Added assign_if transformation (#276)

Fixes #275

Signed-off-by: Kuldeep Singh Pal <tkuldeep.allen@gmail.com>

README.md

@@ -391,6 +391,11 @@ parameters:
             output: value_smaller_than10
             type: add_if
             parameters: <10
+          - input: value
+            output: dir
+            type: add_if
+            parameters: ==1
+            assignee: in
           - input: dstPort
             output: service
             type: add_service
@@ -418,7 +423,8 @@ The second `add_if` generates a new field named `value_smaller_than10` that cont
 the contents of the `value` field for entries that satisfy the condition specified 
 in the `parameters` variable (smaller than 10 in the example above). In addition, the
 field `value_smaller_than10_Evaluate` with value `true` is added to all satisfied
-entries
+entries. if `assignee` field is set, then on satified parmater i.e. if parameter evalutes true then
+`output` value will get value of `assignee` key.
 
 The third rule `add_service` generates a new field named `service` with the known network 
 service name of `dstPort` port and `protocol` protocol. Unrecognized ports are ignored 

docs/api.md

@@ -117,6 +117,7 @@ Following is the supported API format for network transformations:
                      add_service: add output network service field from input port and parameters protocol field
                      add_kubernetes: add output kubernetes fields from input
                  parameters: parameters specific to type
+                 assignee: value needs to assign to output field
          kubeConfigPath: path to kubeconfig file (optional)
          servicesFile: path to services file (optional, default: /etc/services)
          protocolsFile: path to protocols file (optional, default: /etc/protocols)

pkg/api/transform_network.go

@@ -43,6 +43,7 @@ type NetworkTransformRule struct {
 	Output     string `yaml:"output,omitempty" json:"output,omitempty" doc:"entry output field"`
 	Type       string `yaml:"type,omitempty" json:"type,omitempty" enum:"TransformNetworkOperationEnum" doc:"one of the following:"`
 	Parameters string `yaml:"parameters,omitempty" json:"parameters,omitempty" doc:"parameters specific to type"`
+	Assignee   string `yaml:"assignee,omitempty" json:"assignee,omitempty" doc:"value needs to assign to output field"`
 }
 
 type NetworkTransformRules []NetworkTransformRule

pkg/pipeline/transform/transform_network.go

@@ -92,7 +92,11 @@ func (n *Network) TransformEntry(inputEntry config.GenericMap) config.GenericMap
 			}
 			result, evaluateErr := expression.Evaluate(map[string]interface{}{"val": outputEntry[rule.Input]})
 			if evaluateErr == nil && result.(bool) {
-				outputEntry[rule.Output] = outputEntry[rule.Input]
+				if rule.Assignee != "" {
+					outputEntry[rule.Output] = rule.Assignee
+				} else {
+					outputEntry[rule.Output] = outputEntry[rule.Input]
+				}
 				outputEntry[rule.Output+"_Evaluate"] = true
 			}
 		case api.TransformNetworkOperationName("AddSubnet"):

pkg/pipeline/transform/transform_network_test.go

@@ -302,6 +302,20 @@ func Test_Transform_AddIfScientificNotation(t *testing.T) {
 					Type:       "add_if",
 					Parameters: "<10",
 				},
+				api.NetworkTransformRule{
+					Input:      "value",
+					Output:     "dir",
+					Assignee:   "in",
+					Type:       "add_if",
+					Parameters: "==1",
+				},
+				api.NetworkTransformRule{
+					Input:      "value",
+					Output:     "dir",
+					Assignee:   "out",
+					Type:       "add_if",
+					Parameters: "==0",
+				},
 			},
 		},
 	}
@@ -320,6 +334,20 @@ func Test_Transform_AddIfScientificNotation(t *testing.T) {
 	output = newNetworkTransform.Transform([]config.GenericMap{entry})
 	require.Equal(t, true, output[0]["smaller_than_10_Evaluate"])
 	require.Equal(t, 1.2345e-67, output[0]["smaller_than_10"])
+
+	entry = config.GenericMap{
+		"value": 1,
+	}
+	output = newNetworkTransform.Transform([]config.GenericMap{entry})
+	require.Equal(t, true, output[0]["dir_Evaluate"])
+	require.Equal(t, "in", output[0]["dir"])
+
+	entry = config.GenericMap{
+		"value": 0,
+	}
+	output = newNetworkTransform.Transform([]config.GenericMap{entry})
+	require.Equal(t, true, output[0]["dir_Evaluate"])
+	require.Equal(t, "out", output[0]["dir"])
 }
 
 func Test_TransformNetworkOperationNameCustomServices(t *testing.T) {