tagoael

README

tagoæl

Enhanced Hello World written in Go with advanced configuration mechanism provided by Flæg & Stært

Why tagoæl ?

The goal is to understand how to use Flæg & Stært. It's written in Go and french pronunciation of tagoæl means more or less 'shut up': what you will want to say to the program once you will test it with unmodified default values.

Examples

Display automatically formatted help message with -h short flag:

$ ./tagoael -h
tagoæl is an enhanced Hello World program to display messages with
an advanced configuration mechanism provided by flæg & stært.

flæg:   https://github.com/containous/flaeg
stært:  https://github.com/containous/staert
tagoæl: https://github.com/debovema/tagoael


Usage: tagoael [--flag=flag_argument] [-f[flag_argument]] ...     set flag_argument to flag(s)
   or: tagoael [--flag[=true|false| ]] [-f[true|false| ]] ...     set true/false to boolean flag(s)

Flags:
        -c, --commandlineoverridesconfigfile               Whether configuration from command line overrides configuration from configuration file or not. (default "true")
        --configfile                                       Configuration file to use (TOML). (default "tagoael")
        -i, --displayindex                                 Whether to display index of each message (default "false")
        -m, --messagetodisplay                             Message to display (default "HELLO WOLRD")
        -n, --numbertodisplay                              Number of messages to display (default "1000")
        -h, --help                                         Print Help (this message) and exit

Revert to the simplest Hello World:

$ ./tagoael --messageToDisplay='Hello world' --displayIndex=false --numberToDisplay=1
Hello World

It is possible to combine short flags "-in10" = "--displayindex --numbertodisplay=10":

$ ./tagoael -in10 --messageToDisplay='Gooooooo!'
1: Gooooooo!
2: Gooooooo!
3: Gooooooo!
4: Gooooooo!
5: Gooooooo!
6: Gooooooo!
7: Gooooooo!
8: Gooooooo!
9: Gooooooo!
10: Gooooooo!

Last it is possible to provide configuration values from a TOML file:

$ ./tagoael --configFile=tagoael.toml.sample
1: Hello from TOML
2: Hello from TOML
3: Hello from TOML
4: Hello from TOML
5: Hello from TOML
6: Hello from TOML
7: Hello from TOML
8: Hello from TOML
9: Hello from TOML
10: Hello from TOML

By default, configuration from command line will override the one from file:

$ ./tagoael --configFile=tagoael.toml.sample --displayIndex=false
Hello from TOML
Hello from TOML
Hello from TOML
Hello from TOML
Hello from TOML
Hello from TOML
Hello from TOML
Hello from TOML
Hello from TOML
Hello from TOML

unless you define a flag (commandLineOverridesConfigFile) to change this behaviour ("--displayIndex=false" but is true in the TOML file):

$ ./tagoael --configFile=tagoael.toml.sample --displayIndex=false --commandLineOverridesConfigFile=false
1: Hello from TOML
2: Hello from TOML
3: Hello from TOML
4: Hello from TOML
5: Hello from TOML
6: Hello from TOML
7: Hello from TOML
8: Hello from TOML
9: Hello from TOML
10: Hello from TOML