Improve clickhouse mutations waiting

README.md

@@ -451,6 +451,15 @@ get_mutations_in_progress_count("SOME_DATABASE", "SOME_TABLE_IN_DATABASE")
 # 5
 ```
 
+#### notalib.django.clickhouse.mutations.is_mutations_running
+
+True or False, depending on the presence of unfulfilled mutations.
+
+```python
+is_mutations_running("SOME_DATABASE", "SOME_TABLE_IN_DATABASE")
+True
+```
+
 #### notalib.django.clickhouse.wait.wait_result :fire:
 
 Waits until all mutations for the given table are complete.

notalib/django/clickhouse/mutations.py

@@ -7,16 +7,11 @@ def get_mutations_in_progress_count(db_name: str, table_name: str) -> int:
 	"""
 	Requests from the System.Mutants table the number of mutations in progress.
 
-	Parameters
-	----------
-	db_name: str
-		Must contain name of existed database with tables.
-	table_name: str
-		Must contain name of existed table in database with db_name.
-
-	Returns
-	-------
-	int
+	Args:
+		db_name: Must contain name of existed database with tables.
+		table_name: Must contain name of existed table in database with db_name.
+
+	Returns:
 		Number of mutants in progress.
 	"""
 
@@ -39,3 +34,26 @@ def get_mutations_in_progress_count(db_name: str, table_name: str) -> int:
 	query.params = {'db_name': db_name, 'table_name': table_name}
 
 	return query.execute_val()
+
+
+def is_mutations_running(db_name: str, table_name: str) -> bool:
+	"""
+	Checks for the presence of running mutations.
+
+	Args:
+		db_name: Name of database to check.
+		table_name: Name of table to check.
+
+	Returns:
+		Returns True if there are running mutations, otherwise False.
+	"""
+	query = Query()
+	query.q = text("""\
+SELECT 1
+FROM system.mutations
+WHERE database = :db_name AND table = :table_name AND is_done = 0
+LIMIT 1
+""")
+	query.params = {"db_name": db_name, "table_name": table_name}
+
+	return bool(query.execute_list())

notalib/django/clickhouse/mutations_test.py

@@ -1,30 +1,50 @@
-from notalib.django.clickhouse.mutations import get_mutations_in_progress_count
+from notalib.django.clickhouse.mutations import get_mutations_in_progress_count, is_mutations_running
 from notalib.django.clickhouse.base import Query
 
-from unittest.mock import patch
+from unittest.mock import patch, Mock
 
 
-class FakeQuery(Query):
-	instance = None
+def make_fake_query():
+	class FakeQuery(Query):
+		instance = None
 
-	def __new__(cls, *args, **kwargs) -> "FakeQuery":
-		if cls.instance is None:
-			cls.instance = super().__new__(cls, *args, **kwargs)
+		def __new__(cls, *args, **kwargs) -> "FakeQuery":
+			if cls.instance is None:
+				cls.instance = super().__new__(cls, *args, **kwargs)
 
-		return cls.instance
+			return cls.instance
 
-	def __init__(self, q=None, **kwargs):
-		if not self is self.__class__.instance:
-			super().__init__(q, **kwargs)
+		def __init__(self, q=None, **kwargs):
+			if not self is self.__class__.instance:
+				super().__init__(q, **kwargs)
 
-	def execute_val(self) -> None:
-		return None
+		def execute_val(self) -> None:
+			return None
+
+		def execute_list(self) -> None:
+			return None
+
+
+	return FakeQuery
 
 
 def test_get_mutations_in_progress_count():
+	FakeQuery = make_fake_query()
+
 	with patch("notalib.django.clickhouse.mutations.Query", new=FakeQuery):
 		database, table = "TEST_DATABASE", "TEST_TABLE"
 		get_mutations_in_progress_count(database, table)
 		query = FakeQuery()
 
 		assert query.params == {'db_name': database, 'table_name': table}
+
+
+def test_is_mutations_running():
+	FakeQuery = make_fake_query()
+
+	with patch("notalib.django.clickhouse.mutations.Query", new=FakeQuery):
+		database, table = "TEST_DATABASE", "TEST_TABLE"
+		is_mutations_running(database, table)
+		query = FakeQuery()
+
+		assert query.params == {"db_name": database, "table_name": table}

notalib/django/clickhouse/wait.py

@@ -1,4 +1,4 @@
-from .mutations import get_mutations_in_progress_count
+from .mutations import is_mutations_running
 
 from time import sleep
 from typing import Union
@@ -8,20 +8,14 @@ def wait_result(db_name: str, table_name: str, delay: Union[int, float] = 0.25)
 	"""
 	Suspends the program while there are incomplete mutant processes.
 
-	Parameters
-	----------
-	db_name: str
-		Database name in which the deletion operation was performed.
-	table_name: str
-		Table name in the {db_name} database in which the deletion operation was performed.
-	delay: Union[int, float]
-		Delay between system table polls.
+	Args:
+		db_name: Database name in which the deletion operation was performed.
+		table_name: Table name in the {db_name} database in which the deletion operation was performed.
+		delay: Delay between system table polls.
 
-	Notes
-	-----
-	Imagine that you are driving in a car to a railway crossing. A train is going to cross you by rail.
-	This function is a handbrake that will save you from crashing.
+	Notes:
+		Imagine that you are driving in a car to a railway crossing. A train is going to cross you by rail.
+		This function is a handbrake that will save you from crashing.
 	"""
-
-	while get_mutations_in_progress_count(db_name, table_name):
+	while is_mutations_running(db_name, table_name):
 		sleep(delay)

notalib/django/clickhouse/wait_test.py

@@ -5,16 +5,16 @@
 
 
 def test_wait_result():
-	get_mutations_count_fn = SequenceFakeFunction([5, 0])
+	is_mutations_running_fn = SequenceFakeFunction([True, False])
 	sleep_fn = FakeFunction()
 
-	with patch("notalib.django.clickhouse.wait.get_mutations_in_progress_count", new=get_mutations_count_fn):
+	with patch("notalib.django.clickhouse.wait.is_mutations_running", new=is_mutations_running_fn):
 		with patch("notalib.django.clickhouse.wait.sleep", new=sleep_fn):
 			database, table, delay = "TEST_DATABASE", "TEST_TABLE", 5
 
 			wait_result(database, table, delay)
-			assert get_mutations_count_fn.last_call_args == (database, table)
-			assert get_mutations_count_fn.call_count == 2
+			assert is_mutations_running_fn.last_call_args == (database, table)
+			assert is_mutations_running_fn.call_count == 2
 
 			assert sleep_fn.last_call_args == (delay, )
 			assert sleep_fn.call_count == 1

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "notalib"
-version = "2.4.0"
+version = "2.5.0-rc0"
 description = "A collection of utility functions & classes"
 authors = ["m1kc (Max Musatov) <m1kc@yandex.ru>"]
 license = "MIT"