create metrics client using same credentials as bt client

Author: daniel-sanche

google/cloud/bigtable/data/_async/client.py

@@ -86,6 +86,8 @@
 from google.cloud.bigtable.data.row_filters import CellsRowLimitFilter
 from google.cloud.bigtable.data.row_filters import RowFilterChain
 from google.cloud.bigtable.data._metrics import BigtableClientSideMetricsController
+from google.cloud.bigtable.data._metrics.handlers.gcp_exporter import BigtableMetricsExporter
+from google.cloud.bigtable.data._metrics.handlers.gcp_exporter import GoogleCloudMetricsHandler
 
 from google.cloud.bigtable.data._cross_sync import CrossSync
 
@@ -212,6 +214,12 @@ def __init__(
                 credentials = google.auth.credentials.AnonymousCredentials()
             if project is None:
                 project = _DEFAULT_BIGTABLE_EMULATOR_CLIENT
+        # create a metrics exporter using the same client configuration
+        self._gcp_metrics_exporter = BigtableMetricsExporter(
+            credentials=credentials,
+            project=project,
+            client_options=client_options,
+        )
         self._metrics_interceptor = MetricInterceptorType()
         # initialize client
         ClientWithProject.__init__(
@@ -939,13 +947,17 @@ def __init__(
         self.default_retryable_errors: Sequence[type[Exception]] = (
             default_retryable_errors or ()
         )
-
         self._metrics = BigtableClientSideMetricsController(
-            client._metrics_interceptor,
-            project_id=self.client.project,
-            instance_id=instance_id,
-            table_id=table_id,
-            app_profile_id=app_profile_id,
+            interceptor=client._metrics_interceptor,
+            handlers=[
+                GoogleCloudMetricsHandler(
+                    exporter=client._gcp_metrics_exporter,
+                    project_id=self.client.project,
+                    instance_id=instance_id,
+                    table_id=table_id,
+                    app_profile_id=app_profile_id
+                )
+            ]
         )
 
         try:

google/cloud/bigtable/data/_metrics/handlers/gcp_exporter.py

@@ -99,24 +99,25 @@ class GoogleCloudMetricsHandler(OpenTelemetryMetricsHandler):
       - throttling_latencies: latency introduced by waiting when there are too many outstanding requests in a bulk operation.
 
     Args:
-      - project_id: The Google Cloud project ID for the associated Bigtable Table
+      - exporter: The exporter object used to write metrics to Cloud Montitoring. 
+            Should correspond 1:1 with a bigtable client, and share auth configuration
       - export_interval: The interval (in seconds) at which to export metrics to Cloud Monitoring.
+      - *args: configuration positional arguments passed down to super class
+      - *kwargs: configuration keyword arguments passed down to super class
     """
 
-    def __init__(self, *args, project_id: str, export_interval=60, **kwargs):
-        # internal exporter to write metrics to Cloud Monitoring
-        exporter = _BigtableMetricsExporter(project_id=project_id)
+    def __init__(self, exporter, *args, export_interval=60, **kwargs):
         # periodically executes exporter
         gcp_reader = PeriodicExportingMetricReader(
             exporter, export_interval_millis=export_interval * 1000
         )
         # use private meter provider to store instruments and views
         meter_provider = MeterProvider(metric_readers=[gcp_reader], views=VIEW_LIST)
         otel = _OpenTelemetryInstruments(meter_provider=meter_provider)
-        super().__init__(*args, instruments=otel, project_id=project_id, **kwargs)
+        super().__init__(*args, instruments=otel, project_id=exporter.roject_id, **kwargs)
 
 
-class _BigtableMetricsExporter(MetricExporter):
+class BigtableMetricsExporter(MetricExporter):
     """
     OpenTelemetry Exporter implementation for sending metrics to Google Cloud Monitoring.
 
@@ -130,11 +131,12 @@ class _BigtableMetricsExporter(MetricExporter):
       - project_id: GCP project id to associate metrics with
     """
 
-    def __init__(self, project_id: str):
+    def __init__(self, *client_args, **client_kwargs):
         super().__init__()
-        self.client = MetricServiceClient()
+        self.client = MetricServiceClient(*client_args, **client_kwargs)
         self.prefix = "bigtable.googleapis.com/internal/client"
-        self.project_name = self.client.common_project_path(project_id)
+        self.project_id = self.client.project
+        self.project_name = self.client.common_project_path(self.project_id)
 
     def export(
         self, metrics_data: MetricsData, timeout_millis: float = 10_000, **kwargs

google/cloud/bigtable/data/_metrics/metrics_controller.py

@@ -40,7 +40,6 @@ def __init__(
         self,
         interceptor: AsyncBigtableMetricsInterceptor | BigtableMetricsInterceptor,
         handlers: list[MetricsHandler] | None = None,
-        **kwargs,
     ):
         """
         Initializes the metrics controller.
@@ -52,10 +51,6 @@ def __init__(
         """
         self.interceptor = interceptor
         self.handlers: list[MetricsHandler] = handlers or []
-        if handlers is None:
-            # handlers not given. Use default handlers.
-            # TODO: add default handlers
-            pass
 
     def add_handler(self, handler: MetricsHandler) -> None:
         """