Implement Discord notifier with Slack formatting

pkg/notifier/discord.go

@@ -0,0 +1,81 @@
+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, warn bool) error {
+	payload := SlackPayload{
+		Channel:   s.Channel,
+		Username:  s.Username,
+		IconEmoji: ":rocket:",
+	}
+
+	color := "good"
+	if warn {
+		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 err
+	}
+
+	return nil
+}

pkg/notifier/discord_test.go

@@ -0,0 +1,49 @@
+package notifier
+
+import (
+	"encoding/json"
+	"io/ioutil"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+func TestDiscord_Post(t *testing.T) {
+	fields := []Field{
+		{Name: "name1", Value: "value1"},
+		{Name: "name2", Value: "value2"},
+	}
+
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		b, err := ioutil.ReadAll(r.Body)
+		if err != nil {
+			t.Fatal(err)
+		}
+		var payload = SlackPayload{}
+		err = json.Unmarshal(b, &payload)
+
+		if payload.Attachments[0].AuthorName != "podinfo.test" {
+			t.Fatal("wrong author name")
+		}
+
+		if len(payload.Attachments[0].Fields) != len(fields) {
+			t.Fatal("wrong facts")
+		}
+	}))
+	defer ts.Close()
+
+	discord, err := NewDiscord(ts.URL, "test", "test")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !strings.HasSuffix(discord.URL, "/slack") {
+		t.Error("Invalid Discord URL, expected to have /slack prefix")
+	}
+
+	err = discord.Post("podinfo", "test", "test", fields, true)
+	if err != nil {
+		t.Fatal(err)
+	}
+}

pkg/notifier/factory.go

@@ -18,6 +18,8 @@ func (f Factory) Notifier(provider string) (Interface, error) {
 	switch {
 	case provider == "slack":
 		return NewSlack(f.URL, f.Username, f.Channel)
+	case provider == "discord":
+		return NewDiscord(f.URL, f.Username, f.Channel)
 	case provider == "msteams":
 		return NewMSTeams(f.URL)
 	}

pkg/notifier/slack.go

@@ -8,10 +8,9 @@ import (
 
 // Slack holds the hook URL
 type Slack struct {
-	URL       string
-	Username  string
-	Channel   string
-	IconEmoji string
+	URL      string
+	Username string
+	Channel  string
 }
 
 // SlackPayload holds the channel and attachments
@@ -55,18 +54,18 @@ func NewSlack(hookURL string, username string, channel string) (*Slack, error) {
 	}
 
 	return &Slack{
-		Channel:   channel,
-		URL:       hookURL,
-		Username:  username,
-		IconEmoji: ":rocket:",
+		Channel:  channel,
+		URL:      hookURL,
+		Username: username,
 	}, nil
 }
 
 // Post Slack message
 func (s *Slack) Post(workload string, namespace string, message string, fields []Field, warn bool) error {
 	payload := SlackPayload{
-		Channel:  s.Channel,
-		Username: s.Username,
+		Channel:   s.Channel,
+		Username:  s.Username,
+		IconEmoji: ":rocket:",
 	}
 
 	color := "good"