Bring back the proxy setup to Agama

[teclator]

Problem

The proxy configuration was removed when the Ruby code was drop in #2871. Unfortunately it was not only the ruby service but there were also some systemd service which where in charge of configuring the proxy before Agama was started parsing the cmdline.

• https://trello.com/c/ixm9Fz0J/5460-add-support-to-initialize-and-finish-the-network-configuration

Solution

Implemented the proxy configuration in the backend.

• There is a new ProxyConfig struct which is able to write and read the configuration from the kernel cmdline and from the sysconfig configuration file.
• Added a new systemd service for configuring the proxy before agama is run.
• Added an agama proxy service for allowing to configure the proxy in Agama using the CLI or the UI.

Testing

• Added a new unit test
• Tested manually

API Examples

# With no proxy given through the kernel cmdline
suse@vikingo-laptop:~/api_review$ ./server_system.sh | jq ".proxy"
{
  "enabled": false,
  "noProxy": "localhost,127.0.0.1"
}
suse@vikingo-laptop:~/api_review$ ./server_extendend_config.sh | jq ".proxy"
null
suse@vikingo-laptop:~/api_review$ ./server_config.sh 
{}

# With proxy=http://192.168.122.1:3128
suse@vikingo-laptop:~/api_review$ ./server_config.sh 
{}
suse@vikingo-laptop:~/api_review$ ./server_extendend_config.sh | jq ".proxy"
{
  "enabled": true,
  "http": "http://192.168.122.1:3128",
  "https": "http://192.168.122.1:3128",
  "ftp": "http://192.168.122.1:3128",
  "noProxy": "localhost,127.0.0.1"
}
suse@vikingo-laptop:~/api_review$ ./server_system.sh | jq ".proxy"
{
  "enabled": true,
  "http": "http://192.168.122.1:3128",
  "https": "http://192.168.122.1:3128",
  "ftp": "http://192.168.122.1:3128",
  "noProxy": "localhost,127.0.0.1"
}

[imobachgs]

Good job 😉 There are many comments, but most of them are minor things.

[imobachgs]

To make it easier to reuse this logic, I think this could be implemented as a separate struct that takes care of parsing and building a HashMap-like struct.

Not to be done today but, please, add a PBI to work on that once things are settled.

[coveralls]

coverage: 73.628%. remained the same
when pulling b2e5949 on proxy_setup
into 515ec1c on master.