Use separate contextvar with client in it

This avoids the need to create a new client for each tool
use, and hopefully lets us reuse connections.

Author: sd2k

src/mcp_grafana/client.py

@@ -8,6 +8,7 @@
 We should separate HTTP types from tool types.
 """
 
+import contextvars
 import math
 from datetime import datetime
 from typing import Any
@@ -236,3 +237,7 @@ async def list_prometheus_label_values(
             f"/api/datasources/proxy/uid/{datasource_uid}/api/v1/label/{label_name}/values",
             params,
         )
+
+
+grafana_client = contextvars.ContextVar("grafana_client")
+grafana_client.set(GrafanaClient.for_current_request())

src/mcp_grafana/middleware.py

@@ -2,6 +2,7 @@
 
 from starlette.datastructures import Headers
 
+from .client import GrafanaClient, grafana_client
 from .settings import GrafanaSettings, grafana_settings
 
 
@@ -40,13 +41,15 @@ def __init__(self, request):
 
     async def __aenter__(self):
         if (info := GrafanaInfo.from_headers(self.request.headers)) is not None:
-            current = grafana_settings.get()
-            self.token = grafana_settings.set(
-                GrafanaSettings(
-                    url=info.url,
-                    api_key=info.authorization,
-                    tools=current.tools,
-                )
+            current_settings = grafana_settings.get()
+            new_settings = GrafanaSettings(
+                url=info.url,
+                api_key=info.authorization,
+                tools=current_settings.tools,
+            )
+            self.settings_token = grafana_settings.set(new_settings)
+            self.client_token = grafana_client.set(
+                GrafanaClient.from_settings(new_settings)
             )
 
     async def __aexit__(self, exc_type, exc_val, exc_tb):

src/mcp_grafana/tools/datasources.py

@@ -1,27 +1,27 @@
 from mcp.server import FastMCP
 
-from ..client import GrafanaClient
+from ..client import grafana_client
 
 
 async def list_datasources() -> bytes:
     """
     List datasources in the Grafana instance.
     """
-    return await GrafanaClient.for_current_request().list_datasources()
+    return await grafana_client.get().list_datasources()
 
 
 async def get_datasource_by_uid(uid: str) -> bytes:
     """
     Get a datasource by uid.
     """
-    return await GrafanaClient.for_current_request().get_datasource(uid=uid)
+    return await grafana_client.get().get_datasource(uid=uid)
 
 
 async def get_datasource_by_name(name: str) -> bytes:
     """
     Get a datasource by name.
     """
-    return await GrafanaClient.for_current_request().get_datasource(name=name)
+    return await grafana_client.get().get_datasource(name=name)
 
 
 def add_tools(mcp: FastMCP):

src/mcp_grafana/tools/incident.py

@@ -7,7 +7,7 @@
 from ..client import (
     AddActivityToIncidentArguments,
     CreateIncidentArguments,
-    GrafanaClient,
+    grafana_client,
 )
 from ..grafana_types import QueryIncidentPreviewsRequest, IncidentPreviewsQuery
 
@@ -49,14 +49,14 @@ async def list_incidents(arguments: ListIncidentsArguments) -> bytes:
         ),
         includeCustomFieldValues=True,
     )
-    return await GrafanaClient.for_current_request().list_incidents(body)
+    return await grafana_client.get().list_incidents(body)
 
 
 async def create_incident(arguments: CreateIncidentArguments) -> bytes:
     """
     Create an incident in the Grafana Incident incident management tool.
     """
-    return await GrafanaClient.for_current_request().create_incident(arguments)
+    return await grafana_client.get().create_incident(arguments)
 
 
 async def add_activity_to_incident(
@@ -70,7 +70,7 @@ async def add_activity_to_incident(
     :param event_time: The time that the activity occurred. If not provided, the current time will be used.
                        If provided, it must be in RFC3339 format.
     """
-    return await GrafanaClient.for_current_request().add_activity_to_incident(
+    return await grafana_client.get().add_activity_to_incident(
         AddActivityToIncidentArguments(
             incidentId=incident_id,
             body=body,
@@ -89,9 +89,7 @@ async def resolve_incident(incident_id: str, summary: str) -> bytes:
                     This should be succint but thorough and informative,
                     enough to serve as a mini post-incident-report.
     """
-    return await GrafanaClient.for_current_request().close_incident(
-        incident_id, summary
-    )
+    return await grafana_client.get().close_incident(incident_id, summary)
 
 
 def add_tools(mcp: FastMCP):

src/mcp_grafana/tools/prometheus.py

@@ -5,7 +5,7 @@
 
 from mcp.server import FastMCP
 
-from ..client import GrafanaClient
+from ..client import grafana_client
 from ..grafana_types import (
     DatasourceRef,
     DSQueryResponse,
@@ -56,7 +56,7 @@ async def query_prometheus(
         expr=expr,  # type: ignore
         intervalMs=interval_ms,
     )
-    response = await GrafanaClient.for_current_request().query(start, end, [query])
+    response = await grafana_client.get().query(start, end, [query])
     return DSQueryResponse.model_validate_json(response)
 
 
@@ -81,13 +81,11 @@ async def list_prometheus_metric_metadata(
 
     A mapping from metric name to all available metadata for that metric.
     """
-    response = (
-        await GrafanaClient.for_current_request().list_prometheus_metric_metadata(
-            datasource_uid,
-            limit=limit,
-            limit_per_metric=limit_per_metric,
-            metric=metric,
-        )
+    response = await grafana_client.get().list_prometheus_metric_metadata(
+        datasource_uid,
+        limit=limit,
+        limit_per_metric=limit_per_metric,
+        metric=metric,
     )
     return (
         ResponseWrapper[dict[str, list[PrometheusMetricMetadata]]]
@@ -146,7 +144,7 @@ async def list_prometheus_label_names(
     end: Optionally, the end time of the time range to filter the results by.
     limit: Optionally, the maximum number of results to return. Defaults to 100.
     """
-    response = await GrafanaClient.for_current_request().list_prometheus_label_names(
+    response = await grafana_client.get().list_prometheus_label_names(
         datasource_uid,
         matches=matches,
         start=start,
@@ -176,7 +174,7 @@ async def list_prometheus_label_values(
     end: Optionally, the end time of the query.
     limit: Optionally, the maximum number of results to return. Defaults to 100.
     """
-    response = await GrafanaClient.for_current_request().list_prometheus_label_values(
+    response = await grafana_client.get().list_prometheus_label_values(
         datasource_uid,
         label_name,
         matches=matches,

src/mcp_grafana/tools/search.py

@@ -1,13 +1,13 @@
 from mcp.server import FastMCP
 
-from ..client import SearchDashboardsArguments, GrafanaClient
+from ..client import SearchDashboardsArguments, grafana_client
 
 
 async def search_dashboards(arguments: SearchDashboardsArguments) -> bytes:
     """
     Search dashboards in the Grafana instance.
     """
-    return await GrafanaClient.for_current_request().search_dashboards(arguments)
+    return await grafana_client.get().search_dashboards(arguments)
 
 
 def add_tools(mcp: FastMCP):