release: 0.1.0: Phases 0-11: panel, Postfix/DKIM, milter, backup, Docker image

Initial feature-complete implementation of the v1.0 specification (phases 0-11 of `docs/implementation-plan.md`).
Added:
  - Panel (Go, single static binary) with SQLite persistence, one-time
  - Domain management with per-domain DKIM (RSA-2048, generated in pure Go) and
  - Application (sender identity) management: SASL credentials via `sasldb2`,
  - Full Postfix relay config generated from env at container start: SMTPS 465,
  - Journal milter (pure Go, `go-milter`) recording every send to `send_log`;
  … (6 more in CHANGELOG)

Full detail: CHANGELOG.md (0.1.0).

internal/domain/dkim_test.go

@@ -0,0 +1,86 @@
+package domain
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestWriteLoadPrivateKeyRoundtrip(t *testing.T) {
+	key, err := generateDKIMKey()
+	if err != nil {
+		t.Fatalf("generateDKIMKey: %v", err)
+	}
+	path := filepath.Join(t.TempDir(), "selfpost.private")
+	if err := writePrivateKeyPEM(path, key); err != nil {
+		t.Fatalf("writePrivateKeyPEM: %v", err)
+	}
+
+	info, err := os.Stat(path)
+	if err != nil {
+		t.Fatalf("stat: %v", err)
+	}
+	if perm := info.Mode().Perm(); perm != 0o640 {
+		t.Errorf("key perm = %o, want 0640", perm)
+	}
+
+	loaded, err := loadPrivateKeyPEM(path)
+	if err != nil {
+		t.Fatalf("loadPrivateKeyPEM: %v", err)
+	}
+	if loaded.N.Cmp(key.N) != 0 || loaded.E != key.E {
+		t.Error("loaded key does not match generated key")
+	}
+}
+
+func TestLoadPrivateKeyRejectsGarbage(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "bad.private")
+	if err := os.WriteFile(path, []byte("not a pem"), 0o640); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := loadPrivateKeyPEM(path); err == nil {
+		t.Error("expected error for non-PEM key file")
+	}
+}
+
+func TestDKIMRecord(t *testing.T) {
+	key, err := generateDKIMKey()
+	if err != nil {
+		t.Fatal(err)
+	}
+	rec, err := dkimRecord("selfpost", "example.com", &key.PublicKey)
+	if err != nil {
+		t.Fatalf("dkimRecord: %v", err)
+	}
+	if rec.Name != "selfpost._domainkey.example.com" {
+		t.Errorf("record name = %q", rec.Name)
+	}
+	for _, want := range []string{"v=DKIM1", "h=sha256", "k=rsa", "p="} {
+		if !strings.Contains(rec.Value, want) {
+			t.Errorf("record value %q missing %q", rec.Value, want)
+		}
+	}
+}
+
+func TestWriteFileAtomicOverwrite(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "f")
+	if err := writeFileAtomic(path, []byte("one"), 0o640); err != nil {
+		t.Fatal(err)
+	}
+	if err := writeFileAtomic(path, []byte("two"), 0o640); err != nil {
+		t.Fatal(err)
+	}
+	got, err := os.ReadFile(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if string(got) != "two" {
+		t.Errorf("content = %q, want %q", got, "two")
+	}
+	// No stray temp files left behind in the directory.
+	entries, _ := os.ReadDir(filepath.Dir(path))
+	if len(entries) != 1 {
+		t.Errorf("expected 1 file after atomic writes, found %d", len(entries))
+	}
+}