Use comprehensions (#83)

Author: cclauss

.github/workflows/ci.yml

@@ -25,7 +25,7 @@ jobs:
 
     - name: Analysing the code with pylint
       run: |
-        python -m pylint -E partitionmanager
+        python -m pylint --errors-only partitionmanager
 
     - name: Lint Python code with Ruff
       run: |

partitionmanager/cli.py

@@ -182,8 +182,8 @@ def _extract_single_column(row):
 def list_tables(conf):
     """List all tables for the current database."""
     rows = conf.dbcmd.run("SHOW TABLES;")
-    table_names = map(lambda row: _extract_single_column(row), rows)
-    table_objects = map(lambda name: partitionmanager.types.Table(name), table_names)
+    table_names = (_extract_single_column(row) for row in rows)
+    table_objects = (partitionmanager.types.Table(name) for name in table_names)
     return list(table_objects)
 
 
@@ -287,7 +287,7 @@ def do_partition(conf):
         log.info("Database is read-only, only emitting statistics")
         if conf.prometheus_stats_path:
             do_stats(conf)
-        return dict()
+        return {}
 
     if conf.noop:
         log.info("Running in noop mode, no changes will be made")
@@ -304,7 +304,7 @@ def do_partition(conf):
         type_name="counter",
     )
 
-    all_results = dict()
+    all_results = {}
     for table in conf.tables:
         time_start = None
         try:
@@ -384,7 +384,7 @@ def do_stats(conf, metrics=partitionmanager.stats.PrometheusMetrics()):
 
     log = logging.getLogger("do_stats")
 
-    all_results = dict()
+    all_results = {}
     for table in list_tables(conf):
         table_problems = pm_tap.get_table_compatibility_problems(conf.dbcmd, table)
         if table_problems:
@@ -476,7 +476,7 @@ def drop_cmd(args):
 
 
 def do_find_drops_for_tables(conf):
-    all_results = dict()
+    all_results = {}
     for table in conf.tables:
         log = logging.getLogger(f"do_find_drops_for_tables:{table.name}")
 

partitionmanager/cli_test.py

@@ -127,7 +127,7 @@ def test_partition_cmd_several_tables(self):
         output = partition_cmd(args)
 
         self.assertEqual(len(output), 2)
-        self.assertSetEqual(set(output), set(["testtable", "another_table"]))
+        self.assertSetEqual(set(output), {"testtable", "another_table"})
 
     def test_partition_unpartitioned_table(self):
         o = run_partition_cmd_yaml(
@@ -186,7 +186,7 @@ def test_partition_cmd_two_tables(self):
     mariadb: {str(fake_exec)}
 """
         )
-        self.assertSetEqual(set(o), set(["test", "test_with_retention"]))
+        self.assertSetEqual(set(o), {"test", "test_with_retention"})
 
     def test_partition_period_daily(self):
         o = run_partition_cmd_yaml(
@@ -201,7 +201,7 @@ def test_partition_period_daily(self):
 """
         )
         self.assertSequenceEqual(
-            set(o), set(["partitioned_last_week", "partitioned_yesterday"])
+            set(o), {"partitioned_last_week", "partitioned_yesterday"}
         )
 
     def test_partition_period_seven_days(self):
@@ -221,16 +221,14 @@ def test_partition_period_seven_days(self):
 
         self.assertEqual(
             set(logctx.output),
-            set(
-                [
-                    "INFO:partition:Evaluating Table partitioned_last_week "
-                    "(duration=7 days, 0:00:00)",
-                    "DEBUG:partition:Table partitioned_last_week has no pending SQL updates.",  # noqa: E501
-                    "INFO:partition:Evaluating Table partitioned_yesterday "
-                    "(duration=7 days, 0:00:00)",
-                    "DEBUG:partition:Table partitioned_yesterday has no pending SQL updates.",  # noqa: E501
-                ]
-            ),
+            {
+                "INFO:partition:Evaluating Table partitioned_last_week "
+                "(duration=7 days, 0:00:00)",
+                "DEBUG:partition:Table partitioned_last_week has no pending SQL updates.",  # noqa: E501
+                "INFO:partition:Evaluating Table partitioned_yesterday "
+                "(duration=7 days, 0:00:00)",
+                "DEBUG:partition:Table partitioned_yesterday has no pending SQL updates.",  # noqa: E501
+            },
         )
         self.assertSequenceEqual(list(o), [])
 
@@ -249,7 +247,7 @@ def test_partition_period_different_per_table(self):
 """
         )
         self.assertSequenceEqual(
-            set(o), set(["partitioned_yesterday", "partitioned_last_week"])
+            set(o), {"partitioned_yesterday", "partitioned_last_week"}
         )
 
     def test_partition_with_db_url(self):
@@ -283,7 +281,7 @@ def assert_stats_results(self, results):
 
     def assert_stats_prometheus_outfile(self, prom_file):
         lines = prom_file.split("\n")
-        metrics = dict()
+        metrics = {}
         for line in lines:
             if not line.startswith("#") and len(line) > 0:
                 key, value = line.split(" ")
@@ -350,9 +348,7 @@ def test_cli_tables_override_yaml(self):
 """,
             datetime.now(tz=timezone.utc),
         )
-        self.assertEqual(
-            {str(x.name) for x in conf.tables}, set(["table_one", "table_two"])
-        )
+        self.assertEqual({str(x.name) for x in conf.tables}, {"table_one", "table_two"})
 
     def test_cli_mariadb_override_yaml(self):
         args = PARSER.parse_args(["--mariadb", "/usr/bin/true", "stats"])
@@ -651,12 +647,10 @@ def test_drop_invalid_config(self):
             )
         self.assertEqual(
             set(logctx.output),
-            set(
-                [
-                    "WARNING:do_find_drops_for_tables:unused:"
-                    "Cannot process Table unused: no retention specified"
-                ]
-            ),
+            {
+                "WARNING:do_find_drops_for_tables:unused:"
+                "Cannot process Table unused: no retention specified"
+            },
         )
 
     def test_drop_no_sql(self):
@@ -675,10 +669,8 @@ def test_drop_no_sql(self):
             )
         self.assertEqual(
             set(logctx.output),
-            set(
-                [
-                    "WARNING:do_find_drops_for_tables:unused:"
-                    "Cannot process Table unused: no date query specified"
-                ]
-            ),
+            {
+                "WARNING:do_find_drops_for_tables:unused:"
+                "Cannot process Table unused: no date query specified"
+            },
         )

partitionmanager/database_helpers_test.py

@@ -15,7 +15,7 @@
 
 class MockDatabase(DatabaseCommand):
     def __init__(self):
-        self._responses = list()
+        self._responses = []
         self.num_queries = 0
 
     def add_response(self, expected, response):

partitionmanager/dropper.py

@@ -16,7 +16,7 @@ def _drop_statement(table, partition_list):
     if not partition_list:
         raise ValueError("Partition list may not be empty")
 
-    partitions = ",".join(map(lambda x: f"`{x.name}`", partition_list))
+    partitions = ",".join(f"`{x.name}`" for x in partition_list)
 
     alter_cmd = f"ALTER TABLE `{table.name}` DROP PARTITION IF EXISTS {partitions};"
 

partitionmanager/dropper_test.py

@@ -20,7 +20,7 @@ def _timestamp_rsp(year, mo, day):
 
 class MockDatabase(DatabaseCommand):
     def __init__(self):
-        self._responses = list()
+        self._responses = []
         self.num_queries = 0
 
     def add_response(self, expected, response):

partitionmanager/migrate.py

@@ -48,7 +48,7 @@ def write_state_info(conf, out_fp):
     log = logging.getLogger("write_state_info")
 
     log.info("Writing current state information")
-    state_info = {"time": conf.curtime, "tables": dict()}
+    state_info = {"time": conf.curtime, "tables": {}}
     for table in conf.tables:
         map_data = _get_map_data_from_config(conf, table)
 
@@ -90,7 +90,7 @@ def _plan_partitions_for_time_offsets(
 
         rate_of_change: an ordered list of positions per RATE_UNIT.
     """
-    changes = list()
+    changes = []
     for (i, offset), is_final in partitionmanager.tools.iter_show_end(
         enumerate(time_offsets)
     ):
@@ -243,7 +243,7 @@ def calculate_sql_alters_from_state_info(conf, in_fp):
             f"{prior_data['time']} = {time_delta}"
         )
 
-    commands = dict()
+    commands = {}
 
     for table_name, prior_pos in prior_data["tables"].items():
         table = None
@@ -270,7 +270,7 @@ def calculate_sql_alters_from_state_info(conf, in_fp):
         delta_positions = list(
             map(operator.sub, ordered_current_pos, ordered_prior_pos)
         )
-        rate_of_change = list(map(lambda pos: pos / time_delta, delta_positions))
+        rate_of_change = [pos / time_delta for pos in delta_positions]
 
         max_val_part = map_data["partitions"][-1]
         if not isinstance(max_val_part, partitionmanager.types.MaxValuePartition):

partitionmanager/migrate_test.py

@@ -26,7 +26,7 @@
 
 class MockDatabase(DatabaseCommand):
     def __init__(self):
-        self._response = list()
+        self._response = []
         self._select_response = [[{"id": 150}]]
         self.num_queries = 0
 

partitionmanager/sql.py

@@ -53,15 +53,15 @@ def __init__(self):
         self.rows = None
         self.current_row = None
         self.current_field = None
-        self.current_elements = list()
+        self.current_elements = []
         self.statement = None
 
     def parse(self, data):
         """Return rows from an XML Result object."""
         if self.rows is not None:
             raise ValueError("XmlResult objects can only be used once")
 
-        self.rows = list()
+        self.rows = []
         self.xmlparser.Parse(data)
 
         if self.current_elements:
@@ -186,4 +186,4 @@ def run(self, sql_cmd):
         logging.debug(f"IntegratedDatabaseCommand executing {sql_cmd}")
         with self.connection.cursor() as cursor:
             cursor.execute(sql_cmd)
-            return [row for row in cursor]
+            return list(cursor)

partitionmanager/stats.py

@@ -22,14 +22,14 @@ class PrometheusMetrics:
     """A set of metrics that can be rendered for Prometheus."""
 
     def __init__(self):
-        self.metrics = dict()
-        self.help = dict()
-        self.types = dict()
+        self.metrics = {}
+        self.help = {}
+        self.types = {}
 
     def add(self, name, table, data):
         """Record metric data representing the name and table."""
         if name not in self.metrics:
-            self.metrics[name] = list()
+            self.metrics[name] = []
         self.metrics[name].append(PrometheusMetric(name, table, data))
 
     def describe(self, name, help_text=None, type_name=None):
@@ -50,7 +50,7 @@ def render(self, fp):
             if n in self.types:
                 print(f"# TYPE {name} {self.types[n]}", file=fp)
             for m in metrics:
-                labels = list()
+                labels = []
                 if m.table:
                     labels = [f'table="{m.table}"']
                 print(f"{name}{{{','.join(labels)}}} {m.data}", file=fp)