Add device filtering

* Add device include/exclude filters for the automatic scanning.
* Refactor scanning to not scan if devices are manually specified.
* Don't try and filter manually specified devices.

Signed-off-by: SuperQ <superq@gmail.com>

README.md

@@ -28,10 +28,18 @@ Flags:
       --smartctl.interval=60s  The interval between smarctl polls
       --smartctl.device=SMARTCTL.DEVICE ...  
                                The device to monitor (repeatable)
-      --web.listen-address=":9633"  
-                               Address to listen on for web interface and telemetry
+      --smartctl.device-exclude=""
+                               Regexp of devices to exclude from automatic scanning. (mutually exclusive to
+                               device-include)
+      --smartctl.device-include=""
+                               Regexp of devices to exclude from automatic scanning. (mutually exclusive to
+                               device-exclude)
       --web.telemetry-path="/metrics"  
                                Path under which to expose metrics
+      --web.systemd-socket     Use systemd socket activation listeners instead of port listeners (Linux only).
+      --web.listen-address=:9633 ...
+                               Addresses on which to expose metrics and web interface. Repeatable for multiple
+                               addresses.
       --web.config.file=""     [EXPERIMENTAL] Path to configuration file that can enable TLS or authentication.
       --log.level=info         Only log messages with the given severity or above. One of: [debug, info, warn,
                                error]

device_filter.go

@@ -0,0 +1,41 @@
+// Copyright 2022 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"regexp"
+)
+
+type deviceFilter struct {
+	ignorePattern *regexp.Regexp
+	acceptPattern *regexp.Regexp
+}
+
+func newDeviceFilter(ignoredPattern, acceptPattern string) (f deviceFilter) {
+	if ignoredPattern != "" {
+		f.ignorePattern = regexp.MustCompile(ignoredPattern)
+	}
+
+	if acceptPattern != "" {
+		f.acceptPattern = regexp.MustCompile(acceptPattern)
+	}
+
+	return
+}
+
+// ignored returns whether the device should be ignored
+func (f *deviceFilter) ignored(name string) bool {
+	return ((f.ignorePattern != nil && f.ignorePattern.MatchString(name)) ||
+		(f.acceptPattern != nil && !f.acceptPattern.MatchString(name)))
+}

device_filter_test.go

@@ -0,0 +1,43 @@
+// Copyright 2022 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"testing"
+)
+
+func TestDeviceFilter(t *testing.T) {
+	tests := []struct {
+		ignore         string
+		accept         string
+		name           string
+		expectedResult bool
+	}{
+		{"", "", "eth0", false},
+		{"", "^💩0$", "💩0", false},
+		{"", "^💩0$", "💩1", true},
+		{"", "^💩0$", "veth0", true},
+		{"^💩", "", "💩3", true},
+		{"^💩", "", "veth0", false},
+	}
+
+	for _, test := range tests {
+		filter := newDeviceFilter(test.ignore, test.accept)
+		result := filter.ignored(test.name)
+
+		if result != test.expectedResult {
+			t.Errorf("ignorePattern=%v acceptPattern=%v ifname=%v expected=%v result=%v", test.ignore, test.accept, test.name, test.expectedResult, result)
+		}
+	}
+}

main.go

@@ -69,11 +69,38 @@ var (
 	smartctlDevices = kingpin.Flag("smartctl.device",
 		"The device to monitor (repeatable)",
 	).Strings()
+	smartctlDeviceExclude = kingpin.Flag(
+		"smartctl.device-exclude",
+		"Regexp of devices to exclude from automatic scanning. (mutually exclusive to device-include)",
+	).Default("").String()
+	smartctlDeviceInclude = kingpin.Flag(
+		"smartctl.device-include",
+		"Regexp of devices to exclude from automatic scanning. (mutually exclusive to device-exclude)",
+	).Default("").String()
 	smartctlFakeData = kingpin.Flag("smartctl.fake-data",
 		"The device to monitor (repeatable)",
 	).Default("false").Hidden().Bool()
 )
 
+// scanDevices uses smartctl to gather the list of available devices.
+func scanDevices(logger log.Logger) []string {
+	filter := newDeviceFilter(*smartctlDeviceExclude, *smartctlDeviceInclude)
+
+	json := readSMARTctlDevices(logger)
+	scanDevices := json.Get("devices").Array()
+	var scanDeviceResult []string
+	for _, d := range scanDevices {
+		deviceName := d.Get("name").String()
+		if filter.ignored(deviceName) {
+			level.Info(logger).Log("msg", "Ignoring device", "name", deviceName)
+		} else {
+			level.Info(logger).Log("msg", "Found device", "name", deviceName)
+			scanDeviceResult = append(scanDeviceResult, deviceName)
+		}
+	}
+	return scanDeviceResult
+}
+
 func main() {
 	metricsPath := kingpin.Flag(
 		"web.telemetry-path", "Path under which to expose metrics",
@@ -90,34 +117,12 @@ func main() {
 	level.Info(logger).Log("msg", "Starting smartctl_exporter", "version", version.Info())
 	level.Info(logger).Log("msg", "Build context", "build_context", version.BuildContext())
 
-	// Scan the host devices
-	json := readSMARTctlDevices(logger)
-	scanDevices := json.Get("devices").Array()
-	scanDevicesSet := make(map[string]bool)
-	var scanDeviceNames []string
-	for _, d := range scanDevices {
-		deviceName := d.Get("name").String()
-		level.Debug(logger).Log("msg", "Found device", "name", deviceName)
-		scanDevicesSet[deviceName] = true
-		scanDeviceNames = append(scanDeviceNames, deviceName)
-	}
-
-	// Read the configuration and verify that it is available
-	devices := *smartctlDevices
-	var readDeviceNames []string
-	for _, device := range devices {
-		if _, ok := scanDevicesSet[device]; ok {
-			readDeviceNames = append(readDeviceNames, device)
-		} else {
-			level.Warn(logger).Log("msg", "Device unavailable", "name", device)
-		}
-	}
-
-	if len(readDeviceNames) > 0 {
-		devices = readDeviceNames
+	var devices []string
+	if len(*smartctlDevices) > 0 {
+		devices = *smartctlDevices
 	} else {
 		level.Info(logger).Log("msg", "No devices specified, trying to load them automatically")
-		devices = scanDeviceNames
+		devices = scanDevices(logger)
 	}
 
 	if len(devices) == 0 {