modules/dnsmasq_dhcp: respect conf-file/conf-dir

.gitignore

@@ -1,3 +1,4 @@
 .idea
 bin/
 mocks/springboot2/.gradle/
+/godplugin

modules/dnsmasq_dhcp/autodetection.go

@@ -6,28 +6,42 @@ import (
 	"io/ioutil"
 	"net"
 	"os"
-	"path"
+	"path/filepath"
 	"regexp"
 	"strings"
 )
 
+// configDir represents conf-dir directive
+//
+// #conf-dir=/etc/dnsmasq.d
+//
+// # Include all the files in a directory except those ending in .bak
+// #conf-dir=/etc/dnsmasq.d,.bak
+//
+// # Include all files in a directory which end in .conf
+// #conf-dir=/etc/dnsmasq.d/,*.conf
+type configDir struct {
+	path          string
+	includeSuffix []string
+	excludeSuffix []string
+}
+
 func (d *DnsmasqDHCP) findDHCPRanges() ([]string, error) {
-	cs, err := findConfigurations(d.ConfDir)
-	if err != nil {
-		d.Warningf("error during configuration dir scanning : %v", err)
-	}
+	configs := d.findConfigs(d.ConfPath)
+
+	configs = append([]string{d.ConfPath}, configs...)
+
+	configs = unique(configs)
 
-	configs := []string{d.ConfPath}
-	configs = append(configs, cs...)
-	d.Infof("configuration files to read : %v", configs)
+	d.Infof("configuration files to read: %v", configs)
 
 	seen := make(map[string]bool)
 	var ranges []string
 
 	for _, config := range configs {
 		d.Debugf("reading %s", config)
 		rs, err := findDHCPRanges(config)
-		if err != nil {
+		if err != nil && !os.IsNotExist(err) {
 			return nil, err
 		}
 
@@ -46,21 +60,96 @@ func (d *DnsmasqDHCP) findDHCPRanges() ([]string, error) {
 	return ranges, nil
 }
 
-func findConfigurations(confDir string) ([]string, error) {
-	fis, err := ioutil.ReadDir(confDir)
+// findConfigs recursively finds and reads configuration files respecting
+// conf-file and conf-dir directives.
+// findConfigs is tolerant to IO errors and finds as maximum config
+// files as possible, therefore if an error occurrs during scanning process,
+// it will be just logged with warning severity
+func (d *DnsmasqDHCP) findConfigs(confPath string) []string {
+	config, err := os.Open(confPath)
 	if err != nil {
-		return nil, err
+		d.Warningf("error during configuration file %q reading: %v", confPath, err)
+		return nil
 	}
 
-	var configs []string
-	for _, fi := range fis {
-		if !fi.Mode().IsRegular() || !strings.HasSuffix(fi.Name(), ".conf") {
+	defer config.Close()
+
+	var (
+		includeFiles []string
+		includeDirs  []configDir
+	)
+
+	scanner := bufio.NewScanner(config)
+	for scanner.Scan() {
+		line := scanner.Text()
+
+		if path, ok := getConfValue(line, "conf-file"); ok {
+			includeFiles = append(includeFiles, path)
+			continue
+		}
+
+		if path, ok := getConfValue(line, "conf-dir"); ok {
+			args := strings.Split(path, ",")
+
+			dir := configDir{
+				path: args[0],
+			}
+
+			for _, arg := range args[1:] {
+				arg := strings.TrimSpace(arg)
+				// dnsmasq treats suffixes with asterisk as "to include" and without
+				// asterisk as "to exclude"
+				if strings.HasPrefix(arg, "*") {
+					dir.includeSuffix = append(dir.includeSuffix, arg[1:])
+				} else {
+					dir.excludeSuffix = append(dir.excludeSuffix, arg)
+				}
+			}
+
+			includeDirs = append(includeDirs, dir)
+
 			continue
 		}
-		configs = append(configs, path.Join(confDir, fi.Name()))
 	}
 
-	return configs, nil
+	for _, dir := range includeDirs {
+		dirFiles, err := dir.findConfigs()
+		if err != nil {
+			d.Warningf("error during configuration dir %q scanning: %v", dir.path, err)
+		}
+
+		includeFiles = append(includeFiles, dirFiles...)
+	}
+
+	for _, file := range includeFiles {
+		files := d.findConfigs(file)
+
+		includeFiles = append(includeFiles, files...)
+	}
+
+	return includeFiles
+}
+
+func getConfValue(line, prefix string) (value string, ok bool) {
+	if !strings.HasPrefix(line, prefix) {
+		return "", false
+	}
+
+	value = strings.TrimPrefix(line, prefix)
+
+	value = strings.TrimSpace(value)
+
+	if !strings.HasPrefix(value, "=") {
+		// got some unexpected line, has prefix like conf-file but there is no
+		// assign sign
+		return "", false
+	}
+
+	value = strings.TrimPrefix(value, "=")
+
+	value = strings.TrimSpace(value)
+
+	return value, true
 }
 
 func findDHCPRanges(filePath string) ([]string, error) {
@@ -128,3 +217,95 @@ func parseDHCPRangeLine(s string) (r string) {
 
 	return fmt.Sprintf("%s-%s", start, end)
 }
+
+func (dir configDir) findConfigs() ([]string, error) {
+	fis, err := ioutil.ReadDir(dir.path)
+	if err != nil {
+		return nil, err
+	}
+
+	var configs []string
+
+	for _, fi := range fis {
+		if !fi.Mode().IsRegular() {
+			continue
+		}
+
+		name := fi.Name()
+		if !dir.isValidFileName(name) {
+			continue
+		}
+
+		if !dir.matchFileName(name) {
+			continue
+		}
+
+		configs = append(configs, filepath.Join(dir.path, fi.Name()))
+	}
+
+	return configs, nil
+}
+
+func (dir configDir) isValidFileName(name string) bool {
+	// We copy the dnsmasq's logic
+	//
+	// /* ignore emacs backups and dotfiles */
+	// if (len == 0 ||
+	//     ent->d_name[len - 1] == '~' ||
+	//     (ent->d_name[0] == '#' && ent->d_name[len - 1] == '#') ||
+	//     ent->d_name[0] == '.')
+	//    continue;
+
+	if strings.HasSuffix(name, "~") ||
+		(strings.HasPrefix(name, "#") && strings.HasSuffix(name, "#")) ||
+		strings.HasPrefix(name, ".") {
+		return false
+	}
+
+	return true
+}
+
+func (dir configDir) matchFileName(name string) bool {
+	if len(dir.includeSuffix) > 0 {
+		including := false
+		for _, suffix := range dir.includeSuffix {
+			if strings.HasSuffix(name, suffix) {
+				including = true
+				break
+			}
+		}
+
+		if !including {
+			return false
+		}
+	}
+
+	for _, suffix := range dir.excludeSuffix {
+		if strings.HasSuffix(name, suffix) {
+			return false
+		}
+	}
+
+	return true
+}
+
+func unique(slice []string) []string {
+	result := []string{}
+
+	for _, item := range slice {
+		if !contains(result, item) {
+			result = append(result, item)
+		}
+	}
+	return result
+}
+
+func contains(slice []string, target string) bool {
+	for _, item := range slice {
+		if item == target {
+			return true
+		}
+	}
+
+	return false
+}

modules/dnsmasq_dhcp/dhcp_test.go

@@ -91,6 +91,8 @@ func TestDnsmasqDHCP_Collect(t *testing.T) {
 		"1230::-1230::9_percentage":          60,
 		"1231::-1231::9":                     0,
 		"1231::-1231::9_percentage":          0,
+		"172.168.0.0-172.168.0.9":            0,
+		"172.168.0.0-172.168.0.9_percentage": 0,
 		"192.168.0.0-192.168.0.9":            5,
 		"192.168.0.0-192.168.0.9_percentage": 50,
 		"192.168.1.0-192.168.1.9":            4,
@@ -101,3 +103,65 @@ func TestDnsmasqDHCP_Collect(t *testing.T) {
 
 	assert.Equal(t, expected, job.Collect())
 }
+
+func TestConfigDir_findConfigs(t *testing.T) {
+	testcases := []struct {
+		config   configDir
+		expected []string
+	}{
+		0: {
+			configDir{
+				path:          "testdata",
+				includeSuffix: nil,
+				excludeSuffix: nil,
+			},
+			[]string{
+				"testdata/dnsmasq.conf",
+				"testdata/dnsmasq.leases",
+				"testdata/dnsmasq.more.conf",
+			},
+		},
+
+		1: {
+			configDir{
+				path:          "testdata",
+				includeSuffix: []string{".leases"},
+				excludeSuffix: nil,
+			},
+			[]string{
+				"testdata/dnsmasq.leases",
+			},
+		},
+
+		2: {
+			configDir{
+				path:          "testdata",
+				includeSuffix: nil,
+				excludeSuffix: []string{".leases"},
+			},
+			[]string{
+				"testdata/dnsmasq.conf",
+				"testdata/dnsmasq.more.conf",
+			},
+		},
+
+		3: {
+			// weird one, but possible
+			configDir{
+				path:          "testdata",
+				includeSuffix: []string{".conf", ".leases"},
+				excludeSuffix: []string{".conf"},
+			},
+			[]string{
+				"testdata/dnsmasq.leases",
+			},
+		},
+	}
+
+	for i, testcase := range testcases {
+		actual, err := testcase.config.findConfigs()
+		assert.NoError(t, err, "testcase: %d", i)
+
+		assert.Equal(t, testcase.expected, actual, "testcase: %d", i)
+	}
+}

modules/dnsmasq_dhcp/testdata/dnsmasq.conf

@@ -66,3 +66,5 @@ dhcp-range = 1235::2, 1235::500, ra-stateless
 dhcp-range=1234::, ra-stateless, ra-names
 dhcp-range=1234::, ra-stateless
 dhcp-range=1234::, ra-only, 48h
+
+conf-dir=testdata/dnsmasq.d,*.conf,.bak

modules/dnsmasq_dhcp/testdata/dnsmasq.d/dnsmasqv4.conf

@@ -1 +1,2 @@
 dhcp-range=192.168.2.0,192.168.2.9,12h
+conf-file=testdata/dnsmasq.more.conf

modules/dnsmasq_dhcp/testdata/dnsmasq.more.conf

@@ -0,0 +1,2 @@
+dhcp-range= 172.168.0.0,172.168.0.9,12h
+dhcp-range=tag:green,192.168.1.0,192.168.1.9,12h