Merge pull request #15 from ryanleary/14-add-extract

Add extract feature

kazaam.go

@@ -20,6 +20,7 @@ func init() {
 	validSpecTypes = map[string]transformFunc{
 		"pass":    transformPass,
 		"shift":   transformShift,
+		"extract": transformExtract,
 		"default": transformDefault,
 	}
 }
@@ -175,6 +176,15 @@ func transformDefault(spec *spec, data *simplejson.Json) (*simplejson.Json, erro
 	return data, nil
 }
 
+func transformExtract(spec *spec, data *simplejson.Json) (*simplejson.Json, error) {
+	outPath, ok := (*spec.Spec)["path"]
+	if !ok {
+		return nil, fmt.Errorf("Unable to get path")
+	}
+	outData, err := getJSONPath(data, outPath.(string))
+	return outData, err
+}
+
 func transformShift(spec *spec, data *simplejson.Json) (*simplejson.Json, error) {
 	outData := simplejson.New()
 	for k, v := range *spec.Spec {

kazaam_test.go

@@ -261,3 +261,37 @@ func TestKazaamShiftNullSpecValue(t *testing.T) {
 		t.FailNow()
 	}
 }
+
+func TestKazaamExtractTransform(t *testing.T) {
+	spec := `[{"operation": "extract", "spec": {"path": "_source"}}]`
+	jsonIn := `{"data": {"id": true}, "_source": {"a": 123, "b": "str", "c": null, "d": true}}`
+
+	jsonOut := `{"a":123,"b":"str","c":null,"d":true}`
+
+	kazaamTransform, _ := kazaam.NewKazaam(spec)
+	kazaamOut, _ := kazaamTransform.TransformJSONStringToString(jsonIn)
+
+	if kazaamOut != jsonOut {
+		t.Error("Transformed data does not match expectation.")
+		t.Log("Expected: ", jsonOut)
+		t.Log("Actual:   ", kazaamOut)
+		t.FailNow()
+	}
+}
+
+func TestKazaamExtractTransformBadPath(t *testing.T) {
+	spec := `[{"operation": "extract", "spec": {"path": "test"}}]`
+	jsonIn := `{"data": {"id": true}, "_source": {"a": 123, "b": "str", "c": null, "d": true}}`
+
+	jsonOut := "null"
+
+	kazaamTransform, _ := kazaam.NewKazaam(spec)
+	kazaamOut, _ := kazaamTransform.TransformJSONStringToString(jsonIn)
+
+	if kazaamOut != jsonOut {
+		t.Error("Transformed data does not match expectation.")
+		t.Log("Expected: ", jsonOut)
+		t.Log("Actual:   ", kazaamOut)
+		t.FailNow()
+	}
+}