bug fix: exec of DEL cmd caused JSON decode error

When plugin is executed with a DEL command, it does not
print result to stdout unless there is an error. Therefore
it stdout bytes should not be passed to json.Unmarshal.

diff --git a/invoke/exec.go b/invoke/exec.go
index d7c5b7a..cf0cff4 100644 (file)
--- a/invoke/exec.go
+++ b/invoke/exec.go
@@ -41,7 +41,23 @@ func pluginErr(err error, output []byte) error {
        return err
 }
 
-func ExecPlugin(pluginPath string, netconf []byte, args CNIArgs) (*types.Result, error) {
+func ExecPluginWithResult(pluginPath string, netconf []byte, args CNIArgs) (*types.Result, error) {
+       stdoutBytes, err := execPlugin(pluginPath, netconf, args)
+       if err != nil {
+               return nil, err
+       }
+
+       res := &types.Result{}
+       err = json.Unmarshal(stdoutBytes, res)
+       return res, err
+}
+
+func ExecPluginWithoutResult(pluginPath string, netconf []byte, args CNIArgs) error {
+       _, err := execPlugin(pluginPath, netconf, args)
+       return err
+}
+
+func execPlugin(pluginPath string, netconf []byte, args CNIArgs) ([]byte, error) {
        if pluginPath == "" {
                return nil, fmt.Errorf("could not find %q plugin", filepath.Base(pluginPath))
        }
@@ -60,7 +76,5 @@ func ExecPlugin(pluginPath string, netconf []byte, args CNIArgs) (*types.Result,
                return nil, pluginErr(err, stdout.Bytes())
        }
 
-       res := &types.Result{}
-       err := json.Unmarshal(stdout.Bytes(), res)
-       return res, err
+       return stdout.Bytes(), nil
 }

diff --git a/ipam/ipam.go b/ipam/ipam.go
index a76299d..6a593a2 100644 (file)
--- a/ipam/ipam.go
+++ b/ipam/ipam.go
@@ -29,15 +29,14 @@ func ExecAdd(plugin string, netconf []byte) (*types.Result, error) {
        if os.Getenv("CNI_COMMAND") != "ADD" {
                return nil, fmt.Errorf("CNI_COMMAND is not ADD")
        }
-       return invoke.ExecPlugin(invoke.Find(plugin), netconf, invoke.ArgsFromEnv())
+       return invoke.ExecPluginWithResult(invoke.Find(plugin), netconf, invoke.ArgsFromEnv())
 }
 
 func ExecDel(plugin string, netconf []byte) error {
        if os.Getenv("CNI_COMMAND") != "DEL" {
                return fmt.Errorf("CNI_COMMAND is not DEL")
        }
-       _, err := invoke.ExecPlugin(invoke.Find(plugin), netconf, invoke.ArgsFromEnv())
-       return err
+       return invoke.ExecPluginWithoutResult(invoke.Find(plugin), netconf, invoke.ArgsFromEnv())
 }
 
 // ConfigureIface takes the result of IPAM plugin and