mkobaly / slacker

Slack Bot Framework

slacker

Built on top of the Slack API github.com/slack-go/slack with the idea to simplify the Real-Time Messaging feature to easily create Slack Bots, assign commands to them and extract parameters.

Features

• Supports Slack Apps using Socket Mode
• Easy definitions of commands and their input
• Available bot initialization, errors and default handlers
• Simple parsing of String, Integer, Float and Boolean parameters
• Contains support for context.Context
• Built-in help command
• Replies can be new messages or in threads
• Supports authorization
• Bot responds to mentions and direct messages
• Handlers run concurrently via goroutines
• Produces events for executed commands
• Full access to the Slack API github.com/slack-go/slack

Dependencies

• commander github.com/shomali11/commander
• slack github.com/slack-go/slack

Install

go get github.com/shomali11/slacker

Preparing your Slack App

To use Slacker you'll need to create a Slack App, either manually or with an app manifest. The app manifest feature is easier, but is a beta feature from Slack and thus may break/change without much notice.

Manual Steps

Slacker works by communicating with the Slack Events API using the Socket Mode connection protocol.

To get started, you must have or create a Slack App and enable Socket Mode, which will generate your app token (SLACK_APP_TOKEN in the examples) that will be needed to authenticate.

Additionally, you need to subscribe to events for your bot to respond to under the Event Subscriptions section. Common event subscriptions for bots include app_mention or message.im.

After setting up your subscriptions, add scopes necessary to your bot in the OAuth & Permissions. The following scopes are recommended for getting started, though you may need to add/remove scopes depending on your bots purpose:

• app_mentions:read
• channels:history
• chat:write
• groups:history
• im:history
• mpim:history

Once you've selected your scopes install your app to the workspace and navigate back to the OAuth & Permissions section. Here you can retrieve yor bot's OAuth token (SLACK_BOT_TOKEN in the examples) from the top of the page.

With both tokens in hand, you can now proceed with the examples below.

App Manifest

Slack App Manifests make it easy to share a app configurations. We provide a simple manifest that should work with all the examples provided below.

Examples

Example 1

Defining a command using slacker

package main

import (
	"context"
	"log"
	"os"

	"github.com/shomali11/slacker"
)

func main() {
	bot := slacker.NewClient(os.Getenv("SLACK_BOT_TOKEN"), os.Getenv("SLACK_APP_TOKEN"))

	definition := &slacker.CommandDefinition{
		Handler: func(botCtx slacker.BotContext, request slacker.Request, response slacker.ResponseWriter) {
			response.Reply("pong")
		},
	}

	bot.Command("ping", definition)

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	err := bot.Listen(ctx)
	if err != nil {
		log.Fatal(err)
	}
}

Example 2

Defining a command with an optional description and example. The handler replies to a thread.

package main

import (
	"context"
	"log"
	"os"

	"github.com/shomali11/slacker"
)

func main() {
	bot := slacker.NewClient(os.Getenv("SLACK_BOT_TOKEN"), os.Getenv("SLACK_APP_TOKEN"))

	definition := &slacker.CommandDefinition{
		Description: "Ping!",
		Example:     "ping",
		Handler: func(botCtx slacker.BotContext, request slacker.Request, response slacker.ResponseWriter) {
			response.Reply("pong", slacker.WithThreadReply(true))
		},
	}

	bot.Command("ping", definition)

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	err := bot.Listen(ctx)
	if err != nil {
		log.Fatal(err)
	}
}

Example 3

Defining a command with a parameter

package main

import (
	"context"
	"log"
	"os"

	"github.com/shomali11/slacker"
)

func main() {
	bot := slacker.NewClient(os.Getenv("SLACK_BOT_TOKEN"), os.Getenv("SLACK_APP_TOKEN"))

	definition := &slacker.CommandDefinition{
		Description: "Echo a word!",
		Example:     "echo hello",
		Handler: func(botCtx slacker.BotContext, request slacker.Request, response slacker.ResponseWriter) {
			word := request.Param("word")
			response.Reply(word)
		},
	}

	bot.Command("echo <word>", definition)

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	err := bot.Listen(ctx)
	if err != nil {
		log.Fatal(err)
	}
}

Example 4

Defining a command with two parameters. Parsing one as a string and the other as an integer. (The second parameter is the default value in case no parameter was passed or could not parse the value)

package main

import (
	"context"
	"log"
	"os"

	"github.com/shomali11/slacker"
)

func main() {
	bot := slacker.NewClient(os.Getenv("SLACK_BOT_TOKEN"), os.Getenv("SLACK_APP_TOKEN"))

	definition := &slacker.CommandDefinition{
		Description: "Repeat a word a number of times!",
		Example:     "repeat hello 10",
		Handler: func(botCtx slacker.BotContext, request slacker.Request, response slacker.ResponseWriter) {
			word := request.StringParam("word", "Hello!")
			number := request.IntegerParam("number", 1)
			for i := 0; i < number; i++ {
				response.Reply(word)
			}
		},
	}

	bot.Command("repeat <word> <number>", definition)

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	err := bot.Listen(ctx)
	if err != nil {
		log.Fatal(err)
	}
}

Example 5

Defines two commands that display sending errors to the Slack channel. One that replies as a new message. The other replies to the thread.

package main

import (
	"context"
	"errors"
	"log"
	"os"

	"github.com/shomali11/slacker"
)

func main() {
	bot := slacker.NewClient(os.Getenv("SLACK_BOT_TOKEN"), os.Getenv("SLACK_APP_TOKEN"))

	messageReplyDefinition := &slacker.CommandDefinition{
		Description: "Tests errors in new messages",
		Handler: func(botCtx slacker.BotContext, request slacker.Request, response slacker.ResponseWriter) {
			response.ReportError(errors.New("Oops!"))
		},
	}

	threadReplyDefinition := &slacker.CommandDefinition{
		Description: "Tests errors in threads",
		Handler: func(botCtx slacker.BotContext, request slacker.Request, response slacker.ResponseWriter) {
			response.ReportError(errors.New("Oops!"), slacker.WithThreadError(true))
		},
	}

	bot.Command("message", messageReplyDefinition)
	bot.Command("thread", threadReplyDefinition)

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	err := bot.Listen(ctx)
	if err != nil {
		log.Fatal(err)
	}
}

Example 6

Showcasing the ability to access the github.com/slack-go/slack API and upload a file

package main

import (
	"context"
	"fmt"
	"log"
	"os"

	"github.com/shomali11/slacker"
	"github.com/slack-go/slack"
)

func main() {
	bot := slacker.NewClient(os.Getenv("SLACK_BOT_TOKEN"), os.Getenv("SLACK_APP_TOKEN"))

	definition := &slacker.CommandDefinition{
		Description: "Upload a word!",
		Handler: func(botCtx slacker.BotContext, request slacker.Request, response slacker.ResponseWriter) {
			word := request.Param("word")
			client := botCtx.Client()
			ev := botCtx.Event()

			if ev.Channel != "" {
				client.PostMessage(ev.Channel, slack.MsgOptionText("Uploading file ...", false))
				_, err := client.UploadFile(slack.FileUploadParameters{Content: word, Channels: []string{ev.Channel}})
				if err != nil {
					fmt.Printf("Error encountered when uploading file: %+v\n", err)
				}
			}
		},
	}

	bot.Command("upload <word>", definition)

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	err := bot.Listen(ctx)
	if err != nil {
		log.Fatal(err)
	}
}

Example 7

Showcasing the ability to leverage context.Context to add a timeout

package main

import (
	"context"
	"errors"
	"log"
	"os"
	"time"

	"github.com/shomali11/slacker"
)

func main() {
	bot := slacker.NewClient(os.Getenv("SLACK_BOT_TOKEN"), os.Getenv("SLACK_APP_TOKEN"))

	definition := &slacker.CommandDefinition{
		Description: "Process!",
		Handler: func(botCtx slacker.BotContext, request slacker.Request, response slacker.ResponseWriter) {
			timedContext, cancel := context.WithTimeout(botCtx.Context(), time.Second)
			defer cancel()

			select {
			case <-timedContext.Done():
				response.ReportError(errors.New("timed out"))
			case <-time.After(time.Minute):
				response.Reply("Processing done!")
			}
		},
	}

	bot.Command("process", definition)

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	err := bot.Listen(ctx)
	if err != nil {
		log.Fatal(err)
	}
}

Example 8

Showcasing the ability to add attachments to a Reply

package main

import (
	"context"
	"log"
	"os"

	"github.com/shomali11/slacker"
	"github.com/slack-go/slack"
)

func main() {
	bot := slacker.NewClient(os.Getenv("SLACK_BOT_TOKEN"), os.Getenv("SLACK_APP_TOKEN"))

	definition := &slacker.CommandDefinition{
		Description: "Echo a word!",
		Handler: func(botCtx slacker.BotContext, request slacker.Request, response slacker.ResponseWriter) {
			word := request.Param("word")

			attachments := []slack.Attachment{}
			attachments = append(attachments, slack.Attachment{
				Color:      "red",
				AuthorName: "Raed Shomali",
				Title:      "Attachment Title",
				Text:       "Attachment Text",
			})

			response.Reply(word, slacker.WithAttachments(attachments))
		},
	}

	bot.Command("echo <word>", definition)

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	err := bot.Listen(ctx)
	if err != nil {
		log.Fatal(err)
	}
}

Example 9

Showcasing the ability to add blocks to a Reply

package main

import (
	"context"
	"log"
	"os"

	"github.com/shomali11/slacker"
	"github.com/slack-go/slack"
)

func main() {
	bot := slacker.NewClient(os.Getenv("SLACK_BOT_TOKEN"), os.Getenv("SLACK_APP_TOKEN"))

	definition := &slacker.CommandDefinition{
		Description: "Echo a word!",
		Handler: func(botCtx slacker.BotContext, request slacker.Request, response slacker.ResponseWriter) {
			word := request.Param("word")

			attachments := []slack.Block{}
			attachments = append(attachments, slack.NewContextBlock("1",
				slack.NewTextBlockObject("mrkdwn", "Hi!", false, false)),
			)

			response.Reply(word, slacker.WithBlocks(attachments))
		},
	}

	bot.Command("echo <word>", definition)

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	err := bot.Listen(ctx)
	if err != nil {
		log.Fatal(err)
	}
}

Example 10

Showcasing the ability to create custom responses via CustomResponse

package main

import (
	"context"
	"errors"
	"fmt"
	"log"
	"os"

	"github.com/shomali11/slacker"
	"github.com/slack-go/slack"
)

const (
	errorFormat = "> Custom Error: _%s_"
)

func main() {
	bot := slacker.NewClient(os.Getenv("SLACK_BOT_TOKEN"), os.Getenv("SLACK_APP_TOKEN"))

	bot.CustomResponse(NewCustomResponseWriter)

	definition := &slacker.CommandDefinition{
		Description: "Custom!",
		Handler: func(botCtx slacker.BotContext, request slacker.Request, response slacker.ResponseWriter) {
			response.Reply("custom")
			response.ReportError(errors.New("oops"))
		},
	}

	bot.Command("custom", definition)

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	err := bot.Listen(ctx)
	if err != nil {
		log.Fatal(err)
	}
}

// NewCustomResponseWriter creates a new ResponseWriter structure
func NewCustomResponseWriter(botCtx slacker.BotContext) slacker.ResponseWriter {
	return &MyCustomResponseWriter{botCtx: botCtx}
}

// MyCustomResponseWriter a custom response writer
type MyCustomResponseWriter struct {
	botCtx slacker.BotContext
}

// ReportError sends back a formatted error message to the channel where we received the event from
func (r *MyCustomResponseWriter) ReportError(err error, options ...slacker.ReportErrorOption) {
	defaults := slacker.NewReportErrorDefaults(options...)

	client := r.botCtx.Client()
	event := r.botCtx.Event()

	opts := []slack.MsgOption{
		slack.MsgOptionText(fmt.Sprintf(errorFormat, err.Error()), false),
	}
	if defaults.ThreadResponse {
		opts = append(opts, slack.MsgOptionTS(event.TimeStamp))
	}

	_, _, err = client.PostMessage(event.Channel, opts...)
	if err != nil {
		fmt.Println("failed to report error: %v", err)
	}
}

// Reply send a attachments to the current channel with a message
func (r *MyCustomResponseWriter) Reply(message string, options ...slacker.ReplyOption) error {
	defaults := slacker.NewReplyDefaults(options...)

	client := r.botCtx.Client()
	event := r.botCtx.Event()
	if event == nil {
		return fmt.Errorf("Unable to get message event details")
	}

	opts := []slack.MsgOption{
		slack.MsgOptionText(message, false),
		slack.MsgOptionAttachments(defaults.Attachments...),
		slack.MsgOptionBlocks(defaults.Blocks...),
	}
	if defaults.ThreadResponse {
		opts = append(opts, slack.MsgOptionTS(event.TimeStamp))
	}

	_, _, err := client.PostMessage(
		event.Channel,
		opts...,
	)
	return err
}

Example 11

Showcasing the ability to toggle the slack Debug option via WithDebug

package main

import (
	"context"
	"github.com/shomali11/slacker"
	"log"
	"os"
)

func main() {
	bot := slacker.NewClient(os.Getenv("SLACK_BOT_TOKEN"), os.Getenv("SLACK_APP_TOKEN"))

	definition := &slacker.CommandDefinition{
		Description: "Ping!",
		Handler: func(botCtx slacker.BotContext, request slacker.Request, response slacker.ResponseWriter) {
			response.Reply("pong")
		},
	}

	bot.Command("ping", definition)

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	err := bot.Listen(ctx)
	if err != nil {
		log.Fatal(err)
	}
}

Example 12

Defining a command that can only be executed by authorized users

package main

import (
	"context"
	"log"
	"os"

	"github.com/shomali11/slacker"
)

func main() {
	bot := slacker.NewClient(os.Getenv("SLACK_BOT_TOKEN"), os.Getenv("SLACK_APP_TOKEN"))

	authorizedUsers := []string{"<User ID>"}

	authorizedDefinition := &slacker.CommandDefinition{
		Description: "Very secret stuff",
		AuthorizationFunc: func(botCtx slacker.BotContext, request slacker.Request) bool {
			return contains(authorizedUsers, botCtx.Event().User)
		},
		Handler: func(botCtx slacker.BotContext, request slacker.Request, response slacker.ResponseWriter) {
			response.Reply("You are authorized!")
		},
	}

	bot.Command("secret", authorizedDefinition)

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	err := bot.Listen(ctx)
	if err != nil {
		log.Fatal(err)
	}
}

func contains(list []string, element string) bool {
	for _, value := range list {
		if value == element {
			return true
		}
	}
	return false
}

Example 13

Adding handlers to when the bot is connected, encounters an error and a default for when none of the commands match

package main

import (
	"log"
	"os"

	"context"
	"fmt"

	"github.com/shomali11/slacker"
)

func main() {
	bot := slacker.NewClient(os.Getenv("SLACK_BOT_TOKEN"), os.Getenv("SLACK_APP_TOKEN"))

	bot.Init(func() {
		log.Println("Connected!")
	})

	bot.Err(func(err string) {
		log.Println(err)
	})

	bot.DefaultCommand(func(botCtx slacker.BotContext, request slacker.Request, response slacker.ResponseWriter) {
		response.Reply("Say what?")
	})

	bot.DefaultEvent(func(event interface{}) {
		fmt.Println(event)
	})

	definition := &slacker.CommandDefinition{
		Description: "help!",
		Handler: func(botCtx slacker.BotContext, request slacker.Request, response slacker.ResponseWriter) {
			response.Reply("Your own help function...")
		},
	}

	bot.Help(definition)

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	err := bot.Listen(ctx)
	if err != nil {
		log.Fatal(err)
	}
}

Example 14

Listening to the Commands Events being produced

package main

import (
	"fmt"
	"log"
	"os"

	"context"

	"github.com/shomali11/slacker"
)

func printCommandEvents(analyticsChannel <-chan *slacker.CommandEvent) {
	for event := range analyticsChannel {
		fmt.Println("Command Events")
		fmt.Println(event.Timestamp)
		fmt.Println(event.Command)
		fmt.Println(event.Parameters)
		fmt.Println(event.Event)
		fmt.Println()
	}
}

func main() {
	bot := slacker.NewClient(os.Getenv("SLACK_BOT_TOKEN"), os.Getenv("SLACK_APP_TOKEN"))

	go printCommandEvents(bot.CommandEvents())

	bot.Command("ping", &slacker.CommandDefinition{
		Handler: func(botCtx slacker.BotContext, request slacker.Request, response slacker.ResponseWriter) {
			response.Reply("pong")
		},
	})

	bot.Command("echo <word>", &slacker.CommandDefinition{
		Description: "Echo a word!",
		Example:     "echo hello",
		Handler: func(botCtx slacker.BotContext, request slacker.Request, response slacker.ResponseWriter) {
			word := request.Param("word")
			response.Reply(word)
		},
	})

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	err := bot.Listen(ctx)
	if err != nil {
		log.Fatal(err)
	}
}

Troubleshooting

My bot is not responding to events

There are a few common issues that can cause this:

• The OAuth (bot) Token may be incorrect. In this case authentication does not fail like it does if the App Token is incorrect, and the bot will simply have no scopes and be unable to respond.
• Required scopes are missing from the OAuth (bot) Token. Similar to the incorrect OAuth Token, without the necessary scopes, the bot cannot respond.
• The bot does not have the correct event subscriptions setup, and is not receiving events to respond to.