Introduction to Tryer: Error-handling Simplified

Handling errors effectively is essential for building robust applications. The Tryer library offers a compact yet powerful way to manage exceptions in Python. This guide introduces Tryer and its various APIs with code snippets to illustrate their usage.

API Usage Examples

1. The Basic Try Block

Use the basic try block to execute a piece of code that may throw an exception:

 from tryer import tryer
def risky_function():
    return 10 / 0

result = tryer(risky_function) print(result) 

2. Specifying Exception Types

You can catch specific exceptions using the exceptions parameter:

 from tryer import tryer
def another_risky_function():
    return int("not_a_number")

result = tryer(another_risky_function, exceptions=(ValueError,)) print(result) 

3. Providing Default Values

The default parameter allows for a fallback value when an exception is caught:

 from tryer import tryer
def function_that_fails():
    raise RuntimeError("Oops!")

result = tryer(function_that_fails, default="Fallback Value") print(result) 

4. Retrying Execution

Tryer can retry the function a specified number of times before giving up:

 from tryer import tryer
attempts = []
def function_with_retries():
    attempts.append(1)
    if len(attempts) < 3:
        raise RuntimeError("Not enough attempts")
    return "Success"

result = tryer(function_with_retries, retries=4, wait=1, exceptions=(RuntimeError,)) print(result) 

5. Advanced Example: A Simple App

Let's put it all together into a simple application illustrating all the introduced APIs:

 from tryer import tryer import time
class SimpleApp:
    def __init__(self, attempts=3):
        self.attempts = attempts

    def run(self):
        result = tryer(self.unreliable_task, retries=self.attempts, wait=2, default="Failed")
        print(result)

    def unreliable_task(self):
        self.attempts -= 1
        if self.attempts > 0:
            raise RuntimeError("Unreliable task failed")
        return "Task Completed Successfully"

app = SimpleApp() app.run() 

This SimpleApp will retry unreliable_task up to 3 times before giving a final result.

With such flexible error-handling mechanisms, Tryer makes it easier to build resilient applications.

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