Merge pull request #173 from fcgravalos/get_host_by_name

add getHostByName function to resolve dns names to ips

docs/network.md

@@ -0,0 +1,11 @@
+# Network Functions
+
+Sprig network manipulation functions.
+
+## getHostByName
+
+The `getHostByName` receives a domain name and returns the ip address.
+
+```
+getHostByName "www.google.com" would return the corresponding ip address of www.google.com
+```

functions.go

@@ -85,6 +85,9 @@ var nonhermeticFunctions = []string{
 	// OS
 	"env",
 	"expandenv",
+
+	// Network
+	"getHostByName",
 }
 
 var genericMap = map[string]interface{}{
@@ -224,6 +227,9 @@ var genericMap = map[string]interface{}{
 	"env":       func(s string) string { return os.Getenv(s) },
 	"expandenv": func(s string) string { return os.ExpandEnv(s) },
 
+	// Network:
+	"getHostByName": getHostByName,
+
 	// File Paths:
 	"base":  path.Base,
 	"dir":   path.Dir,

network.go

@@ -0,0 +1,12 @@
+package sprig
+
+import (
+	"math/rand"
+	"net"
+)
+
+func getHostByName(name string) string {
+	addrs, _ := net.LookupHost(name)
+	//TODO: add error handing when release v3 cames out
+	return addrs[rand.Intn(len(addrs))]
+}

network_test.go

@@ -0,0 +1,18 @@
+package sprig
+
+import (
+	"net"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGetHostByName(t *testing.T) {
+	tpl := `{{"www.google.com" | getHostByName}}`
+
+	resolvedIP, _ := runRaw(tpl, nil)
+
+	ip := net.ParseIP(resolvedIP)
+	assert.NotNil(t, ip)
+	assert.NotEmpty(t, ip)
+}