[Refactor]: Core/API Split (#1506)

Refactors api folder to core, creates firm split between backend code and api frontend.

core/services/metrics.go

@@ -0,0 +1,29 @@
+package services
+
+import (
+	"github.com/go-skynet/LocalAI/pkg/schema"
+	"go.opentelemetry.io/otel/exporters/prometheus"
+	api "go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/sdk/metric"
+)
+
+// setupOTelSDK bootstraps the OpenTelemetry pipeline.
+// If it does not return an error, make sure to call shutdown for proper cleanup.
+func SetupMetrics() (*schema.LocalAIMetrics, error) {
+	exporter, err := prometheus.New()
+	if err != nil {
+		return nil, err
+	}
+	provider := metric.NewMeterProvider(metric.WithReader(exporter))
+	meter := provider.Meter("github.com/go-skynet/LocalAI")
+
+	apiTimeMetric, err := meter.Float64Histogram("api_call", api.WithDescription("api calls"))
+	if err != nil {
+		return nil, err
+	}
+
+	return &schema.LocalAIMetrics{
+		Meter:         meter,
+		ApiTimeMetric: apiTimeMetric,
+	}, nil
+}