trino: Add an experimental FARM_FINGERPRINT UDF

.vscode/settings.json

@@ -1,3 +1,5 @@
 {
-    "editor.formatOnSave": true
-}
+  "editor.formatOnSave": true,
+  "java.compile.nullAnalysis.mode": "automatic",
+  "java.configuration.updateBuildConfiguration": "automatic"
+}

java/trino-plugin/.gitignore

@@ -0,0 +1 @@
+/target/

java/trino-plugin/.tool-versions

@@ -0,0 +1,2 @@
+java adoptopenjdk-17.0.9+9
+maven 3.9.5

java/trino-plugin/README.md

@@ -0,0 +1,39 @@
+# Experimental Trino Plugin
+
+Install the [`asdf` version manager][asdf] and the plugins needed for Java:
+
+```sh
+asdf plugin-add java https://github.com/halcyon/asdf-java.git
+asdf plugin-add maven https://github.com/halcyon/asdf-maven.git
+```
+
+Then install a Java environment using versions specified in `.tool-versions`:
+
+```sh
+asdf install
+```
+
+You should be able to "package" the plugin into `./target/` using:
+
+```sh
+mvn package
+```
+
+Then you can run Trino with the plugin using:
+
+```sh
+docker run --name trino -d --mount type=bind,source="$(pwd)"/target,target=/usr/lib/trino/plugin/joinery -p 8080:8080 trinodb/trino
+```
+
+This should give you a working `FARM_FINGERPRINT` function, which you can test
+as follows:
+
+```txt
+❯ docker exec -it trino trino
+trino> select farm_fingerprint('Hello');
+        _col0         
+----------------------
+ -3042045079152025465 
+```
+
+[asdf]: https://asdf-vm.com/

java/trino-plugin/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <groupId>ai.faraday.joinery</groupId>
+  <artifactId>trino-plugin</artifactId>
+  <version>1.0-SNAPSHOT</version>
+
+  <name>trino-plugin</name>
+  <!-- FIXME change it to the project's website -->
+  <url>http://www.example.com</url>
+
+  <properties>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    <maven.compiler.source>11</maven.compiler.source>
+    <maven.compiler.target>11</maven.compiler.target>
+  </properties>
+
+  <dependencies>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <version>4.11</version>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>com.google.guava</groupId>
+      <artifactId>guava</artifactId>
+      <version>32.1.3-jre</version>
+    </dependency>
+    <dependency>
+      <groupId>io.trino</groupId>
+      <artifactId>trino-spi</artifactId>
+      <version>429</version>
+      <!-- <scope>provided</scope> -->
+    </dependency>
+  </dependencies>
+
+  <build>
+    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
+      <plugins>
+        <!-- clean lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#clean_Lifecycle -->
+        <plugin>
+          <artifactId>maven-clean-plugin</artifactId>
+          <version>3.1.0</version>
+        </plugin>
+        <!-- default lifecycle, jar packaging: see https://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
+        <plugin>
+          <artifactId>maven-resources-plugin</artifactId>
+          <version>3.0.2</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-compiler-plugin</artifactId>
+          <version>3.8.0</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-surefire-plugin</artifactId>
+          <version>2.22.1</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-jar-plugin</artifactId>
+          <version>3.0.2</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-install-plugin</artifactId>
+          <version>2.5.2</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-deploy-plugin</artifactId>
+          <version>2.8.2</version>
+        </plugin>
+        <!-- site lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#site_Lifecycle -->
+        <plugin>
+          <artifactId>maven-site-plugin</artifactId>
+          <version>3.7.1</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-project-info-reports-plugin</artifactId>
+          <version>3.0.0</version>
+        </plugin>
+      </plugins>
+    </pluginManagement>
+    <!-- Copy dependencies into ./target for now so we can mount the
+         whole directory into a Trino Docker container. -->
+    <plugins>
+      <plugin>
+        <artifactId>maven-dependency-plugin</artifactId>
+        <executions>
+          <execution>
+            <!-- Originally this was "install". -->
+            <phase>package</phase>
+            <goals>
+              <goal>copy-dependencies</goal>
+            </goals>
+            <configuration>
+              <outputDirectory>${project.build.directory}</outputDirectory>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+</project>

java/trino-plugin/src/main/java/ai/faraday/joinery/FarmFingerprintFunction.java

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+package ai.faraday.joinery;
+
+import java.nio.charset.StandardCharsets;
+
+import com.google.common.hash.Hashing;
+
+import io.airlift.slice.Slice;
+import io.trino.spi.function.Description;
+import io.trino.spi.function.ScalarFunction;
+import io.trino.spi.function.SqlNullable;
+import io.trino.spi.function.SqlType;
+import io.trino.spi.type.StandardTypes;
+
+public class FarmFingerprintFunction {
+    @ScalarFunction("farm_fingerprint")
+    @Description("Returns FARM_FINGERPRINT of the given string")
+    @SqlNullable
+    @SqlType(StandardTypes.BIGINT)
+    public static Long farmFingerprint(
+            @SqlNullable @SqlType(StandardTypes.VARCHAR) Slice string) {
+        if (string == null) {
+            return null;
+        }
+        return Hashing.farmHashFingerprint64().hashString(string.toStringUtf8(), StandardCharsets.UTF_8).asLong();
+    }
+}

java/trino-plugin/src/main/java/ai/faraday/joinery/JoineryPlugin.java

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+package ai.faraday.joinery;
+
+import java.util.Set;
+
+import com.google.common.collect.ImmutableSet;
+
+public class JoineryPlugin implements io.trino.spi.Plugin {
+    @Override
+    public Set<Class<?>> getFunctions() {
+        return ImmutableSet.<Class<?>>builder()
+                .add(FarmFingerprintFunction.class)
+                .build();
+    }
+}

java/trino-plugin/src/main/resources/META-INF/services/io.trino.spi.Plugin

@@ -0,0 +1 @@
+ai.faraday.joinery.JoineryPlugin

java/trino-plugin/src/test/java/ai/faraday/joinery/FarmFingerprintFunctionTest.java

@@ -0,0 +1,27 @@
+package ai.faraday.joinery;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+
+import io.airlift.slice.Slice;
+import io.airlift.slice.Slices;
+
+/**
+ * Unit test for simple App.
+ */
+public class FarmFingerprintFunctionTest {
+    @Test
+    public void handlesNull() {
+        assertEquals(FarmFingerprintFunction.farmFingerprint(null), null);
+    }
+
+    @Test
+    public void calculatesExpectedHash() {
+        Slice hello = Slices.copiedBuffer("Hello", UTF_8);
+        Long expected = -3042045079152025465L;
+        assertEquals(FarmFingerprintFunction.farmFingerprint(hello), expected);
+    }
+}

tests/sql/functions/simple/farm_fingerprint.sql

@@ -1,6 +1,8 @@
 -- pending: snowflake FARM_FINGERPRINT only exists on BigQuery
 -- pending: sqlite3 FARM_FINGERPRINT only exists on BigQuery
--- pending: trino FARM_FINGERPRINT only exists on BigQuery
+--
+-- This works on Trino if you load the UDF as described in `./java/README.md`.
+
 CREATE OR REPLACE TABLE __result1 AS
 SELECT
     FARM_FINGERPRINT('foo') AS str_farm,