Home / Unlabelled / Sampler - A Tool For Shell Commands Execution, Visualization And Alerting (Configured With A Simple YAML File)

Sampler - A Tool For Shell Commands Execution, Visualization And Alerting (Configured With A Simple YAML File)


Sampler is a tool for shell commands execution, visualization and alerting. Configured with a simple YAML file.

Installation

macOS
brew cask install sampler
or
curl -Lo /usr/local/bin/sampler https://github.com/sqshq/sampler/releases/download/v1.0.1/sampler-1.0.1-darwin-amd64
 chmod +x /usr/local/bin/sampler

Linux
wget https://github.com/sqshq/sampler/releases/download/v1.0.1/sampler-1.0.1-linux-amd64 -O /usr/local/bin/sampler
 chmod +x /usr/local/bin/sampler
Note: libasound2-dev system library is required to be installed for Sampler to play a trigger sound tone. Usually the library is in place, but if not - you can do it with your favorite package manager, e.g apt install libasound2-dev

Windows (experimental)
Recommended to use with advanced console emulators, e.g. Cmder
Download .exe

Usage
You specify shell commands, Sampler executes them with a required rate. The output is used for visualization.
One can sample any dynamic process right from the terminal - observe changes in the database, monitor MQ in-flight messages, trigger deployment process and get notification when it's done.
Using Sampler is basically a 3-step process:
  • Define your configuration in a YAML file
  • Run sampler -c config.yml
  • Adjust components size and location on UI

Components
The following is a list of configuration examples for each component type, with macOS compatible sampling scripts.

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

Bells and whistles

Triggers
Triggers allow to perform conditional actions, like visual/sound alerts or an arbitrary shell command. The following examples illustrate the concept.

Clock gauge, which shows minute progress and announces current time at the beginning of each minute
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

Search engine latency chart, which alerts user when latency exceeds a threshold
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

Interactive shell support
In addition to the sample command, one can specify init command (executed only once before sampling) and transform command (to post-process sample command output). That covers interactive shell use case, e.g. to establish connection to a database only once, and then perform polling within an interactive shell session.

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
In some cases interactive shell won't work, because its stdin is not a terminal. We can fool it, using PTY mode:
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

Multistep init
It is also possible to execute multiple init commands one after another, before you start sampling.
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

Variables
If the configuration file contains repeated patterns, they can be extracted into the variables section. Also variables can be specified using -v/--variable flag on startup, and any system environment variables will also be available in the scripts.
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()

Color theme


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

Real-world recipes

Databases
The following are different database connection examples. Interactive shell (init script) usage is recommended to establish connection only once and then reuse it during sampling.

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 lag per consumer group 
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 containers stats (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

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

JMX

Java application uptime example 
# 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}'



Via: feedproxy.google.com
Sampler - A Tool For Shell Commands Execution, Visualization And Alerting (Configured With A Simple YAML File) Sampler - A Tool For Shell Commands Execution, Visualization And Alerting (Configured With A Simple YAML File) Reviewed by Anónimo on 9:19 Rating: 5

Tags