Add a VPP API liveness check before reading the stats segment.

vppstats/stats.go

@@ -2,11 +2,12 @@ package vppstats
 
 import (
 	"flag"
-	"log"
 	"time"
 
+	"go.fd.io/govpp/adapter/socketclient"
 	"go.fd.io/govpp/adapter/statsclient"
 	"go.fd.io/govpp/api"
+	"go.fd.io/govpp/binapi/vpe"
 	"go.fd.io/govpp/core"
 
 	"govpp-snmp-agentx/logger"
@@ -30,31 +31,208 @@ func StartStatsRoutine(callback StatsCallback) {
 func statsRoutine(period time.Duration, callback StatsCallback) {
 	logger.Debugf("Starting VPP stats routine with socket: %s, period: %v", *StatsAddr, period)
 
-	// Create stats client
-	client := statsclient.NewStatsClient(*StatsAddr)
-
-	// Connect using core.ConnectStats (proper way)
-	c, err := core.ConnectStats(client)
-	if err != nil {
-		log.Printf("Failed to connect to VPP stats: %v", err)
-		return
-	}
-	defer c.Disconnect()
-
-	// Query stats immediately on startup
-	queryInterfaceStats(c, callback)
+	var conn *core.Connection
+	var statsConn *core.StatsConnection
+	var connected = false
+	var wasConnected = false
 
 	ticker := time.NewTicker(period)
 	defer ticker.Stop()
 
+	defer func() {
+		// Safely disconnect connections with panic recovery
+		if conn != nil {
+			func() {
+				defer func() {
+					if r := recover(); r != nil {
+						logger.Debugf("Recovered from conn.Disconnect panic: %v", r)
+					}
+				}()
+				conn.Disconnect()
+			}()
+		}
+		if statsConn != nil {
+			func() {
+				defer func() {
+					if r := recover(); r != nil {
+						logger.Debugf("Recovered from statsConn.Disconnect panic: %v", r)
+					}
+				}()
+				statsConn.Disconnect()
+			}()
+		}
+	}()
+
 	for {
+		// Check if we need to connect/reconnect
+		if !connected {
+			// Clean up existing connections
+			if conn != nil {
+				func() {
+					defer func() {
+						if r := recover(); r != nil {
+							logger.Debugf("Recovered from conn.Disconnect during reconnect: %v", r)
+						}
+					}()
+					conn.Disconnect()
+				}()
+				conn = nil
+			}
+			if statsConn != nil {
+				func() {
+					defer func() {
+						if r := recover(); r != nil {
+							logger.Debugf("Recovered from statsConn.Disconnect during reconnect: %v", r)
+						}
+					}()
+					statsConn.Disconnect()
+				}()
+				statsConn = nil
+			}
+
+			// Create API connection first - only proceed if this succeeds
+			var err error
+			conn, err = core.Connect(socketclient.NewVppClient("/var/run/vpp/api.sock"))
+			if err != nil {
+				if wasConnected {
+					logger.Printf("VPP API connection lost: %v", err)
+					wasConnected = false
+				} else {
+					logger.Debugf("Failed to connect to VPP API: %v", err)
+				}
+				connected = false
+				time.Sleep(time.Second)
+				continue
+			}
+
+			// Only try stats connection if API connection succeeded
+			statsClient := statsclient.NewStatsClient(*StatsAddr)
+			statsConn, err = core.ConnectStats(statsClient)
+			if err != nil {
+				logger.Printf("VPP stats connection failed: %v", err)
+				// Close the API connection since we can't get stats
+				func() {
+					defer func() {
+						if r := recover(); r != nil {
+							logger.Debugf("Recovered from conn.Disconnect during stats error: %v", r)
+						}
+					}()
+					conn.Disconnect()
+				}()
+				conn = nil
+				connected = false
+				time.Sleep(time.Second)
+				continue
+			}
+
+			logger.Printf("Connected to VPP (API: /var/run/vpp/api.sock, Stats: %s)", *StatsAddr)
+			connected = true
+			wasConnected = true
+		}
+
+		// Query stats if connected
+		if connected {
+			if !queryInterfaceStatsWithLivenessCheck(conn, statsConn, callback) {
+				connected = false
+				continue
+			}
+		}
+
+		// Wait for next tick
 		select {
 		case <-ticker.C:
-			queryInterfaceStats(c, callback)
+			continue
 		}
 	}
 }
 
+func queryInterfaceStatsWithLivenessCheck(conn *core.Connection, statsConn *core.StatsConnection, callback StatsCallback) bool {
+	// Check VPP liveness using API call
+	if !checkVPPLiveness(conn) {
+		logger.Printf("VPP liveness check failed")
+		return false
+	}
+
+	// Create the proper struct for interface stats
+	stats := new(api.InterfaceStats)
+
+	// Use the GetInterfaceStats method - this is the correct approach
+	if err := statsConn.GetInterfaceStats(stats); err != nil {
+		logger.Printf("Failed to get interface stats: %v", err)
+		return false
+	}
+
+	// Always log basic info
+	logger.Printf("Retrieved stats for %d interfaces", len(stats.Interfaces))
+
+	// Debug logging for individual interfaces
+	for _, iface := range stats.Interfaces {
+		logger.Debugf("Interface %d (%s): RX %d pkts/%d bytes, TX %d pkts/%d bytes",
+			iface.InterfaceIndex, iface.InterfaceName,
+			iface.Rx.Packets, iface.Rx.Bytes,
+			iface.Tx.Packets, iface.Tx.Bytes)
+	}
+
+	// Call the callback to update the MIB
+	if callback != nil {
+		callback(stats)
+	}
+
+	return true
+}
+
+func checkVPPLiveness(conn *core.Connection) bool {
+	// Create a channel for the API call
+	ch, err := conn.NewAPIChannel()
+	if err != nil {
+		logger.Debugf("Failed to create API channel: %v", err)
+		return false
+	}
+
+	// Use a flag to track if channel was closed successfully
+	var channelClosed bool
+	defer func() {
+		if !channelClosed {
+			// Recover from potential panic when closing already closed channel
+			defer func() {
+				if r := recover(); r != nil {
+					logger.Debugf("Recovered from channel close panic: %v", r)
+				}
+			}()
+			ch.Close()
+		}
+	}()
+
+	// Create ShowVersion request
+	req := &vpe.ShowVersion{}
+	reply := &vpe.ShowVersionReply{}
+
+	// Send the request with timeout
+	if err := ch.SendRequest(req).ReceiveReply(reply); err != nil {
+		logger.Debugf("VPP ShowVersion failed: %v", err)
+		// Try to close the channel properly on error
+		func() {
+			defer func() {
+				if r := recover(); r != nil {
+					logger.Debugf("Channel already closed during error handling")
+				}
+			}()
+			ch.Close()
+			channelClosed = true
+		}()
+		return false
+	}
+
+	// Close channel successfully
+	ch.Close()
+	channelClosed = true
+
+	// If we got here, VPP is responsive
+	logger.Debugf("VPP liveness check passed (version: %s)", string(reply.Version))
+	return true
+}
+
+// Keep the old function for compatibility
 func queryInterfaceStats(c *core.StatsConnection, callback StatsCallback) {
 	// Create the proper struct for interface stats
 	stats := new(api.InterfaceStats)