feat: store integration test metrics in metrics.json

For each test store metrics it emits into a metrics.json
file. This makes it easier to look at the metrics.

Signed-off-by: Egor Lazarchuk <yegorlz@amazon.co.uk>

Author: ShadowCurse

tests/conftest.py

@@ -172,7 +172,7 @@ def pytest_runtest_logreport(report):
 
 
 @pytest.fixture()
-def metrics(request):
+def metrics(results_dir, request):
     """Fixture to pass the metrics scope
 
     We use a fixture instead of the @metrics_scope decorator as that conflicts
@@ -188,6 +188,8 @@ def metrics(request):
         metrics_logger.set_property(prop_name, prop_val)
     yield metrics_logger
     metrics_logger.flush()
+    if results_dir:
+        metrics_logger.store_data(results_dir)
 
 
 @pytest.fixture
@@ -391,17 +393,29 @@ def results_dir(request):
     """
     Fixture yielding the path to a directory into which the test can dump its results
 
-    Directories are unique per test, and named after the test name. Everything the tests puts
-    into its directory will to be uploaded to S3. Directory will be placed inside defs.TEST_RESULTS_DIR.
+    Directories are unique per test, and their names include test name and test parameters.
+    Everything the tests puts into its directory will to be uploaded to S3.
+    Directory will be placed inside defs.TEST_RESULTS_DIR.
 
     For example
     ```py
-    def test_my_file(results_dir):
+    @pytest.mark.parametrize("p", ["a", "b"])
+    def test_my_file(p, results_dir):
         (results_dir / "output.txt").write_text("Hello World")
     ```
-    will result in `defs.TEST_RESULTS_DIR`/test_my_file/output.txt.
+    will result in:
+    - `defs.TEST_RESULTS_DIR`/test_my_file/test_my_file[a]/output.txt.
+    - `defs.TEST_RESULTS_DIR`/test_my_file/test_my_file[b]/output.txt.
+
+    When this fixture is called with DoctestItem as a request.node
+    during doc tests, it will return None.
     """
-    results_dir = defs.TEST_RESULTS_DIR / request.node.originalname
+    try:
+        results_dir = (
+            defs.TEST_RESULTS_DIR / request.node.originalname / request.node.name
+        )
+    except AttributeError:
+        return None
     results_dir.mkdir(parents=True, exist_ok=True)
     return results_dir
 

tests/host_tools/metrics.py

@@ -46,52 +46,59 @@
 import json
 import os
 import socket
+from pathlib import Path
 from urllib.parse import urlparse
 
 from aws_embedded_metrics.constants import DEFAULT_NAMESPACE
 from aws_embedded_metrics.logger.metrics_logger_factory import create_metrics_logger
 
 
-class MetricsWrapperDummy:
-    """Send metrics to /dev/null"""
+class MetricsWrapper:
+    """A convenient metrics logger"""
+
+    def __init__(self, logger):
+        self.data = {}
+        self.logger = logger
 
     def set_dimensions(self, *args, **kwargs):
         """Set dimensions"""
+        if self.logger:
+            self.logger.set_dimensions(*args, **kwargs)
 
-    def put_metric(self, *args, **kwargs):
+    def put_metric(self, name, data, unit):
         """Put a datapoint with given dimensions"""
+        if name not in self.data:
+            self.data[name] = []
+        self.data[name].append(data)
+
+        if self.logger:
+            self.logger.put_metric(name, data, unit)
 
     def set_property(self, *args, **kwargs):
         """Set a property"""
+        if self.logger:
+            self.logger.set_property(*args, **kwargs)
 
     def flush(self):
         """Flush any remaining metrics"""
+        if self.logger:
+            asyncio.run(self.logger.flush())
 
-
-class MetricsWrapper:
-    """A convenient metrics logger"""
-
-    def __init__(self, logger):
-        self.logger = logger
-
-    def __getattr__(self, attr):
-        """Dispatch methods to logger instance"""
-        if attr not in self.__dict__:
-            return getattr(self.logger, attr)
-        return getattr(self, attr)
-
-    def flush(self):
-        """Flush any remaining metrics"""
-        asyncio.run(self.logger.flush())
+    def store_data(self, dir_path):
+        """Store data into a file"""
+        metrics_path = Path(dir_path / "metrics.json")
+        with open(metrics_path, "w", encoding="utf-8") as f:
+            json.dump(self.data, f)
 
 
 def get_metrics_logger():
     """Get a new metrics logger object"""
     # if no metrics namespace, don't output metrics
-    if "AWS_EMF_NAMESPACE" not in os.environ:
-        return MetricsWrapperDummy()
-    logger = create_metrics_logger()
-    logger.reset_dimensions(False)
+    if "AWS_EMF_NAMESPACE" in os.environ:
+        logger = create_metrics_logger()
+        logger.reset_dimensions(False)
+    else:
+        logger = None
     return MetricsWrapper(logger)