sampler-fork/README.md

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

![sampler](https://user-images.githubusercontent.com/6069066/56404396-70b14d00-6234-11e9-93cd-54461bf40c96.gif)

## 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
```bash
brew cask install sampler
```
or
```bash
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
```bash
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
![runchart](https://user-images.githubusercontent.com/6069066/59168666-aff96d00-8b04-11e9-99b6-34d8bae37bd2.png)
```yml
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
![sparkline](https://user-images.githubusercontent.com/6069066/59167746-de754900-8b00-11e9-9305-c9a4176634d2.png)
```yml
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
![barchart](https://user-images.githubusercontent.com/6069066/59167751-de754900-8b00-11e9-8d01-efd04ae1eec6.png)
```yml
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
![gauge](https://user-images.githubusercontent.com/6069066/59318799-4c06ae00-8c96-11e9-868a-7fef803f3739.png)
```yml
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
![textbox](https://user-images.githubusercontent.com/6069066/59168949-192db000-8b06-11e9-900b-0e92ff494f62.png)
```yml
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
![asciibox](https://user-images.githubusercontent.com/6069066/59169283-aa515680-8b07-11e9-8beb-716a387aed1b.png)
```yml
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

```yml
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

```yml
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
```yml
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:
```yml
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.
```yml
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
![light-theme](https://user-images.githubusercontent.com/6069066/59959405-994c0200-9484-11e9-856b-c4d18716e1de.png)
```yml
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.

<details><summary>MySQL</summary>

```yml
# 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();
```

</details>

<details><summary>PostgreSQL</summary>

```yml
# 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();
```

</details>

<details><summary>MongoDB</summary>

```yml
# prerequisite: installed mongo shell

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

</details>

<details><summary>Neo4j</summary>

```yml
# 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
```

</details>

### Kafka

<details><summary>Kafka lag per consumer group</summary>

```yml
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}'
```

</details>

### Docker

<details><summary>Docker containers stats (CPU, MEM, O/I)</summary>

```yml
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}}"
```

</details>

### SSH

<details><summary>TOP command on a remote server</summary>

```yml
variables:
  sshconnection: ssh -i ~/my-key-pair.pem ec2-user@1.2.3.4
textboxes:
  - title: SSH
    pty: true
    init: $sshconnection
    sample: top
```

</details>

### JMX

<details><summary>Java application uptime example</summary>

```yml
# 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}'
```

</details>