skel: Plugins require a cniVersion in the NetConf

pkg/skel/skel.go

@@ -17,6 +17,7 @@
 package skel
 
 import (
+	"encoding/json"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -143,12 +144,28 @@ func createTypedError(f string, args ...interface{}) *types.Error {
 	}
 }
 
+func (t *dispatcher) validateVersion(stdinData []byte) error {
+	var netconf types.NetConf
+	if err := json.Unmarshal(stdinData, &netconf); err != nil {
+		return err
+	}
+	if netconf.CNIVersion == "" {
+		return fmt.Errorf("missing required config cniVersion")
+	}
+
+	return nil
+}
+
 func (t *dispatcher) pluginMain(cmdAdd, cmdDel func(_ *CmdArgs) error, versionInfo version.PluginInfo) *types.Error {
 	cmd, cmdArgs, err := t.getCmdArgsFromEnv()
 	if err != nil {
 		return createTypedError(err.Error())
 	}
 
+	if err = t.validateVersion(cmdArgs.StdinData); err != nil {
+		return createTypedError(err.Error())
+	}
+
 	switch cmd {
 	case "ADD":
 		err = cmdAdd(cmdArgs)

pkg/skel/skel_test.go

@@ -17,7 +17,6 @@ package skel
 import (
 	"bytes"
 	"errors"
-	"io"
 	"strings"
 
 	"github.com/containernetworking/cni/pkg/types"
@@ -48,7 +47,7 @@ func (c *fakeCmd) Func(args *CmdArgs) error {
 var _ = Describe("dispatching to the correct callback", func() {
 	var (
 		environment     map[string]string
-		stdin           io.Reader
+		stdinData       string
 		stdout, stderr  *bytes.Buffer
 		cmdAdd, cmdDel  *fakeCmd
 		dispatch        *dispatcher
@@ -65,13 +64,14 @@ var _ = Describe("dispatching to the correct callback", func() {
 			"CNI_ARGS":        "some;extra;args",
 			"CNI_PATH":        "/some/cni/path",
 		}
-		stdin = strings.NewReader(`{ "some": "config" }`)
+
+		stdinData = `{ "some": "config", "cniVersion": "9.8.7" }`
 		stdout = &bytes.Buffer{}
 		stderr = &bytes.Buffer{}
 		versionInfo = version.PluginSupports("9.8.7")
 		dispatch = &dispatcher{
 			Getenv: func(key string) string { return environment[key] },
-			Stdin:  stdin,
+			Stdin:  strings.NewReader(stdinData),
 			Stdout: stdout,
 			Stderr: stderr,
 		}
@@ -83,7 +83,7 @@ var _ = Describe("dispatching to the correct callback", func() {
 			IfName:      "eth0",
 			Args:        "some;extra;args",
 			Path:        "/some/cni/path",
-			StdinData:   []byte(`{ "some": "config" }`),
+			StdinData:   []byte(stdinData),
 		}
 	})
 
@@ -144,6 +144,22 @@ var _ = Describe("dispatching to the correct callback", func() {
 
 			})
 		})
+
+		Context("when the stdin data is missing the required cniVersion config", func() {
+			BeforeEach(func() {
+				dispatch.Stdin = strings.NewReader(`{ "some": "config" }`)
+			})
+
+			It("immediately returns a useful error", func() {
+				err := dispatch.pluginMain(cmdAdd.Func, cmdDel.Func, versionInfo)
+				Expect(err).To(MatchError("missing required config cniVersion"))
+			})
+
+			It("does not call either callback", func() {
+				Expect(cmdAdd.CallCount).To(Equal(0))
+				Expect(cmdDel.CallCount).To(Equal(0))
+			})
+		})
 	})
 
 	Context("when the CNI_COMMAND is DEL", func() {