Quick Python: Refactoring Exceptions with Context Manager
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I generally find exception syntax a little clunky…
try:
for _ in range(5):
sleep(1)
except KeyboardInterrupt:
# Awesome task 1
# Awesome task 2...
pass
Especially if you end up capturing the same exceptions and handling it the same way.
try:
for _ in range(5):
sleep(1)
except KeyboardInterrupt:
# Awesome task 1
# Awesome task 2...
pass
try:
for _ in range(2):
sleep(1)
except KeyboardInterrupt:
# Awesome task 1
# Awesome task 2...
pass
One way to make our code more DRY (don’t-repeat-yourself) is to make use of Python’s context managers.
@contextmanager
def handle_sigint():
try:
yield
except KeyboardInterrupt:
# Awesome task 1
# Awesome task 2...
pass
Using the context manager, everything within the indented block gets executed within the try block.
with handle_sigint():
for _ in range(5):
sleep(1)
with handle_sigint():
for _ in range(2):
sleep(1)
In fact, we can write this in a generic way to give us an alternative syntax for handling exceptions.
@contextmanager
def handle_exception(f, *exceptions):
try:
yield
except exceptions as e:
f(e)
For example, let’s tell the user that we’re explicitly ignoring their exception
def ignore(e):
print("Ignoring", e.__class__.__name__)
with handle_exception(ignore, NotImplementedError, KeyboardInterrupt):
for _ in range(5):
sleep(1)