feat: initialized meter (strands-agents#219)

Author: poshinchen

src/strands/agent/agent.py

@@ -308,7 +308,6 @@ def __init__(
         # Initialize tracer instance (no-op if not configured)
         self.tracer = get_tracer()
         self.trace_span: Optional[trace.Span] = None
-
         self.tool_caller = Agent.ToolCaller(self)
 
     @property

src/strands/telemetry/__init__.py

@@ -3,7 +3,8 @@
 This module provides metrics and tracing functionality.
 """
 
-from .metrics import EventLoopMetrics, Trace, metrics_to_string
+from .config import get_otel_resource
+from .metrics import EventLoopMetrics, MetricsClient, Trace, metrics_to_string
 from .tracer import Tracer, get_tracer
 
 __all__ = [
@@ -12,4 +13,6 @@
     "metrics_to_string",
     "Tracer",
     "get_tracer",
+    "MetricsClient",
+    "get_otel_resource",
 ]

src/strands/telemetry/config.py

@@ -0,0 +1,33 @@
+"""OpenTelemetry configuration and setup utilities for Strands agents.
+
+This module provides centralized configuration and initialization functionality
+for OpenTelemetry components and other telemetry infrastructure shared across Strands applications.
+"""
+
+from importlib.metadata import version
+
+from opentelemetry.sdk.resources import Resource
+
+
+def get_otel_resource() -> Resource:
+    """Create a standard OpenTelemetry resource with service information.
+
+    This function implements a singleton pattern - it will return the same
+    Resource object for the same service_name parameter.
+
+    Args:
+        service_name: Name of the service for OpenTelemetry.
+
+    Returns:
+        Resource object with standard service information.
+    """
+    resource = Resource.create(
+        {
+            "service.name": __name__,
+            "service.version": version("strands-agents"),
+            "telemetry.sdk.name": "opentelemetry",
+            "telemetry.sdk.language": "python",
+        }
+    )
+
+    return resource

src/strands/telemetry/metrics.py

@@ -6,6 +6,10 @@
 from dataclasses import dataclass, field
 from typing import Any, Dict, Iterable, List, Optional, Set, Tuple
 
+import opentelemetry.metrics as metrics_api
+from opentelemetry.metrics import Counter, Meter
+
+from ..telemetry import metrics_constants as constants
 from ..types.content import Message
 from ..types.streaming import Metrics, Usage
 from ..types.tools import ToolUse
@@ -355,3 +359,45 @@ def metrics_to_string(event_loop_metrics: EventLoopMetrics, allowed_names: Optio
         A formatted string representation of the metrics.
     """
     return "\n".join(_metrics_summary_to_lines(event_loop_metrics, allowed_names or set()))
+
+
+class MetricsClient:
+    """Singleton client for managing OpenTelemetry metrics instruments.
+
+    The actual metrics export destination (console, OTLP endpoint, etc.) is configured
+    through OpenTelemetry SDK configuration by users, not by this client.
+    """
+
+    _instance: Optional["MetricsClient"] = None
+    meter: Meter
+    strands_agent_invocation_count: Counter
+
+    def __new__(cls) -> "MetricsClient":
+        """Create or return the singleton instance of MetricsClient.
+
+        Returns:
+            The single MetricsClient instance.
+        """
+        if cls._instance is None:
+            cls._instance = super().__new__(cls)
+        return cls._instance
+
+    def __init__(self) -> None:
+        """Initialize the MetricsClient.
+
+        This method only runs once due to the singleton pattern.
+        Sets up the OpenTelemetry meter and creates metric instruments.
+        """
+        if hasattr(self, "meter"):
+            return
+
+        logger.info("Creating Strands MetricsClient")
+        meter_provider: metrics_api.MeterProvider = metrics_api.get_meter_provider()
+        self.meter = meter_provider.get_meter(__name__)
+        self.create_instruments()
+
+    def create_instruments(self) -> None:
+        """Create and initialize all OpenTelemetry metric instruments."""
+        self.strands_agent_invocation_count = self.meter.create_counter(
+            name=constants.STRANDS_AGENT_INVOCATION_COUNT, unit="Count"
+        )

src/strands/telemetry/metrics_constants.py

@@ -0,0 +1,3 @@
+"""Metrics that are emitted in Strands-Agent."""
+
+STRANDS_AGENT_INVOCATION_COUNT = "strands.agent.invocation_count"

src/strands/telemetry/tracer.py

@@ -8,20 +8,19 @@
 import logging
 import os
 from datetime import date, datetime, timezone
-from importlib.metadata import version
 from typing import Any, Dict, Mapping, Optional
 
 import opentelemetry.trace as trace_api
 from opentelemetry import propagate
 from opentelemetry.baggage.propagation import W3CBaggagePropagator
 from opentelemetry.propagators.composite import CompositePropagator
-from opentelemetry.sdk.resources import Resource
 from opentelemetry.sdk.trace import TracerProvider as SDKTracerProvider
 from opentelemetry.sdk.trace.export import BatchSpanProcessor, ConsoleSpanExporter, SimpleSpanProcessor
 from opentelemetry.trace import Span, StatusCode
 from opentelemetry.trace.propagation.tracecontext import TraceContextTextMapPropagator
 
 from ..agent.agent_result import AgentResult
+from ..telemetry import get_otel_resource
 from ..types.content import Message, Messages
 from ..types.streaming import Usage
 from ..types.tools import ToolResult, ToolUse
@@ -151,7 +150,6 @@ def __init__(
         self.otlp_headers = otlp_headers or {}
         self.tracer_provider: Optional[trace_api.TracerProvider] = None
         self.tracer: Optional[trace_api.Tracer] = None
-
         propagate.set_global_textmap(
             CompositePropagator(
                 [
@@ -173,15 +171,7 @@ def _initialize_tracer(self) -> None:
             self.tracer = self.tracer_provider.get_tracer(self.service_name)
             return
 
-        # Create resource with service information
-        resource = Resource.create(
-            {
-                "service.name": self.service_name,
-                "service.version": version("strands-agents"),
-                "telemetry.sdk.name": "opentelemetry",
-                "telemetry.sdk.language": "python",
-            }
-        )
+        resource = get_otel_resource()
 
         # Create tracer provider
         self.tracer_provider = SDKTracerProvider(resource=resource)
@@ -216,6 +206,7 @@ def _initialize_tracer(self) -> None:
                 batch_processor = BatchSpanProcessor(otlp_exporter)
                 self.tracer_provider.add_span_processor(batch_processor)
                 logger.info("endpoint=<%s> | OTLP exporter configured with endpoint", endpoint)
+
             except Exception as e:
                 logger.exception("error=<%s> | Failed to configure OTLP exporter", e)
         elif self.otlp_endpoint and self.tracer_provider:

tests/strands/telemetry/test_metrics.py

@@ -1,9 +1,13 @@
 import dataclasses
 import unittest
+from unittest import mock
 
 import pytest
+from opentelemetry.metrics._internal import _ProxyMeter
+from opentelemetry.sdk.metrics import MeterProvider
 
 import strands
+from strands.telemetry import MetricsClient
 from strands.types.streaming import Metrics, Usage
 
 
@@ -117,6 +121,30 @@ def test_trace_end(mock_time, end_time, trace):
     assert tru_end_time == exp_end_time
 
 
+@pytest.fixture
+def mock_get_meter_provider():
+    with mock.patch("strands.telemetry.metrics.metrics_api.get_meter_provider") as mock_get_meter_provider:
+        meter_provider_mock = mock.MagicMock(spec=MeterProvider)
+        mock_get_meter_provider.return_value = meter_provider_mock
+
+        mock_meter = mock.MagicMock()
+        meter_provider_mock.get_meter.return_value = mock_meter
+
+        yield mock_get_meter_provider
+
+
+@pytest.fixture
+def mock_sdk_meter_provider():
+    with mock.patch("strands.telemetry.metrics.metrics_sdk.MeterProvider") as mock_meter_provider:
+        yield mock_meter_provider
+
+
+@pytest.fixture
+def mock_resource():
+    with mock.patch("opentelemetry.sdk.resources.Resource") as mock_resource:
+        yield mock_resource
+
+
 def test_trace_add_child(child_trace, trace):
     trace.add_child(child_trace)
 
@@ -379,3 +407,31 @@ def test_metrics_to_string(trace, child_trace, tool_metrics, exp_str, event_loop
     tru_str = strands.telemetry.metrics.metrics_to_string(event_loop_metrics)
 
     assert tru_str == exp_str
+
+
+def test_setup_meter_if_meter_provider_is_set(
+    mock_get_meter_provider,
+    mock_resource,
+):
+    """Test global meter_provider and meter are used"""
+    mock_resource_instance = mock.MagicMock()
+    mock_resource.create.return_value = mock_resource_instance
+
+    metrics_client = MetricsClient()
+
+    mock_get_meter_provider.assert_called()
+    mock_get_meter_provider.return_value.get_meter.assert_called()
+
+    assert metrics_client is not None
+
+
+def test_use_ProxyMeter_if_no_global_meter_provider():
+    """Return _ProxyMeter"""
+    # Reset the singleton instance
+    strands.telemetry.metrics.MetricsClient._instance = None
+
+    # Create a new instance which should use the real _ProxyMeter
+    metrics_client = MetricsClient()
+
+    # Verify it's using a _ProxyMeter
+    assert isinstance(metrics_client.meter, _ProxyMeter)

tests/strands/telemetry/test_tracer.py

@@ -73,7 +73,9 @@ def mock_console_exporter():
 
 @pytest.fixture
 def mock_resource():
-    with mock.patch("strands.telemetry.tracer.Resource") as mock_resource:
+    with mock.patch("strands.telemetry.tracer.get_otel_resource") as mock_resource:
+        mock_resource_instance = mock.MagicMock()
+        mock_resource.return_value = mock_resource_instance
         yield mock_resource
 
 
@@ -175,14 +177,12 @@ def test_initialize_tracer_with_console(
 ):
     """Test initializing the tracer with console exporter."""
     mock_is_initialized.return_value = False
-    mock_resource_instance = mock.MagicMock()
-    mock_resource.create.return_value = mock_resource_instance
 
     # Initialize Tracer
     Tracer(enable_console_export=True)
 
     # Verify the tracer provider was created with correct resource
-    mock_tracer_provider.assert_called_once_with(resource=mock_resource_instance)
+    mock_tracer_provider.assert_called_once_with(resource=mock_resource.return_value)
 
     # Verify console exporter was added
     mock_console_exporter.assert_called_once()
@@ -198,9 +198,6 @@ def test_initialize_tracer_with_otlp(
     """Test initializing the tracer with OTLP exporter."""
     mock_is_initialized.return_value = False
 
-    mock_resource_instance = mock.MagicMock()
-    mock_resource.create.return_value = mock_resource_instance
-
     # Initialize Tracer
     with (
         mock.patch("strands.telemetry.tracer.HAS_OTEL_EXPORTER_MODULE", True),
@@ -209,7 +206,7 @@ def test_initialize_tracer_with_otlp(
         Tracer(otlp_endpoint="http://test-endpoint")
 
     # Verify the tracer provider was created with correct resource
-    mock_tracer_provider.assert_called_once_with(resource=mock_resource_instance)
+    mock_tracer_provider.assert_called_once_with(resource=mock_resource.return_value)
 
     # Verify OTLP exporter was added with correct endpoint
     mock_otlp_exporter.assert_called_once()
@@ -508,8 +505,6 @@ def test_initialize_tracer_with_invalid_otlp_endpoint(
     """Test initializing the tracer with an invalid OTLP endpoint."""
     mock_is_initialized.return_value = False
 
-    mock_resource_instance = mock.MagicMock()
-    mock_resource.create.return_value = mock_resource_instance
     mock_otlp_exporter.side_effect = Exception("Connection error")
 
     # This should not raise an exception, but should log an error
@@ -522,7 +517,7 @@ def test_initialize_tracer_with_invalid_otlp_endpoint(
         Tracer(otlp_endpoint="http://invalid-endpoint")
 
     # Verify the tracer provider was created with correct resource
-    mock_tracer_provider.assert_called_once_with(resource=mock_resource_instance)
+    mock_tracer_provider.assert_called_once_with(resource=mock_resource.return_value)
 
     # Verify OTLP exporter was attempted
     mock_otlp_exporter.assert_called_once()
@@ -537,9 +532,6 @@ def test_initialize_tracer_with_missing_module(
     """Test initializing the tracer when the OTLP exporter module is missing."""
     mock_is_initialized.return_value = False
 
-    mock_resource_instance = mock.MagicMock()
-    mock_resource.create.return_value = mock_resource_instance
-
     # Initialize Tracer with OTLP endpoint but missing module
     with (
         mock.patch("strands.telemetry.tracer.HAS_OTEL_EXPORTER_MODULE", False),
@@ -552,13 +544,13 @@ def test_initialize_tracer_with_missing_module(
     assert "otel http exporting is currently DISABLED" in str(excinfo.value)
 
     # Verify the tracer provider was created with correct resource
-    mock_tracer_provider.assert_called_once_with(resource=mock_resource_instance)
+    mock_tracer_provider.assert_called_once_with(resource=mock_resource.return_value)
 
     # Verify set_tracer_provider was not called since an exception was raised
     mock_set_tracer_provider.assert_not_called()
 
 
-def test_initialize_tracer_with_custom_tracer_provider(mock_get_tracer_provider, mock_resource):
+def test_initialize_tracer_with_custom_tracer_provider(mock_is_initialized, mock_get_tracer_provider, mock_resource):
     """Test initializing the tracer with NoOpTracerProvider."""
     mock_is_initialized.return_value = True
     tracer = Tracer(otlp_endpoint="http://invalid-endpoint")