00 Getting Started

Getting started with data-driven arbitrary text generation.

The driving data

YAML

The data are provided in .YAML format. E.g., example.yaml:

# individual variables
Name: html2md
ProgramName: html2md
PackageName: main

# nested individual variables
Colormaps:
  ColorRed:   red  
  ColorBlue:  blue 
  ColorWhite: white

# Simple string, to demo the string `split` function
Colorlist: red blue white

# Array variable in normal way
Colors:
  - red
  - blue
  - white

# Multi-dimension array variable
Cars:

  - Make: Ford
    Module: T1

  - Make: GM
    Module: T2

Examples

list0.tmpl from test cases

The colors are: {{range .Colors}}{{.}}, {{end}}.

The result is in list0.ref:

The colors are: red, blue, white, .

Testing the templates on the fly:

$ easygen -ts 'The color maps are: {{range $key, $value := .Colormaps}}{{$key}}={{$value}}, {{end}}.' example
The color maps are: ColorBlue=blue, ColorRed=red, ColorWhite=white, .

Examples from other test cases

Also check the variation of such transforming:

• list1.tmpl
  to use quotes in the driving data
  check result: list1.ref
• list1HTML.tmpl
  to output above quotes in the driving data in html format
  check result: list1HTML.ref
• listfunc1.tmpl
  to eliminate the last comma "," before the end
  check result: listfunc1.ref
• listfunc2.tmpl
  to rename variables using different naming conventions via egVar builtin functions
  check result: listfunc2.ref
• list0E.tmpl
  to use environment variables in template
  check result: list0E.ref

I'll document more of them when I have time...

Builtin Functions

The above listfunc1.tmpl example showcases using some basic easygen builtin functions. What else are the easygen builtin functions?

The full list of easygen builtin functions is available here.

Real-life Example

To generate sgdisk.sh like the following,

 # format /dev/sdb as GPT, GUID Partition Table
 sgdisk -Z /dev/sdb

 sgdisk -n 0:0:+200M -t 0:ef02 -c 0:"bios_boot" /dev/sdb
 sgdisk -n 0:0:+20G -t 0:8300 -c 0:"linux_boot" /dev/sdb
 sgdisk -n 0:0:+30G -t 0:0700 -c 0:"windows" /dev/sdb
 sgdisk -n 0:0:+10G -t 0:8200 -c 0:"linux_swap" /dev/sdb
 sgdisk -n 0:0:+12G -t 0:8300 -c 0:"os1" /dev/sdb
 sgdisk -n 0:0:+12G -t 0:8300 -c 0:"os2" /dev/sdb
 sgdisk -n 0:0:+12G -t 0:8300 -c 0:"os3" /dev/sdb
 sgdisk -n 0:0:0 -t 0:8300 -c 0:"data" /dev/sdb

 sgdisk -p /dev/sdb

 # inform the OS of partition table changes
 partprobe /dev/sdb
 fdisk -l /dev/sdb

check out its

driving data: sgdisk.yaml

Disk: /dev/sdb

Partitions:
  - Name: bios_boot
    Type: ef02
    Size: +200M

  - Name: linux_boot
    Type: 8300
    Size: +20G

  - Name: windows
    Type: "0700"
    Size: +30G

  - Name: linux_swap
    Type: 8200
    Size: +10G

  - Name: os1
    Type: 8300
    Size: +12G
. . .

template: sgdisk.tmpl

 # format {{.Disk}} as GPT, GUID Partition Table
 sgdisk -Z {{.Disk}}
{{range .Partitions}}
 sgdisk -n 0:0:{{.Size}} -t 0:{{.Type}} -c 0:"{{.Name}}" {{$.Disk}}{{end}}

 sgdisk -p {{.Disk}}

 # inform the OS of partition table changes
 partprobe {{.Disk}}
 fdisk -l {{.Disk}}

Continue Reading

Testing the templates on the fly

See Testing the templates on the fly

How to include nested templates from other files

See How to include nested templates from other files

Jump start the cli based projects

See

• Jump start the cli based project
• easygen cli code-gen example for go-flags and its results at https://github.com/go-easygen/go-flags-demo