Add missing file

Signed-off-by: Kevin Fox <Kevin.Fox@pnnl.gov>

Author: kfox1111

cmd/spire-agent/cli/common/template.go

@@ -0,0 +1,22 @@
+package common
+
+import (
+    "os"
+    "strings"
+)
+
+func ResolveSocketPath(socketPath, defaultPath, templateEnv, instance string) string {
+    tpl := os.Getenv(templateEnv)
+    if tpl != "" && strings.Contains(tpl, "%i") {
+        if instance == "" {
+            instance = "main"
+        }
+        if socketPath == "" || socketPath == defaultPath {
+            return strings.ReplaceAll(tpl, "%i", instance)
+        }
+    }
+    if socketPath == "" {
+        return defaultPath
+    }
+    return socketPath
+}