Mavsdk_server not starting

[Owen-K]

I have installed mavsdk for python in a virtual environment using pip3 install mavsdk. When I run the telemetry.py example the program hangs at Waiting for mavsdk_server to be ready.... I am using MacOS Catalina as my OS. I have tested the same code on an ubuntu vm and it works as expected. Any suggestions or help debugging is greatly appreciated.

[JonasVautherin]

Can you find the mavsdk_server executable (it got installed by pip3 install mavsdk somewhere) and run it manually? That would give you more output to share here 👍.

[Owen-K]

When I run mavsdk_server which is located in /usr/local/bin/ it returns the following.

mavsdk_server udp://:14550    
[05:41:08|Info ] MAVSDK version: 0.27.0 (mavsdk_impl.cpp:26)
[05:41:08|Debug] New: System ID: 0 Comp ID: 0 (mavsdk_impl.cpp:372)
[05:41:08|Info ] Server started (grpc_server.cpp:43)
[05:41:08|Info ] Server set to listen on 0.0.0.0:51875 (grpc_server.cpp:44)
[05:41:08|Info ] Waiting to discover system on udp://:14550... (connection_initiator.h:22)
[05:41:08|Info ] New system on: 192.168.64.3:18570 (udp_connection.cpp:256)
[05:41:08|Debug] Component Autopilot (1) added. (system_impl.cpp:352)
[05:41:09|Debug] Discovered 1 component(s) (UUID: 5283920058631409231) (system_impl.cpp:525)
[05:41:09|Info ] System discovered [UUID: 5283920058631409231] (connection_initiator.h:61)
[05:41:09|Warn ] Command ack 520 not matching our current command: 511 (mavlink_commands.cpp:142)
[05:41:09|Warn ] Command ack 511 not matching our current command: 520 (mavlink_commands.cpp:142)
[05:41:09|Warn ] Command ack 520 not matching our current command: 528 (mavlink_commands.cpp:142)
[05:41:09|Debug] MAVLink: critical: Connection to ground station lost (system_impl.cpp:257)
[05:41:09|Debug] MAVLink: info: Data link regained (system_impl.cpp:257)

[JonasVautherin]

[05:41:08|Info ] MAVSDK version: 0.27.0 (mavsdk_impl.cpp:26)

That's an older version, and I think it came from brew install mavsdk. You should be able to update it with brew. But that's not the one that is called by python.

Do you have another one, that would be installed where the mavsdk python package is installed?

[Owen-K]

Here is the output from the mavsdk_server in the python packages directory.

./mavsdk_server udp://:14550
[11:07:53|Info ] MAVSDK version: v0.30.1 (mavsdk_impl.cpp:27)
[11:07:53|Debug] New: System ID: 0 Comp ID: 0 (mavsdk_impl.cpp:405)
[11:07:53|Info ] Server started (grpc_server.cpp:44)
[11:07:53|Info ] Server set to listen on 0.0.0.0:60564 (grpc_server.cpp:45)
[11:07:53|Info ] Waiting to discover system on udp://:14550... (connection_initiator.h:22)
[11:07:53|Info ] New system on: 192.168.64.3:18570 (with sysid: 1) (udp_connection.cpp:190)
[11:07:53|Debug] Component Autopilot (1) added. (system_impl.cpp:340)
[11:07:53|Debug] Discovered 1 component(s) (UUID: 5283920058631409231) (system_impl.cpp:513)
[11:07:53|Info ] System discovered [UUID: 5283920058631409231] (connection_initiator.h:61)
[11:07:53|Debug] MAVLink: critical: Connection to ground station lost (system_impl.cpp:255)
[11:07:54|Debug] MAVLink: info: Data link regained (system_impl.cpp:255)
[11:07:54|Warn ] command denied (512). (mavlink_commands.cpp:164)
[11:07:54|Debug] Falling back to Gimbal Version 1 (gimbal_impl.cpp:53

edited because I realized that it was still running the command in /usr/local/bin

[JonasVautherin]

hmm that seems normal. What if you run it again, but with ./mavsdk_server -p 50051 udp://:14550, and connect your Python script to that (instead of letting it start mavsdk_server itself), like so:

from mavsdk import System

drone = System(mavsdk_server_address="localhost")
await drone.connect()

Does it hang, too? Does mavsdk_server react at all, or does it crash or something?

[Owen-K]

It won't run with the above command and throws an error because the port is in use. It appears that launchd is bound to port 50051. If I change the port to 50052 it works as expected.

[JonasVautherin]

If I change the port to 50052 it works as expected.

Meaning that it solves your problem? Or that it still fails but running on 50052?

[Owen-K]

It solves the problem. It appears that apple has a service running on port 50051 causing mavsdk to not be able to use the default port.

[JonasVautherin]

Good to know!