add icon emoij and icon url support for slack messages (#48)

docs/argocd-notifications-secret.yaml

@@ -13,6 +13,7 @@ stringData:
     slack:
       token: <my-token>
       username: <override-username> # optional username
+      icon: <override-icon> # optional icon for the message (supports both emoij and url notation)
     opsgenie:
       apiUrl: api.opsgenie.com
       apiKeys:

notifiers/slack.go

@@ -5,12 +5,16 @@ import (
 	"crypto/tls"
 	"encoding/json"
 	"net/http"
+	"net/url"
+	"regexp"
 
 	"github.com/nlopes/slack"
+	log "github.com/sirupsen/logrus"
 )
 
 type SlackOptions struct {
 	Username           string   `json:"username"`
+	Icon               string   `json:"icon"`
 	Token              string   `json:"token"`
 	SigningSecret      string   `json:"signingSecret"`
 	Channels           []string `json:"channels"`
@@ -21,6 +25,8 @@ type slackNotifier struct {
 	opts SlackOptions
 }
 
+var validIconEmoij = regexp.MustCompile(`^:.+:$`)
+
 func NewSlackNotifier(opts SlackOptions) Notifier {
 	return &slackNotifier{opts: opts}
 }
@@ -38,6 +44,15 @@ func (n *slackNotifier) Send(notification Notification, recipient string) error
 	if n.opts.Username != "" {
 		msgOptions = append(msgOptions, slack.MsgOptionUsername(n.opts.Username))
 	}
+	if n.opts.Icon != "" {
+		if validIconEmoij.MatchString(n.opts.Icon) {
+			msgOptions = append(msgOptions, slack.MsgOptionIconEmoji(n.opts.Icon))
+		} else if isValidIconURL(n.opts.Icon) {
+			msgOptions = append(msgOptions, slack.MsgOptionIconURL(n.opts.Icon))
+		} else {
+			log.Warnf("Icon reference '%v' is not a valid emoij or url", n.opts.Icon)
+		}
+	}
 
 	if notification.Slack != nil {
 		attachments := make([]slack.Attachment, 0)
@@ -59,3 +74,17 @@ func (n *slackNotifier) Send(notification Notification, recipient string) error
 	_, _, err := s.PostMessageContext(context.TODO(), recipient, msgOptions...)
 	return err
 }
+
+func isValidIconURL(iconURL string) bool {
+	_, err := url.ParseRequestURI(iconURL)
+	if err != nil {
+		return false
+	}
+
+	u, err := url.Parse(iconURL)
+	if err != nil || (u.Scheme == "" || !(u.Scheme == "http" || u.Scheme == "https")) || u.Host == "" {
+		return false
+	}
+
+	return true
+}

notifiers/slack_test.go

@@ -0,0 +1,21 @@
+package notifiers
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestValidIconEmoij(t *testing.T) {
+	assert.Equal(t, true, validIconEmoij.MatchString(":slack:"))
+	assert.Equal(t, true, validIconEmoij.MatchString(":chart_with_upwards_trend:"))
+	assert.Equal(t, false, validIconEmoij.MatchString("http://lorempixel.com/48/48"))
+}
+
+func TestValidIconURL(t *testing.T) {
+	assert.Equal(t, true, isValidIconURL("http://lorempixel.com/48/48"))
+	assert.Equal(t, true, isValidIconURL("https://lorempixel.com/48/48"))
+	assert.Equal(t, false, isValidIconURL("favicon.ico"))
+	assert.Equal(t, false, isValidIconURL("ftp://favicon.ico"))
+	assert.Equal(t, false, isValidIconURL("ftp://lorempixel.com/favicon.ico"))
+}