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)

## Installation

### macOS
```bash
sudo curl -Lo /usr/local/bin/sampler https://github.com/sqshq/sampler/releases/download/v0.9.1-beta/sampler-0.9.1-darwin-amd64
sudo chmod +x /usr/local/bin/sampler
```
### Linux
```bash
sudo wget https://github.com/sqshq/sampler/releases/download/v0.9.1-beta/sampler-0.9.1-linux-amd64 -O /usr/local/bin/sampler
sudo chmod +x /usr/local/bin/sampler
```
### Windows
[download .exe](https://github.com/sqshq/sampler/releases/download/v0.9.1-beta/sampler-0.9.1-windows)

## 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

## 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 examples (contributions welcome)](#real-world-examples)  

## 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 announce current time at the beginning of each minute

```yml
gauges:
  - title: MINUTE PROGRESS
    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)
    items:
      - label: GOOGLE
        sample: curl -o /dev/null -s -w '%{time_total}'  https://www.google.com
    triggers:
      - title: Latency threshold exceeded
        condition: echo "$prev < 0.8 && $cur > 0.8" |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 intractive 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    
```

### 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 examples
...