tests: enable prometheus_test.py to test metrics without aggregation

in order to reduce the replicated code, this change adds a test to
prometheus_test.py, to verify the metrics without aggregations.

since we already have the coverage for this feature, let's drop it
from test_metrics.py.

Signed-off-by: Kefu Chai <[email protected]>

tests/unit/prometheus_test.py

@@ -21,33 +21,85 @@
 #
 
 import argparse
+import math
 import re
 import subprocess
 import sys
 import unittest
 import urllib.request
 import urllib.parse
+import yaml
 
 from typing import Optional
 from collections import namedtuple
 
 
 class Exposition:
+    @classmethod
+    def from_hist(cls,
+                  name: str,
+                  hist: list[tuple[float, int]],
+                  sum_: int,
+                  count: int) -> 'Exposition':
+        # ignore these values, we might need to verify them in future
+        _, _ = sum_, count
+        buckets = (cls.value_to_bucket(le - 1) for le, _ in hist)
+        deltas = []
+        last_n = 0
+        for _, n in hist:
+            delta = n - last_n
+            last_n = n
+            deltas.append(delta)
+        return cls(name, dict(zip(buckets, deltas)), {})
+
+    @staticmethod
+    def value_to_bucket(value):
+        low = 2 ** math.floor(math.log(value, 2))
+        high = 2 * low
+        dif = (high - low) / 4
+        return low + dif * math.floor((value - low) / dif)
+
+    @staticmethod
+    def _values_to_histogram(values):
+        hist = {}
+        for val in values:
+            bucket = Exposition.value_to_bucket(val)
+            if bucket in hist:
+                hist[bucket] += 1
+            else:
+                hist[bucket] = 1
+        return hist
+
+    @classmethod
+    def from_conf(cls,
+                  name: str,
+                  type_: str,
+                  values: list[str],
+                  labels: dict[str, str]) -> 'Exposition':
+        if type_ in ('gauge', 'counter'):
+            assert len(values) == 1
+            return Exposition(name, float(values[0]), labels)
+        if type_ == 'histogram':
+            hist = cls._values_to_histogram(float(v) for v in values)
+            return cls(name, hist, {})
+        raise NotImplementedError(f'unsupported type: {type_}')
+
     def __init__(self,
                  name: str,
-                 type_: str,
-                 value: str,
-                 labels: Optional[dict[str, str]] = None) -> None:
+                 value: int | list[tuple[float, int]],
+                 labels: dict[str, str]) -> None:
         self.name = name
-        if type_ == 'counter':
-            self.value = float(value)
-        elif type_ == 'gauge':
-            self.value = float(value)
-        else:
-            # we don't verify histogram or summary yet
-            self.value = None
+        self.value = value
         self.labels = labels
 
+    def __repr__(self):
+        return f"{self.name=}, {self.value=}, {self.labels=}"
+
+    def __eq__(self, other):
+        if not isinstance(other, Exposition):
+            return False
+        return self.value == other.value
+
 
 class Metrics:
     prefix = 'seastar'
@@ -89,36 +141,67 @@ def get(self,
         full_name = None
         if name is not None:
             full_name = f'{self.prefix}_{self.group}_{name}'
-        results: list[Exposition] = []
         metric_type = None
 
+        # for histogram and summary as they are represented with multiple lines
+        hist_name = ''
+        hist_buckets = []
+        hist_sum = 0
+        hist_count = 0
+
         for line in self.lines:
             if not line:
                 continue
             if line.startswith('# HELP'):
                 continue
             if line.startswith('# TYPE'):
-                _, _, metric_name, type_ = line.split()
-                if full_name is None or metric_name == full_name:
-                    metric_type = type_
+                _, _, type_metric_name, metric_type = line.split()
+                if hist_buckets:
+                    yield Exposition.from_hist(hist_name,
+                                               hist_buckets,
+                                               hist_sum,
+                                               hist_count)
+                    hist_buckets = []
+                if metric_type in ('histogram', 'summary'):
+                    hist_name = type_metric_name
                 continue
             matched = self.pattern.match(line)
             assert matched, f'malformed metric line: {line}'
 
-            metric_name = matched.group('metric_name')
-            if full_name and metric_name != full_name:
+            value_metric_name = matched.group('metric_name')
+            if full_name and not value_metric_name.startswith(full_name):
                 continue
 
             metric_labels = self._parse_labels(matched.group('labels'))
             if labels is not None and metric_labels != labels:
                 continue
 
-            metric_value = matched.group('value')
-            results.append(Exposition(metric_name,
-                                      metric_type,
-                                      metric_value,
-                                      metric_labels))
-        return results
+            metric_value = float(matched.group('value'))
+            if metric_type == 'histogram':
+                if value_metric_name == f'{type_metric_name}_bucket':
+                    last_value = 0
+                    if hist_buckets:
+                        last_value = hist_buckets[-1][1]
+                    if metric_value - last_value != 0:
+                        le = metric_labels['le'].strip('"')
+                        hist_buckets.append((float(le), metric_value))
+                elif value_metric_name == f'{type_metric_name}_sum':
+                    hist_sum = metric_value
+                elif value_metric_name == f'{type_metric_name}_count':
+                    hist_count = metric_value
+                else:
+                    raise RuntimeError(f'unknown histogram value: {line}')
+            elif metric_type == 'summary':
+                raise NotImplementedError('unsupported type: summary')
+            else:
+                yield Exposition(type_metric_name,
+                                 metric_value,
+                                 metric_labels)
+        if hist_buckets:
+            yield Exposition.from_hist(hist_name,
+                                       hist_buckets,
+                                       hist_sum,
+                                       hist_count)
 
     def get_help(self, name: str) -> Optional[str]:
         full_name = f'{self.prefix}_{self.group}_{name}'
@@ -175,7 +258,27 @@ def _get_metrics(cls,
             body = f.read().decode('utf-8')
             return Metrics(body.rstrip().split('\n'))
 
-    def test_filtering_by_label(self) -> None:
+    def test_filtering_by_label_sans_aggregation(self) -> None:
+        labels = {'private': '1'}
+        metrics = self._get_metrics(labels=labels)
+        actual_values = list(metrics.get())
+        expected_values = []
+        with open(self.exporter_config, encoding='utf-8') as f:
+            config = yaml.safe_load(f)
+        for metric in config['metrics']:
+            name = metric['name']
+            metric_name = f'{Metrics.prefix}_{Metrics.group}_{name}'
+            metric_labels = metric['labels']
+            if metric_labels != labels:
+                continue
+            e = Exposition.from_conf(metric_name,
+                                     metric['type'],
+                                     metric['values'],
+                                     metric_labels)
+            expected_values.append(e)
+        self.assertCountEqual(actual_values, expected_values)
+
+    def test_filtering_by_label_with_aggregation(self) -> None:
         TestCase = namedtuple('TestCase', ['label', 'regex', 'found'])
         label = 'private'
         tests = [
@@ -188,7 +291,8 @@ def test_filtering_by_label(self) -> None:
         for test in tests:
             with self.subTest(regex=test.regex, found=test.found):
                 metrics = self._get_metrics(labels={test.label: test.regex})
-                self.assertEqual(len(metrics.get()), test.found)
+                values = list(metrics.get())
+                self.assertEqual(len(values), test.found)
 
     def test_aggregated(self) -> None:
         name = 'counter_1'
@@ -219,6 +323,7 @@ def test_help(self) -> None:
                     self.assertIsNone(msg)
 
 
+
 if __name__ == '__main__':
     parser = argparse.ArgumentParser()
     parser.add_argument('--exporter',

tests/unit/test_metrics.py

@@ -29,44 +29,6 @@ def query_prometheus(host, query, type):
     )
 
 
-def validate_text(url):
-    resp = requests.get("http://" + url)
-    val = None
-    res = {}
-    for l in resp.iter_lines():
-        if not l:
-            continue
-        ln = l.decode("utf-8")
-        if "HELP" in ln:
-            continue
-        if "TYPE" in ln:
-            if val:
-                res[name] = {"name": name, "type": type, "value": val}
-            m = MATCH_TYPE.match(ln)
-            name = m.group(1)
-            type = m.group(2)
-            last_val = 0
-            val = None
-        else:
-            if type == "histogram":
-                m = MATCH_HISTOGRAM.match(ln)
-                if not m:
-                    continue
-                le = val_to_bucket(float(m.group(1)) - 1)
-                value = float(m.group(2))
-                if not val:
-                    val = {}
-                if value > last_val:
-                    val[le] = value - last_val
-                    last_val = value
-            else:
-                m = MATCH_VALUE.match(ln)
-                val = float(m.group(1))
-    if val:
-        res[name] = {"name": name, "type": type, "value": val}
-    return res
-
-
 def val_to_bucket(val):
     low = 2 ** math.floor(math.log(val, 2))
     high = 2 * low
@@ -118,16 +80,6 @@ def conf_to_metrics(conf):
     metrics = yaml.safe_load(file)
     conf_metrics = conf_to_metrics(metrics)
 
-from_text_metrics = validate_text(args.host)
-
-# Validate text format
-for v in conf_metrics:
-    if v not in from_text_metrics:
-        print("Text format: metrics ", v, "is missing")
-    if from_text_metrics[v]["value"] != conf_metrics[v]["value"]:
-        print('Text format: Metrics', v, 'type', from_text_metrics[v]['type'],
-              'Mismatch, expected', from_text_metrics[v]['value'], '!=', conf_metrics[v]['value'])
-
 # Validate protobuf
 for v in conf_metrics:
     res = query_prometheus(args.prometheus, v, conf_metrics[v]["type"])