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Ubuntu 上的 ROS 核心问题

tag-icon • tag-icon ubuntu-core snap ros
Ubuntu 上的 ROS 核心问题

我在使用 Ubuntu Core 和 ROS 时遇到了一些问题。我正在使用 Snapcraft。我能够完成“创建您的第一个 snap”教程 (https://snapcraft.io/docs/build-snaps/your-first-snap），一切都很好。

然后我按照 ROS 教程（https://github.com/snapcore/snapcraft/blob/master/docs/ros-snap.md)。我没有使用 talker 和 listener，而只使用一个“hello world”节点向屏幕输出消息。我可以顺利构建和安装，但在运行时我得到以下输出：

$USER@localhost:~$ ros-example.launch-project  
... logging to /home/$USER/snap/ros-example/x1/ros/log/a413e04a-efb3-11e6-bf45-3d232f894a41/roslaunch-localhost.localdomain-7392.log 
Checking log directory for disk usage. This may take awhile. 
Press Ctrl-C to interrupt

Traceback (most recent call last):   
  File "/snap/ros-example/x1/opt/ros/kinetic/lib/python2.7/dist-packages/roslaunch/__init__.py", line 307, in main
      p.start()   
  File "/snap/ros-example/x1/opt/ros/kinetic/lib/python2.7/dist-packages/roslaunch/parent.py", line 268, in start
    self._start_infrastructure()
  File "/snap/ros-example/x1/opt/ros/kinetic/lib/python2.7/dist-packages/roslaunch/parent.py", line 217, in _start_infrastructure
    self._load_config()   
  File "/snap/ros-example/x1/opt/ros/kinetic/lib/python2.7/dist-packages/roslaunch/parent.py", line 132, in _load_config
    roslaunch_strs=self.roslaunch_strs, verbose=self.verbose)   
  File "/snap/ros-example/x1/opt/ros/kinetic/lib/python2.7/dist-packages/roslaunch/config.py", line 471, in load_config_default
    config.assign_machines()   
  File "/snap/ros-example/x1/opt/ros/kinetic/lib/python2.7/dist-packages/roslaunch/config.py", line 222, in assign_machines
    if [m for m in machine_unify_dict.values() if not is_machine_local(m)]:   
  File "/snap/ros-example/x1/opt/ros/kinetic/lib/python2.7/dist-packages/roslaunch/core.py", line 97, in is_machine_local
    local_addresses = ['localhost'] + rosgraph.network.get_local_addresses()   
  File "/snap/ros-example/x1/opt/ros/kinetic/lib/python2.7/dist-packages/rosgraph/network.py", line 218, in get_local_addresses
    for iface in netifaces.interfaces(): 
OSError: [Errno 13] Permission denied

我已经在 cmake 列表中添加了 .cpp、.hpp 和 .launch 文件的安装规则，并且运行命令roslaunch可以运行节点。但在核心环境中以 snap 方式运行不起作用。任何建议都将不胜感激。

这是我的 cmake 列表：

cmake_minimum_required(VERSION 2.8.3)
project(hello_world)

find_package(catkin REQUIRED COMPONENTS
  roscpp
  rospy
  std_msgs
)

catkin_package()

include_directories(${catkin_INCLUDE_DIRS})

add_executable(write_prompt src/write_prompt.cpp)
target_link_libraries(write_prompt ${catkin_LIBRARIES})

install(TARGETS write_prompt
  ARCHIVE DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION}
  LIBRARY DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION}
  RUNTIME DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION}
)

install(DIRECTORY include/${PROJECT_NAME}/
  DESTINATION ${CATKIN_PACKAGE_INCLUDE_DESTINATION}
  FILES_MATCHING PATTERN "*.h"
  PATTERN "*.hpp"
  PATTERN ".svn" EXCLUDE
)

install(FILES
  launch/run_code.launch
  DESTINATION ${CATKIN_PACKAGE_SHARE_DESTINATION}
)

还有我的 snapcraft.yaml：

name: ros-example
version: 1.0
summary: ROS Example
description: Runs a modified Hello World node
confinement: strict

apps:
  launch-project:
    command: roslaunch hello_world run_code.launch

parts:
  ros-project:
    plugin: catkin
    source: .
    catkin-packages:
      - hello_world
    rosdistro: kinetic

答案1

您已经很接近了！您的快照没有请求访问网络，默认情况下快照不会获得网络访问权限。您可以通过设置plugs相关应用程序的属性来做到这一点。尝试让您的apps部分看起来像这样：

apps:
  launch-project:
    command: roslaunch hello_world run_code.launch
    plugs: [network, network-bind]

安装完成后，运行snap interfaces，您将看到network和network-bind插头都连接到核心插槽。要了解更多信息，请查看snapd 接口 wiki。

作为额外的练习，一旦它工作正常，请尝试断开接口：

sudo snap disconnect ros-example:network
sudo snap disconnect ros-example:network-bind

然后再次运行你的应用。你应该看到它再次失败并出现相同的错误。

最后要注意的是，当你开发/测试某些东西时，请记住你可以安装以--devmode跳过限制：sudo snap install --devmode <my snap>。

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