feat(notify): release v1.8.0 — Slack/Teams/Google Chat/Telegram/webhook notifications

- Add internal/notify package: best-effort release notifications to Slack, Microsoft Teams, Google Chat, Telegram, and a generic JSON webhook; every target is independently opt-in and a failed notification never fails the release
- Add notify config section (slack_webhook_url, teams_webhook_url, google_chat_webhook_url, telegram_bot_token/telegram_chat_id, webhook_url) with matching env var fallbacks; 100% coverage plus FuzzMessagePayloads
- Wire notification sending into run() — fires after tag+push (including --no-release), skipped on --no-push/--no-commit since nothing was published yet
- Document the notify section in README, Hugo docs, and .releaser.yml template; update CLAUDE.md architecture/fuzzing tables
- Also commit the Apache License 2.0 docs-site footer link (docs/hugo.toml geekdocContentLicense), left uncommitted from a prior change

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/notify/googlechat.go

@@ -0,0 +1,20 @@
+package notify
+
+import (
+	"context"
+	"fmt"
+)
+
+// googleChatPayload matches the Google Chat Incoming Webhook contract: a
+// single "text" field.
+type googleChatPayload struct {
+	Text string `json:"text"`
+}
+
+func newGoogleChatPayload(msg Message) googleChatPayload {
+	return googleChatPayload{Text: fmt.Sprintf("*Released %s*\n\n%s", msg.Version, msg.Notes)}
+}
+
+func sendGoogleChat(ctx context.Context, webhookURL string, msg Message) error {
+	return postJSON(ctx, webhookURL, newGoogleChatPayload(msg))
+}

internal/notify/googlechat_test.go

@@ -0,0 +1,37 @@
+package notify
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+func TestSendGoogleChat(t *testing.T) {
+	var got googleChatPayload
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		json.NewDecoder(r.Body).Decode(&got) //nolint:errcheck
+		w.WriteHeader(http.StatusOK)
+	}))
+	defer srv.Close()
+
+	if err := sendGoogleChat(context.Background(), srv.URL, Message{Version: "v1.2.3", Notes: "- feat: y"}); err != nil {
+		t.Fatalf("sendGoogleChat: %v", err)
+	}
+	if !strings.Contains(got.Text, "v1.2.3") || !strings.Contains(got.Text, "feat: y") {
+		t.Errorf("payload text = %q", got.Text)
+	}
+}
+
+func TestSendGoogleChatError(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusBadRequest)
+	}))
+	defer srv.Close()
+
+	if err := sendGoogleChat(context.Background(), srv.URL, Message{Version: "v1.0.0"}); err == nil {
+		t.Fatal("expected error for 400 response")
+	}
+}

internal/notify/notify.go

@@ -0,0 +1,88 @@
+// Package notify sends best-effort release notifications to chat and webhook targets.
+package notify
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"time"
+)
+
+// Message is the content of a release notification, shared across all targets.
+type Message struct {
+	Version string // tag name, e.g. "v1.2.3"
+	Notes   string // release notes body
+}
+
+// Config holds the destination for every supported notification target.
+// Every field is opt-in — a target is skipped when its required fields are empty.
+type Config struct {
+	SlackWebhookURL      string
+	TeamsWebhookURL      string
+	GoogleChatWebhookURL string
+	TelegramBotToken     string
+	TelegramChatID       string
+	WebhookURL           string
+}
+
+var httpClient = &http.Client{Timeout: 15 * time.Second}
+
+// SendAll sends msg to every target configured in cfg. Each target is attempted
+// independently — a failure on one does not prevent the others from being tried.
+// Returns one error per failed target, or nil if every configured target
+// succeeded (or none were configured).
+func SendAll(ctx context.Context, cfg Config, msg Message) []error {
+	var errs []error
+
+	if cfg.SlackWebhookURL != "" {
+		if err := sendSlack(ctx, cfg.SlackWebhookURL, msg); err != nil {
+			errs = append(errs, fmt.Errorf("slack: %w", err))
+		}
+	}
+	if cfg.TeamsWebhookURL != "" {
+		if err := sendTeams(ctx, cfg.TeamsWebhookURL, msg); err != nil {
+			errs = append(errs, fmt.Errorf("teams: %w", err))
+		}
+	}
+	if cfg.GoogleChatWebhookURL != "" {
+		if err := sendGoogleChat(ctx, cfg.GoogleChatWebhookURL, msg); err != nil {
+			errs = append(errs, fmt.Errorf("google chat: %w", err))
+		}
+	}
+	if cfg.TelegramBotToken != "" && cfg.TelegramChatID != "" {
+		if err := sendTelegram(ctx, cfg.TelegramBotToken, cfg.TelegramChatID, msg); err != nil {
+			errs = append(errs, fmt.Errorf("telegram: %w", err))
+		}
+	}
+	if cfg.WebhookURL != "" {
+		if err := sendWebhook(ctx, cfg.WebhookURL, msg); err != nil {
+			errs = append(errs, fmt.Errorf("webhook: %w", err))
+		}
+	}
+
+	return errs
+}
+
+// postJSON POSTs payload as JSON to url and treats any non-2xx response as an error.
+func postJSON(ctx context.Context, url string, payload any) error {
+	body, _ := json.Marshal(payload) // payload fields are always plain strings — Marshal cannot fail here
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewReader(body))
+	if err != nil {
+		return err
+	}
+	req.Header.Set("Content-Type", "application/json")
+
+	resp, err := httpClient.Do(req)
+	if err != nil {
+		return fmt.Errorf("request failed: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		return fmt.Errorf("returned status %d", resp.StatusCode)
+	}
+	return nil
+}

internal/notify/notify_fuzz_test.go

@@ -0,0 +1,28 @@
+package notify
+
+import (
+	"encoding/json"
+	"strings"
+	"testing"
+)
+
+// FuzzMessagePayloads verifies that building a notification payload never
+// panics on arbitrary version/notes strings, no matter the target — release
+// notes are generated from free-form commit messages and end up embedded in
+// every payload below.
+func FuzzMessagePayloads(f *testing.F) {
+	f.Add("v1.2.3", "release notes")
+	f.Add("", "")
+	f.Add("v1.0.0", "* markdown _weird_ [chars] `code` <html> & \"quotes\"")
+	f.Add("tag\nwith\nnewline", "notes\x00with\xffbinary")
+	f.Add("v1.0.0", strings.Repeat("x", 10000))
+
+	f.Fuzz(func(t *testing.T, version, notes string) {
+		msg := Message{Version: version, Notes: notes}
+		_, _ = json.Marshal(newSlackPayload(msg))
+		_, _ = json.Marshal(newGoogleChatPayload(msg))
+		_, _ = json.Marshal(newTeamsPayload(msg))
+		_, _ = json.Marshal(newTelegramPayload("chat-id", msg))
+		_, _ = json.Marshal(newWebhookPayload(msg))
+	})
+}

internal/notify/notify_test.go

@@ -0,0 +1,137 @@
+package notify
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+// alwaysFailTransport returns an error for every request.
+type alwaysFailTransport struct{}
+
+func (alwaysFailTransport) RoundTrip(*http.Request) (*http.Response, error) {
+	return nil, &testTransportError{"connection refused"}
+}
+
+type testTransportError struct{ msg string }
+
+func (e *testTransportError) Error() string { return e.msg }
+
+func TestPostJSONSuccess(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+	}))
+	defer srv.Close()
+
+	if err := postJSON(context.Background(), srv.URL, map[string]string{"a": "b"}); err != nil {
+		t.Fatalf("postJSON: %v", err)
+	}
+}
+
+func TestPostJSONBadURL(t *testing.T) {
+	err := postJSON(context.Background(), "http://\x00bad", map[string]string{"a": "b"})
+	if err == nil {
+		t.Fatal("expected error for invalid URL")
+	}
+}
+
+func TestPostJSONRequestFails(t *testing.T) {
+	orig := httpClient
+	httpClient = &http.Client{Transport: alwaysFailTransport{}}
+	defer func() { httpClient = orig }()
+
+	err := postJSON(context.Background(), "http://127.0.0.1:1", map[string]string{"a": "b"})
+	if err == nil {
+		t.Fatal("expected error when HTTP request fails")
+	}
+}
+
+func TestPostJSONNon2xx(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusInternalServerError)
+	}))
+	defer srv.Close()
+
+	err := postJSON(context.Background(), srv.URL, map[string]string{"a": "b"})
+	if err == nil {
+		t.Fatal("expected error for 500 response")
+	}
+}
+
+func TestSendAllNoneConfigured(t *testing.T) {
+	errs := SendAll(context.Background(), Config{}, Message{Version: "v1.0.0"})
+	if errs != nil {
+		t.Fatalf("expected no errors, got %v", errs)
+	}
+}
+
+func TestSendAllAllSucceed(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+	}))
+	defer srv.Close()
+
+	origBase := telegramAPIBase
+	telegramAPIBase = srv.URL
+	defer func() { telegramAPIBase = origBase }()
+
+	cfg := Config{
+		SlackWebhookURL:      srv.URL,
+		TeamsWebhookURL:      srv.URL,
+		GoogleChatWebhookURL: srv.URL,
+		TelegramBotToken:     "tok",
+		TelegramChatID:       "123",
+		WebhookURL:           srv.URL,
+	}
+	errs := SendAll(context.Background(), cfg, Message{Version: "v1.0.0", Notes: "notes"})
+	if errs != nil {
+		t.Fatalf("expected no errors, got %v", errs)
+	}
+}
+
+func TestSendAllAllFail(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusInternalServerError)
+	}))
+	defer srv.Close()
+
+	origBase := telegramAPIBase
+	telegramAPIBase = srv.URL
+	defer func() { telegramAPIBase = origBase }()
+
+	cfg := Config{
+		SlackWebhookURL:      srv.URL,
+		TeamsWebhookURL:      srv.URL,
+		GoogleChatWebhookURL: srv.URL,
+		TelegramBotToken:     "tok",
+		TelegramChatID:       "123",
+		WebhookURL:           srv.URL,
+	}
+	errs := SendAll(context.Background(), cfg, Message{Version: "v1.0.0"})
+	if len(errs) != 5 {
+		t.Fatalf("expected 5 errors, got %d: %v", len(errs), errs)
+	}
+}
+
+func TestSendAllTelegramRequiresBothFields(t *testing.T) {
+	calls := 0
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		calls++
+		w.WriteHeader(http.StatusOK)
+	}))
+	defer srv.Close()
+
+	origBase := telegramAPIBase
+	telegramAPIBase = srv.URL
+	defer func() { telegramAPIBase = origBase }()
+
+	// Only bot token set — chat ID missing — Telegram target must be skipped.
+	errs := SendAll(context.Background(), Config{TelegramBotToken: "tok"}, Message{Version: "v1.0.0"})
+	if errs != nil {
+		t.Fatalf("expected no errors, got %v", errs)
+	}
+	if calls != 0 {
+		t.Fatalf("expected telegram to be skipped, got %d calls", calls)
+	}
+}

internal/notify/slack.go

@@ -0,0 +1,20 @@
+package notify
+
+import (
+	"context"
+	"fmt"
+)
+
+// slackPayload matches the Slack Incoming Webhook contract: a single "text"
+// field, interpreted as Slack mrkdwn.
+type slackPayload struct {
+	Text string `json:"text"`
+}
+
+func newSlackPayload(msg Message) slackPayload {
+	return slackPayload{Text: fmt.Sprintf("*Released %s*\n\n%s", msg.Version, msg.Notes)}
+}
+
+func sendSlack(ctx context.Context, webhookURL string, msg Message) error {
+	return postJSON(ctx, webhookURL, newSlackPayload(msg))
+}

internal/notify/slack_test.go

@@ -0,0 +1,40 @@
+package notify
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+func TestSendSlack(t *testing.T) {
+	var got slackPayload
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if ct := r.Header.Get("Content-Type"); ct != "application/json" {
+			t.Errorf("Content-Type = %q", ct)
+		}
+		json.NewDecoder(r.Body).Decode(&got) //nolint:errcheck
+		w.WriteHeader(http.StatusOK)
+	}))
+	defer srv.Close()
+
+	if err := sendSlack(context.Background(), srv.URL, Message{Version: "v1.2.3", Notes: "- fix: x"}); err != nil {
+		t.Fatalf("sendSlack: %v", err)
+	}
+	if !strings.Contains(got.Text, "v1.2.3") || !strings.Contains(got.Text, "fix: x") {
+		t.Errorf("payload text = %q", got.Text)
+	}
+}
+
+func TestSendSlackError(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusForbidden)
+	}))
+	defer srv.Close()
+
+	if err := sendSlack(context.Background(), srv.URL, Message{Version: "v1.0.0"}); err == nil {
+		t.Fatal("expected error for 403 response")
+	}
+}

internal/notify/teams.go

@@ -0,0 +1,31 @@
+package notify
+
+import (
+	"context"
+	"fmt"
+)
+
+// teamsPayload is a Microsoft Teams "Incoming Webhook" O365 connector card
+// (MessageCard schema) — the format Teams webhook URLs still accept.
+type teamsPayload struct {
+	Type    string `json:"@type"`
+	Context string `json:"@context"`
+	Summary string `json:"summary"`
+	Title   string `json:"title"`
+	Text    string `json:"text"`
+}
+
+func newTeamsPayload(msg Message) teamsPayload {
+	title := fmt.Sprintf("Released %s", msg.Version)
+	return teamsPayload{
+		Type:    "MessageCard",
+		Context: "http://schema.org/extensions",
+		Summary: title,
+		Title:   title,
+		Text:    msg.Notes,
+	}
+}
+
+func sendTeams(ctx context.Context, webhookURL string, msg Message) error {
+	return postJSON(ctx, webhookURL, newTeamsPayload(msg))
+}

internal/notify/teams_test.go

@@ -0,0 +1,43 @@
+package notify
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+func TestSendTeams(t *testing.T) {
+	var got teamsPayload
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		json.NewDecoder(r.Body).Decode(&got) //nolint:errcheck
+		w.WriteHeader(http.StatusOK)
+	}))
+	defer srv.Close()
+
+	if err := sendTeams(context.Background(), srv.URL, Message{Version: "v1.2.3", Notes: "- fix: z"}); err != nil {
+		t.Fatalf("sendTeams: %v", err)
+	}
+	if got.Type != "MessageCard" {
+		t.Errorf("Type = %q, want MessageCard", got.Type)
+	}
+	if !strings.Contains(got.Title, "v1.2.3") || !strings.Contains(got.Summary, "v1.2.3") {
+		t.Errorf("Title/Summary = %q/%q, want to contain v1.2.3", got.Title, got.Summary)
+	}
+	if !strings.Contains(got.Text, "fix: z") {
+		t.Errorf("Text = %q", got.Text)
+	}
+}
+
+func TestSendTeamsError(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusServiceUnavailable)
+	}))
+	defer srv.Close()
+
+	if err := sendTeams(context.Background(), srv.URL, Message{Version: "v1.0.0"}); err == nil {
+		t.Fatal("expected error for 503 response")
+	}
+}

internal/notify/telegram.go

@@ -0,0 +1,30 @@
+package notify
+
+import (
+	"context"
+	"fmt"
+)
+
+// telegramAPIBase is the Telegram Bot API host. Overridden in tests.
+var telegramAPIBase = "https://api.telegram.org"
+
+// telegramPayload matches the Telegram Bot API sendMessage contract. Notes
+// are sent as plain text (no parse_mode) — release notes come from arbitrary
+// commit messages and are not guaranteed to be valid Telegram Markdown/HTML,
+// and a malformed entity makes the whole request fail with a 400.
+type telegramPayload struct {
+	ChatID string `json:"chat_id"`
+	Text   string `json:"text"`
+}
+
+func newTelegramPayload(chatID string, msg Message) telegramPayload {
+	return telegramPayload{
+		ChatID: chatID,
+		Text:   fmt.Sprintf("Released %s\n\n%s", msg.Version, msg.Notes),
+	}
+}
+
+func sendTelegram(ctx context.Context, botToken, chatID string, msg Message) error {
+	url := fmt.Sprintf("%s/bot%s/sendMessage", telegramAPIBase, botToken)
+	return postJSON(ctx, url, newTelegramPayload(chatID, msg))
+}

internal/notify/telegram_test.go

@@ -0,0 +1,53 @@
+package notify
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+func TestSendTelegram(t *testing.T) {
+	var got telegramPayload
+	var path string
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		path = r.URL.Path
+		json.NewDecoder(r.Body).Decode(&got) //nolint:errcheck
+		w.WriteHeader(http.StatusOK)
+	}))
+	defer srv.Close()
+
+	orig := telegramAPIBase
+	telegramAPIBase = srv.URL
+	defer func() { telegramAPIBase = orig }()
+
+	if err := sendTelegram(context.Background(), "bot-token", "chat-1", Message{Version: "v1.2.3", Notes: "notes body"}); err != nil {
+		t.Fatalf("sendTelegram: %v", err)
+	}
+	if !strings.Contains(path, "bot-token") {
+		t.Errorf("path = %q, want to contain bot token", path)
+	}
+	if got.ChatID != "chat-1" {
+		t.Errorf("ChatID = %q, want chat-1", got.ChatID)
+	}
+	if !strings.Contains(got.Text, "v1.2.3") || !strings.Contains(got.Text, "notes body") {
+		t.Errorf("Text = %q", got.Text)
+	}
+}
+
+func TestSendTelegramError(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusBadRequest)
+	}))
+	defer srv.Close()
+
+	orig := telegramAPIBase
+	telegramAPIBase = srv.URL
+	defer func() { telegramAPIBase = orig }()
+
+	if err := sendTelegram(context.Background(), "bot-token", "chat-1", Message{Version: "v1.0.0"}); err == nil {
+		t.Fatal("expected error for 400 response")
+	}
+}

internal/notify/webhook.go

@@ -0,0 +1,18 @@
+package notify
+
+import "context"
+
+// webhookPayload is a generic JSON envelope for arbitrary API webhooks
+// (e.g. n8n, Zapier, a custom receiver) that don't follow a chat-app schema.
+type webhookPayload struct {
+	Version string `json:"version"`
+	Notes   string `json:"notes"`
+}
+
+func newWebhookPayload(msg Message) webhookPayload {
+	return webhookPayload(msg)
+}
+
+func sendWebhook(ctx context.Context, url string, msg Message) error {
+	return postJSON(ctx, url, newWebhookPayload(msg))
+}

internal/notify/webhook_test.go

@@ -0,0 +1,39 @@
+package notify
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestSendWebhook(t *testing.T) {
+	var got webhookPayload
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		json.NewDecoder(r.Body).Decode(&got) //nolint:errcheck
+		w.WriteHeader(http.StatusOK)
+	}))
+	defer srv.Close()
+
+	if err := sendWebhook(context.Background(), srv.URL, Message{Version: "v1.2.3", Notes: "notes body"}); err != nil {
+		t.Fatalf("sendWebhook: %v", err)
+	}
+	if got.Version != "v1.2.3" {
+		t.Errorf("Version = %q, want v1.2.3", got.Version)
+	}
+	if got.Notes != "notes body" {
+		t.Errorf("Notes = %q, want %q", got.Notes, "notes body")
+	}
+}
+
+func TestSendWebhookError(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusInternalServerError)
+	}))
+	defer srv.Close()
+
+	if err := sendWebhook(context.Background(), srv.URL, Message{Version: "v1.0.0"}); err == nil {
+		t.Fatal("expected error for 500 response")
+	}
+}