Feat/network discovery engine

README.md

@@ -75,7 +75,7 @@ spec:
 - [x] DMI/BIOS discovery engine #2
 - [x] Local file / HTTP discovery engine #3
 - [x] Hostname / node name discovery engine #4
-- [ ] Network config discovery engine #5
+- [x] Network config discovery engine #5
 - [ ] Taint management #6
 - [ ] Prometheus Exporter #7
 - [ ] Better RBAC / admission webhook #8
@@ -109,6 +109,11 @@ The `labelsTemplates` section defines which Kubernetes labels Topomatik will man
 
 The [Sprig library](http://masterminds.github.io/sprig/) is available for advanced template operations, giving you access to string manipulation, regular expressions, and more.
 
+> [!NOTE]
+> Labels must be an empty string or consist of alphanumeric characters, "-", "\_" or ".", and must start and end with an alphanumeric character. Invalid characters will be replaced by "\_" and trailing non alpha-numeric characters will be removed.
+>
+> Example: "@@@foo+bar.foobar----." will be rendered as "foo_bar.foobar".
+
 ### Auto-Discovery Engine Configuration
 
 Each auto-discovery engine has its own configuration section.
@@ -215,6 +220,24 @@ hostname:
 
 Template variables are defined by the name of an file entry in the configuration. For instance, with the above configuration, this engine exposes `.hostname.zone`, `.hostname.region` and `.hostname.node`, but since the `pattern` in the configuration is optional, it also exposes the whole hostname as `.hostname.value`.
 
+#### Network
+
+Reads network information of the device in order to group machines by subnet.
+
+##### Network configuration
+
+| Name      | Description                                                                             | Default value |
+| --------- | --------------------------------------------------------------------------------------- | ------------- |
+| enabled   | Enable or disable this auto discovery engine                                            | false         |
+| interval  | Polling interval of the hardware information                                            | `<required>`  |
+| interface | Interface name to get the subnet from or auto to use any interface with default gateway | auto          |
+
+##### Available template variables from the network engine
+
+| Name           | Description                                      |
+| ---------------| ------------------------------------------------ |
+| network.subnet | The subnet associated with the defined interface |
+
 ## 🤝 Contributing
 
 Found a bug? Want to add support for another discovery engine? We welcome contributions! Just be sure your code is as clean as your commit messages.

cmd/main.go

@@ -8,6 +8,7 @@ import (
 	"github.com/enix/topomatik/internal/autodiscovery/hardware"
 	"github.com/enix/topomatik/internal/autodiscovery/hostname"
 	"github.com/enix/topomatik/internal/autodiscovery/lldp"
+	"github.com/enix/topomatik/internal/autodiscovery/network"
 	"github.com/enix/topomatik/internal/config"
 	"github.com/enix/topomatik/internal/controller"
 	"github.com/enix/topomatik/internal/schedulers"
@@ -74,5 +75,8 @@ func main() {
 		ctrl.Register("hostname", &hostname.HostnameDiscoveryEngine{Config: config.Hostname.Config})
 	}
 
+	if config.Network.Enabled {
+		ctrl.Register("network", &network.NetworkDiscoveryEngine{Config: config.Network.Config})
+	}
 	panic(ctrl.Start())
 }

internal/autodiscovery/lldp/lldp.go

@@ -1,9 +1,9 @@
 package lldp
 
 import (
-	"errors"
 	"fmt"
 
+	"github.com/enix/topomatik/internal/autodiscovery/network"
 	"github.com/google/gopacket"
 	"github.com/google/gopacket/afpacket"
 	"github.com/google/gopacket/layers"
@@ -85,21 +85,15 @@ func (l *LLDPDiscoveryEngine) Watch(callback func(data map[string]string, err er
 }
 
 func getDefaultRouteInterfaceName() (string, error) {
-	routes, err := netlink.RouteList(nil, netlink.FAMILY_ALL)
+	defaultRoute, err := network.GetDefaultRoute()
 	if err != nil {
 		return "", err
 	}
 
-	for _, route := range routes {
-		ones, _ := route.Dst.Mask.Size()
-		if route.Dst == nil || (route.Dst.IP.IsUnspecified() && ones == 0) {
-			link, err := netlink.LinkByIndex(route.LinkIndex)
-			if err != nil {
-				return "", err
-			}
-			return link.Attrs().Name, nil
-		}
+	link, err := netlink.LinkByIndex(defaultRoute.LinkIndex)
+	if err != nil {
+		return "", err
 	}
 
-	return "", errors.New("default route not found")
+	return link.Attrs().Name, nil
 }

internal/autodiscovery/network/network.go

@@ -0,0 +1,94 @@
+package network
+
+import (
+	"errors"
+	"fmt"
+	"time"
+
+	"github.com/vishvananda/netlink"
+)
+
+type Config struct {
+	Interval  time.Duration `yaml:"interval" validate:"required"`
+	Interface string        `yaml:"interface"`
+}
+
+type NetworkDiscoveryEngine struct {
+	Config
+}
+
+func (n *NetworkDiscoveryEngine) Setup() (err error) {
+	return
+}
+
+func (n *NetworkDiscoveryEngine) Watch(callback func(data map[string]string, err error)) {
+	var route *netlink.Route
+	var err error
+
+	ticker := time.NewTicker(n.Interval)
+
+	for {
+		if n.Interface == "" {
+			route, err = GetDefaultRoute()
+		} else {
+			route, err = getRouteByInterfaceName(n.Interface)
+		}
+
+		if err != nil {
+			callback(nil, err)
+			return
+		}
+
+		if route.Family != netlink.FAMILY_V4 {
+			callback(nil, fmt.Errorf("unsupported IP family (code: %d), must be IPV4", route.Family))
+			return
+		}
+
+		ones, _ := route.Src.DefaultMask().Size()
+		callback(map[string]string{
+			"subnet": fmt.Sprintf("%s/%d", route.Src.Mask(route.Src.DefaultMask()), ones),
+		}, nil)
+
+		<-ticker.C
+	}
+}
+
+func GetDefaultRoute() (*netlink.Route, error) {
+	routes, err := netlink.RouteList(nil, netlink.FAMILY_ALL)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, route := range routes {
+		if route.Dst == nil {
+			return &route, nil
+		}
+
+		ones, _ := route.Dst.Mask.Size()
+		if route.Dst.IP.IsUnspecified() && ones == 0 {
+			return &route, nil
+		}
+	}
+
+	return nil, errors.New("default route not found")
+}
+
+func getRouteByInterfaceName(interfaceName string) (*netlink.Route, error) {
+	routes, err := netlink.RouteList(nil, netlink.FAMILY_ALL)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, route := range routes {
+		link, err := netlink.LinkByIndex(route.LinkIndex)
+		if err != nil {
+			return nil, err
+		}
+
+		if link.Attrs().Name == interfaceName {
+			return &route, nil
+		}
+	}
+
+	return nil, fmt.Errorf("route with interface name \"%s\" not found", interfaceName)
+}

internal/config/config.go

@@ -11,6 +11,7 @@ import (
 	"github.com/enix/topomatik/internal/autodiscovery/hardware"
 	"github.com/enix/topomatik/internal/autodiscovery/hostname"
 	"github.com/enix/topomatik/internal/autodiscovery/lldp"
+	"github.com/enix/topomatik/internal/autodiscovery/network"
 	"github.com/go-playground/validator/v10"
 	"gopkg.in/yaml.v2"
 )
@@ -23,6 +24,7 @@ type Config struct {
 	Files    files.Config                  `yaml:"files" validate:"dive"`
 	Hardware EngineConfig[hardware.Config] `yaml:"hardware"`
 	Hostname EngineConfig[hostname.Config] `yaml:"hostname"`
+	Network  EngineConfig[network.Config]  `yaml:"network"`
 }
 
 type EngineConfig[T any] struct {
@@ -79,6 +81,9 @@ func Load(path string) (*Config, error) {
 	if !config.Hostname.Enabled {
 		ignoredEngines = append(ignoredEngines, "Hostname")
 	}
+	if !config.Network.Enabled {
+		ignoredEngines = append(ignoredEngines, "Network")
+	}
 
 	if err := validate.StructExcept(config, ignoredEngines...); err != nil {
 		if errs, ok := err.(validator.ValidationErrors); ok {

internal/controller/controller.go

@@ -6,6 +6,8 @@ import (
 	"encoding/json"
 	"fmt"
 	"os"
+	"regexp"
+	"strings"
 	"text/template"
 
 	"github.com/Masterminds/sprig"
@@ -17,6 +19,8 @@ import (
 	"k8s.io/client-go/kubernetes"
 )
 
+var labelRegexp = regexp.MustCompile(`[^A-Za-z0-9._-]`)
+
 type ReconciliationScheduler interface {
 	Trigger()
 	C() <-chan struct{}
@@ -121,9 +125,13 @@ func (c *Controller) reconcileNode() error {
 		if err != nil {
 			fmt.Printf("could not render template for %s: %s\n", label, err.Error())
 		} else {
-			if node.Labels[label] != value.String() {
-				labels[label] = value.String()
-				fmt.Printf("%s: %s\n", label, value)
+			sanitizedValue := labelRegexp.ReplaceAllString(value.String(), "_")
+			sanitizedValue = strings.TrimFunc(sanitizedValue, func(r rune) bool {
+				return strings.Contains("_.-", string(r))
+			})
+			if node.Labels[label] != sanitizedValue {
+				labels[label] = sanitizedValue
+				fmt.Printf("%s: %s\n", label, sanitizedValue)
 			}
 		}
 	}