Adding preflight command to check deps

nex-node/cmd/nex-node/main.go

@@ -73,11 +73,10 @@ func main() {
 	switch cmd {
 	case "up":
 		cmdUp(opts, ctx, cancel, log)
+		<-ctx.Done()
 	case "preflight":
 		cmdPreflight(opts, ctx, cancel, log)
 	}
-
-	<-ctx.Done()
 }
 
 func cmdUp(opts *nexnode.CliOptions, ctx context.Context, cancel context.CancelFunc, log *logrus.Logger) {
@@ -112,6 +111,13 @@ func cmdUp(opts *nexnode.CliOptions, ctx context.Context, cancel context.CancelF
 }
 
 func cmdPreflight(opts *nexnode.CliOptions, ctx context.Context, cancel context.CancelFunc, log *logrus.Logger) {
+	config, err := nexnode.LoadNodeConfiguration(opts.NodeConfigFile)
+	if err != nil {
+		fmt.Printf("Failed to load configuration file: %s\n", err)
+		os.Exit(1)
+	}
+
+	nexnode.CheckPreRequisites(config)
 }
 
 // TODO : look into also pre-removing /var/lib/cni/networks/fcnet/ during startup sequence

nex-node/prereq.go

@@ -0,0 +1,85 @@
+package nexnode
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"os"
+	"os/exec"
+
+	"github.com/fatih/color"
+
+	_ "embed"
+)
+
+var (
+	requiredPlugins = [...]fileSpec{
+		{name: "/opt/cni/bin/host-local", description: "host-local CNI plugin"},
+		{name: "/opt/cni/bin/ptp", description: "ptp CNI plugin"},
+		{name: "/opt/cni/bin/tc-redirect-tap", description: "tc-redirect-tap CNI plugin"},
+	}
+)
+
+type fileSpec struct {
+	name        string
+	description string
+}
+
+func CheckPreRequisites(config *NodeConfiguration) {
+	cyan := color.New(color.FgCyan).SprintFunc()
+	red := color.New(color.FgRed).SprintFunc()
+
+	fmt.Printf("\nChecking for required files and dependencies...\n\n")
+	for _, p := range requiredPlugins {
+		if _, err := os.Stat(p.name); errors.Is(err, os.ErrNotExist) {
+			fmt.Printf("⛔ %s was not found (%s)\n", p.description, red(p.name))
+		} else {
+			fmt.Printf("✅ %s found (%s)\n", p.description, cyan(p.name))
+		}
+	}
+
+	cniConfig := fmt.Sprintf("/etc/cni/conf.d/%s.conflist", config.CNI.NetworkName)
+	if _, err := os.Stat(cniConfig); errors.Is(err, os.ErrNotExist) {
+		err = writeCniConf(cniConfig, config.CNI.NetworkName)
+		if err != nil {
+			fmt.Printf("⛔ CNI network configuration file not found (%s), Unable to write a default\n", red(cniConfig))
+		} else {
+			fmt.Printf("✅ Created a default CNI configuration for %s (%s)\n", cyan(config.CNI.NetworkName), cyan(cniConfig))
+		}
+
+	} else {
+		fmt.Printf("✅ CNI network configuration file found (%s)\n", cyan(cniConfig))
+	}
+
+	firecrackerBinary, err := exec.LookPath("firecracker")
+	if err != nil {
+		fmt.Println("⛔ Could not locate the 'firecracker' binary in path")
+	} else {
+		fmt.Printf("✅ Located the firecracker executable in path (%s)\n", cyan(firecrackerBinary))
+	}
+}
+
+func writeCniConf(fileName string, networkName string) error {
+	f, err := os.Create(fileName)
+	if err != nil {
+		return err
+	}
+
+	var fcConfig map[string]interface{}
+	err = json.Unmarshal(defaultFcNetConf, &fcConfig)
+	if err != nil {
+		return err
+	}
+	fcConfig["name"] = networkName
+	raw, _ := json.Marshal(fcConfig)
+
+	_, err = f.Write(raw)
+	if err != nil {
+		return nil
+	}
+	f.Close()
+	return nil
+}
+
+//go:embed templates/fcnet.conflist
+var defaultFcNetConf []byte

nex-node/templates/fcnet.conflist

@@ -0,0 +1,18 @@
+{
+  "name": "fcnet",
+  "cniVersion": "0.4.0",
+  "plugins": [
+    {
+      "type": "ptp",
+      "ipMasq": true,
+      "ipam": {
+        "type": "host-local",
+        "subnet": "192.168.127.0/24",
+        "resolvConf": "/etc/resolv.conf"
+      }
+    },
+    {
+      "type": "tc-redirect-tap"
+    }
+  ]
+}