PYL-W0703 · Exception caught is very general

graphite-project / carbon

Active

Exception caught is very general PYL-W0703

Anti-pattern

Major

4 years ago — 4 years old

Catching too general exception Exception

159
160  try:  # This only works on Linux
161    record('memUsage', getMemUsage())
162  except Exception:163    pass
164
165

Catching too general exception Exception

lib/carbon/writer.py

144          if not settings.SKIP_TAGS_FOR_NONTAGGED or ';' in metric:
145            tagQueue.add(metric)
146        instrumentation.increment('creates')
147      except Exception as e:148        log.err()
149        log.msg("Error creating %s: %s" % (metric, e))
150        instrumentation.increment('errors')

Catching too general exception Exception

lib/carbon/writer.py

168        if not settings.SKIP_TAGS_FOR_NONTAGGED or ';' in metric:
169          tagQueue.update(metric)
170      updateTime = time.time() - t1
171    except Exception as e:172      log.err()
173      log.msg("Error writing to %s: %s" % (metric, e))
174      instrumentation.increment('errors')

Catching too general exception Exception

lib/carbon/writer.py

189  while reactor.running:
190    try:
191      writeCachedDataPoints()
192    except Exception:193      log.err()
194      # Back-off on error to give the backend time to recover.
195      time.sleep(0.1)

Catching too general exception Exception

lib/carbon/writer.py

210  while reactor.running:
211    try:
212      writeTags()
213    except Exception:214      log.err()
215      # Back-off on error to give the backend time to recover.
216      time.sleep(0.1)

Description

If the except block catches a very general exception, it is likely to catch any unrelated errors too. Try to be more explicit about which exception(s) you're trying to catch.

If you need to catch every other exception, then mark it as intentional by adding a # skipcq comment.

Bad practice

try:
    x = a / b
except Exception:
    x = a / (b + 1)

try:
    line = input('Enter numbers:')
    numbers = [int(i) for i in line.split()]
except BaseException:
    print('Only use numbers for the input')

Preferred:

try:
    x = a / b
except ZeroDivisionError:
    x = a / (b + 1)

try:
    event_loop.run()
except Exception as exc:  # skipcq: PYL-W0703 - Loop can sometimes crash.
    sentry.report(exc)

try:
    line = input('Enter numbers:')
    numbers = [int(i) for i in line.split()]
except ValueError:
    print('Only use numbers for the input')