Retry(): Support negative retries value (#2110)

* Support negative `retries` value * Add unit test * Add unittest for blocking api

Author: kristjanvalur

CHANGES

@@ -1,4 +1,5 @@
 
+ * Allow negative `retries` for `Retry` class to retry forever
  * Add `items` parameter to `hset` signature
  * Create codeql-analysis.yml (#1988). Thanks @chayim
  * Add limited support for Lua scripting with RedisCluster

redis/asyncio/retry.py

@@ -27,6 +27,7 @@ def __init__(
  """
  Initialize a `Retry` object with a `Backoff` object
  that retries a maximum of `retries` times.
+ `retries` can be negative to retry forever.
  You can specify the types of supported errors which trigger
  a retry with the `supported_errors` parameter.
  """
@@ -51,7 +52,7 @@ async def call_with_retry(
  except self._supported_errors as error:
  failures += 1
  await fail(error)
- if failures > self._retries:
+ if self._retries >= 0 and failures > self._retries:
  raise error
  backoff = self._backoff.compute(failures)
  if backoff > 0:

redis/retry.py

@@ -16,6 +16,7 @@ def __init__(
  """
  Initialize a `Retry` object with a `Backoff` object
  that retries a maximum of `retries` times.
+ `retries` can be negative to retry forever.
  You can specify the types of supported errors which trigger
  a retry with the `supported_errors` parameter.
  """
@@ -46,7 +47,7 @@ def call_with_retry(self, do, fail):
  except self._supported_errors as error:
  failures += 1
  fail(error)
- if failures > self._retries:
+ if self._retries >= 0 and failures > self._retries:
  raise error
  backoff = self._backoff.compute(failures)
  if backoff > 0:

tests/test_asyncio/test_retry.py

@@ -56,6 +56,11 @@ async def _do(self):
  async def _fail(self, error):
  self.actual_failures += 1
 
+ async def _fail_inf(self, error):
+ self.actual_failures += 1
+ if self.actual_failures == 5:
+ raise ConnectionError()
+
  @pytest.mark.parametrize("retries", range(10))
  @pytest.mark.asyncio
  async def test_retry(self, retries: int):
@@ -68,3 +73,14 @@ async def test_retry(self, retries: int):
  assert self.actual_failures == 1 + retries
  assert backoff.reset_calls == 1
  assert backoff.calls == retries
+
+ @pytest.mark.asyncio
+ async def test_infinite_retry(self):
+ backoff = BackoffMock()
+ # specify infinite retries, but give up after 5
+ retry = Retry(backoff, -1)
+ with pytest.raises(ConnectionError):
+ await retry.call_with_retry(self._do, self._fail_inf)
+
+ assert self.actual_attempts == 5
+ assert self.actual_failures == 5

tests/test_retry.py

@@ -95,6 +95,11 @@ def _do(self):
  def _fail(self, error):
  self.actual_failures += 1
 
+ def _fail_inf(self, error):
+ self.actual_failures += 1
+ if self.actual_failures == 5:
+ raise ConnectionError()
+
  @pytest.mark.parametrize("retries", range(10))
  def test_retry(self, retries):
  backoff = BackoffMock()
@@ -107,6 +112,16 @@ def test_retry(self, retries):
  assert backoff.reset_calls == 1
  assert backoff.calls == retries
 
+ def test_infinite_retry(self):
+ backoff = BackoffMock()
+ # specify infinite retries, but give up after 5
+ retry = Retry(backoff, -1)
+ with pytest.raises(ConnectionError):
+ retry.call_with_retry(self._do, self._fail_inf)
+
+ assert self.actual_attempts == 5
+ assert self.actual_failures == 5
+
 
 @pytest.mark.onlynoncluster
 class TestRedisClientRetry: