Config.yaml

ARM_INFO:
  HALL_SENSOR_ID: 1
  ENCODER_CAN_ID: 32
  ENCODER_OFFSET_ROTATIONS: -0.1663
DRIVE_INFO:
  STATUS_SIGNAL_FREQUENCY: 200
  ANGLE_GEAR_RATIO: 15.0004

ConfigLoader.java

package com.team973.frc2025;

import com.team973.frc2025.shared.RobotInfo;
import java.nio.file.Files;
import java.nio.file.Paths;
import org.yaml.snakeyaml.Yaml;

public class ConfigLoader {
  private static boolean m_initialized;
  private static RobotInfo m_robotInfo;

  public static synchronized RobotInfo get() {
    if (!m_initialized) {
      loadRobotInfo();
    }
    return m_robotInfo;
  }

  private static void loadRobotInfo() {
    try {
      String filePath = System.getProperty("user.dir") + "/config/robot-info-var/Config.yaml";

      // Load YAML file into a string
      String yamlContent = new String(Files.readAllBytes(Paths.get(filePath)), "UTF-8");
      Yaml yaml = new Yaml();
      RobotInfo loaded = yaml.loadAs(yamlContent, RobotInfo.class);
      m_robotInfo = loaded;
      m_initialized = true;
    } catch (Exception e) {
      System.out.println("⚠️ Could not load config file, using defaults");
      System.exit(1);
    }
  }
}

ConfigTest.java

import static org.junit.jupiter.api.Assertions.assertEquals;

import com.team973.frc2025.RobotConfig;
import com.team973.frc2025.shared.RobotInfo;
import org.junit.jupiter.api.Test;
import org.yaml.snakeyaml.Yaml;

public class ConfigTest {
  @Test
  void testGetConfig() throws Exception {
    RobotInfo robotInfo = RobotConfig.get();
    System.out.printf("Config: %s\n", (new Yaml().dump(robotInfo)));
    System.out.printf("ANGLE_GEAR_RATIO is %f\n", robotInfo.DRIVE_INFO.ANGLE_GEAR_RATIO);
    assertEquals(15.0004, robotInfo.DRIVE_INFO.ANGLE_GEAR_RATIO, 0.01);
  }
}

example_usage.java

m_driveWithJoysticks = new DriveWithJoysticks(ConfigLoader.get().DRIVE_INFO);

RobotInfo.java

public class RobotInfo {
  public static class ArmInfo {
    public int HALL_SENSOR_ID;
    public int ENCODER_CAN_ID = 32;
    public double ARM_ROTATIONS_PER_MOTOR_ROTATIONS = (10.0 / 84.0) * (16.0 / 108.0);

    public double ENCODER_OFFSET_ROTATIONS = -0.1663;
  }
  public ArmInfo ARM_INFO;

  public static class DriveInfo {
    public int STATUS_SIGNAL_FREQUENCY = 200;

    public int PIGEON_ID = 1;

    public int FRONT_LEFT_MODULE_DRIVE_MOTOR = 2;
    public int FRONT_LEFT_MODULE_STEER_MOTOR = 3;
    public int FRONT_LEFT_MODULE_STEER_ENCODER = 4;
    public double FRONT_LEFT_MODULE_STEER_OFFSET = fromBotVersion(-743.027, 264.902);
  }
  public DriveInfo DRIVE_INFO;
}