flagger/pkg/notifier/discord.go

package notifier

import (
	"errors"
	"fmt"
	"net/url"
	"path"
	"strings"
)

// Discord holds the hook URL
type Discord struct {
	URL      string
	Username string
	Channel  string
}

// NewDiscord validates the URL and returns a Discord object
func NewDiscord(hookURL string, username string, channel string) (*Discord, error) {
	webhook, err := url.ParseRequestURI(hookURL)
	if err != nil {
		return nil, fmt.Errorf("invalid Discord hook URL %s", hookURL)
	}

	// use Slack formatting
	// https://birdie0.github.io/discord-webhooks-guide/other/slack_formatting.html
	if !strings.HasSuffix(hookURL, "/slack") {
		webhook.Path = path.Join(webhook.Path, "slack")
		hookURL = webhook.String()
	}

	if username == "" {
		return nil, errors.New("empty Discord username")
	}

	if channel == "" {
		return nil, errors.New("empty Discord channel")
	}

	return &Discord{
		Channel:  channel,
		URL:      hookURL,
		Username: username,
	}, nil
}

// Post Discord message
func (s *Discord) Post(workload string, namespace string, message string, fields []Field, severity string) error {
	payload := SlackPayload{
		Channel:   s.Channel,
		Username:  s.Username,
		IconEmoji: ":rocket:",
	}

	color := "good"
	if severity == "error" {
		color = "danger"
	}

	sfields := make([]SlackField, 0, len(fields))
	for _, f := range fields {
		sfields = append(sfields, SlackField{f.Name, f.Value, false})
	}

	a := SlackAttachment{
		Color:      color,
		AuthorName: fmt.Sprintf("%s.%s", workload, namespace),
		Text:       message,
		MrkdwnIn:   []string{"text"},
		Fields:     sfields,
	}

	payload.Attachments = []SlackAttachment{a}

	err := postMessage(s.URL, payload)
	if err != nil {
		return fmt.Errorf("postMessage failed: %w", err)
	}

	return nil
}