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
or
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 |