removed loguru, added more namespaces

Author: NikitaKozlovtcev

circuit_breaker_box/__init__.py

@@ -0,0 +1,13 @@
+from circuit_breaker_box.circuit_breaker_base import BaseCircuitBreaker
+from circuit_breaker_box.circuit_breaker_in_memory import CircuitBreakerInMemory
+from circuit_breaker_box.circuit_breaker_redis import CircuitBreakerRedis
+from circuit_breaker_box.errors import BaseCircuitBreakerError, HostUnavailableError
+
+
+__all__ = [
+    "BaseCircuitBreaker",
+    "BaseCircuitBreakerError",
+    "CircuitBreakerInMemory",
+    "CircuitBreakerRedis",
+    "HostUnavailableError",
+]

circuit_breaker_box/circuit_breaker.py

@@ -0,0 +1,18 @@
+import abc
+import dataclasses
+import typing
+
+
+@dataclasses.dataclass(kw_only=True, slots=True)
+class BaseCircuitBreaker:
+    reset_timeout_in_seconds: int
+    max_failure_count: int
+
+    @abc.abstractmethod
+    async def increment_failures_count(self, host: str) -> None: ...
+
+    @abc.abstractmethod
+    async def is_host_available(self, host: str) -> bool: ...
+
+    @abc.abstractmethod
+    async def raise_host_unavailable_error(self, host: str) -> typing.NoReturn: ...

circuit_breaker_box/circuit_breaker_base.py

@@ -0,0 +1,45 @@
+import dataclasses
+import logging
+import typing
+
+from cachetools import TTLCache
+
+from circuit_breaker_box import BaseCircuitBreaker, errors
+
+
+logger = logging.getLogger(__name__)
+
+
+@dataclasses.dataclass(kw_only=True, slots=True)
+class CircuitBreakerInMemory(BaseCircuitBreaker):
+    max_cache_size: int
+    cache_hosts_with_errors: TTLCache[typing.Any, typing.Any] = dataclasses.field(init=False)
+
+    def __post_init__(self) -> None:
+        self.cache_hosts_with_errors: TTLCache[typing.Any, typing.Any] = TTLCache(
+            maxsize=self.max_cache_size, ttl=self.reset_timeout_in_seconds
+        )
+
+    async def increment_failures_count(self, host: str) -> None:
+        if host in self.cache_hosts_with_errors:
+            self.cache_hosts_with_errors[host] = self.cache_hosts_with_errors[host] + 1
+            logger.debug("Incremented error for host: '%s', errors: %s", host, self.cache_hosts_with_errors[host])
+        else:
+            self.cache_hosts_with_errors[host] = 1
+            logger.debug("Added host: %s, errors: %s", host, self.cache_hosts_with_errors[host])
+
+    async def is_host_available(self, host: str) -> bool:
+        failures_count: typing.Final = int(self.cache_hosts_with_errors.get(host) or 0)
+        is_available: bool = failures_count <= self.max_failure_count
+        logger.debug(
+            "host: '%s', failures_count: '%s', self.max_failure_count: '%s', is_available: '%s'",
+            host,
+            failures_count,
+            self.max_failure_count,
+            is_available,
+        )
+        return is_available
+
+    async def raise_host_unavailable_error(self, host: str) -> typing.NoReturn:
+        msg = f"Host {host} is unavailable"
+        raise errors.HostUnavailableError(msg)

circuit_breaker_box/circuit_breaker_in_memory.py

@@ -0,0 +1,59 @@
+import dataclasses
+import logging
+import typing
+
+import tenacity
+from redis import asyncio as aioredis
+from redis.exceptions import ConnectionError as RedisConnectionError
+from redis.exceptions import WatchError
+
+from circuit_breaker_box import BaseCircuitBreaker, errors
+
+
+logger = logging.getLogger(__name__)
+
+
+def _log_attempt(retry_state: tenacity.RetryCallState) -> None:
+    logger.info("Attempt redis_reconnect: %s", retry_state)
+
+
+@dataclasses.dataclass(kw_only=True, slots=True)
+class CircuitBreakerRedis(BaseCircuitBreaker):
+    redis_connection: "aioredis.Redis[str]"
+
+    @tenacity.retry(
+        stop=tenacity.stop_after_attempt(3),
+        wait=tenacity.wait_exponential_jitter(),
+        retry=tenacity.retry_if_exception_type((WatchError, RedisConnectionError, ConnectionResetError, TimeoutError)),
+        reraise=True,
+        before=_log_attempt,
+    )
+    async def increment_failures_count(self, host: str) -> None:
+        redis_key: typing.Final = f"circuit-breaker-{host}"
+        increment_result: int = await self.redis_connection.incr(redis_key)
+        logger.debug("Incremented error for redis_key: %s, increment_result: %s", redis_key, increment_result)
+        is_expire_set: bool = await self.redis_connection.expire(redis_key, self.reset_timeout_in_seconds)
+        logger.debug("Expire set for redis_key: %s, is_expire_set: %s", redis_key, is_expire_set)
+
+    @tenacity.retry(
+        stop=tenacity.stop_after_attempt(3),
+        wait=tenacity.wait_exponential_jitter(),
+        retry=tenacity.retry_if_exception_type((WatchError, RedisConnectionError, ConnectionResetError, TimeoutError)),
+        reraise=True,
+        before=_log_attempt,
+    )
+    async def is_host_available(self, host: str) -> bool:
+        failures_count: typing.Final = int(await self.redis_connection.get(f"circuit-breaker-{host}") or 0)
+        is_available: bool = failures_count <= self.max_failure_count
+        logger.debug(
+            "host: '%s', failures_count: '%s', self.max_failure_count: '%s', is_available: '%s'",
+            host,
+            failures_count,
+            self.max_failure_count,
+            is_available,
+        )
+        return is_available
+
+    async def raise_host_unavailable_error(self, host: str) -> typing.NoReturn:
+        msg = f"Host {host} is unavailable"
+        raise errors.HostUnavailableError(msg)

circuit_breaker_box/circuit_breaker_redis.py

@@ -1,16 +1,17 @@
 import asyncio
+import logging
 import typing
 
 import fastapi
 
-from circuit_breaker_box.circuit_breaker import CircuitBreakerInMemory
+from circuit_breaker_box import CircuitBreakerInMemory
 
 
 HTTP_MAX_TRIES = 4
 MAX_CACHE_SIZE = 256
 CIRCUIT_BREAKER_MAX_FAILURE_COUNT = 1
 RESET_TIMEOUT_IN_SECONDS = 10
-SOME_HOST = "some_host"
+SOME_HOST = "http://example.com/"
 
 
 class CustomCircuitBreakerInMemory(CircuitBreakerInMemory):
@@ -19,6 +20,7 @@ async def raise_host_unavailable_error(self, host: str) -> typing.NoReturn:
 
 
 async def main() -> None:
+    logging.basicConfig(level=logging.DEBUG)
     circuit_breaker = CustomCircuitBreakerInMemory(
         reset_timeout_in_seconds=RESET_TIMEOUT_IN_SECONDS,
         max_failure_count=CIRCUIT_BREAKER_MAX_FAILURE_COUNT,

examples/example_circuit_breaker.py

@@ -6,7 +6,6 @@ requires-python = ">=3.10,<4"
 dependencies = [
     "cachetools",
     "httpx",
-    "loguru",
     "redis",
     "tenacity",
 ]
@@ -79,6 +78,6 @@ run.concurrency = ["thread"]
 report.exclude_also = ["if typing.TYPE_CHECKING:"]
 
 [project.urls]
-Issues = "https://github.com/community-of-python/circuit-breaker-box/issues"
 Repository = "https://github.com/community-of-python/circuit-breaker-box"
+Issues = "https://github.com/community-of-python/circuit-breaker-box/issues"
 Changelogs = "https://github.com/community-of-python/circuit-breaker-box/releases"

pyproject.toml

@@ -1,14 +1,16 @@
 import dataclasses
+import logging
 import typing
 
 import pytest
-from loguru import logger
 from redis import asyncio as aioredis
 
-from circuit_breaker_box.circuit_breaker import CircuitBreakerInMemory, CircuitBreakerRedis
+from circuit_breaker_box import CircuitBreakerInMemory, CircuitBreakerRedis
 from examples.example_circuit_breaker import CustomCircuitBreakerInMemory
 
 
+logger = logging.getLogger(__name__)
+
 HTTP_MAX_TRIES = 4
 MAX_CACHE_SIZE = 256
 CIRCUIT_BREAKER_MAX_FAILURE_COUNT = 1
@@ -21,16 +23,16 @@ class TestRedisConnection(aioredis.Redis):  # type: ignore[type-arg]
     errors: int = 0
 
     async def incr(self, host: str | bytes, amount: int = 1) -> int:
-        logger.debug(f"host: {host!s}, amount: {amount}")
+        logger.debug("host: %s, amount: %d{amount}", host, amount)
         self.errors = self.errors + 1
         return amount + 1
 
     async def expire(self, *args: typing.Any, **kwargs: typing.Any) -> bool:  # noqa: ANN401
-        logger.debug(f"{args=}, {kwargs=}")
+        logger.debug(args, kwargs)
         return True
 
     async def get(self, host: str | bytes) -> int:
-        logger.debug(f"host: {host!s}, errors: {self.errors}")
+        logger.debug("host: %s, errors: %s", host, self.errors)
         return self.errors
 
 

tests/conftest.py

@@ -1,8 +1,7 @@
 import fastapi
 import pytest
 
-from circuit_breaker_box import errors
-from circuit_breaker_box.circuit_breaker import CircuitBreakerInMemory, CircuitBreakerRedis
+from circuit_breaker_box import CircuitBreakerInMemory, CircuitBreakerRedis, errors
 from examples.example_circuit_breaker import CustomCircuitBreakerInMemory
 from tests.conftest import HTTP_MAX_TRIES, SOME_HOST