add basic error handling

app/helpers/service_helper.py

@@ -61,6 +61,13 @@ def solution_to_file(buffer, total_form_items, forms):
 
   return buff2
 
+def error_to_file(buffer, error):
+  wr = csv.writer(buffer, dialect='excel', delimiter=',')
+  wr.writerow(['status'])
+  wr.writerow([error.args[0]])
+
+  return io.BytesIO(buffer.getvalue().encode())
+
 def key_to_uuid(key):
   return re.split("_", key)[0]
 

app/lib/irt/item_information_function.py

@@ -1,4 +1,7 @@
+import logging
+
 from lib.irt.models.three_parameter_logistic import ThreeParameterLogistic
+from lib.errors.item_generation_error import ItemGenerationError
 
 class ItemInformationFunction():
   def __init__(self, irt_model):
@@ -8,10 +11,14 @@ class ItemInformationFunction():
   # further detailed on page 161, equation 4 here:
   #  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5978482/pdf/10.1177_0146621615613308.pdf
   def calculate(self, **kwargs):
-    if self.model_data.model == '3PL':
-      p = ThreeParameterLogistic(self.model_data, kwargs).result()
-      q = 1 - p
-      return (self.model_data.a_param * q * (p - self.model_data.c_param)**2) / (p * ((1 - self.model_data.c_param)**2))
-    else:
-      # potentially error out
-      return None
+    try:
+      if self.model_data.model == '3PL':
+        p = ThreeParameterLogistic(self.model_data, kwargs).result()
+        q = 1 - p
+        return (self.model_data.a_param * q * (p - self.model_data.c_param)**2) / (p * ((1 - self.model_data.c_param)**2))
+      else:
+        # potentially error out
+        raise ItemGenerationError("irt model not supported or provided")
+    except ZeroDivisionError as error:
+      logging.error(error)
+      raise ItemGenerationError("params not well formatted", error.args[0])

app/services/loft_service.py

@@ -3,6 +3,7 @@ import os, json, random, io, logging
 from pulp import LpProblem, LpVariable, LpMinimize, LpStatus, lpSum
 
 from helpers import aws_helper, tar_helper, csv_helper, service_helper, solver_helper
+from lib.errors.item_generation_error import ItemGenerationError
 
 from models.solver_run import SolverRun
 from models.solution import Solution
@@ -12,9 +13,12 @@ from services.base import Base
 
 class LoftService(Base):
   def process(self):
-    self.solver_run = SolverRun.parse_obj(self.retreive_attributes_from_message())
-    self.solution = self.generate_solution()
-    self.result = self.stream_to_s3_bucket()
+    try:
+      self.solver_run = SolverRun.parse_obj(self.retreive_attributes_from_message())
+      self.solution = self.generate_solution()
+      self.result = self.stream_to_s3_bucket()
+    except ItemGenerationError as error:
+      self.result = self.stream_to_s3_bucket(error)
 
   def retreive_attributes_from_message(self):
     logging.info('Retrieving attributes from message...')
@@ -96,12 +100,18 @@ class LoftService(Base):
 
     return solution
 
-  def stream_to_s3_bucket(self):
+  def stream_to_s3_bucket(self, error = None):
     self.file_name = f'{service_helper.key_to_uuid(self.key)}.csv'
-    logging.info('Streaming %s to s3 bucket - %s', self.file_name, os.environ['S3_PROCESSED_BUCKET'])
+    solution_file = None
     # setup writer buffer and write processed forms to file
     buffer = io.StringIO()
-    solution_file = service_helper.solution_to_file(buffer, self.solver_run.total_form_items, self.solution.forms)
+
+    if error:
+      logging.info('Streaming %s error response to s3 bucket - %s', self.file_name, os.environ['S3_PROCESSED_BUCKET'])
+      solution_file = service_helper.error_to_file(buffer, error)
+    else:
+      logging.info('Streaming %s to s3 bucket - %s', self.file_name, os.environ['S3_PROCESSED_BUCKET'])
+      solution_file = service_helper.solution_to_file(buffer, self.solver_run.total_form_items, self.solution.forms)
 
     # upload generated file to s3 and return result
     return aws_helper.file_stream_upload(solution_file, self.file_name, os.environ['S3_PROCESSED_BUCKET'])