Post random text to Slack using Go

slack-post.go

package main

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"os"
	"strings"
)

const (
	URL            string = "https://example.org"
	CONTENT_TYPE   string = "application/json"
	SLACK_USERNAME string = "The tiny Go bot"
	SLACK_EMOJI    string = "https://blog.golang.org/gopher/gopher.png"
)

func main() {
	slackRequest := map[string]string{
		"text":     strings.Join(os.Args[2:], " "),
		"username": SLACK_USERNAME,
		"icon_url": SLACK_EMOJI,
		"channel":  os.Args[1],
	}

	jsonRequest, _ := json.Marshal(&slackRequest)

	resp, err := http.Post(URL, CONTENT_TYPE, bytes.NewReader(jsonRequest))
	if err != nil {
		log.Fatalf("Error building request: %s", err)
	}

	if resp.StatusCode != http.StatusOK {
		log.Printf("Wrong status code: %s", resp.Status)
	}
	defer resp.Body.Close()

	body, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		log.Fatalf("Error parsing response: %s", err)
	}
	fmt.Println(string(body))
}

Usage

First replace the URL constant with the URL from your configured incoming webhook

go build slack-post.go
./slack-post "#your-channel" "This is a test"

#your-channel can also be replaced by @a_username