从源码上解决rosdep update失败问题

（一）卸载官方的rosdep、rosdistro

1. 卸载rosdistro

# python2
sudo apt-get purge python-rosdistro

# python3
sudo apt-get purge python3-rosdistro

2. 卸载rosdep

# python2
sudo apt-get purge python-rosdep

# python3
sudo apt-get purge python3-rosdep

3. 删除下载的20-default.list

sudo rm -rf /etc/ros/rosdep/sources.list.d/20-default.list

(二)下载安装rosdep、rosdistro

根据系统版本下载相应的rosdep、rosdistro：

1. ROS Kinetic（Ubuntu 16.04 python2）

# 下载国内的rosdep
wget http://www.aigrantli.com:1080/GrantLi/rosdep/uploads/35cf1afb1107970c1ec78dbf5ef6663b/rosdep-0.22.1-py2-none-any.whl
# 下载国内的rosdistro
wget http://www.aigrantli.com:1080/GrantLi/rosdistro-python/uploads/35ef18efc558999d4c4e32015eebc20b/rosdistro-0.9.0-py2-none-any.whl

# 安装rosdistro
sudo pip install rosdistro-0.9.0-py2-none-any.whl
# 安装rosdep
sudo pip install rosdep-0.22.1-py2-none-any.whl

2. ROS Melodic（Ubuntu 18.04 python2）

# 下载国内的rosdep
wget http://www.aigrantli.com:1080/GrantLi/rosdep/uploads/35cf1afb1107970c1ec78dbf5ef6663b/rosdep-0.22.1-py2-none-any.whl
# 下载国内的rosdistro
wget http://www.aigrantli.com:1080/GrantLi/rosdistro-python/uploads/35ef18efc558999d4c4e32015eebc20b/rosdistro-0.9.0-py2-none-any.whl

# 安装rosdistro
sudo pip install rosdistro-0.9.0-py2-none-any.whl
# 安装rosdep
sudo pip install rosdep-0.22.1-py2-none-any.whl

3. ROS Noetic（Ubuntu 20.04）

# 下载国内的rosdep
wget http://www.aigrantli.com:1080/GrantLi/rosdep/uploads/49ea4ce804b58bc7e16c4336c04d1664/rosdep-0.22.1-py3-none-any.whl
# 下载国内的rosdistro
wget http://www.aigrantli.com:1080/GrantLi/rosdistro-python/uploads/bb3db475bf0fab68b98dd2af22733a8e/rosdistro-0.9.0-py3-none-any.whl

# 安装rosdistro
sudo pip install rosdistro-0.9.0-py3-none-any.whl

# 安装rosdep
sudo pip install rosdep-0.22.1-py3-none-any.whl

如果需要根据自己的系统手动编译，请见(四)手动编译rosdep、rosdistro。

(三)测试rosdep update

sudo rosdep init
rosdep update

(四)手动编译rosdep、rosdistro(可选)

1.下载修改的rosdep、rosdistro源码

mkdir -p ~/rosdep_ws
git clone http://www.aigrantli.com:1080/GrantLi/rosdep.git
git clone http://www.aigrantli.com:1080/GrantLi/rosdistro-python.git

2.安装依赖及编译生成的目录

# 下载wheel，用于打包成python软件包
sudo pip install wheel

# 创建rosdep whl文件保存目录
mkdir -p ~/rosdep_ws/rosdep_whl
# 创建rosdistro whl文件保存目录
mkdir -p ~/rosdep_ws/rosdistro_whl

3. 编译rosdep

# 进入rosdep源码目录
cd ~/rosdep_ws/rosdep

# 编译rosdep
pip wheel --wheel-dir=~/rosdep_ws/rosdep_whl ./

4. 编译rosdistro

# 进入rosdistro源码目录
cd ~/rosdep_ws/rosdistro-python

# 编译rosdistro
pip wheel --wheel-dir=~/rosdep_ws/rosdistro_whl ./

5.安装rosdistro

# 进入rosdistro_whl目录
cd ~/rosdep_ws/rosdistro_whl

# 安装rosdistro whl
sudo pip install rosdistro-0.9.0-py3-none-any.whl

其中rosdistro-0.9.0-py3-none-any.whl按照实际生成的whl文件名替换。

6.安装rosdep

# 进入rosdep_whl源码目录
cd ~/rosdep_ws/rosdep_whl

# 安装rosdep whl
sudo pip install rosdep-0.22.1-py3-none-any.whl

其中rosdep-0.22.1-py3-none-any.whl按照实际生成的whl文件名替换。

7.测试rosdep update
见(三)测试rosdep update。