Sampler.(Visualization)

shell

Sampler.(Visualization)

⟨https://travis-ci.com/sqshq/sampler⟩ ⟨https://goreportcard.com/report/github.com/sqshq/sampler⟩

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

Why do I need it?¶

One can sample any dynamic process right from the terminal - observe changes in the database, monitor MQ in-flight messages, trigger a deployment script and get notification when it's done.

If there is a way to get a metric using a shell command - then it can be visualized with Sampler momentarily.

Installation¶

macOS¶

brew cask install sampler

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

Note: libasound2-dev system library is required to be installed for Sampler to play a trigger ⟨https://github.com/sqshq/sampler#triggers⟩ sound tone. Usually the library is in place, but if not - you can install it with your favorite package manager, e.g apt install libasound2-dev

Windows (experimental)¶

Recommended to use with advanced console emulators, e.g. Cmder ⟨https://cmder.net/⟩

Download .exe ⟨https://github.com/sqshq/sampler/releases/download/v1.0.3/sampler-1.0.3-windows-amd64.exe⟩

Usage¶

You specify shell commands, Sampler executes them with a required rate. The output is used for visualization.

Using Sampler is basically a 3-step process: - Define your shell commands in a YAML configuration file - Run sampler -c config.yml - Adjust components size and location on UI

But there are so many monitoring systems already¶

Sampler is by no means an alternative to full-scale monitoring systems, but rather an easy to setup development tool.

If spinning up and configuring Prometheus with Grafana ⟨https://prometheus.io⟩ is complete overkill for you task, Sampler might be the right solution. No servers, no databases, no deploy - you specify shell commands, and it just works.

Then it should be installed on every server I monitor?¶

No, you can run Sampler on local, but still gather telemetry from multiple remote machines. Any visualization might have init command, where you can ssh to a remote server. See the SSH example ⟨https://github.com/sqshq/sampler#ssh⟩

Contents¶

•: Components ⟨#components⟩

Runchart ⟨#runchart⟩
Sparkline ⟨#sparkline⟩
Barchart ⟨#barchart⟩
Gauge ⟨#gauge⟩
Textbox ⟨#textbox⟩
Asciibox ⟨#asciibox⟩

•: Bells and whistles ⟨#bells-and-whistles⟩

Triggers (conditional actions) ⟨#triggers⟩
Interactive shell (database interaction, remote server access, etc) ⟨#interactive-shell-support⟩
Variables ⟨#variables⟩
Color theme ⟨#color-theme⟩

•: Real-world recipes (contributions welcome!) ⟨#real-world-recipes⟩

Databases (MySQL, PostgreSQL, MongoDB, Neo4j) ⟨#databases⟩
Kafka ⟨#kafka⟩
Docker ⟨#docker⟩
SSH ⟨#ssh⟩
JMX ⟨#jmx⟩

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 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 ec2-user@1.2.3.4


    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.
```yml
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¶

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¶

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 ec2-user@1.2.3.4
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}'

for

any

Source file:	sampler.1.en.gz (from sampler 1.1.0-2.21)
Source last updated:	2020-12-03T02:30:12Z
Converted to HTML:	2024-05-06T01:10:09Z