feat: New UNIX_TIMESTAMP and UNIX_DATE datetime functions (#2459)

docs/changelog.rst

@@ -21,6 +21,8 @@ KSQL 5.4.0 includes new features, including:
 * A new config ``ksql.metrics.tags.custom`` for adding custom tags to emitted JMX metrics.
   See :ref:`ksql-metrics-tags-custom` for usage.
 
+* New ``UNIX_TIMESTAMP()`` and ``UNIX_DATE()`` functions.
+
 KSQL 5.4.0 includes the following misc. changes:
 
 * Require either the value for a ``@UdfParameter`` or for the UDF JAR to be compiled with

docs/developer-guide/syntax-reference.rst

@@ -1516,6 +1516,15 @@ Scalar functions
 +------------------------+---------------------------------------------------------------------------+---------------------------------------------------+
 | CONCAT                 |  ``CONCAT(col1, '_hello')``                                               | Concatenate two strings.                          |
 +------------------------+---------------------------------------------------------------------------+---------------------------------------------------+
+| UNIX_DATE              |  ``UNIX_DATE()``                                                          | Gets an integer representing days since epoch.    |
+|                        |                                                                           | The returned timestamp may differ depending on    |
+|                        |                                                                           | the local time of different KSQL Server instances.|
++------------------------+---------------------------------------------------------------------------+---------------------------------------------------+
+| UNIX_TIMESTAMP         |  ``UNIX_TIMESTAMP()``                                                     | Gets the Unix timestamp in milliseconds,          |
+|                        |                                                                           | represented as a BIGINT.                          |
+|                        |                                                                           | The returned timestamp may differ depending on    |
+|                        |                                                                           | the local time of different KSQL Server instances.|
++------------------------+---------------------------------------------------------------------------+---------------------------------------------------+
 | DATETOSTRING           |  ``DATETOSTRING(START_DATE, 'yyyy-MM-dd')``                               | Converts an integer representation of a date into |
 |                        |                                                                           | a string representing the date in                 |
 |                        |                                                                           | the given format. Single quotes in the            |

ksql-engine/src/main/java/io/confluent/ksql/function/udf/datetime/UnixDate.java

@@ -0,0 +1,30 @@
+/*
+ * Copyright 2018 Confluent Inc.
+ *
+ * Licensed under the Confluent Community License; you may not use this file
+ * except in compliance with the License.  You may obtain a copy of the License at
+ *
+ * http://www.confluent.io/confluent-community-license
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OF ANY KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations under the License.
+ */
+
+package io.confluent.ksql.function.udf.datetime;
+
+import io.confluent.ksql.function.udf.Udf;
+import io.confluent.ksql.function.udf.UdfDescription;
+import java.time.LocalDate;
+
+@UdfDescription(name = "unix_date",
+    description = "Gets an integer representing days since epoch.")
+public class UnixDate {
+
+  @Udf(description = "Gets an integer representing days since epoch.")
+  public int unixDate() {
+    return ((int) LocalDate.now().toEpochDay());
+  }
+
+}

ksql-engine/src/main/java/io/confluent/ksql/function/udf/datetime/UnixTimestamp.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2018 Confluent Inc.
+ *
+ * Licensed under the Confluent Community License; you may not use this file
+ * except in compliance with the License.  You may obtain a copy of the License at
+ *
+ * http://www.confluent.io/confluent-community-license
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OF ANY KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations under the License.
+ */
+
+package io.confluent.ksql.function.udf.datetime;
+
+import io.confluent.ksql.function.udf.Udf;
+import io.confluent.ksql.function.udf.UdfDescription;
+
+@UdfDescription(name = "unix_timestamp",
+    description = "Gets the Unix timestamp in milliseconds, represented as a BIGINT.")
+public class UnixTimestamp {
+
+  @Udf(description = "Gets a BIGINT millisecond from the Unix timestamp.")
+  public long unixTimestamp() {
+    return System.currentTimeMillis();
+  }
+
+}

ksql-engine/src/test/java/io/confluent/ksql/function/udf/datetime/UnixDateTest.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2018 Confluent Inc.
+ *
+ * Licensed under the Confluent Community License; you may not use this file
+ * except in compliance with the License.  You may obtain a copy of the License at
+ *
+ * http://www.confluent.io/confluent-community-license
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OF ANY KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations under the License.
+ */
+
+package io.confluent.ksql.function.udf.datetime;
+
+import org.junit.Before;
+import org.junit.Test;
+import java.time.LocalDate;
+
+import static org.junit.Assert.assertEquals;
+
+public class UnixDateTest {
+
+  private UnixDate udf;
+
+  @Before
+  public void setUp() {
+    udf = new UnixDate();
+  }
+
+  @Test
+  public void shouldGetTheUnixDate() {
+    // Given:
+    final int now = ((int) LocalDate.now().toEpochDay());
+
+    // When:
+    final int result = udf.unixDate();
+
+    // Then:
+    assertEquals(now, result);
+  }
+
+}

ksql-engine/src/test/java/io/confluent/ksql/function/udf/datetime/UnixTimestampTest.java

@@ -0,0 +1,50 @@
+/*
+ * Copyright 2018 Confluent Inc.
+ *
+ * Licensed under the Confluent Community License; you may not use this file
+ * except in compliance with the License.  You may obtain a copy of the License at
+ *
+ * http://www.confluent.io/confluent-community-license
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OF ANY KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations under the License.
+ */
+
+package io.confluent.ksql.function.udf.datetime;
+
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+
+import java.sql.Timestamp;
+
+import static org.junit.Assert.assertTrue;
+
+public class UnixTimestampTest {
+
+  private UnixTimestamp udf;
+
+  @Rule
+  public final ExpectedException expectedException = ExpectedException.none();
+
+  @Before
+  public void setUp() {
+    udf = new UnixTimestamp();
+  }
+
+  @Test
+  public void shouldGetTheUnixTimestamp() {
+    // Given:
+    final long before = System.currentTimeMillis();
+
+    // When:
+    final long result = udf.unixTimestamp();
+    final long after = System.currentTimeMillis();
+
+    // Then:
+    assertTrue(before <= result && result <= after);
+  }
+}