feat(ingestion): runtime symlink tripwire removes what it finds, 30s scans (#157) (#160)

Co-authored-by: Mathias <mthbqv@gmail.com>

ingestion/internal/audit/ntfy.go

@@ -49,7 +49,19 @@ func (n *NtfyNotifier) Notify(ctx context.Context, msg string) error {
 	}
 	defer func() { _ = resp.Body.Close() }()
 	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
-		return fmt.Errorf("ntfy notify: status %d", resp.StatusCode)
+		return &RejectedError{Status: resp.StatusCode}
 	}
 	return nil
 }
+
+// RejectedError is a non-2xx ntfy response.
+type RejectedError struct{ Status int }
+
+func (e *RejectedError) Error() string { return fmt.Sprintf("ntfy notify: status %d", e.Status) }
+
+// Permanent reports whether resending the same message cannot succeed: a 4xx
+// other than 429 (rate limited). Callers may drop such a message; anything
+// else (5xx, 429, transport errors) is an outage and must be retried.
+func (e *RejectedError) Permanent() bool {
+	return e.Status >= 400 && e.Status < 500 && e.Status != http.StatusTooManyRequests
+}

ingestion/internal/audit/ntfy_rejected_test.go

@@ -0,0 +1,27 @@
+package audit
+
+import (
+	"context"
+	"errors"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// A non-2xx ntfy response is a *RejectedError, and only a client-side refusal
+// other than rate limiting is permanent: callers may drop a message on a
+// permanent rejection and must retry the rest (hyperguild#157, PR #160).
+func TestNotifyClassifiesRejectionsAsPermanentOrNot(t *testing.T) {
+	for status, permanent := range map[int]bool{413: true, 400: true, 403: true, 429: false, 500: false, 503: false} {
+		srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) { w.WriteHeader(status) }))
+		err := NewNtfyNotifier(srv.URL, "").Notify(context.Background(), "m")
+		srv.Close()
+		var rej *RejectedError
+		require.True(t, errors.As(err, &rej), "status %d: %v", status, err)
+		assert.Equal(t, status, rej.Status)
+		assert.Equal(t, permanent, rej.Permanent(), "status %d", status)
+	}
+}