Moved spamd check to a custom file and cached the result

app/email_utils.py

@@ -70,10 +70,6 @@ from app.models import (
     TransactionalEmail,
     IgnoreBounceSender,
     InvalidMailboxDomain,
-    DmarcCheckResult,
-    SpamdResult,
-    SPFCheckResult,
-    Phase,
 )
 from app.utils import (
     random_string,
@@ -1442,31 +1438,3 @@ def save_email_for_debugging(msg: Message, file_name_prefix=None) -> str:
         return file_name
 
     return ""
-
-
-def get_spamd_result(
-    msg: Message, send_event: bool = True, phase: Phase = Phase.unknown
-) -> Optional[SpamdResult]:
-    spam_result_header = msg.get_all(headers.SPAMD_RESULT)
-    if not spam_result_header:
-        newrelic.agent.record_custom_event("SpamdCheck", {"header": "missing"})
-        return None
-
-    spam_entries = [entry.strip() for entry in str(spam_result_header[-1]).split("\n")]
-    for entry_pos in range(len(spam_entries)):
-        sep = spam_entries[entry_pos].find("(")
-        if sep > -1:
-            spam_entries[entry_pos] = spam_entries[entry_pos][:sep]
-
-    spamd_result = SpamdResult(phase)
-
-    for header_value, dmarc_result in DmarcCheckResult.get_string_dict().items():
-        if header_value in spam_entries:
-            spamd_result.set_dmarc_result(dmarc_result)
-    for header_value, spf_result in SPFCheckResult.get_string_dict().items():
-        if header_value in spam_entries:
-            spamd_result.set_spf_result(spf_result)
-
-    if send_event:
-        newrelic.agent.record_custom_event("SpamdCheck", spamd_result.event_data())
-    return spamd_result

app/handler/spamd_result.py

@@ -0,0 +1,125 @@
+from __future__ import annotations
+from typing import Dict, Optional
+
+import newrelic
+
+from app.email import headers
+from app.models import EnumE
+from email.message import Message
+
+
+class Phase(EnumE):
+    unknown = 0
+    forward = 1
+    reply = 2
+
+
+class DmarcCheckResult(EnumE):
+    allow = 0
+    soft_fail = 1
+    quarantine = 2
+    reject = 3
+    not_available = 4
+    bad_policy = 5
+
+    @staticmethod
+    def get_string_dict():
+        return {
+            "DMARC_POLICY_ALLOW": DmarcCheckResult.allow,
+            "DMARC_POLICY_SOFTFAIL": DmarcCheckResult.soft_fail,
+            "DMARC_POLICY_QUARANTINE": DmarcCheckResult.quarantine,
+            "DMARC_POLICY_REJECT": DmarcCheckResult.reject,
+            "DMARC_NA": DmarcCheckResult.not_available,
+            "DMARC_BAD_POLICY": DmarcCheckResult.bad_policy,
+        }
+
+
+class SPFCheckResult(EnumE):
+    allow = 0
+    fail = 1
+    soft_fail = 1
+    neutral = 2
+    temp_error = 3
+    not_available = 4
+    perm_error = 5
+
+    @staticmethod
+    def get_string_dict():
+        return {
+            "R_SPF_ALLOW": SPFCheckResult.allow,
+            "R_SPF_FAIL": SPFCheckResult.fail,
+            "R_SPF_SOFTFAIL": SPFCheckResult.soft_fail,
+            "R_SPF_NEUTRAL": SPFCheckResult.neutral,
+            "R_SPF_DNSFAIL": SPFCheckResult.temp_error,
+            "R_SPF_NA": SPFCheckResult.not_available,
+            "R_SPF_PERMFAIL": SPFCheckResult.perm_error,
+        }
+
+
+class SpamdResult:
+    def __init__(self, phase: Phase = Phase.unknown):
+        self.phase: Phase = phase
+        self.dmarc: DmarcCheckResult = DmarcCheckResult.not_available
+        self.spf: SPFCheckResult = SPFCheckResult.not_available
+
+    def set_dmarc_result(self, dmarc_result: DmarcCheckResult):
+        self.dmarc = dmarc_result
+
+    def set_spf_result(self, spf_result: SPFCheckResult):
+        self.spf = spf_result
+
+    def event_data(self) -> Dict:
+        return {
+            "header": "present",
+            "dmarc": self.dmarc,
+            "spf": self.spf,
+            "phase": self.phase,
+        }
+
+    @classmethod
+    def extract_from_headers(
+        cls, msg: Message, phase: Phase = Phase.unknown
+    ) -> Optional[SpamdResult]:
+        cached = cls._get_from_message(msg)
+        if cached:
+            return cached
+
+        spam_result_header = msg.get_all(headers.SPAMD_RESULT)
+        if not spam_result_header:
+            return None
+
+        spam_entries = [
+            entry.strip() for entry in str(spam_result_header[-1]).split("\n")
+        ]
+        for entry_pos in range(len(spam_entries)):
+            sep = spam_entries[entry_pos].find("(")
+            if sep > -1:
+                spam_entries[entry_pos] = spam_entries[entry_pos][:sep]
+
+        spamd_result = SpamdResult(phase)
+
+        for header_value, dmarc_result in DmarcCheckResult.get_string_dict().items():
+            if header_value in spam_entries:
+                spamd_result.set_dmarc_result(dmarc_result)
+        for header_value, spf_result in SPFCheckResult.get_string_dict().items():
+            if header_value in spam_entries:
+                spamd_result.set_spf_result(spf_result)
+
+        cls._store_in_message(spamd_result, msg)
+        return spamd_result
+
+    @classmethod
+    def _store_in_message(cls, check: SpamdResult, msg: Message):
+        msg.spamd_check = check
+
+    @classmethod
+    def _get_from_message(cls, msg: Message) -> Optional[SpamdResult]:
+        return getattr(msg, "spamd_check", None)
+
+    @classmethod
+    def send_to_new_relic(cls, msg: Message):
+        check = cls._get_from_message(msg)
+        if check:
+            newrelic.agent.record_custom_event("SpamdCheck", check.event_data())
+        else:
+            newrelic.agent.record_custom_event("SpamdCheck", {"header": "missing"})

app/models.py

@@ -3,7 +3,7 @@ import os
 import random
 import uuid
 from email.utils import formataddr
-from typing import List, Tuple, Optional, Dict
+from typing import List, Tuple, Optional
 
 import arrow
 import sqlalchemy as sa
@@ -237,75 +237,6 @@ class AuditLogActionEnum(EnumE):
     extend_subscription = 7
 
 
-class Phase(EnumE):
-    unknown = 0
-    forward = 1
-    reply = 2
-
-
-class DmarcCheckResult(EnumE):
-    allow = 0
-    soft_fail = 1
-    quarantine = 2
-    reject = 3
-    not_available = 4
-    bad_policy = 5
-
-    @staticmethod
-    def get_string_dict():
-        return {
-            "DMARC_POLICY_ALLOW": DmarcCheckResult.allow,
-            "DMARC_POLICY_SOFTFAIL": DmarcCheckResult.soft_fail,
-            "DMARC_POLICY_QUARANTINE": DmarcCheckResult.quarantine,
-            "DMARC_POLICY_REJECT": DmarcCheckResult.reject,
-            "DMARC_NA": DmarcCheckResult.not_available,
-            "DMARC_BAD_POLICY": DmarcCheckResult.bad_policy,
-        }
-
-
-class SPFCheckResult(EnumE):
-    allow = 0
-    fail = 1
-    soft_fail = 1
-    neutral = 2
-    temp_error = 3
-    not_available = 4
-    perm_error = 5
-
-    @staticmethod
-    def get_string_dict():
-        return {
-            "R_SPF_ALLOW": SPFCheckResult.allow,
-            "R_SPF_FAIL": SPFCheckResult.fail,
-            "R_SPF_SOFTFAIL": SPFCheckResult.soft_fail,
-            "R_SPF_NEUTRAL": SPFCheckResult.neutral,
-            "R_SPF_DNSFAIL": SPFCheckResult.temp_error,
-            "R_SPF_NA": SPFCheckResult.not_available,
-            "R_SPF_PERMFAIL": SPFCheckResult.perm_error,
-        }
-
-
-class SpamdResult:
-    def __init__(self, phase: Phase = Phase.unknown):
-        self.phase: Phase = phase
-        self.dmarc: DmarcCheckResult = DmarcCheckResult.not_available
-        self.spf: SPFCheckResult = SPFCheckResult.not_available
-
-    def set_dmarc_result(self, dmarc_result: DmarcCheckResult):
-        self.dmarc = dmarc_result
-
-    def set_spf_result(self, spf_result: SPFCheckResult):
-        self.spf = spf_result
-
-    def event_data(self) -> Dict:
-        return {
-            "header": "present",
-            "dmarc": self.dmarc,
-            "spf": self.spf,
-            "phase": self.phase,
-        }
-
-
 class Hibp(Base, ModelMixin):
     __tablename__ = "hibp"
     name = sa.Column(sa.String(), nullable=False, unique=True, index=True)

email_handler.py

@@ -92,6 +92,12 @@ from app.config import (
     ALERT_DMARC_FAILED_REPLY_PHASE,
 )
 from app.db import Session
+from app.handler.spamd_result import (
+    SpamdResult,
+    Phase,
+    DmarcCheckResult,
+    SPFCheckResult,
+)
 from app.email import status, headers
 from app.email.rate_limit import rate_limited
 from app.email.spam import get_spam_score
@@ -131,7 +137,6 @@ from app.email_utils import (
     get_orig_message_from_yahoo_complaint,
     get_mailbox_bounce_info,
     save_email_for_debugging,
-    get_spamd_result,
 )
 from app.errors import (
     NonReverseAliasInReplyPhase,
@@ -157,9 +162,6 @@ from app.models import (
     DeletedAlias,
     DomainDeletedAlias,
     Notification,
-    DmarcCheckResult,
-    SPFCheckResult,
-    Phase,
 )
 from app.pgp_utils import PGPException, sign_data_with_pgpy, sign_data
 from app.utils import sanitize_email
@@ -547,7 +549,7 @@ def handle_email_sent_to_ourself(alias, from_addr: str, msg: Message, user):
 def apply_dmarc_policy_for_forward_phase(
     alias: Alias, contact: Contact, envelope: Envelope, msg: Message
 ) -> Optional[str]:
-    spam_result = get_spamd_result(msg, Phase.forward)
+    spam_result = SpamdResult.extract_from_headers(msg, Phase.forward)
     if not DMARC_CHECK_ENABLED or not spam_result:
         return None
 
@@ -640,7 +642,7 @@ def quarantine_dmarc_failed_forward_email(alias, contact, envelope, msg) -> Emai
 def apply_dmarc_policy_for_reply_phase(
     alias_from: Alias, contact_recipient: Contact, envelope: Envelope, msg: Message
 ) -> Optional[str]:
-    spam_result = get_spamd_result(msg, Phase.reply)
+    spam_result = SpamdResult.extract_from_headers(msg, Phase.reply)
     if not DMARC_CHECK_ENABLED or not spam_result:
         return None
 
@@ -2657,9 +2659,9 @@ class MailHandler:
             return_status = handle(envelope, msg)
             elapsed = time.time() - start
             # Only bounce messages if the return-path passes the spf check. Otherwise black-hole it.
+            spamd_result = SpamdResult.extract_from_headers(msg)
             if return_status[0] == "5":
-                spamd_result = get_spamd_result(msg, send_event=False)
+                if spamd_result and spamd_result.spf in (
-                if spamd_result and get_spamd_result(msg).spf in (
                     SPFCheckResult.fail,
                     SPFCheckResult.soft_fail,
                 ):
@@ -2675,6 +2677,8 @@ class MailHandler:
                 elapsed,
                 return_status,
             )
+
+            SpamdResult.send_to_new_relic(msg)
             newrelic.agent.record_custom_metric("Custom/email_handler_time", elapsed)
             newrelic.agent.record_custom_metric("Custom/number_incoming_email", 1)
             return return_status

tests/handler/test_spamd_result.py

@@ -0,0 +1,34 @@
+from app.handler.spamd_result import DmarcCheckResult, SpamdResult
+from tests.utils import load_eml_file
+
+
+def test_dmarc_result_softfail():
+    msg = load_eml_file("dmarc_gmail_softfail.eml")
+    assert DmarcCheckResult.soft_fail == SpamdResult.extract_from_headers(msg).dmarc
+
+
+def test_dmarc_result_quarantine():
+    msg = load_eml_file("dmarc_quarantine.eml")
+    assert DmarcCheckResult.quarantine == SpamdResult.extract_from_headers(msg).dmarc
+
+
+def test_dmarc_result_reject():
+    msg = load_eml_file("dmarc_reject.eml")
+    assert DmarcCheckResult.reject == SpamdResult.extract_from_headers(msg).dmarc
+
+
+def test_dmarc_result_allow():
+    msg = load_eml_file("dmarc_allow.eml")
+    assert DmarcCheckResult.allow == SpamdResult.extract_from_headers(msg).dmarc
+
+
+def test_dmarc_result_na():
+    msg = load_eml_file("dmarc_na.eml")
+    assert DmarcCheckResult.not_available == SpamdResult.extract_from_headers(msg).dmarc
+
+
+def test_dmarc_result_bad_policy():
+    msg = load_eml_file("dmarc_bad_policy.eml")
+    assert SpamdResult._get_from_message(msg) is None
+    assert DmarcCheckResult.bad_policy == SpamdResult.extract_from_headers(msg).dmarc
+    assert SpamdResult._get_from_message(msg) is not None

tests/test_email_utils.py

@@ -36,7 +36,6 @@ from app.email_utils import (
     get_orig_message_from_bounce,
     get_mailbox_bounce_info,
     is_invalid_mailbox_domain,
-    get_spamd_result,
 )
 from app.models import (
     User,
@@ -46,7 +45,6 @@ from app.models import (
     EmailLog,
     IgnoreBounceSender,
     InvalidMailboxDomain,
-    DmarcCheckResult,
 )
 
 # flake8: noqa: E101, W191
@@ -793,33 +791,3 @@ def test_is_invalid_mailbox_domain(flask_client):
     assert is_invalid_mailbox_domain("sub1.sub2.ab.cd")
 
     assert not is_invalid_mailbox_domain("xy.zt")
-
-
-def test_dmarc_result_softfail():
-    msg = load_eml_file("dmarc_gmail_softfail.eml")
-    assert DmarcCheckResult.soft_fail == get_spamd_result(msg).dmarc
-
-
-def test_dmarc_result_quarantine():
-    msg = load_eml_file("dmarc_quarantine.eml")
-    assert DmarcCheckResult.quarantine == get_spamd_result(msg).dmarc
-
-
-def test_dmarc_result_reject():
-    msg = load_eml_file("dmarc_reject.eml")
-    assert DmarcCheckResult.reject == get_spamd_result(msg).dmarc
-
-
-def test_dmarc_result_allow():
-    msg = load_eml_file("dmarc_allow.eml")
-    assert DmarcCheckResult.allow == get_spamd_result(msg).dmarc
-
-
-def test_dmarc_result_na():
-    msg = load_eml_file("dmarc_na.eml")
-    assert DmarcCheckResult.not_available == get_spamd_result(msg).dmarc
-
-
-def test_dmarc_result_bad_policy():
-    msg = load_eml_file("dmarc_bad_policy.eml")
-    assert DmarcCheckResult.bad_policy == get_spamd_result(msg).dmarc