update to function definition types

api/src/main/java/io/serverlessworkflow/api/deserializers/FunctionDefinitionTypeDeserializer.java

@@ -0,0 +1,71 @@
+/*
+ * Copyright 2020-Present The Serverless Workflow Specification Authors
+ * <p>
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+package io.serverlessworkflow.api.deserializers;
+
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.databind.DeserializationContext;
+import com.fasterxml.jackson.databind.deser.std.StdDeserializer;
+import io.serverlessworkflow.api.functions.FunctionDefinition;
+import io.serverlessworkflow.api.interfaces.WorkflowPropertySource;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+
+public class FunctionDefinitionTypeDeserializer extends StdDeserializer<FunctionDefinition.Type> {
+
+    private static final long serialVersionUID = 510l;
+    private static Logger logger = LoggerFactory.getLogger(FunctionDefinitionTypeDeserializer.class);
+
+    private WorkflowPropertySource context;
+
+    public FunctionDefinitionTypeDeserializer() {
+        this(FunctionDefinition.Type.class);
+    }
+
+    public FunctionDefinitionTypeDeserializer(WorkflowPropertySource context) {
+        this(FunctionDefinition.Type.class);
+        this.context = context;
+    }
+
+    public FunctionDefinitionTypeDeserializer(Class<?> vc) {
+        super(vc);
+    }
+
+    @Override
+    public FunctionDefinition.Type deserialize(JsonParser jp,
+                                           DeserializationContext ctxt) throws IOException {
+
+        String value = jp.getText();
+        if (context != null) {
+            try {
+                String result = context.getPropertySource().getProperty(value);
+
+                if (result != null) {
+                    return FunctionDefinition.Type.fromValue(result);
+                } else {
+                    return FunctionDefinition.Type.fromValue(jp.getText());
+                }
+            } catch (Exception e) {
+                logger.info("Exception trying to evaluate property: {}", e.getMessage());
+                return FunctionDefinition.Type.fromValue(jp.getText());
+            }
+        } else {
+            return FunctionDefinition.Type.fromValue(jp.getText());
+        }
+    }
+}

api/src/main/java/io/serverlessworkflow/api/mapper/WorkflowModule.java

@@ -21,6 +21,7 @@
 import io.serverlessworkflow.api.end.End;
 import io.serverlessworkflow.api.events.EventDefinition;
 import io.serverlessworkflow.api.events.OnEvents;
+import io.serverlessworkflow.api.functions.FunctionDefinition;
 import io.serverlessworkflow.api.interfaces.Extension;
 import io.serverlessworkflow.api.interfaces.State;
 import io.serverlessworkflow.api.interfaces.WorkflowPropertySource;
@@ -91,6 +92,7 @@ private void addDefaultDeserializers() {
         addDeserializer(Start.class, new StartDefinitionDeserializer(workflowPropertySource));
         addDeserializer(End.class, new EndDefinitionDeserializer(workflowPropertySource));
         addDeserializer(Extension.class, extensionDeserializer);
+        addDeserializer(FunctionDefinition.Type.class, new FunctionDefinitionTypeDeserializer(workflowPropertySource));
 
     }
 

api/src/main/resources/schema/functions/functiondef.json

@@ -9,9 +9,18 @@
     },
     "operation": {
       "type": "string",
-      "description": "Combination of the function/service OpenAPI definition URI and the operationID of the operation that needs to be invoked, separated by a '#'. For example 'https://petstore.swagger.io/v2/swagger.json#getPetById'",
+      "description": "If type `rest`, combination of the function/service OpenAPI definition URI and the operationID of the operation that needs to be invoked, separated by a '#'. If type is `expression` defines the workflow expression.",
       "minLength": 1
     },
+    "type": {
+      "type": "string",
+      "description": "Defines the function type. Is either `rest` or `expression`. Default is `rest`",
+      "enum": [
+        "rest",
+        "expression"
+      ],
+      "default": "rest"
+    },
     "metadata": {
       "$ref": "../metadata/metadata.json"
     }

api/src/main/resources/schema/transitions/transition.json

@@ -2,10 +2,6 @@
   "type": "object",
   "javaType": "io.serverlessworkflow.api.transitions.Transition",
   "properties": {
-    "expression": {
-      "type": "string",
-      "description": "Common Expression Language (CEL) expression. Must evaluate to true for the transition to be valid"
-    },
     "produceEvents": {
       "type": "array",
       "description": "Array of events to be produced",

api/src/test/java/io/serverlessworkflow/api/test/MarkupToWorkflowTest.java

@@ -17,13 +17,16 @@
 package io.serverlessworkflow.api.test;
 
 import io.serverlessworkflow.api.Workflow;
+import io.serverlessworkflow.api.functions.FunctionDefinition;
 import io.serverlessworkflow.api.interfaces.State;
 import io.serverlessworkflow.api.states.EventState;
 import io.serverlessworkflow.api.states.OperationState;
 import io.serverlessworkflow.api.test.utils.WorkflowTestUtils;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.ValueSource;
 
+import java.util.List;
+
 import static org.junit.jupiter.api.Assertions.*;
 
 public class MarkupToWorkflowTest {
@@ -117,4 +120,31 @@ public void testSpecFreatureCompensation(String workflowLocation) {
 
         assertTrue(operationState.isUsedForCompensation());
     }
+
+    @ParameterizedTest
+    @ValueSource(strings = {"/features/functiontypes.json", "/features/functiontypes.yml"})
+    public void testFunctionTypes(String workflowLocation) {
+        Workflow workflow = Workflow.fromSource(WorkflowTestUtils.readWorkflowFile(workflowLocation));
+
+        assertNotNull(workflow);
+        assertNotNull(workflow.getId());
+        assertNotNull(workflow.getName());
+        assertNotNull(workflow.getStates());
+
+        assertNotNull(workflow.getStates());
+        assertTrue(workflow.getStates().size() == 1);
+
+        State state = workflow.getStates().get(0);
+        assertTrue(state instanceof OperationState);
+
+        List<FunctionDefinition> functionDefs = workflow.getFunctions().getFunctionDefs();
+        assertNotNull(functionDefs);
+        assertTrue(functionDefs.size() == 2);
+
+        FunctionDefinition restFunc = functionDefs.get(0);
+        assertEquals(restFunc.getType(), FunctionDefinition.Type.REST);
+
+        FunctionDefinition restFunc2 = functionDefs.get(1);
+        assertEquals(restFunc2.getType(), FunctionDefinition.Type.EXPRESSION);
+    }
 }

api/src/test/resources/features/functiontypes.json

@@ -0,0 +1,35 @@
+{
+  "id": "functiontypes",
+  "version": "1.0",
+  "name": "Function Types Workflow",
+  "description": "Determine if applicant request is valid",
+  "functions": [
+    {
+      "name": "restFunction",
+      "operation": "http://myapis.org/applicationapi.json#emailRejection"
+    },
+    {
+      "name": "expressionFunction",
+      "operation": "$.my.data",
+      "type" : "expression"
+    }
+  ],
+  "states":[
+    {
+      "name":"CheckFunctions",
+      "type":"operation",
+      "start": true,
+      "actions":[
+        {
+          "functionRef": {
+            "refName": "restFunction",
+            "parameters": {
+              "data": "{{ fn(expressionFunction) }}"
+            }
+          }
+        }
+      ],
+      "end": true
+    }
+  ]
+}

api/src/test/resources/features/functiontypes.yml

@@ -0,0 +1,20 @@
+id: functiontypes
+version: '1.0'
+name: Function Types Workflow
+description: Determine if applicant request is valid
+functions:
+  - name: restFunction
+    operation: http://myapis.org/applicationapi.json#emailRejection
+  - name: expressionFunction
+    operation: "$.my.data"
+    type: expression
+states:
+  - name: CheckFunctions
+    type: operation
+    start: true
+    actions:
+      - functionRef:
+          refName: restFunction
+          parameters:
+            data: "{{ fn(expressionFunction) }}"
+    end: true