RD-3794 - clean the wrapping line when reporting an error (#176)

* clean the wrapping line when reporting an error

Author: saartochner-lumigo

src/lumigo_tracer/lumigo_utils.py

@@ -14,6 +14,7 @@
 from contextlib import contextmanager
 from base64 import b64encode
 import inspect
+import traceback
 
 try:
     import botocore
@@ -66,6 +67,7 @@
 ERROR_SIZE_LIMIT_MULTIPLIER = 2
 CHINA_REGION = "cn-northwest-1"
 EDGE_KINESIS_STREAM_NAME = "prod_trc-inges-edge_edge-kinesis-stream"
+STACKTRACE_LINE_TO_DROP = "lumigo_tracer/tracer.py"
 Container = TypeVar("Container", dict, list)
 
 _logger: Dict[str, logging.Logger] = {}
@@ -701,3 +703,8 @@ def is_aws_arn(string_to_validate: Optional[str]) -> bool:
 
 def is_provision_concurrency_initialization() -> bool:
     return os.environ.get("AWS_LAMBDA_INITIALIZATION_TYPE") == "provisioned-concurrency"
+
+
+def get_stacktrace(exception: Exception) -> str:
+    original_traceback = traceback.format_tb(exception.__traceback__)
+    return "".join(filter(lambda line: STACKTRACE_LINE_TO_DROP not in line, original_traceback))

src/lumigo_tracer/spans_container.py

@@ -6,7 +6,6 @@
 import time
 import uuid
 import signal
-import traceback
 from typing import List, Dict, Optional, Callable, Set
 
 from lumigo_tracer.event.event_dumper import EventDumper
@@ -24,6 +23,7 @@
     get_current_ms_time,
     get_region,
     is_provision_concurrency_initialization,
+    get_stacktrace,
 )
 from lumigo_tracer import lumigo_utils
 from lumigo_tracer.parsing_utils import parse_trace_id, safe_split_get, recursive_json_join
@@ -202,7 +202,7 @@ def add_exception_event(
             self.function_span["error"] = self._create_exception_event(
                 exc_type=exception.__class__.__name__,
                 message=message,
-                stacktrace=traceback.format_exc(),
+                stacktrace=get_stacktrace(exception),
                 frames=format_frames(frames_infos) if Configuration.verbose else [],
             )
 

src/test/unit/test_tracer.py

@@ -1,5 +1,7 @@
 import datetime
 import json
+import re
+import traceback
 from decimal import Decimal
 import http.client
 import os
@@ -439,3 +441,25 @@ def lambda_test_function(event, context):
         aws_secret_access_key=secret_access_key,
         config=ANY,
     )
+
+
+def test_lumigo_tracer_doesnt_change_exception(context):
+    @lumigo_tracer(token="123")
+    def wrapped(event, context):
+        raise Exception("Inner exception")
+
+    with pytest.raises(Exception):
+        wrapped({}, context)
+
+    def wrapped(event, context):
+        raise Exception("Inner exception")
+
+    with pytest.raises(Exception) as e:
+        wrapped({}, context)
+
+    stacktrace = SpansContainer.get_span().function_span["error"]["stacktrace"]
+    assert "lumigo_tracer/tracer.py" not in stacktrace
+    line_dropper = re.compile(r"\d{3}")
+    from_lumigo = line_dropper.sub("-", stacktrace)
+    original = line_dropper.sub("-", traceback.format_tb(e.value.__traceback__)[1])
+    assert from_lumigo == original