Use Java and the Flight SQL package to query data

# Use the official Maven image as the base image
FROM maven:3.8.3-openjdk-11 AS build

# Set the working directory
WORKDIR /app

# Copy the pom.xml file into the container
COPY pom.xml .

# Download and cache dependencies
RUN mvn dependency:go-offline

# Copy the rest of the source code into the container
COPY src/ ./src/

# Compile the source code and copy dependencies
RUN mvn compile dependency:copy-dependencies

# Use the official OpenJDK image as the runtime base image
FROM openjdk:11-jre-slim

# Set the working directory
WORKDIR /app

# Copy the compiled classes and dependencies from the build stage
COPY --from=build /app/target/classes ./classes
COPY --from=build /app/target/dependency ./dependency

# Set ARGs for --build-arg options passed in the build command
ARG DATABASE_FIELD
ARG DATABASE_NAME
ARG HOST
ARG TOKEN

# Set run-time ENVs from ARGs
ENV DATABASE_FIELD=${DATABASE_FIELD}
ENV DATABASE_NAME=${DATABASE_NAME}
ENV HOST=${HOST}
ENV TOKEN=${TOKEN}

# Set the entrypoint to run your Java application
ENTRYPOINT ["java", "-cp", "classes:dependency/*", "com.influxdb.examples.FlightExamples"]

<?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.influxdb</groupId>
  <artifactId>examples</artifactId>
  <version>1.0-SNAPSHOT</version>

  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-jar-plugin</artifactId>
        <version>3.2.0</version>
        <configuration>
          <archive>
            <manifest>
              <addClasspath>true</addClasspath>
              <classpathPrefix>lib/</classpathPrefix>
              <mainClass>com.influxdb.examples.FlightExamples</mainClass>
            </manifest>
          </archive>
        </configuration>
      </plugin>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-help-plugin</artifactId>
        <version>3.2.0</version>
      </plugin>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-shade-plugin</artifactId>
        <version>3.4.1</version>
        <executions>
          <execution>
            <goals>
              <goal>shade</goal>
            </goals>
            <configuration>
              <shadedArtifactAttached>true</shadedArtifactAttached>
            </configuration>
          </execution>
        </executions>
        <configuration>
          <minimizeJar>false</minimizeJar>
          <filters>
            <filter>
              <artifact>*:*</artifact>
              <excludes>
                <exclude>META-INF/*.SF</exclude>
                <exclude>META-INF/*.DSA</exclude>
                <exclude>META-INF/*.RSA</exclude>
              </excludes>
            </filter>
          </filters>
        </configuration>
      </plugin>
    </plugins>
  </build>

  <properties>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
  </properties>

  <dependencies>
    <dependency>
      <groupId>org.apache.arrow</groupId>
      <artifactId>flight-sql</artifactId>
      <version>11.0.0</version>
    </dependency>
    <dependency>
      <groupId>io.netty</groupId>
      <artifactId>netty-all</artifactId>
      <version>4.1.74.Final</version>
    </dependency>
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-simple</artifactId>
      <version>1.7.30</version>
    </dependency>
  </dependencies>

</project>

package com.influxdb.examples;

import org.apache.arrow.flight.auth2.BearerCredentialWriter;
import org.apache.arrow.flight.CallHeaders;
import org.apache.arrow.flight.CallStatus;
import org.apache.arrow.flight.grpc.CredentialCallOption;
import org.apache.arrow.flight.Location;
import org.apache.arrow.flight.FlightClient;
import org.apache.arrow.flight.FlightClientMiddleware;
import org.apache.arrow.flight.FlightInfo;
import org.apache.arrow.flight.FlightStream;
import org.apache.arrow.flight.sql.FlightSqlClient;
import org.apache.arrow.flight.Ticket;
import org.apache.arrow.memory.BufferAllocator;
import org.apache.arrow.memory.RootAllocator;
import org.apache.arrow.vector.VectorSchemaRoot;

public class FlightQuery {

    /* Get server credentials from environment variables */
    public static final String DATABASE_NAME = System.getenv("DATABASE_NAME");
    public static final String HOST = System.getenv("HOST");
    public static final String TOKEN = System.getenv("TOKEN");

    public static void main() {

        System.out.println("Query InfluxDB with the Java Flight SQL Client");

        // Create an interceptor that injects header metadata (database name) in every request.
        FlightClientMiddleware.Factory f = info -> new FlightClientMiddleware() {
            @Override
            public void onBeforeSendingHeaders(CallHeaders outgoingHeaders) {
                outgoingHeaders.insert("database", DATABASE_NAME);
            }

            @Override
            public void onHeadersReceived(CallHeaders incomingHeaders) {

            }

            @Override
            public void onCallCompleted(CallStatus status) {

            }
        };

        // Create a gRPC+TLS channel URI with HOST and port 443.
        Location location = Location.forGrpcTls(HOST, 443);

        // Set the allowed memory.
        BufferAllocator allocator = new RootAllocator(Long.MAX_VALUE);

        // Create a client with the allocator and gRPC channel.
        FlightClient client = FlightClient.builder(allocator, location)
                .intercept(f)
                .build();
        System.out.println("client" + client);

        FlightSqlClient sqlClient = new FlightSqlClient(client);
        System.out.println("sqlClient: " + sqlClient);

        // Define the SQL query to execute.
        String query = "SELECT * FROM home";
        
        /*  Construct a bearer credential using TOKEN.
            Construct a credentials option using the bearer credential.
        */
        CredentialCallOption auth = new CredentialCallOption(new BearerCredentialWriter(TOKEN));

        /*  Execute the query.
            If successful, execute returns a FlightInfo object that contains metadata
            and an endpoints list.
            Each endpoint contains the following:
                - A list of addresses where you can retrieve the data.
                - A `ticket` value that identifies the data to retrieve.
        */
        FlightInfo flightInfo = sqlClient.execute(query, auth);

        // Extract the Flight ticket from the response.
        Ticket ticket = flightInfo.getEndpoints().get(0).getTicket();
        
        // Pass the ticket to request the Arrow stream data from the endpoint.
        final FlightStream stream = sqlClient.getStream(ticket, auth);

        // Process all the Arrow stream data.
        while (stream.next()) {
            try {
                // Get the current vector data from the stream.
                final VectorSchemaRoot root = stream.getRoot();
                System.out.println(root.contentToTSVString());
            } catch (Exception e) {
                // Handle exceptions.
                System.out.println("Error executing FlightSqlClient: " + e.getMessage());
            }
        }
        try {
            // Close the stream and release resources.
            stream.close();
        } catch (Exception e) {
            // Handle exceptions.
            System.out.println("Error closing stream: " + e.getMessage());
        }

        try {
            // Close the client
            sqlClient.close();
        } catch (Exception e) {
            // Handle exceptions.
            System.out.println("Error closing client: " + e.getMessage());
        }
    }
}