Unable to Launch airsim_ros_pkgs airsim_node.launch: Unable to Load Vehicle Settings

[Alvinosaur]

Bug report

• AirSim Version/#commit: 950a559
• UE/Unity version: N/A
• autopilot version:
• OS Version: Ubuntu 18.04

What's the issue you encountered?

I'm unable to run the following launch command:

roslaunch airsim_ros_pkgs airsim_node.launch

Airsim isn't properly loading my settings.json or any default settings.json file, since the SimMode entry is just an empty string.

Settings

This settings file is located in the path: path/to/Airsim/settings.json

{
  "SeeDocsAt": "https://github.com/Microsoft/AirSim/blob/master/docs/settings_json.md",
  "SettingsVersion": 1.2,
  "ClockSpeed": 1,
  "SimMode": "Multirotor",
  "Vehicles": {
  "Drone1": {
    "VehicleType": "simpleflight",
    "AutoCreate": true,
    "X": 0, "Y": 0, "Z": 0,
    "Sensors": {
      "LidarSensor2": {
         "SensorType": 6,
        "Enabled" : true,
        "NumberOfChannels": 1,
        "X": 0, "Y": 0, "Z": -1,
        "DrawDebugPoints": true,
        "DataFrame": "SensorLocalFrame"
      }
    }
  }
  }
}

How can the issue be reproduced?

I directly followed the tutorial on the docs.

## currently in ~/drone_ws/src  ##
git clone https://github.com/Microsoft/AirSim.git;
cd AirSim;
./setup.sh;
./build.sh;
cd ros;
catkin build -DCMAKE_C_COMPILER=gcc-8 -DCMAKE_CXX_COMPILER=g++-8
source ~/drone_ws/devel/setup.bash;
roslaunch airsim_ros_pkgs airsim_node.launch;

You'll notice the only differences are that I specify g++8 compiler and I source my workspace rather than Airsim's ros package directly. This is because Airsim is a package in my workspace and is located in the src directory:
drone_ws
---- src
---------Airsim
---------------ros

Include full error message in text form

I get the following output:

(venv) alvin@alvin:~/drone_ws/src/AirSim$ roslaunch airsim_ros_pkgs airsim_node.launch
... logging to /home/alvin/.ros/log/58335e6c-841f-11eb-b39a-40ec993a4bde/roslaunch-alvin-4895.log
Checking log directory for disk usage. This may take a while.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

started roslaunch server http://alvin:45243/

SUMMARY
========

PARAMETERS
 * /airsim_node/host_ip: localhost
 * /airsim_node/is_vulkan: False
 * /airsim_node/publish_clock: False
 * /airsim_node/update_airsim_control_every_n_sec: 0.01
 * /airsim_node/update_airsim_img_response_every_n_sec: 0.05
 * /airsim_node/update_lidar_every_n_sec: 0.01
 * /rosdistro: melodic
 * /rosversion: 1.14.10

NODES
  /
    airsim_node (airsim_ros_pkgs/airsim_node)
    ned_to_enu_pub (tf/static_transform_publisher)

auto-starting new master
process[master]: started with pid [4908]
ROS_MASTER_URI=http://localhost:11311

setting /run_id to 58335e6c-841f-11eb-b39a-40ec993a4bde
process[rosout-1]: started with pid [4923]
started core service [/rosout]
process[airsim_node-2]: started with pid [4927]
terminate called after throwing an instance of 'std::invalid_argument'
  what():  Unknown SimMode: , failed to set default vehicle settings
[airsim_node-2] process has died [pid 4927, exit code -6, cmd /home/alvin/drone_ws/devel/lib/airsim_ros_pkgs/airsim_node __name:=airsim_node __log:=/home/alvin/.ros/log/58335e6c-841f-11eb-b39a-40ec993a4bde/airsim_node-2.log].
log file: /home/alvin/.ros/log/58335e6c-841f-11eb-b39a-40ec993a4bde/airsim_node-2*.log
process[ned_to_enu_pub-3]: started with pid [4932]
^C[ned_to_enu_pub-3] killing on exit
^C^C[rosout-1] killing on exit
[master] killing on exit
shutting down processing monitor...
... shutting down processing monitor complete
done

What's better than filing an issue? Filing a pull request :).

[jonyMarino]

Hi Alvin Shek (@Alvinosaur), and welcome!
Please move your settings.json file to ~/Documents