Refactor do_partition to reduce the statement count (#81)

Co-authored-by: Christian Clauss <cclauss@me.com>

Author: jcjones

partitionmanager/cli.py

@@ -266,6 +266,55 @@ def migrate_cmd(args):
 MIGRATE_PARSER.set_defaults(func=migrate_cmd)
 
 
+def _partition_table(conf, log, table, metrics):
+    if table_problems := pm_tap.get_table_compatibility_problems(conf.dbcmd, table):
+        log.error(f"Cannot proceed: {table} {table_problems}")
+        return None
+
+    map_data = pm_tap.get_partition_map(conf.dbcmd, table)
+
+    duration = table.partition_period or conf.partition_period
+
+    log.info(f"Evaluating {table} (duration={duration})")
+    cur_pos = partitionmanager.database_helpers.get_position_of_table(
+        conf.dbcmd, table, map_data
+    )
+
+    sql_cmds = pm_tap.get_pending_sql_reorganize_partition_commands(
+        database=conf.dbcmd,
+        table=table,
+        partition_list=map_data["partitions"],
+        current_position=cur_pos,
+        allowed_lifespan=duration,
+        num_empty_partitions=conf.num_empty,
+        evaluation_time=conf.curtime,
+    )
+
+    if not sql_cmds:
+        log.debug(f"{table} has no pending SQL updates.")
+        return None
+
+    composite_sql_command = "\n".join(sql_cmds)
+
+    if conf.noop:
+        log.info(f"{table} planned SQL: {composite_sql_command}")
+        return {"sql": composite_sql_command, "noop": True}
+
+    log.info(f"{table} running SQL: {composite_sql_command}")
+
+    time_start = datetime.now(tz=timezone.utc)
+    output = conf.dbcmd.run(composite_sql_command)
+    time_end = datetime.now(tz=timezone.utc)
+    metrics.add(
+        "alter_time_seconds",
+        table.name,
+        (time_end - time_start).total_seconds(),
+    )
+
+    log.info(f"{table} results: {output}")
+    return {"sql": composite_sql_command, "output": output}
+
+
 def do_partition(conf):
     """Produces SQL statements to manage partitions per the supplied configuration.
 
@@ -298,56 +347,15 @@ def do_partition(conf):
 
     all_results = {}
     for table in conf.tables:
-        time_start = None
         try:
-            table_problems = pm_tap.get_table_compatibility_problems(conf.dbcmd, table)
-            if table_problems:
-                log.error(f"Cannot proceed: {table} {table_problems}")
-                continue
-
-            map_data = pm_tap.get_partition_map(conf.dbcmd, table)
-
-            duration = conf.partition_period
-            if table.partition_period:
-                duration = table.partition_period
-
-            log.info(f"Evaluating {table} (duration={duration})")
-            cur_pos = partitionmanager.database_helpers.get_position_of_table(
-                conf.dbcmd, table, map_data
-            )
-
-            sql_cmds = pm_tap.get_pending_sql_reorganize_partition_commands(
-                database=conf.dbcmd,
-                table=table,
-                partition_list=map_data["partitions"],
-                current_position=cur_pos,
-                allowed_lifespan=duration,
-                num_empty_partitions=conf.num_empty,
-                evaluation_time=conf.curtime,
-            )
-
-            if not sql_cmds:
-                log.debug(f"{table} has no pending SQL updates.")
-                continue
-
-            composite_sql_command = "\n".join(sql_cmds)
-
-            if conf.noop:
-                all_results[table.name] = {"sql": composite_sql_command, "noop": True}
-                log.info(f"{table} planned SQL: {composite_sql_command}")
-                continue
-
-            log.info(f"{table} running SQL: {composite_sql_command}")
-            time_start = datetime.now(tz=timezone.utc)
-            output = conf.dbcmd.run(composite_sql_command)
-
-            all_results[table.name] = {"sql": composite_sql_command, "output": output}
-            log.info(f"{table} results: {output}")
+            if results := _partition_table(conf, log, table, metrics):
+                all_results[table.name] = results
 
         except partitionmanager.types.NoEmptyPartitionsAvailableException:
             log.warning(
-                f"Unable to automatically handle {table}: No empty "
-                "partition is available."
+                "Unable to automatically handle %s: No empty "
+                "partition is available.",
+                table,
             )
         except partitionmanager.types.DatabaseCommandException as e:
             log.warning("Failed to automatically handle %s: %s", table, e)
@@ -358,14 +366,6 @@ def do_partition(conf):
             log.warning("Failed to handle %s: %s", table, e)
             metrics.add("alter_errors", table.name, 1)
 
-        time_end = datetime.now(tz=timezone.utc)
-        if time_start:
-            metrics.add(
-                "alter_time_seconds",
-                table.name,
-                (time_end - time_start).total_seconds(),
-            )
-
     if conf.prometheus_stats_path:
         do_stats(conf, metrics=metrics)
     return all_results

pyproject.toml

@@ -109,7 +109,7 @@ ignore = [
 max-complexity = 16  # default is 10
 
 [tool.ruff.lint.per-file-ignores]
-"partitionmanager/cli.py" = ["B008"]  # TODO: Fix me
+"partitionmanager/cli.py" = ["B008", "PERF203"]  # TODO: Fix B008, upgrade to Py3.11 for PERF203
 "partitionmanager/cli_test.py" = ["S608", "SIM115", "SIM117"]  # TODO: Fix SIMs
 "partitionmanager/sql.py" = ["B904", "S603"]  # TODO: Fix S603
 "partitionmanager/table_append_partition.py" = ["S608", "SIM102"]  # TODO: Fix S608
@@ -119,4 +119,3 @@ max-complexity = 16  # default is 10
 [tool.ruff.lint.pylint]
 max-args = 7  # default is 5
 max-branches = 15  # default is 12
-max-statements = 54  # default is 50