Add Prometheus metrics for NX-API client

internal/transport/nxapi/metrics.go

@@ -0,0 +1,34 @@
+// SPDX-FileCopyrightText: 2026 SAP SE or an SAP affiliate company and IronCore contributors
+// SPDX-License-Identifier: Apache-2.0
+
+package nxapi
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+	"sigs.k8s.io/controller-runtime/pkg/metrics"
+)
+
+var (
+	rpcDurationSeconds = prometheus.NewHistogramVec(
+		prometheus.HistogramOpts{
+			Name:    "nxapi_rpc_duration_seconds",
+			Help:    "Duration of NX-API JSON-RPC requests in seconds.",
+			Buckets: prometheus.DefBuckets,
+		},
+		[]string{"target", "status"},
+	)
+	rpcCommandsTotal = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "nxapi_rpc_commands_total",
+			Help: "Total number of NX-API CLI commands sent.",
+		},
+		[]string{"target", "command", "status"},
+	)
+)
+
+func init() {
+	metrics.Registry.MustRegister(
+		rpcDurationSeconds,
+		rpcCommandsTotal,
+	)
+}

internal/transport/nxapi/nxapi.go

@@ -34,6 +34,7 @@ func (f RoundTripFunc) RoundTrip(r *http.Request) (*http.Response, error) {
 type Client struct {
 	client *http.Client
 	url    url.URL
+	target string
 }
 
 // Option configures a [Client].
@@ -62,6 +63,14 @@ func WithTimeout(d time.Duration) Option {
 	}
 }
 
+// WithTarget sets the device target label used in metrics.
+func WithTarget(target string) Option {
+	return func(c *Client) error {
+		c.target = target
+		return nil
+	}
+}
+
 // NewClient creates a new [Client] for the given connection.
 // If the connection has a TLS configuration set, HTTPS is used; otherwise HTTP.
 func NewClient(conn *deviceutil.Connection, opts ...Option) (*Client, error) {
@@ -111,8 +120,13 @@ func (c *Client) Do(ctx context.Context, r Request) ([]json.RawMessage, error) {
 		return nil, fmt.Errorf("nxapi: failed to create request: %w", err)
 	}
 
+	start := time.Now()
 	resp, err := c.client.Do(req)
 	if err != nil {
+		rpcDurationSeconds.WithLabelValues(c.target, "error").Observe(time.Since(start).Seconds())
+		for _, cmd := range r {
+			rpcCommandsTotal.WithLabelValues(c.target, cmd.Params.Cmd, "error").Inc()
+		}
 		return nil, fmt.Errorf("nxapi: failed to send request: %w", err)
 	}
 	defer resp.Body.Close()
@@ -123,6 +137,10 @@ func (c *Client) Do(ctx context.Context, r Request) ([]json.RawMessage, error) {
 	}
 
 	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		rpcDurationSeconds.WithLabelValues(c.target, "error").Observe(time.Since(start).Seconds())
+		for _, cmd := range r {
+			rpcCommandsTotal.WithLabelValues(c.target, cmd.Params.Cmd, "error").Inc()
+		}
 		// Try to extract JSON-RPC errors from the body, but fall back to a
 		// plain HTTPError if the response is not valid JSON-RPC (e.g. a 401
 		// from an nginx reverse proxy).
@@ -140,6 +158,11 @@ func (c *Client) Do(ctx context.Context, r Request) ([]json.RawMessage, error) {
 		return nil, &HTTPError{Code: resp.StatusCode, Body: body}
 	}
 
+	rpcDurationSeconds.WithLabelValues(c.target, "success").Observe(time.Since(start).Seconds())
+	for _, cmd := range r {
+		rpcCommandsTotal.WithLabelValues(c.target, cmd.Params.Cmd, "success").Inc()
+	}
+
 	res, err := decode(body)
 	if err != nil {
 		return nil, fmt.Errorf("nxapi: failed to decode response: %w", err)