pkg/invoke: ensure that custom env vars are prepended to the env

Ensure that custom values take priority over values defined in the
environment by prepending them to the env, not appending.

diff --git a/pkg/invoke/args.go b/pkg/invoke/args.go
index ba9d0c3..39b6397 100644 (file)
--- a/pkg/invoke/args.go
+++ b/pkg/invoke/args.go
@@ -57,13 +57,16 @@ func (args *Args) AsEnv() []string {
                pluginArgsStr = stringify(args.PluginArgs)
        }
 
-       env = append(env,
-               "CNI_COMMAND="+args.Command,
-               "CNI_CONTAINERID="+args.ContainerID,
-               "CNI_NETNS="+args.NetNS,
-               "CNI_ARGS="+pluginArgsStr,
-               "CNI_IFNAME="+args.IfName,
-               "CNI_PATH="+args.Path)
+       // Ensure that the custom values are first, so any value present in
+       // the process environment won't override them.
+       env = append([]string{
+               "CNI_COMMAND=" + args.Command,
+               "CNI_CONTAINERID=" + args.ContainerID,
+               "CNI_NETNS=" + args.NetNS,
+               "CNI_ARGS=" + pluginArgsStr,
+               "CNI_IFNAME=" + args.IfName,
+               "CNI_PATH=" + args.Path,
+       }, env...)
        return env
 }