libcni: add util function InjectConf

libcni/conf.go

@@ -83,3 +83,28 @@ func LoadConf(dir, name string) (*NetworkConfig, error) {
 	}
 	return nil, fmt.Errorf(`no net configuration with name "%s" in %s`, name, dir)
 }
+
+func InjectConf(original *NetworkConfig, key string, newValue interface{}) (*NetworkConfig, error) {
+	config := make(map[string]interface{})
+	err := json.Unmarshal(original.Bytes, &config)
+	if err != nil {
+		return nil, fmt.Errorf("unmarshal existing network bytes: %s", err)
+	}
+
+	if key == "" {
+		return nil, fmt.Errorf("key value can not be empty")
+	}
+
+	if newValue == nil {
+		return nil, fmt.Errorf("newValue must be specified")
+	}
+
+	config[key] = newValue
+
+	newBytes, err := json.Marshal(config)
+	if err != nil {
+		return nil, err
+	}
+
+	return ConfFromBytes(newBytes)
+}

libcni/conf_test.go

@@ -29,6 +29,7 @@ var _ = Describe("Loading configuration from disk", func() {
 	var (
 		configDir     string
 		pluginConfig  []byte
+		testNetConfig *libcni.NetworkConfig
 	)
 
 	BeforeEach(func() {
@@ -38,6 +39,9 @@ var _ = Describe("Loading configuration from disk", func() {
 
 		pluginConfig = []byte(`{ "name": "some-plugin", "some-key": "some-value" }`)
 		Expect(ioutil.WriteFile(filepath.Join(configDir, "50-whatever.conf"), pluginConfig, 0600)).To(Succeed())
+
+		testNetConfig = &libcni.NetworkConfig{Network: &types.NetConf{Name: "some-plugin"},
+			Bytes: []byte(`{ "name": "some-plugin" }`)}
 	})
 
 	AfterEach(func() {
@@ -107,4 +111,89 @@ var _ = Describe("Loading configuration from disk", func() {
 			})
 		})
 	})
+
+	Describe("InjectConf", func() {
+		Context("when function parameters are incorrect", func() {
+			It("returns unmarshal error", func() {
+				conf := &libcni.NetworkConfig{Network: &types.NetConf{Name: "some-plugin"},
+					Bytes: []byte(`{ cc cc cc}`)}
+
+				_, err := libcni.InjectConf(conf, "", nil)
+				Expect(err).To(MatchError(HavePrefix(`unmarshal existing network bytes`)))
+			})
+
+			It("returns key  error", func() {
+				_, err := libcni.InjectConf(testNetConfig, "", nil)
+				Expect(err).To(MatchError(HavePrefix(`key value can not be empty`)))
+			})
+
+			It("returns newValue  error", func() {
+				_, err := libcni.InjectConf(testNetConfig, "test", nil)
+				Expect(err).To(MatchError(HavePrefix(`newValue must be specified`)))
+			})
+		})
+
+		Context("when new string value added", func() {
+			It("adds the new key & value to the config", func() {
+				newPluginConfig := []byte(`{"name":"some-plugin","test":"test"}`)
+
+				resultConfig, err := libcni.InjectConf(testNetConfig, "test", "test")
+				Expect(err).NotTo(HaveOccurred())
+				Expect(resultConfig).To(Equal(&libcni.NetworkConfig{
+					Network: &types.NetConf{Name: "some-plugin"},
+					Bytes:   newPluginConfig,
+				}))
+			})
+
+			It("adds the new value for exiting key", func() {
+				newPluginConfig := []byte(`{"name":"some-plugin","test":"changedValue"}`)
+
+				resultConfig, err := libcni.InjectConf(testNetConfig, "test", "test")
+				Expect(err).NotTo(HaveOccurred())
+
+				resultConfig, err = libcni.InjectConf(resultConfig, "test", "changedValue")
+				Expect(err).NotTo(HaveOccurred())
+
+				Expect(resultConfig).To(Equal(&libcni.NetworkConfig{
+					Network: &types.NetConf{Name: "some-plugin"},
+					Bytes:   newPluginConfig,
+				}))
+			})
+
+			It("adds existing key & value", func() {
+				newPluginConfig := []byte(`{"name":"some-plugin","test":"test"}`)
+
+				resultConfig, err := libcni.InjectConf(testNetConfig, "test", "test")
+				Expect(err).NotTo(HaveOccurred())
+
+				resultConfig, err = libcni.InjectConf(resultConfig, "test", "test")
+				Expect(err).NotTo(HaveOccurred())
+
+				Expect(resultConfig).To(Equal(&libcni.NetworkConfig{
+					Network: &types.NetConf{Name: "some-plugin"},
+					Bytes:   newPluginConfig,
+				}))
+			})
+
+			It("adds sub-fields of NetworkConfig.Network to the config", func() {
+
+				expectedPluginConfig := []byte(`{"dns":{"domain":"local","nameservers":["server1","server2"]},"name":"some-plugin","type":"bridge"}`)
+				servers := []string{"server1", "server2"}
+				newDNS := &types.DNS{Nameservers: servers, Domain: "local"}
+
+				// inject DNS
+				resultConfig, err := libcni.InjectConf(testNetConfig, "dns", newDNS)
+				Expect(err).NotTo(HaveOccurred())
+
+				// inject type
+				resultConfig, err = libcni.InjectConf(resultConfig, "type", "bridge")
+				Expect(err).NotTo(HaveOccurred())
+
+				Expect(resultConfig).To(Equal(&libcni.NetworkConfig{
+					Network: &types.NetConf{Name: "some-plugin", Type: "bridge", DNS: types.DNS{Nameservers: servers, Domain: "local"}},
+					Bytes:   expectedPluginConfig,
+				}))
+			})
+		})
+	})
 })