refactor(dns-processor): move mx diff check to isolated package and put behind feature flag

scanners/dns-processor/.env.example

@@ -8,3 +8,5 @@ NOTIFICATION_API_KEY=
 NOTIFICATION_API_URL=
 NOTIFICATION_ASSET_CHANGE_ALERT_EMAIL=
 ALERT_SUBS=
+
+ENABLE_MX_DIFF_ALERTS=false

scanners/dns-processor/Dockerfile

@@ -34,6 +34,7 @@ COPY --from=python-builder /working/install/lib /usr/local/lib
 
 COPY service.py dns_processor_cli.py ./
 COPY dns_processor ./dns_processor
+COPY check_mx_diff ./check_mx_diff 
 COPY notify ./notify
 
 RUN adduser -D scanner

scanners/dns-processor/check_mx_diff/check_mx_diff.py

@@ -0,0 +1,84 @@
+import os
+
+from notify.send_mx_diff_email_alerts import send_mx_diff_email_alerts
+
+
+def check_mx_diff(processed_results, domain_id, db):
+    new_mx = processed_results.get("mx_records").get("hosts")
+    mx_record_diff = False
+    # fetch most recent scan of domain
+    last_mx_cursor = db.aql.execute(
+        """
+            FOR v, e IN 1..1 OUTBOUND @domain_id domainsDNS
+                SORT v.timestamp DESC
+                LIMIT 1
+                RETURN v
+            """,
+        bind_vars={"domain_id": domain_id},
+    )
+    # if no previous scan, return False as we can't compare records
+    if last_mx_cursor.empty():
+        return False
+
+    last_mx = last_mx_cursor.next().get("mxRecords", {}).get("hosts", [])
+
+    # compare mx_records to most recent scan
+    # if different, set mx_records_diff to True
+    # check number of hosts
+    if len(new_mx) != len(last_mx):
+        mx_record_diff = True
+    else:
+        # check hostnames
+        hostnames_new = []
+        hostnames_last = []
+        for i in range(len(new_mx)):
+            hostnames_new.append(new_mx[i]["hostname"])
+            hostnames_last.append(last_mx[i]["hostname"])
+
+        if set(hostnames_new) != set(hostnames_last):
+            mx_record_diff = True
+
+    # fetch domain org, filter by verified and externally managed
+    domain_org_cursor = db.aql.execute(
+        """
+            FOR v, e IN 1..1 INBOUND @domain_id claims
+                FILTER v.verified == true
+                LIMIT 1
+                RETURN v
+            """,
+        bind_vars={"domain_id": domain_id},
+    )
+    # if no org, return early
+    if domain_org_cursor.empty():
+        return mx_record_diff
+
+    domain_org = domain_org_cursor.next()
+
+    # send alerts if true
+    if mx_record_diff and os.getenv("ALERT_SUBS"):
+        current_val = []
+        for host in new_mx:
+            current_val.append(f"{host['hostname']} {host['preference']}")
+        if len(current_val) == 0:
+            current_val = "null"
+        else:
+            current_val = ";".join(current_val)
+
+        prev_val = []
+        for host in last_mx:
+            prev_val.append(f"{host['hostname']} {host['preference']}")
+
+        if len(prev_val) == 0:
+            prev_val = "null"
+        else:
+            prev_val = ";".join(prev_val)
+
+        send_mx_diff_email_alerts(
+            domain=processed_results.get("domain"),
+            record_type="MX",
+            org=domain_org,
+            prev_val=prev_val,
+            current_val=current_val,
+        )
+
+    return mx_record_diff

scanners/dns-processor/service.py

@@ -21,7 +21,7 @@
 from nats.errors import TimeoutError as NatsTimeoutError
 
 from dns_processor.dns_processor import process_results
-from notify.send_mx_diff_email_alerts import send_mx_diff_email_alerts
+from check_mx_diff.check_mx_diff import check_mx_diff
 
 load_dotenv()
 
@@ -60,6 +60,8 @@
 CNAME_MONITOR_ONLY_LIST = os.getenv("CNAME_MONITOR_ONLY_LIST", "").split(",")
 SERVICE_ACCOUNT_EMAIL = os.getenv("SERVICE_ACCOUNT_EMAIL")
 
+ENABLE_MX_DIFF_ALERTS = os.getenv("ENABLE_MX_DIFF_ALERTS", "false").lower() == "true"
+
 SCAN_THREAD_COUNT = int(os.getenv("SCAN_THREAD_COUNT", 1))
 
 # Establish DB connection
@@ -92,87 +94,6 @@ def snake_to_camel(d):
         }
 
 
-def check_mx_diff(processed_results, domain_id):
-    new_mx = processed_results.get("mx_records").get("hosts")
-    mx_record_diff = False
-    # fetch most recent scan of domain
-    last_mx_cursor = db.aql.execute(
-        """
-            FOR v, e IN 1..1 OUTBOUND @domain_id domainsDNS
-                SORT v.timestamp DESC
-                LIMIT 1
-                RETURN v
-            """,
-        bind_vars={"domain_id": domain_id},
-    )
-    # if no previous scan, return False as we can't compare records
-    if last_mx_cursor.empty():
-        return False
-
-    last_mx = last_mx_cursor.next().get("mxRecords", {}).get("hosts", [])
-
-    # compare mx_records to most recent scan
-    # if different, set mx_records_diff to True
-    # check number of hosts
-    if len(new_mx) != len(last_mx):
-        mx_record_diff = True
-    else:
-        # check hostnames
-        hostnames_new = []
-        hostnames_last = []
-        for i in range(len(new_mx)):
-            hostnames_new.append(new_mx[i]["hostname"])
-            hostnames_last.append(last_mx[i]["hostname"])
-
-        if set(hostnames_new) != set(hostnames_last):
-            mx_record_diff = True
-
-    # fetch domain org, filter by verified and externally managed
-    domain_org_cursor = db.aql.execute(
-        """
-            FOR v, e IN 1..1 INBOUND @domain_id claims
-                FILTER v.verified == true
-                LIMIT 1
-                RETURN v
-            """,
-        bind_vars={"domain_id": domain_id},
-    )
-    # if no org, return early
-    if domain_org_cursor.empty():
-        return mx_record_diff
-
-    domain_org = domain_org_cursor.next()
-
-    # send alerts if true
-    if mx_record_diff and os.getenv("ALERT_SUBS"):
-        current_val = []
-        for host in new_mx:
-            current_val.append(f"{host['hostname']} {host['preference']}")
-        if len(current_val) == 0:
-            current_val = "null"
-        else:
-            current_val = ";".join(current_val)
-
-        prev_val = []
-        for host in last_mx:
-            prev_val.append(f"{host['hostname']} {host['preference']}")
-
-        if len(prev_val) == 0:
-            prev_val = "null"
-        else:
-            prev_val = ";".join(prev_val)
-
-        send_mx_diff_email_alerts(
-            domain=processed_results.get("domain"),
-            record_type="MX",
-            org=domain_org,
-            prev_val=prev_val,
-            current_val=current_val,
-        )
-
-    return mx_record_diff
-
-
 def is_cname_target(resolve_chain, domains):
     # Check if any CNAME record in the resolve chain points to a domain in the provided list
     for rrset in resolve_chain:
@@ -209,10 +130,11 @@ def process_msg(msg):
 
     processed_results = process_results(scan_results)
     try:
-        if processed_results.get("mx_records") is not None:
+        if ENABLE_MX_DIFF_ALERTS and processed_results.get("mx_records") is not None:
             mx_record_diff = check_mx_diff(
                 processed_results=processed_results,
                 domain_id=f"domains/{domain_key}",
+                db=db,
             )
             processed_results["mx_records"].update({"diff": mx_record_diff})
     except Exception as e: