Rethrow exceptions

strax/mailbox.py

@@ -1,5 +1,6 @@
 from concurrent.futures import Future, TimeoutError
 import heapq
+import sys
 import threading
 import typing
 import logging
@@ -164,12 +165,7 @@ def _send_from(self, iterable):
             self.kill(reason=e.args[0])
             # Do NOT raise! One traceback on the screen is enough.
         except Exception as e:
-            try:
-                e_args = e.args[0]
-            except IndexError:
-                e_args = ''
-            self.kill(reason=f"{e.__class__.__name__}('{e_args}') "
-                             f'in {threading.current_thread().name}')
+            self.kill(reason=(e.__class__, e, sys.exc_info()[2]))
             raise
         else:
             self.close()

strax/processor.py

@@ -93,15 +93,24 @@ def iter(self):
         self.log.debug(f"Yielding {target}")
         try:
             yield from final_generator
+            traceback = None
+            exc = None
         except strax.MailboxKilled as e:
             self.log.debug(f"Target Mailbox ({target}) killed")
             for m in self.mailboxes.values():
                 if m != target:
                     self.log.debug(f"Killing {m}")
                     m.kill(upstream=True,
                            reason=e.args[0])
-            raise
+            _, exc, traceback = e.args[0]
         finally:
             self.log.debug("Closing threads")
             for m in self.mailboxes.values():
                 m.cleanup()
+
+        # Reraise exception. This is outside the except block
+        # to avoid the 'during handling of this exception, another
+        # exception occurred' stuff from confusing the traceback
+        # which is printed for the user
+        if traceback is not None:
+            raise exc.with_traceback(traceback)

strax/storage/common.py

@@ -63,6 +63,11 @@ def __init__(self, at, message=''):
         self.at = at
 
 
+@export
+class CorruptedData(Exception):
+    pass
+
+
 @export
 class RunMetadataNotAvailable(Exception):
     pass
@@ -297,7 +302,7 @@ def loader(self, backend_key, n_range=None, executor=None):
         """
         metadata = self.get_metadata(backend_key)
         if not len(metadata['chunks']):
-            self.log.warning(f"No actual data in {backend_key}?")
+            raise CorruptedData(f"No chunks of data in {backend_key}")
         dtype = literal_eval(metadata['dtype'])
         compressor = metadata['compressor']
 
@@ -409,7 +414,12 @@ def close(self, wait_for=None, timeout=120):
         self.closed = True
 
         exc_info = sys.exc_info()
-        if exc_info[0] not in [None, StopIteration]:
+        if exc_info[0] == strax.MailboxKilled:
+            # Get the original exception back out, and put that
+            # in the metadata
+            self.md['exception'] = '\n'.join(
+                traceback.format_exception(*exc_info[1].args[0]))
+        elif exc_info[0] not in [None, StopIteration]:
             self.md['exception'] = traceback.format_exc()
         self.md['writing_ended'] = time.time()
 

tests/test_core.py

@@ -11,12 +11,17 @@
 import strax
 
 
+@strax.takes_config(
+    strax.Option('crash', default=False)
+)
 class Records(strax.Plugin):
     provides = 'records'
     depends_on = tuple()
     dtype = strax.record_dtype()
 
     def iter(self, *args, **kwargs):
+        if self.config['crash']:
+            raise SomeCrash("CRASH!!!!")
         for t in range(n_chunks):
             r = np.zeros(recs_per_chunk, self.dtype)
             r['time'] = t
@@ -26,6 +31,10 @@ def iter(self, *args, **kwargs):
             yield r
 
 
+class SomeCrash(Exception):
+    pass
+
+
 @strax.takes_config(
     strax.Option('some_option', default=0)
 )
@@ -147,6 +156,22 @@ def test_storage_converter():
             store_2.find(key)
 
 
+def test_exception():
+    with tempfile.TemporaryDirectory() as temp_dir:
+        st = strax.Context(storage=strax.DataDirectory(temp_dir),
+                           register=[Records, Peaks],
+                           config=dict(crash=True))
+
+        # Check correct exception is thrown
+        with pytest.raises(SomeCrash):
+            st.make(run_id=run_id, targets='peaks')
+
+        # Check exception is recorded in metadata
+        # in both its original data type and dependents
+        for target in ('peaks', 'records'):
+            assert 'SomeCrash' in st.get_meta(run_id, target)['exception']
+
+
 def test_random_access():
     """Test basic random access
     TODO: test random access when time info is not provided directly
@@ -157,6 +182,7 @@ def test_random_access():
 
         st = strax.Context(storage=strax.DataDirectory(temp_dir),
                            register=[Records, Peaks])
+
         with pytest.raises(strax.DataNotAvailable):
             # Time range selection requires data already available
             st.get_df(run_id, 'peaks', time_range=(3, 5))
@@ -168,6 +194,9 @@ def test_random_access():
                                str(st._key_for(run_id, 'peaks')),
                                '000000'))
 
+        with pytest.raises(FileNotFoundError):
+            st.get_array(run_id, 'peaks')
+
         df = st.get_array(run_id, 'peaks', time_range=(3, 5))
         assert len(df) == 2 * recs_per_chunk
         assert df['time'].min() == 3