ROS官网安装教程：Ubuntu install of ROS Melodic 在1.3 Set up your keys这一步遇到了可疑的返回信息

gpg: no valid OpenPGP data found. 

这似乎是一个老问题CSDN找容易找到安装教程

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys F42ED6FBAB17C654 

然后更新和安装命令

sudo apt update sudo apt install ros-melodic-desktop-full 

果然，报一堆Err，仔细看看，你会发现大部分(其实都是)都连不上服务器。 打开~/.bashrc一看，果然当时装子系统的时候没有准备好代理，就查了一下CFW里面的LAN最后加上地址

# WSL using CFW LAN export all_proxy="socks5://172.17.32.1:7890" 

拿油管做测试，没有返回信息，真的连接了

source ~/.bashrc curl www.youtube.com 

更新和安装命令仍然与服务器无关。在这里，我怀疑我的节点不好。经过几次尝试，我无法完全解决这个问题。最后，放弃撞墙。让我们改变源头。

先备份原件

sudo cp /etc/apt/sources.list /etc/apt/sourses.list_bk 

然后将source.list更换文件内容，阿里云源、中科大源、清华源，随意选择一个

deb http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse 

deb https://mirrors.ustc.edu.cn/ubuntu/ bionic main restricted universe multiverse deb https://mirrors.ustc.edu.cn/ubuntu/ bionic-updates main restricted universe multiverse deb https://mirrors.ustc.edu.cn/ubuntu/ bionic-backports main restricted universe multiverse deb https://mirrors.ustc.edu.cn/ubuntu/ bionic-security main restricted universe multiverse deb https://mirrors.ustc.edu.cn/ubuntu/ bionic-proposed main restricted universe multiverse deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic main restricted universe multiverse deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic-updates main restricted universe multiverse deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic-backports main restricted universe multiverse deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic-security main restricted universe multiverse deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic-proposed main restricted universe multiverse 

deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic main restricted universe multiverse deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-updates main restricted universe multiverse deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-backports main restricted universe multiverse deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-security main restricted universe multiverse deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-proposed main restricted universe multiverse deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic main restricted universe multiverse deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-updates main restricted universe multiverse deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-backports main restricted universe multiverse deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-security main restricted universe multiverse deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-proposed main restricted universe multiverse 

最后，直接更新命令，让它重新加载源地址，轻松秒杀

sudo apt update 

毫无疑问，安装命令也可以逃跑

sudo apt install ros-melodic-desktop-full 

继续跟着官方教程走，需要注意的是，官方教程是先让你手动安装了很多编译所需的依库，这与一些博客中写的不一样，大概是因为之前这些依赖库可能会在安装的时候就被带着装进来了，因此也没有产生问题。如果只是跑完上面的安装命令，就直接sudo rosdep init会遇到没装库的问题。 然而就算你把库装齐全了，还是会卡壳：

ERROR: cannot download default sources list from:
https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/sources.list.d/20-default.list
Website may be down.

用浏览器能够访问这个网址，就是一个小文件

# os-specific listings first
yaml https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/osx-homebrew.yaml osx

# generic
yaml https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/base.yaml
yaml https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/python.yaml
yaml https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/ruby.yaml
gbpdistro https://raw.githubusercontent.com/ros/rosdistro/master/releases/fuerte.yaml fuerte

# newer distributions (Groovy, Hydro, ...) must not be listed anymore, they are being fetched from the rosdistro index.yaml instead

能搜到这个closed issue: rosdep init gives “Website may be down.” 按说，把文件复制到/etc/ros/rosdep/sources.list.d/20-default.list也算是一个workaround吧

行吧OK咱接着搞

rosdep update

还是

reading in sources list data from /etc/ros/rosdep/sources.list.d
ERROR: unable to process source [https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/osx-homebrew.yaml]:
        <urlopen error [Errno 111] Connection refused> (https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/osx-homebrew.yaml)
ERROR: unable to process source [https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/base.yaml]:
        <urlopen error [Errno 111] Connection refused> (https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/base.yaml)
ERROR: unable to process source [https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/python.yaml]:
        <urlopen error [Errno 111] Connection refused> (https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/python.yaml)
ERROR: unable to process source [https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/ruby.yaml]:
        <urlopen error [Errno 111] Connection refused> (https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/ruby.yaml)
ERROR: unable to process source [https://raw.githubusercontent.com/ros/rosdistro/master/releases/fuerte.yaml]:
        Failed to download target platform data for gbpdistro:
        <urlopen error [Errno 111] Connection refused>
Query rosdistro index https://raw.githubusercontent.com/ros/rosdistro/master/index-v4.yaml
ERROR: error loading sources list:
        <urlopen error <urlopen error [Errno 111] Connection refused> (https://raw.githubusercontent.com/ros/rosdistro/master/index-v4.yaml)>

换源应该没法解决github被墙的问题，找到这篇博客确认了我的想法：rosdep init 及update报错的解决办法汇总（亲测） 并且博文也提醒了我，让我反思自己最开始设置代理的方式，确实是比较粗暴，不管你是什么协议，都给我去用socks5，的确不够温柔，于是我

export http_proxy=http://172.17.32.1:7890
export https_proxy=http://172.17.32.1:7890
export socks_proxy=socks5://172.17.32.1:7890

果然，就动起来了

reading in sources list data from /etc/ros/rosdep/sources.list.d
Hit https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/osx-homebrew.yaml
Hit https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/base.yaml
Hit https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/python.yaml
Hit https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/ruby.yaml
Hit https://raw.githubusercontent.com/ros/rosdistro/master/releases/fuerte.yaml
Query rosdistro index https://raw.githubusercontent.com/ros/rosdistro/master/index-v4.yaml
Skip end-of-life distro "ardent"
Skip end-of-life distro "bouncy"
Skip end-of-life distro "crystal"
Skip end-of-life distro "dashing"
Skip end-of-life distro "eloquent"
Add distro "foxy"
Add distro "galactic"
Skip end-of-life distro "groovy"
Skip end-of-life distro "hydro"
Skip end-of-life distro "indigo"
Skip end-of-life distro "jade"
Skip end-of-life distro "kinetic"
Skip end-of-life distro "lunar"
Add distro "melodic"
Add distro "noetic"
Add distro "rolling"
updated cache in /home/ian/.ros/rosdep/sources.cache