Snek is a lite wrapper around both cobra and zerolog. It generates a configurable root command, adds some command line arguments and environment variables to configure both the log format and level and then initialized logging prior to executing the command. Another way to look at snek is as a builder pattern for cobra.

Usage focuses mostly around the Run / RunExit functions. With these functions you define a configuration, initialize the generated command and then run the generated command.

Command configurations are generated by calling the NewConfig function with any desired configurators. A configurator is a function that accepts a *Config as a parameter and may modify the *Config in any way. You may write your own configurators, however some built-in configurators are provided:

The following generates a configuration with the following set:

• The default log format set to json
• The default log level set to debug
• The environment variable prefix set to MY_AWESOME_APP_

cfg := snek.NewConfig(
	snek.WithDefaultLogFormat("json"),
	snek.WithDefaultLogLevel("debug"),
	snek.WithEnvironmentVariablePrefix("MY_AWESOME_APP_"),
)

Commands are generated by calling the NewCommand function with any desired Initializer functions. An Initializer is a function that accepts a *cobra.Command as a parameter and may modify the *cobra.Command in any way, or return an error. You may write your own Initializer, however some are built-in:

Initializers are also passed to the Run and RunExit functions. These initializers are used to generate the root command that is executed by snek.

cmd, err := snek.NewCommand(
	snek.WithUse("my-awesome-command"),
	snek.WithShort("The shortened description for my command"),
	snek.WithLong("The lengthier description for my command"),
	snek.WithRunE(func(cmd *cobra.Command, args []string) error {
		// ...
		return nil
	})
)

Flags can be added to a generated command by calling the WithFlags function with any desired FlagInitializer functions. A FlagInitializer is a function that accepts a *pflag.FlagSet as a parameter and may modify the *pflag.FlagSet in any way, add one or more flags, or return an error. You may write your own FlagInitializer, however some are built-in:

greeting := "hello!"
quantity := 1
cmd, err := snek.NewCommand(
	snek.WithFlag(
		snek.WithStringVarP(&greeting, "greeting", "g", greeting, "The greeting to use"),
		snek.WithStringVarP(&quantity, "quantity", "q", quantity, "The quantity of times to greet"),
	),
	// ...
)

package main

import (
	"io"
	"net/http"

	"github.com/ronelliott/snek"
	"github.com/rs/zerolog/log"
	"github.com/spf13/cobra"
)

func main() {
	snek.RunExit(
		snek.NewConfig(
			snek.WithDefaultLogFormat("json"),
			snek.WithDefaultLogLevel("debug"),
			snek.WithEnvironmentVariablePrefix("MY_AWESOME_APP_"),
		),
		snek.WithUse("my-awesome-command"),
		snek.WithSubCommandGenerator(
			newRunCommand,
		),
	)
}

func newRunCommand() (*cobra.Command, error) {
	port := ":3000"
	return snek.NewCommand(
		snek.WithUse("run"),
		snek.WithShort("Run the application"),
		snek.WithFlag(
			snek.WithStringVarP(&port, "port", "p", port, "The port to bind to"),
		),
		snek.WithSimpleRunE(func(args []string) error {
			helloHandler := func(w http.ResponseWriter, req *http.Request) {
				io.WriteString(w, "Hello, world!\n")
			}

			http.HandleFunc("/hello", helloHandler)
			log.Info().Str("port", port).Msg("Listening")
			return http.ListenAndServe(port, nil)
		}),
	)
}