go get github.com/ajm188/slack

package main

import (
    "fmt"

    "github.com/ajm188/slack"
)

func main() {
    bot := slack.NewBot("my_slack_token")
    err := bot.Start()
    if err != nil {
        fmt.Println(err)
    }
}

Note that you need to pass your Slack token to the bot, so your bot can authenticate with the Slack API.

The design of slack is built around a handler pattern. The bot listens for incoming events from the Slack RTM API, and then invokes any handlers for that type of event.

A valid handler takes a reference to the bot and the event and returns a reference to a Message, and a Status, which tells the main loop whether or not to continue interacting with the RTM API.

slack has some factory methods for constructing handlers for common operations, such as responding to a message or posting a reaction to a message. If you need something more fine-grained, feel free to write your own.

There are also convenience methods for registering handlers specifically for "message" type events. The Bot defines instance methods Listen - which finds text that matches the given pattern - and Respond which finds text that first mentions the bot by name and then matches the given pattern. These helper methods have Regexp variants which can take a compiled regular expression directly instead of a string.

package main

// ... imports blah, blah

func main() {
    bot := slack.NewBot("")
    bot.Respond("hi!", slack.Respond("hi!"))
    bot.Start()
}

package main

// imports

func main() {
    bot := slack.NewBot("")
    bot.Listen("ship ?it\\?", slack.React("shipit"))
    bot.Start()
}

slack uses logrus for logging. Feel free to set your log level appropriately in an init function.