开发自定义的dremio 函数

├── pom.xml

├── src

│   ├── main

│   │   ├── java

│   │   │   └── com

│   │   │       └── dalong

│   │   │           └── udf

│   │   │               └── MyFunc.java

│   │   └── resources

│   │       └── sabot-module.conf

<?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>com.dalong</groupId>

    <artifactId>dremio-func</artifactId>

    <version>1.2-SNAPSHOT</version>

    <properties>

        <maven.compiler.source>8</maven.compiler.source>

        <maven.compiler.target>8</maven.compiler.target>

        <version.dremio>13.0.0-202101272034330307-20fb9275</version.dremio>

    </properties>

    <dependencies>

        <dependency>

            <groupId>com.dremio.sabot</groupId>

            <artifactId>dremio-sabot-kernel</artifactId>

            <version>${version.dremio}</version>

            <scope>provided</scope>

        </dependency>

    </dependencies>

    <repositories>

        <repository>

            <id>dremio-free</id>

            <url>http://maven.dremio.com/free/</url>

        </repository>

        <repository>

            <id>dremio-public</id>

            <url>http://maven.dremio.com/public/</url>

        </repository>

    </repositories>

    <build>

        <plugins>

            <plugin>

                <groupId>org.apache.maven.plugins</groupId>

                <artifactId>maven-source-plugin</artifactId>

                <version>3.2.1</version>

                <executions>

                    <execution>

                        <id>attach-sources</id>

                        <phase>package</phase>

                        <goals>

                            <goal>jar-no-fork</goal>

                        </goals>

                    </execution>

                </executions>

            </plugin>

        </plugins>

    </build>

</project>

dremio.classpath.scanning.packages += com.dalong.udf

package com.dalong.udf;

import com.dremio.exec.expr.SimpleFunction;

import com.dremio.exec.expr.annotations.FunctionTemplate;

import com.dremio.exec.expr.annotations.Output;

import com.dremio.exec.expr.annotations.Param;

import com.dremio.exec.expr.fn.FunctionErrorContext;

import org.apache.arrow.memory.ArrowBuf;

import org.apache.arrow.vector.holders.IntHolder;

import org.apache.arrow.vector.holders.VarCharHolder;

import javax.inject.Inject;

@FunctionTemplate(names = {"mychar_len"},desc = "char length",scope = FunctionTemplate.FunctionScope.SIMPLE,nulls = FunctionTemplate.NullHandling.NULL_IF_NULL )

public class MyFunc implements SimpleFunction {

    @Param

    VarCharHolder input;

    @Output

    IntHolder out;

    @Inject

    FunctionErrorContext errCtx;

    @Override

    public void setup() {

    }

    @Override

    public void eval() {

         // 需要使用完整的包名，同时使用了dremio内部包装的函数

        out.value = com.dremio.exec.expr.fn.impl.StringFunctionUtil.getUTF8CharLength(io.netty.buffer.NettyArrowBuf.unwrapBuffer(input.buffer),

                input.start, input.end, errCtx);

    }

}

FROM dremio/dremio-oss:13.0

COPY demodremio-driver-1.2-SNAPSHOT.jar /opt/dremio/jars/

COPY dremio-func-1.2-SNAPSHOT.jar /opt/dremio/jars/

COPY dremio-func-1.2-SNAPSHOT-sources.jar /opt/dremio/jars/