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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]( “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]( “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” |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}' Download Sampler