sources/pci: make device label format configurable

Add new config option for specifying the device label, i.e. the
<device-label> part in
    node.alpha.kubernetes-incubator.io/nfd-pci-<device label>.present

The option is a list of field names:
    "class"             PCI device class
    "vendor"            Vendor ID
    "device"            Device ID
    "subsystem_vendor"  Subsystem vendor ID
    "subsystem_device"  Subsystem device ID

E.g. the following command line flag can be used to use all of the
above:
  --options='{"sources": {"pci": {"deviceLabelFields": ["class", "vendor", "device", "subsystem_vendor", "subsystem_device"] } } }'

README.md

@@ -183,16 +183,21 @@ such as restricting discovered features with the --label-whitelist option._
 | -------------------- | --------- | ----------------------------------------- |
 | <device label> | present   | PCI device is detected
 
-The `<device label>` part is composed of raw PCI IDs, and has the following
-format: `<class>_<vendor>`. E.g.
+The `<device label>` part is composed of raw PCI IDs, separated by dashes.
+The set of fields used in `<device label>` is configurable, valid fields being
+`class`, `vendor`, `device`, `subsystem_vendor` and `subsystem_device`.
+Defaults fields are `class` and `vendor`. An example label using the default
+label fields:
 ```
 node.alpha.kubernetes-incubator.io/nfd-pci-1200_8086.present=true
 ```
 
-The set of PCI device classes that the feature source detects is configurable.
-By default, device classes (0x)03, (0x)0b40 and (0x)12, i.e. GPUs,
-co-processors and accelerator cards are deteted.
-See [configuration options](#configuration-options) for more information.
+Also  the set of PCI device classes that the feature source detects is
+configurable. By default, device classes (0x)03, (0x)0b40 and (0x)12, i.e.
+GPUs, co-processors and accelerator cards are deteted.
+
+See [configuration options](#configuration-options)
+for more information on NFD config.
 
 ### RDT (Intel Resource Director Technology) Features
 

node-feature-discovery.conf.example

@@ -4,3 +4,9 @@
 #      - "0200"
 #      - "03"
 #      - "12"
+#    deviceLabelFields:
+#      - "class"
+#      - "vendor"
+#      - "device"
+#      - "subsystem_vendor"
+#      - "subsystem_device"

source/pci/pci.go

@@ -31,12 +31,16 @@ var logger = log.New(os.Stderr, "", log.LstdFlags)
 
 type NFDConfig struct {
 	DeviceClassWhitelist []string `json:"deviceClassWhitelist,omitempty"`
+	DeviceLabelFields    []string `json:"deviceLabelFields,omitempty"`
 }
 
 var Config = NFDConfig{
 	DeviceClassWhitelist: []string{"03", "0b40", "12"},
+	DeviceLabelFields:    []string{"class", "vendor"},
 }
 
+var devLabelAttrs = []string{"class", "vendor", "device", "subsystem_vendor", "subsystem_device"}
+
 // Implement FeatureSource interface
 type Source struct{}
 
@@ -52,11 +56,45 @@ func (s Source) Discover() ([]string, error) {
 		return nil, fmt.Errorf("Failed to detect PCI devices: %s", err.Error())
 	}
 
+	// Construct a device label format, a sorted list of valid attributes
+	deviceLabelFields := []string{}
+	configLabelFields := map[string]bool{}
+	for _, field := range Config.DeviceLabelFields {
+		configLabelFields[field] = true
+	}
+
+	for _, attr := range devLabelAttrs {
+		if _, ok := configLabelFields[attr]; ok {
+			deviceLabelFields = append(deviceLabelFields, attr)
+			delete(configLabelFields, attr)
+		}
+	}
+	if len(configLabelFields) > 0 {
+		keys := []string{}
+		for key := range configLabelFields {
+			keys = append(keys, key)
+		}
+		log.Printf("WARNING: invalid fields '%v' in deviceLabelFields, ignoring...", keys)
+	}
+	if len(deviceLabelFields) == 0 {
+		log.Printf("WARNING: no valid fields in deviceLabelFields defined, using the defaults")
+		deviceLabelFields = []string{"class", "vendor"}
+	}
+
+	// Iterate over all device classes
 	for class, classDevs := range devs {
 		for _, white := range Config.DeviceClassWhitelist {
 			if strings.HasPrefix(class, strings.ToLower(white)) {
 				for _, dev := range classDevs {
-					features[fmt.Sprintf("%s_%s.present", dev["class"], dev["vendor"])] = true
+					devLabel := ""
+					for i, attr := range deviceLabelFields {
+						devLabel += dev[attr]
+						if i < len(deviceLabelFields)-1 {
+							devLabel += "_"
+						}
+					}
+					devLabel += ".present"
+					features[devLabel] = true
 				}
 			}
 		}
@@ -74,8 +112,7 @@ func (s Source) Discover() ([]string, error) {
 func readDevInfo(devPath string) (pciDeviceInfo, error) {
 	info := pciDeviceInfo{}
 
-	attrs := []string{"class", "vendor", "device", "subsystem_vendor", "subsystem_device"}
-	for _, attr := range attrs {
+	for _, attr := range devLabelAttrs {
 		data, err := ioutil.ReadFile(path.Join(devPath, attr))
 		if err != nil {
 			return info, fmt.Errorf("Failed to read device %s: %s", attr, err)