Add UUID transforms supports v3, v4, v5 (#43)

README.md

@@ -43,6 +43,7 @@ Kazaam currently supports the following transforms:
 - coalesce
 - extract
 - timestamp
+- uuid
 - default
 - pass
 
@@ -240,6 +241,98 @@ would result in
 }
 ```
 
+### UUID
+A `uuid` transform generates a UUID based on the spec. Currently supports UUIDv3, UUIDv4, UUIDv5.
+
+For version 4 is a very simple spec
+
+```javascript
+{
+    "operation": "uuid",
+    "spec": {
+        "doc.uuid": {
+            "version": 4, //required
+        }
+    }
+}
+```
+
+executed on a json message with format
+```javascript
+{
+  "doc": {
+    "author_id": 11122112,
+    "document_id": 223323,
+    "meta": {
+      "id": 23
+    }
+  }
+}
+```
+
+would result in
+```javascript
+{
+  "doc": {
+    "author_id": 11122112,
+    "document_id": 223323,
+    "meta": {
+      "id": 23
+    }
+    "uuid": "f03bacc1-f4e0-4371-a5c5-e8160d3d6c0c"
+  }
+}
+```
+
+For UUIDv3 & UUIDV5 are a bit more complex. These require a Name Space which is a valid UUID already, and a set of paths, which generate UUID's based on the value of that path. If that path doesn't exist in the incoming document, a default field will be used instead. **Note** both of these fields must be strings. 
+**Additionally** you can use the 4 predefined namespaces such as `DNS`, `URL`, `OID`, & `X500` in the name space field otherwise pass your own UUID. 
+
+```javascript
+{
+   "operation":"uuid",
+   "spec":{
+      "doc.uuid":{
+         "version":5,
+         "nameSpace":"DNS",
+         "names":[
+            {"path":"doc.author_name", "default":"some string"},
+            {"path":"doc.type", "default":"another string"},
+         ]
+      }
+   }
+}
+```
+
+executed on a json message with format
+```javascript
+{
+  "doc": {
+    "author_name": "jason",
+    "type": "secret-document"
+    "document_id": 223323,
+    "meta": {
+      "id": 23
+    }
+  }
+}
+```
+
+would result in
+```javascript
+{
+  "doc": {
+    "author_name": "jason",
+    "type": "secret-document",
+    "document_id": 223323,
+    "meta": {
+      "id": 23
+    },
+    "uuid": "f03bacc1-f4e0-4371-a7c5-e8160d3d6c0c"
+  }
+}
+```
+
+
 ### Default
 A default transform provides the ability to set a key's value explicitly. For example
 ```javascript

glide.yaml

@@ -2,3 +2,5 @@ package: github.com/qntfy/kazaam
 import:
 - package: github.com/buger/jsonparser
   version: bb14bb6c38f6cf1706ef55278891d184b6a51b0e
+- package: github.com/satori/go.uuid
+  version: v1.1.0

kazaam.go

@@ -34,6 +34,7 @@ func init() {
 		"concat":    transform.Concat,
 		"coalesce":  transform.Coalesce,
 		"timestamp": transform.Timestamp,
+		"uuid":      transform.UUID,
 	}
 }
 

kazaam_test.go

@@ -38,7 +38,7 @@ func TestReregisterKazaamTransform(t *testing.T) {
 }
 
 func TestDefaultTransformsSetCardinarily(t *testing.T) {
-	if len(validSpecTypes) != 7 {
+	if len(validSpecTypes) != 8 {
 		t.Error("Unexpected number of default transforms. Missing tests?")
 	}
 }

transform/uuid.go

@@ -0,0 +1,125 @@
+package transform
+
+import (
+	"strings"
+
+	"github.com/buger/jsonparser"
+	uuid "github.com/satori/go.uuid"
+)
+
+var (
+	versionError = SpecError("Please set version 3 || 4 || 5")
+)
+
+// UUID tries to generate a UUID based on spec components
+func UUID(spec *Config, data []byte) ([]byte, error) {
+
+	// iterate through the spec
+	for k, v := range *spec.Spec {
+		outPath := strings.Split(k, ".")
+
+		// convert to corrct type
+		uuidSpec, ok := v.(map[string]interface{})
+		if !ok {
+			return nil, SpecError("Invalid Spec for UUID")
+		}
+
+		//grab version
+		version, ok := uuidSpec["version"]
+
+		if !ok {
+			return nil, versionError
+		}
+
+		var u uuid.UUID
+		var err error
+
+		switch version {
+		case 4.0:
+			u = uuid.NewV4()
+
+		case 3.0, 5.0:
+
+			names, ok := uuidSpec["names"]
+			if !ok {
+				return nil, SpecError("Must provide names field")
+			}
+
+			nameSpace, ok := uuidSpec["nameSpace"].(string)
+			if !ok {
+				return nil, SpecError("Must provide namesapce, Must be a string")
+			}
+
+			var nameSpaceUUID uuid.UUID
+
+			// swtich on the namespace
+			switch nameSpace {
+			case "DNS":
+				nameSpaceUUID = uuid.NamespaceDNS
+			case "URL":
+				nameSpaceUUID = uuid.NamespaceURL
+			case "OID":
+				nameSpaceUUID = uuid.NamespaceOID
+			case "X500":
+				nameSpaceUUID = uuid.NamespaceX500
+			default:
+				nameSpaceUUID, err = uuid.FromString(nameSpace)
+				if err != nil {
+					return nil, SpecError("nameSpace is not a valid UUID or is not DNS, URL, OID, X500")
+				}
+			}
+
+			nameFields, ok := names.([]interface{})
+			if !ok {
+				return nil, SpecError("Spec is invalid")
+			}
+
+			// loop over the names field
+			for _, field := range nameFields {
+				p, _ := field.(map[string]interface{})["path"].(string)
+
+				name, err := getJSONRaw(data, p, false)
+				if err == jsonparser.KeyPathNotFoundError {
+
+					d, ok := field.(map[string]interface{})["default"].(string)
+					if !ok {
+						return nil, SpecError("Spec is invalid")
+
+					}
+					name = []byte(d)
+
+				}
+
+				// check if there is an empty uuid & version 3
+				if u.String() == "00000000-0000-0000-0000-000000000000" && version == 3.0 {
+
+					u = uuid.NewV3(nameSpaceUUID, string(name))
+
+					// same as above except version 5
+				} else if u.String() == "00000000-0000-0000-0000-000000000000" && version == 5.0 {
+
+					u = uuid.NewV5(nameSpaceUUID, string(name))
+
+				} else if version == 3.0 {
+
+					u = uuid.NewV3(u, string(name))
+
+				} else if version == 5.0 {
+
+					u = uuid.NewV3(u, string(name))
+				}
+			}
+
+		default:
+			return nil, versionError
+
+		}
+		d, err := jsonparser.Set(data, bookend([]byte(u.String()), '"', '"'), outPath...)
+		if err != nil {
+			return nil, err
+		}
+
+		return d, nil
+	}
+	return nil, SpecError("Spec invalid for UUID")
+}