feat: Add IP lookup by interface to template funcs (#33)

integration/confdir/templates/basic.conf.tmpl

@@ -4,3 +4,5 @@ host={{ getv "/database/host" }}
 password={{ getv "/database/password" }}
 port={{ getv "/database/port" }}
 username={{ getv "/database/username" }}
+
+AccessAddress: {{ lookupIfaceIPV4 "lo" }}

integration/expect/basic.conf

@@ -4,3 +4,5 @@ host=127.0.0.1
 password=p@sSw0rd
 port=3306
 username=confd
+
+AccessAddress: 127.0.0.1

integration/vault-v1/confdir/templates/basic.conf.tmpl

@@ -4,3 +4,5 @@ host={{ getv "/kv-v1/database/host" }}
 password={{ getv "/kv-v1/database/password" }}
 port={{ getv "/kv-v1/database/port" }}
 username={{ getv "/kv-v1/database/username" }}
+
+AccessAddress: {{ lookupIfaceIPV4 "lo" }}

integration/vault-v2/confdir/templates/basic.conf.tmpl

@@ -4,3 +4,5 @@ host={{ getv "/kv-v2/data/database/host" }}
 password={{ getv "/kv-v2/data/database/password" }}
 port={{ getv "/kv-v2/data/database/port" }}
 username={{ getv "/kv-v2/data/database/username" }}
+
+AccessAddress: {{ lookupIfaceIPV4 "lo" }}

resource/template/template_funcs.go

@@ -37,6 +37,8 @@ func newFuncMap() map[string]interface{} {
 	m["lookupIPV4"] = LookupIPV4
 	m["lookupIPV6"] = LookupIPV6
 	m["lookupSRV"] = LookupSRV
+	m["lookupIfaceIPV4"] = LookupIfaceIPV4
+	m["lookupIfaceIPV6"] = LookupIfaceIPV6
 	m["fileExists"] = util.IsFileExist
 	m["base64Encode"] = Base64Encode
 	m["base64Decode"] = Base64Decode
@@ -210,6 +212,52 @@ func LookupIPV4(data string) []string {
 	return addresses
 }
 
+func LookupIfaceIPV4(data string) (addr string) {
+	var (
+		ief      *net.Interface
+		addrs    []net.Addr
+		ipv4Addr net.IP
+	)
+	ief, err := net.InterfaceByName(data)
+	if err != nil {
+		return
+	}
+	addrs, err = ief.Addrs()
+	if err != nil { // get addresses
+		return
+	}
+	for _, addr := range addrs { // get ipv4 address
+		ipv4Addr = addr.(*net.IPNet).IP.To4()
+		if ipv4Addr != nil {
+			break
+		}
+	}
+	return ipv4Addr.String()
+}
+
+func LookupIfaceIPV6(data string) (addr string) {
+	var (
+		ief      *net.Interface
+		addrs    []net.Addr
+		ipv6Addr net.IP
+	)
+	ief, err := net.InterfaceByName(data)
+	if err != nil {
+		return
+	}
+	addrs, err = ief.Addrs()
+	if err != nil { // get addresses
+		return
+	}
+	for _, addr := range addrs { // get ipv6 address
+		ipv6Addr = addr.(*net.IPNet).IP.To16()
+		if ipv6Addr != nil {
+			break
+		}
+	}
+	return ipv6Addr.String()
+}
+
 type sortSRV []*net.SRV
 
 func (s sortSRV) Len() int {

version.go

@@ -1,6 +1,6 @@
 package main
 
-const Version = "0.18.1"
+const Version = "0.18.2"
 
 // We want to replace this variable at build time with "-ldflags -X main.GitSHA=xxx", where const is not supported.
 var GitSHA = ""