Instanciate the SMTP class only when needed

instead of creating it in the VaultBackend constructor: when configured (with host and port), SMTP.connect() is immediately called, which makes it mandatory to have the smtp server up and running to be able to create the VaultBackend object (which makes it hard to run properly in an elastic environment like docker or k8s).

---

Migrated from D8205 (view on Phabricator)

swh/vault/tests/test_backend.py

@@ -5,12 +5,15 @@
 
 import contextlib
 import datetime
+import re
+import smtplib
 from unittest.mock import MagicMock, patch
 
 import attr
 import psycopg2
 import pytest
 
+from swh.core.sentry import init_sentry
 from swh.model.model import Content
 from swh.model.swhids import CoreSWHID
 from swh.vault.exc import NotFoundExc
@@ -212,10 +215,10 @@ def test_send_all_emails(swh_vault):
 
     swh_vault.set_status(TEST_TYPE, TEST_SWHID, "done")
 
-    with patch.object(swh_vault, "smtp_server") as m:
+    with patch.object(swh_vault, "_smtp_send") as m:
         swh_vault.send_notif(TEST_TYPE, TEST_SWHID)
 
-        sent_emails = {k[0][0] for k in m.send_message.call_args_list}
+        sent_emails = {k[0][0] for k in m.call_args_list}
         assert {k["To"] for k in sent_emails} == set(emails)
 
         for e in sent_emails:
@@ -234,6 +237,64 @@ def test_send_all_emails(swh_vault):
         m.assert_not_called()
 
 
+def test_send_email_error_no_smtp(swh_vault):
+    reports = []
+    init_sentry("http://example.org", extra_kwargs={"transport": reports.append})
+
+    emails = ("a@example.com", "billg@example.com", "test+42@example.org")
+    with mock_cooking(swh_vault):
+        for email in emails:
+            swh_vault.cook(TEST_TYPE, TEST_SWHID, email=email)
+    swh_vault.set_status(TEST_TYPE, TEST_SWHID, "done")
+    swh_vault.send_notif(TEST_TYPE, TEST_SWHID)
+
+    assert len(reports) == 6
+    for i, email in enumerate(emails):
+        # first report is the logger.error
+        assert reports[2 * i]["level"] == "error"
+        assert reports[2 * i]["logger"] == "swh.vault.backend"
+        reg = re.compile(
+            "Unable to send SMTP message 'Bundle ready: gitfast [0-9a-f]{7}' "
+            f"to {email.replace('+', '[+]')}: cannot connect to server"
+        )
+        assert reg.match(reports[2 * i]["logentry"]["message"])
+        # second is the sentry_sdk.capture_message
+        assert reports[2 * i + 1]["level"] == "error"
+        assert reg.match(reports[2 * i + 1]["message"])
+
+
+def test_send_email_error_send_failed(swh_vault):
+    reports = []
+    init_sentry("http://example.org", extra_kwargs={"transport": reports.append})
+
+    emails = ("a@example.com", "billg@example.com", "test+42@example.org")
+    with mock_cooking(swh_vault):
+        for email in emails:
+            swh_vault.cook(TEST_TYPE, TEST_SWHID, email=email)
+    swh_vault.set_status(TEST_TYPE, TEST_SWHID, "done")
+
+    with patch("smtplib.SMTP") as MockSMTP:
+        smtp = MockSMTP.return_value
+        smtp.noop.return_value = [250]
+        smtp.send_message.side_effect = smtplib.SMTPHeloError(404, "HELO Failed")
+
+        swh_vault.send_notif(TEST_TYPE, TEST_SWHID)
+
+    assert len(reports) == 4
+    # first one is the captured exception
+    assert reports[0]["level"] == "error"
+    assert reports[0]["exception"]["values"][0]["type"] == "SMTPHeloError"
+
+    # the following 3 ones are the sentry_sdk.capture_message() calls
+    for i, email in enumerate(emails, start=1):
+        assert reports[i]["level"] == "error"
+        reg = re.compile(
+            "Unable to send SMTP message 'Bundle ready: gitfast [0-9a-f]{7}' "
+            f"to {email.replace('+', '[+]')}: [(]404, 'HELO Failed'[)]"
+        )
+        assert reg.match(reports[i]["message"])
+
+
 def test_available(swh_vault):
     assert not swh_vault.is_available(TEST_TYPE, TEST_SWHID)
 
@@ -327,10 +388,10 @@ def test_send_failure_email(swh_vault):
     swh_vault.set_status(TEST_TYPE, TEST_SWHID, "failed")
     swh_vault.set_progress(TEST_TYPE, TEST_SWHID, "test error")
 
-    with patch.object(swh_vault, "smtp_server") as m:
+    with patch.object(swh_vault, "_smtp_send") as m:
         swh_vault.send_notif(TEST_TYPE, TEST_SWHID)
 
-        e = [k[0][0] for k in m.send_message.call_args_list][0]
+        e = [k[0][0] for k in m.call_args_list][0]
         assert e["To"] == "a@example.com"
 
         assert "bot@softwareheritage.org" in e["From"]