tranq 0.2.4

Modern, decorator-based error handling for Python – calm your code.

tranq

Calm error handling for Python – decorator-based, zero boilerplate.

GitHub: https://github.com/RaptorVampire/tranq

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Why tranq?

Writing repetitive try/except blocks clutters your code. tranq gives you declarative error handling with decorators, context managers, and smart retry strategies.

• 🧘 Tranquil – clean, readable, and maintainable.
• 🔁 Smart retries – exponential, linear, Fibonacci backoff, jitter, and max delay.
• 🚦 Circuit Breaker – prevent cascading failures (sync & async).
• 🧪 Conditional retry – on specific exceptions or result values.
• 📦 Retry groups – all-or-nothing execution for multiple functions.
• 📊 Built‑in metrics & profiling – monitor performance and error rates.
• 📝 Pluggable reporters – send errors to files, Sentry, Slack, or custom destinations.
• 🧩 Context manager API – use with tranq.retry(...): when decorators aren't ideal.
• 🔧 Stateful retry – persist attempt count across calls.
• 🎭 Mock error injection – test your error handling with ease.

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Installation

pip install tranq

Requires Python 3.9 or later.

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Quick Start

Decorator (@handle)

import tranq

@tranq.handle(on=ValueError, retry=3, delay=0.5, backoff=2.0)
def risky():
    ...

Async (@handle_async)

@tranq.handle_async(on=ConnectionError, retry=2, fallback=lambda: "offline")
async def fetch_data():
    ...

Circuit Breaker

cb = tranq.CircuitBreaker(failure_threshold=5, timeout=60)
@tranq.handle(circuit_breaker=cb)
def call_unstable_service():
    ...

Context Manager

with tranq.retry(on=ValueError, retry=2) as ctx:
    result = ctx.run(my_function, arg1, arg2)

Retry Group

group = tranq.retry_group(step1, step2, step3, on=Exception, retry=1)
results = group.run()

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Features in Depth

Retry with Backoff

@tranq.handle(
    on=TimeoutError,
    retry=5,
    delay=0.1,
    backoff=2.0,
    backoff_strategy="exponential",
    max_delay=10.0,
    jitter=True,
)
def fetch():
    ...

Conditional Retry

@tranq.handle(
    on=requests.RequestException,
    retry_if=lambda e: e.response.status_code == 429,
    retry=3,
)
def call_api():
    ...

@tranq.handle(
    retry_on_result=lambda result: result is None,
    retry=2,
)
def get_data():
    ...

Error Handlers

@tranq.handle(
    on=(ValueError, ConnectionError),
    on_error={ValueError: log_warning, ConnectionError: alert_admin},
)
def process():
    ...

Circuit Breaker (Sync & Async)

from tranq import CircuitBreaker, AsyncCircuitBreaker

cb = CircuitBreaker(failure_threshold=3, timeout=30)
acb = AsyncCircuitBreaker(failure_threshold=3, timeout=30)

Reporters

from tranq import FileReporter, SentryReporter, SlackReporter

reporters = [
    FileReporter("/var/log/tranq_errors.log"),
    SentryReporter(dsn="..."),
    SlackReporter(webhook_url="..."),
]

@tranq.handle(on=Exception, reporters=reporters)
def critical_task():
    ...

Metrics & Profiling

@tranq.handle(metrics=True, metric_prefix="myapp")
def expensive_op():
    ...

from tranq import get_metrics, profile, get_profile

@profile
def heavy_computation():
    ...

print(get_metrics())
print(get_profile("heavy_computation"))

Mock Error Injection

from tranq import mock_errors

with mock_errors(ValueError, probability=0.8):
    result = my_function()

Dependency Injection

@tranq.handle(inject={"logger": logging.getLogger("app")})
def do_work(logger=None):
    logger.info("Working...")

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Advanced Examples

Combining Features

cb = CircuitBreaker(failure_threshold=3, timeout=60)

@tranq.handle(
    on=requests.RequestException,
    retry=5,
    backoff_strategy="fibonacci",
    max_delay=30,
    jitter=True,
    retry_if=lambda e: e.response.status_code in (429, 503),
    circuit_breaker=cb,
    metrics=True,
    metric_prefix="api",
    reporters=[FileReporter("api_errors.log")],
    fallback=lambda: {"status": "fallback"},
)
def fetch_from_external_api():
    ...

Retry Group with Mixed Sync/Async

from tranq import retry_group, async_retry_group

group = retry_group(step1, step2, on=ValueError, retry=2)
results = group.run()

async_group = async_retry_group(step1, step3, on=Exception, retry=1)
results = await async_group.run()

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API Reference

· Decorators: handle(...), handle_async(...) · Context Manager: retry(...) · Retry Groups: retry_group(...), async_retry_group(...) · Circuit Breakers: CircuitBreaker(...), AsyncCircuitBreaker(...) · Policies: Policy, set_global_policy(), get_global_policy() · Reporters: Reporter, FileReporter, SentryReporter, SlackReporter · Utilities: get_metrics(), reset_metrics(), profile(), get_profile(), mock_errors() · Exceptions: TranqError, RetryExhaustedError, CircuitBreakerError, ResultNotAcceptedError, RetryGroupError

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License

MIT © RaptorVampire

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Happy error handling! 🧘