Fix a race condition which allowed duplicate consultations to be created

care/facility/api/serializers/patient_consultation.py

@@ -353,55 +353,50 @@ def create(self, validated_data):
 
         create_diagnosis = validated_data.pop("create_diagnoses")
         create_symptoms = validated_data.pop("create_symptoms")
-        action = -1
-        review_interval = -1
-        if "action" in validated_data:
-            action = validated_data.pop("action")
-        if "review_interval" in validated_data:
-            review_interval = validated_data.pop("review_interval")
+
+        action = validated_data.pop("action", -1)
+        review_interval = validated_data.get("review_interval", -1)
 
         # Authorisation Check
 
-        allowed_facilities = get_home_facility_queryset(self.context["request"].user)
+        user = self.context["request"].user
+        allowed_facilities = get_home_facility_queryset(user)
         if not allowed_facilities.filter(
-            id=self.validated_data["patient"].facility.id
+            id=self.validated_data["patient"].facility_id
         ).exists():
             raise ValidationError(
                 {"facility": "Consultation creates are only allowed in home facility"}
             )
 
         # End Authorisation Checks
 
-        if validated_data["patient"].last_consultation:
-            if (
-                self.context["request"].user
-                == validated_data["patient"].last_consultation.assigned_to
-            ):
+        patient = PatientRegistration.objects.select_for_update().get(
+            id=validated_data["patient"].id
+        )
+
+        if patient.last_consultation:
+            if patient.last_consultation.assigned_to == user:
                 raise ValidationError(
                     {
                         "Permission Denied": "Only Facility Staff can create consultation for a Patient"
                     },
                 )
 
-        if validated_data["patient"].last_consultation:
-            if not validated_data["patient"].last_consultation.discharge_date:
+            if not patient.last_consultation.discharge_date:
                 raise ValidationError(
                     {"consultation": "Exists please Edit Existing Consultation"}
                 )
 
         if "is_kasp" in validated_data:
             if validated_data["is_kasp"]:
-                validated_data["kasp_enabled_date"] = localtime(now())
+                validated_data["kasp_enabled_date"] = now()
 
-        bed = validated_data.pop("bed", None)
+        # Coercing facility as the patient's facility
+        validated_data["facility_id"] = patient.facility_id
 
-        validated_data["facility_id"] = validated_data[
-            "patient"
-        ].facility_id  # Coercing facility as the patient's facility
-        consultation = super().create(validated_data)
-        consultation.created_by = self.context["request"].user
-        consultation.last_edited_by = self.context["request"].user
-        patient = consultation.patient
+        consultation: PatientConsultation = super().create(validated_data)
+        consultation.created_by = user
+        consultation.last_edited_by = user
         consultation.previous_consultation = patient.last_consultation
         last_consultation = patient.last_consultation
         if (
@@ -413,7 +408,6 @@ def create(self, validated_data):
             > consultation.encounter_date
         ):
             consultation.is_readmission = True
-        consultation.save()
 
         diagnosis = ConsultationDiagnosis.objects.bulk_create(
             [
@@ -422,7 +416,7 @@ def create(self, validated_data):
                     diagnosis_id=obj["diagnosis"].id,
                     is_principal=obj["is_principal"],
                     verification_status=obj["verification_status"],
-                    created_by=self.context["request"].user,
+                    created_by=user,
                 )
                 for obj in create_diagnosis
             ]
@@ -436,11 +430,12 @@ def create(self, validated_data):
                 cure_date=obj.get("cure_date"),
                 clinical_impression_status=obj.get("clinical_impression_status"),
                 other_symptom=obj.get("other_symptom") or "",
-                created_by=self.context["request"].user,
+                created_by=user,
             )
             for obj in create_symptoms
         )
 
+        bed = validated_data.pop("bed", None)
         if bed and consultation.suggestion == SuggestionChoices.A:
             consultation_bed = ConsultationBed(
                 bed=bed,
@@ -449,11 +444,9 @@ def create(self, validated_data):
             )
             consultation_bed.save()
             consultation.current_bed = consultation_bed
-            consultation.save(update_fields=["current_bed"])
 
         if consultation.suggestion == SuggestionChoices.OP:
-            consultation.discharge_date = localtime(now())
-            consultation.save()
+            consultation.discharge_date = now()
             patient.is_active = False
             patient.allow_transfer = True
         else:
@@ -462,19 +455,14 @@ def create(self, validated_data):
 
         if action != -1:
             patient.action = action
-        consultation.review_interval = review_interval
+
         if review_interval > 0:
-            patient.review_time = localtime(now()) + timedelta(minutes=review_interval)
+            patient.review_time = now() + timedelta(minutes=review_interval)
         else:
             patient.review_time = None
 
+        consultation.save()
         patient.save()
-        NotificationGenerator(
-            event=Notification.Event.PATIENT_CONSULTATION_CREATED,
-            caused_by=self.context["request"].user,
-            caused_object=consultation,
-            facility=patient.facility,
-        ).generate()
 
         create_consultation_events(
             consultation.id,
@@ -483,10 +471,17 @@ def create(self, validated_data):
             consultation.created_date,
         )
 
+        NotificationGenerator(
+            event=Notification.Event.PATIENT_CONSULTATION_CREATED,
+            caused_by=user,
+            caused_object=consultation,
+            facility=patient.facility,
+        ).generate()
+
         if consultation.assigned_to:
             NotificationGenerator(
                 event=Notification.Event.PATIENT_CONSULTATION_ASSIGNMENT,
-                caused_by=self.context["request"].user,
+                caused_by=user,
                 caused_object=consultation,
                 facility=consultation.patient.facility,
                 notification_mediums=[