diff --git a/ui/build/environment.go b/ui/build/environment.go
index d8ff7f2..9bca7c0 100644
--- a/ui/build/environment.go
+++ b/ui/build/environment.go
@@ -19,6 +19,7 @@
 	"fmt"
 	"io"
 	"os"
+	"strconv"
 	"strings"
 )
 
@@ -44,6 +45,17 @@
 	return "", false
 }
 
+// Get returns the int value associated with the key, and whether it exists
+// and is a valid int.
+func (e *Environment) GetInt(key string) (int, bool) {
+	if v, ok := e.Get(key); ok {
+		if i, err := strconv.Atoi(v); err == nil {
+			return i, true
+		}
+	}
+	return 0, false
+}
+
 // Set sets the value associated with the key, overwriting the current value
 // if it exists.
 func (e *Environment) Set(key, value string) {