            # number of digits after sample decimal point, default = 1
    percent-only: false # toggle display of the current value, default = false
    color: 178          # 8-bit color number, default one is chosen from a pre-defined palette
    cur:
      sample: date +%S  # sample script for current value
    max:
      sample: echo 60   # sample script for max value
    min:
      sample: echo 0    # sample script for min value
  - title: Year progress
    cur:
      sample: date +%j
    max:
      sample: echo 365
    min:
      sample: echo 0

Textbox

textboxes:
  - title: Local weather
    rate-ms: 10000      # sampling rate, default = 1000
    sample: curl wttr.in?0ATQF
    border: false       # border around the item, default = true
    color: 178          # 8-bit color number, default is white
  - title: Docker containers stats
    rate-ms: 500
    sample: docker stats --no-stream --format "table {{.Name}}\t{{.CPUPerc}}\t{{.MemUsage}}\t{{.PIDs}}"

Asciibox

asciiboxes:
  - title: UTC time
    rate-ms: 500        # sampling rate, default = 1000
    font: 3d            # font type, default = 2d
    border: false       # border around the item, default = true    
    color: 43           # 8-bit color number, default is white
    sample: env TZ=UTC date +%r

额外功能

Triggers

触发器允许执行条件操作，如视觉/声音告警或任意shell命令。以下示例说明了此概念。

Clock gauge，从开始的每分钟显示时间进度和当前时间

gauges:
  - title: MINUTE PROGRESS
    position: [[0, 18], [80, 0]]  
    cur:
      sample: date +%S
    max:
      sample: echo 60
    min:
      sample: echo 0
    triggers:
      - title: CLOCK BELL EVERY MINUTE
        condition: '[ $label == "cur" ] && [ $cur -eq 0 ] && echo 1 || echo 0'  # expects "1" as TRUE indicator
        actions:
          terminal-bell: true  # standard terminal bell, default = false
          sound: true    # NASA quindar tone, default = false
          visual: false  # notification with current value on top of the component area, default = false
          script: say -v samantha `date +%I:%M%p`  # an arbitrary script, which can use $cur, $prev and $label variables

搜索引擎延迟图表，在延迟超过阈值时向用户发出告警

runcharts:
  - title: SEARCH ENGINE RESPONSE TIME (sec)
    rate-ms: 200
    items:
      - label: GOOGLE
        sample: curl -o /dev/null -s -w '%{time_total}'  https://www.google.com
      - label: YAHOO
        sample: curl -o /dev/null -s -w '%{time_total}'  https://search.yahoo.com     
    triggers:
      - title: Latency threshold exceeded
        condition: echo "$prev < 0.3 && $cur > 0.3" |bc -l  # expects "1" as TRUE indicator
        actions:
          terminal-bell: true  # standard terminal bell, default = false
          sound: true   # NASA quindar tone, default = false
          visual: true  # visual notification on top of the component area, default = false
          script: 'say alert: ${label} latency exceeded ${cur} second' # an arbitrary script, which can use $cur, $prev and $label variables

交互式 shell 支持

除了sample命令之外，还可以指定init命令（在采样前仅执行一次）和transform命令（后处理采样命令输出）。这包括交互式shell用例，例如仅建立与数据库的连接一次，然后在交互式shell会话中执行轮询。

Basic mode

textboxes:
  - title: MongoDB polling
    rate-ms: 500
    init: mongo --quiet --host=localhost test # executes only once to start the interactive session
    sample: Date.now();                       # executes with a required rate, in scope of the interactive session
    transform: echo result = $sample          # executes in scope of local session, $sample variable is available for transformation

PTY mode

在某些情况下，交互式shell将无法工作，因为它的stdin不是终端。这种情况下我们可以使用PTY模式：

textboxes:
  - title: Neo4j polling
    pty: true  # enables pseudo-terminal mode, default = false
    init: cypher-shell -u neo4j -p pwd --format plain
    sample: RETURN rand();
    transform: echo "$sample" | tail -n 1
  - title: Top on a remote server
    pty: true  # enables pseudo-terminal mode, default = false
    init: ssh -i ~/user.pem [email protected]
    sample: top

 init 命令逐步执行

在开始采样之前，还可以逐个执行多个init命令。

textboxes:
  - title: Java application uptime
    multistep-init:
      - java -jar jmxterm-1.0.0-uber.jar
      - open host:port # or local PID
      - bean java.lang:type=Runtime
    sample: get Uptime

变量

如果配置文件包含重复的模式，则可以将它们提取到变量部分。此外，还可以在启动时使用-v/–variable标志指定变量，并且任意的系统环境变量也可以在脚本中使用。

variables:
    mongoconnection: mongo --quiet --host=localhost test
barcharts:
  - title: MongoDB documents by status
    items:
      - label: IN_PROGRESS
        init: $mongoconnection
        sample: db.getCollection('events').find({status:'IN_PROGRESS'}).count()
      - label: SUCCESS
        init: $mongoconnection
        sample: db.getCollection('events').find({status:'SUCCESS'}).count()
      - label: FAIL
        init: $mongoconnection
        sample: db.getCollection('events').find({status:'FAIL'}).count()

颜色主题

theme: light # default = dark
sparklines:
  - title: CPU usage
    sample: ps -A -o %cpu | awk '{s+=$1} END {print s}'

真实场景

数据库

以下是不同的数据库连接示例。建议使用交互式shell（init脚本）仅建立一次连接，然后在采样期间重用即可。

MySQL

# prerequisite: installed mysql shell
variables:
  mysql_connection: mysql -u root -s --database mysql --skip-column-names
sparklines:  
  - title: MySQL (random number example)
    pty: true
    init: $mysql_connection
    sample: select rand();

PostgreSQL

# prerequisite: installed psql shell
variables:
  PGPASSWORD: pwd
  postgres_connection: psql -h localhost -U postgres --no-align --tuples-only
sparklines:
  - title: PostgreSQL (random number example)
    init: $postgres_connection
    sample: select random();

MongoDB

# prerequisite: installed mongo shell
variables:
  mongo_connection: mongo --quiet --host=localhost test
sparklines:
  - title: MongoDB (random number example)
    init: $mongo_connection
    sample: Math.random();

Neo4j

# prerequisite: installed cypher shell
variables:
  neo4j_connection: cypher-shell -u neo4j -p pwd --format plain
sparklines:
  - title: Neo4j (random number example)
    pty: true
    init: $neo4j_connection
    sample: RETURN rand();
    transform: echo "$sample" | tail -n 1

Kafka

检查kafka lag值，计算每个队列lag值的和，高于阈值报警，多consumergroup，多topic。

variables:
  kafka_connection: $KAFKA_HOME/bin/kafka-consumer-groups --bootstrap-server localhost:9092
runcharts:
  - title: Kafka lag per consumer group
    rate-ms: 5000
    scale: 0
    items:
      - label: A->B
        sample: $kafka_connection --group group_a --describe | awk 'NR>1 {sum += $5} END {print sum}'
      - label: B->C
        sample: $kafka_connection --group group_b --describe | awk 'NR>1 {sum += $5} END {print sum}'
      - label: C->D
        sample: $kafka_connection --group group_c --describe | awk 'NR>1 {sum += $5} END {print sum}'

Docker

Docker容器统计信息（CPU，MEM，O/I）

textboxes:
  - title: Docker containers stats
    sample: docker stats --no-stream --format "table {{.Name}}\t{{.CPUPerc}}\t{{.MemPerc}}\t{{.MemUsage}}\t{{.NetIO}}\t{{.BlockIO}}\t{{.PIDs}}"

SSH

远程服务器上的TOP命令

variables:
  sshconnection: ssh -i ~/my-key-pair.pem [email protected]
textboxes:
  - title: SSH
    pty: true
    init: $sshconnection
    sample: top

JMX

Java应用程序的正常运行示例

# prerequisite: download [jmxterm jar file](https://docs.cyclopsgroup.org/jmxterm)
textboxes:
  - title: Java application uptime
    multistep-init:
      - java -jar jmxterm-1.0.0-uber.jar
      - open host:port # or local PID
      - bean java.lang:type=Runtime
    sample: get Uptime
    transform: echo $sample | tr -dc '0-9' | awk '{printf "%.1f min", $1/1000/60}'

*参考来源：GitHub，FB小编secist编译，转载请注明来自FreeBuf.COM