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).

cmd/panel/journal.go

@@ -0,0 +1,45 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"log"
+	"net"
+	"os"
+	"path/filepath"
+
+	"codeberg.org/mix/selfpost/internal/milter"
+	"codeberg.org/mix/selfpost/internal/store"
+)
+
+// serveJournal opens the journal-milter Unix socket and runs the real milter
+// (spec 7.3), recording accepted messages into the send log. Socket lifecycle
+// (creation, stale cleanup, group permissions) lives here; the protocol handler
+// lives in internal/milter.
+func serveJournal(ctx context.Context, cfg config, st *store.Store) error {
+	socketPath := cfg.journalSocket
+	if err := os.MkdirAll(filepath.Dir(socketPath), 0o755); err != nil {
+		return err
+	}
+	// Clear a stale socket left behind by an unclean shutdown, otherwise the
+	// listen below fails with "address already in use".
+	if err := os.Remove(socketPath); err != nil && !errors.Is(err, os.ErrNotExist) {
+		return err
+	}
+
+	ln, err := net.Listen("unix", socketPath)
+	if err != nil {
+		return err
+	}
+	// Postfix (user `postfix`) connects to this socket as a milter and needs
+	// group access. The socket inherits group `selfpost` from the setgid parent
+	// dir entrypoint.sh prepares; make it group read/write so postfix can reach
+	// it (connecting to a Unix socket needs write permission on the node).
+	if err := os.Chmod(socketPath, 0o660); err != nil {
+		ln.Close()
+		return err
+	}
+
+	log.Printf("journal-milter listening on %s", socketPath)
+	return milter.Serve(ctx, ln, st)
+}