Add Postfix+OpenDKIM MTA with txt-based domain management

- mail/ ディレクトリ追加: Postfix + OpenDKIM の Docker コンテナ
- mail/domains.txt で送信ドメインを管理（現在: golive.yyamashita.com）
- install.sh が domains.txt から KeyTable/SigningTable を動的生成
- setup-route53.py で SPF/DKIM/DMARC を Route 53 に一括設定
- post-receive フックに mail/deploy.sh を追加

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

1 files changed, 32 insertions, 0 deletions

diff --git a/mail/entrypoint.sh b/mail/entrypoint.sh
new file mode 100755
index 0000000..2dc8f26
--- /dev/null
+++ b/mail/entrypoint.sh
@@ -0,0 +1,32 @@
+#!/usr/bin/env bash
+set -e
+
+KEY_FILE=/etc/opendkim/keys/mail.private
+
+# Wait for DKIM key (mounted from host)
+for i in $(seq 1 30); do
+    [[ -f "$KEY_FILE" ]] && break
+    echo "Waiting for DKIM key at $KEY_FILE ... (run mail/install.sh on host)"
+    sleep 2
+done
+if [[ ! -f "$KEY_FILE" ]]; then
+    echo "ERROR: DKIM key not found at $KEY_FILE" >&2
+    exit 1
+fi
+
+chmod 600 "$KEY_FILE"
+chown opendkim:opendkim "$KEY_FILE"
+
+# Start rsyslog for Postfix logging
+rsyslogd
+
+# Start OpenDKIM (inet socket on localhost:8891)
+opendkim -x /etc/opendkim.conf
+sleep 2
+
+# Start Postfix
+postfix start
+
+# Keep container alive, forward mail log to stdout
+touch /var/log/mail.log
+exec tail -f /var/log/mail.log