Allow nested partition keys

README.md

@@ -47,6 +47,20 @@ second, which would look like the following:
 { "myConstant": "Hello, World!", "randomNumber": 33}
 ```
 
+Partition keys can also be nested in the json as long as they are not nested in an array eg.
+
+```yaml
+topic: testTopic
+partitionKey: "nested.id"
+fields:
+  nested:
+    type: json
+    components:
+        id: "id123"
+```
+
+Will result in "id123" being used as the partition key.
+
 You can find a full example of config file in [this file](https://github.com/redBorder/synthetic-producer/blob/master/configProducer.yml)
 
 ## Fields types

src/main/java/net/redborder/utils/scheduler/StandardScheduler.java

@@ -13,7 +13,6 @@
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
-import java.util.Random;
 import java.util.concurrent.TimeUnit;
 
 public class StandardScheduler implements Scheduler {
@@ -68,13 +67,42 @@ public void run() {
             while (!currentThread().isInterrupted()) {
                 rateLimiter.acquire();
                 Map<String, Object> message = generator.generate();
-                Object partitionKeyObject = message.get(producer.getPartitionKey());
-                String partitionKey = null;
-                if(partitionKeyObject != null) partitionKey = partitionKeyObject.toString();
+                String partitionKey = extractPartitionKey(message);
                 String json = gson.toJson(message);
                 producer.send(json, partitionKey);
                 messages.mark();
             }
         }
     }
+
+    String extractPartitionKey(final Map<String, Object> message) {
+        try {
+            // No partition key field results in null
+            final String partitionKey = producer.getPartitionKey();
+            if (partitionKey == null) {
+                return null;
+            }
+
+            // Try to get the key from the object, then treat it as a nested path
+            Object partitionKeyObject = message.get(partitionKey);
+            if (partitionKeyObject != null) {
+                return partitionKeyObject.toString();
+            } else {
+                final String[] keys = partitionKey.split("\\.");
+                Map currentMessage = message;
+                for (final String key : keys) {
+                    partitionKeyObject = currentMessage.get(key);
+                    if (partitionKeyObject == null) {
+                        break;
+                    } else if (partitionKeyObject instanceof Map) {
+                        currentMessage = (Map) partitionKeyObject;
+                    }
+                }
+                return partitionKeyObject.toString();
+            }
+        } catch (final Exception e) {
+            log.warn(e.getMessage(), e);
+            return null;
+        }
+    }
 }

src/test/java/net/redborder/utils/scheduler/StandardSchedulerTest.java

@@ -0,0 +1,45 @@
+package net.redborder.utils.scheduler;
+
+import static org.junit.Assert.*;
+import static org.mockito.Mockito.*;
+import static org.mockito.MockitoAnnotations.initMocks;
+
+import java.util.HashMap;
+import java.util.Map;
+import net.redborder.utils.producers.IProducer;
+import org.junit.Before;
+import org.junit.Test;
+
+public class StandardSchedulerTest {
+
+    private Map<String, Object> message;
+
+    private IProducer producer;
+
+    private StandardScheduler standardScheduler;
+
+    @Before
+    @SuppressWarnings("unchecked")
+    public void before() throws Exception {
+
+        message = new HashMap<>();
+        message.put("id", "123");
+        message.put("nested", new HashMap<String, Object>());
+        ((Map<String, Object>) message.get("nested")).put("id", "345");
+
+        producer = mock(IProducer.class);
+
+        standardScheduler = new StandardScheduler(null, producer, 1D, 1);
+    }
+
+    @Test
+    public void extractPartitionKey() {
+        when(producer.getPartitionKey()).thenReturn("id");
+        String result = standardScheduler.extractPartitionKey(message);
+        assertEquals("123", result);
+
+        when(producer.getPartitionKey()).thenReturn("nested.id");
+        result = standardScheduler.extractPartitionKey(message);
+        assertEquals("345", result);
+    }
+}