WIP - prometheus tests

Author: sd2k

docker-compose.yaml

@@ -12,5 +12,12 @@ services:
       - ./tests/provisioning:/etc/grafana/provisioning
       - ./tests/dashboards:/var/lib/grafana/dashboards
 
+  prometheus:
+    image: prom/prometheus
+    ports:
+      - "9090:9090"
+    command:
+      - --config.file=/etc/prometheus/prometheus.yml
+
 volumes:
   var-lib-grafana:

mcpgrafana.go

@@ -14,6 +14,9 @@ import (
 )
 
 const (
+	defaultGrafanaHost = "localhost:3000"
+	defaultGrafanaURL  = "http://" + defaultGrafanaHost
+
 	grafanaURLEnvVar = "GRAFANA_URL"
 	grafanaAPIEnvVar = "GRAFANA_API_KEY"
 
@@ -62,12 +65,18 @@ func WithGrafanaAPIKey(ctx context.Context, apiKey string) context.Context {
 
 // GrafanaURLFromContext extracts the Grafana URL from the context.
 func GrafanaURLFromContext(ctx context.Context) string {
-	return ctx.Value(grafanaURLKey{}).(string)
+	if u, ok := ctx.Value(grafanaURLKey{}).(string); ok {
+		return u
+	}
+	return defaultGrafanaURL
 }
 
 // GrafanaAPIKeyFromContext extracts the Grafana API key from the context.
 func GrafanaAPIKeyFromContext(ctx context.Context) string {
-	return ctx.Value(grafanaAPIKeyKey{}).(string)
+	if k, ok := ctx.Value(grafanaAPIKeyKey{}).(string); ok {
+		return k
+	}
+	return ""
 }
 
 type grafanaClientKey struct{}

tests/prometheus.yml

@@ -0,0 +1,8 @@
+global:
+  scrape_interval:     1s
+
+scrape_configs:
+  - job_name: 'prometheus'
+    static_configs:
+      - targets: ['localhost:9090']
+

tools/prometheus.go

@@ -42,7 +42,7 @@ type ListPrometheusMetricMetadataParams struct {
 	Metric         string `json:"metric" jsonschema:"description=The metric to query"`
 }
 
-func listPrometheusMetricMetadata(ctx context.Context, args ListPrometheusMetricMetadataParams) (*mcp.CallToolResult, error) {
+func listPrometheusMetricMetadata(ctx context.Context, args ListPrometheusMetricMetadataParams) (map[string][]promv1.Metadata, error) {
 	promClient, err := promClientFromContext(ctx, args.DatasourceUID)
 	if err != nil {
 		return nil, fmt.Errorf("getting Prometheus client: %w", err)
@@ -57,11 +57,7 @@ func listPrometheusMetricMetadata(ctx context.Context, args ListPrometheusMetric
 	if err != nil {
 		return nil, fmt.Errorf("listing Prometheus metric metadata: %w", err)
 	}
-	b, err := json.Marshal(metadata)
-	if err != nil {
-		return nil, fmt.Errorf("marshalling Prometheus metric metadata: %w", err)
-	}
-	return mcp.NewToolResultText(string(b)), nil
+	return metadata, nil
 }
 
 var ListPrometheusMetricMetadata = mcpgrafana.MustTool(

tools/prometheus_test.go

@@ -0,0 +1,19 @@
+package tools
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestPrometheusTools(t *testing.T) {
+	t.Run("list prometheus metric metadata", func(t *testing.T) {
+		ctx := newTestContext()
+		result, err := listPrometheusMetricMetadata(ctx, ListPrometheusMetricMetadataParams{
+			DatasourceUID: "prometheus",
+		})
+		require.NoError(t, err)
+		assert.Len(t, result, 10)
+	})
+}