Don't emit metrics for tables not in the config file (#78)

This fixes #67 , which causes unnecessary alerts (and silences) for tables
we're not trying to keep track of.

Author: jcjones

partitionmanager/cli.py

@@ -119,7 +119,7 @@ def from_yaml_file(self, file):
                 self.dbcmd = partitionmanager.sql.SubprocessDatabaseCommand(
                     data["mariadb"]
                 )
-        if not self.tables:  # Only load tables froml YAML if not supplied via args
+        if not self.tables:  # Only load tables from YAML if not supplied via args
             for key in data["tables"]:
                 tab = partitionmanager.types.Table(key)
                 tabledata = data["tables"][key]
@@ -179,14 +179,6 @@ def _extract_single_column(row):
     return row[columns[0]]
 
 
-def list_tables(conf):
-    """List all tables for the current database."""
-    rows = conf.dbcmd.run("SHOW TABLES;")
-    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)
-
-
 def partition_cmd(args):
     """Runs do_partition on the config that results from the CLI arguments.
 
@@ -379,13 +371,16 @@ def do_partition(conf):
     return all_results
 
 
-def do_stats(conf, metrics=partitionmanager.stats.PrometheusMetrics()):
+def do_stats(conf, metrics=None):
     """Populates a metrics object from the tables in the configuration."""
 
     log = logging.getLogger("do_stats")
 
+    if not metrics:
+        metrics = partitionmanager.stats.PrometheusMetrics()
+
     all_results = {}
-    for table in list_tables(conf):
+    for table in conf.tables:
         table_problems = pm_tap.get_table_compatibility_problems(conf.dbcmd, table)
         if table_problems:
             log.debug(f"Cannot gather statistics for {table}: {table_problems}")

partitionmanager/cli_test.py

@@ -279,13 +279,17 @@ def assert_stats_results(self, results):
             results["partitioned_yesterday"]["max_partition_delta"].days, 2
         )
 
-    def assert_stats_prometheus_outfile(self, prom_file):
+    def parse_prometheus_outfile(self, prom_file):
         lines = prom_file.split("\n")
         metrics = {}
         for line in lines:
             if not line.startswith("#") and len(line) > 0:
                 key, value = line.split(" ")
                 metrics[key] = value
+        return metrics
+
+    def assert_stats_prometheus_outfile(self, prom_file):
+        metrics = self.parse_prometheus_outfile(prom_file)
 
         for table in ["partitioned_last_week", "partitioned_yesterday", "other"]:
             self.assertIn(f'partition_total{{table="{table}"}}', metrics)
@@ -303,7 +307,7 @@ def assert_stats_prometheus_outfile(self, prom_file):
     def test_stats_cli_flag(self):
         args = PARSER.parse_args(["--mariadb", str(fake_exec), "stats"])
         results = stats_cmd(args)
-        self.assert_stats_results(results)
+        assert results == {}
 
     def test_stats_yaml(self):
         with tempfile.NamedTemporaryFile(
@@ -314,7 +318,9 @@ def test_stats_yaml(self):
         mariadb: {str(fake_exec)}
         prometheus_stats: {stats_outfile.name}
         tables:
-            unused:
+            other:
+            partitioned_last_week:
+            partitioned_yesterday:
     """
             insert_into_file(tmpfile, yaml)
             args = PARSER.parse_args(["--config", tmpfile.name, "stats"])
@@ -324,6 +330,36 @@ def test_stats_yaml(self):
             self.assert_stats_results(results)
             self.assert_stats_prometheus_outfile(stats_outfile.read())
 
+    def test_stats_yaml_ignore_unconfigured_tables(self):
+        with tempfile.NamedTemporaryFile(
+            mode="w+", encoding="UTF-8"
+        ) as stats_outfile, tempfile.NamedTemporaryFile() as tmpfile:
+            yaml = f"""
+    partitionmanager:
+        mariadb: {str(fake_exec)}
+        prometheus_stats: {stats_outfile.name}
+        tables:
+            other:
+    """
+            insert_into_file(tmpfile, yaml)
+            args = PARSER.parse_args(["--config", tmpfile.name, "stats"])
+
+            results = stats_cmd(args)
+
+            assert list(results.keys()) == ["other"]
+
+            out_data = stats_outfile.read()
+
+            metrics = self.parse_prometheus_outfile(out_data)
+            assert list(metrics.keys()) == [
+                'partition_total{table="other"}',
+                'partition_time_remaining_until_partition_overrun{table="other"}',
+                'partition_age_of_retained_partitions{table="other"}',
+                'partition_mean_delta_seconds{table="other"}',
+                'partition_max_delta_seconds{table="other"}',
+                "partition_last_run_timestamp{}",
+            ]
+
 
 class TestConfig(unittest.TestCase):
     def test_cli_tables_override_yaml(self):