Switching email script for codex to use hosted server SMTP to resolve

deliverability issues

scripts/catalog.json

@@ -9,7 +9,7 @@
     {
       "name": "email_send.py",
       "path": "scripts/email_send.py",
-      "purpose": "Send SMTP email via mail.elphel.com using env vars for credentials."
+      "purpose": "Send email via SSH+sendmail on community.elphel.com by default (set ELPHEL_SEND_MODE=smtp to force SMTP)."
     },
     {
       "name": "email_fetch.py",

scripts/email_send.py

 #!/usr/bin/env python3
 import os
 import smtplib
+import subprocess
 import email.utils
 from email.message import EmailMessage
 from pathlib import Path
@@ -9,6 +10,13 @@ SMTP_HOST = os.environ.get("ELPHEL_SMTP_HOST", "mail.elphel.com")
 SMTP_PORT = int(os.environ.get("ELPHEL_SMTP_PORT", "465"))
 SMTP_USER = os.environ.get("ELPHEL_SMTP_USER", "codex@elphel.com")
 SMTP_PASS = os.environ.get("ELPHEL_SMTP_PASS")
+# ELPHEL_SEND_MODE=ssh_sendmail (default) or smtp.
+# Defaulting to ssh_sendmail avoids sending from the local LAN IP, which can trigger
+# recipient-side policy/reputation blocks.
+SEND_MODE = os.environ.get("ELPHEL_SEND_MODE", "ssh_sendmail").lower()
+SEND_SSH_HOST = os.environ.get("ELPHEL_SEND_SSH_HOST", "community.elphel.com")
+SEND_SSH_USER = os.environ.get("ELPHEL_SEND_SSH_USER", "elphel5")
+SEND_SSH_PORT = os.environ.get("ELPHEL_SEND_SSH_PORT", "")
 OUT_DIR = os.environ.get("EMAIL_OUT_DIR", "attic/email_outbox")
 
 
@@ -23,9 +31,27 @@ def _write_index(index_path, values):
         f.write(line + "\n")
 
 
-def send_email(subject, body, to_addrs, cc_addrs=None):
+def _send_via_smtp(msg, recipients):
     if not SMTP_PASS:
         raise SystemExit("Set ELPHEL_SMTP_PASS")
+    with smtplib.SMTP_SSL(SMTP_HOST, SMTP_PORT) as s:
+        s.login(SMTP_USER, SMTP_PASS)
+        s.send_message(msg, to_addrs=recipients)
+
+
+def _send_via_ssh_sendmail(msg):
+    ssh_target = f"{SEND_SSH_USER}@{SEND_SSH_HOST}"
+    ssh_cmd = ["ssh"]
+    if SEND_SSH_PORT:
+        ssh_cmd += ["-p", SEND_SSH_PORT]
+    ssh_cmd += [ssh_target, "/usr/sbin/sendmail", "-t", "-f", SMTP_USER]
+    try:
+        subprocess.run(ssh_cmd, input=msg.as_bytes(), check=True)
+    except FileNotFoundError:
+        raise SystemExit("ssh not found; install openssh-client or use SMTP mode")
+
+
+def send_email(subject, body, to_addrs, cc_addrs=None):
     msg = EmailMessage()
     msg["Subject"] = subject
     msg["From"] = SMTP_USER
@@ -48,9 +74,10 @@ def send_email(subject, body, to_addrs, cc_addrs=None):
         encoding="utf-8",
     )
     _write_index(out_dir / "index.csv", [email.utils.formatdate(localtime=True), SMTP_USER, ",".join(to_addrs), ",".join(cc_addrs or []), subject, str(out_path)])
-    with smtplib.SMTP_SSL(SMTP_HOST, SMTP_PORT) as s:
-        s.login(SMTP_USER, SMTP_PASS)
-        s.send_message(msg, to_addrs=recipients)
+    if SEND_MODE == "ssh_sendmail":
+        _send_via_ssh_sendmail(msg)
+    else:
+        _send_via_smtp(msg, recipients)
 
 
 def main():