Powerline Tailscale

A Powerline segment for showing the status of Tailscale

Since Tailscale doesn't (seemingly) have a configuration file where it reads and stores state, this segment implementation relies on the tailscaled API server. I haven't found any official documentation regarding it, but its capabilities are available here. There exists a Python library to interact with this API in limited form called 'tailscale-localapi', though I decided against using it because I didn't want to introduce any Python-specific dependencies; this is something I may reconsider in the future keeping in mind that the current implementation relies on curl instead.

Requirements

Besides having Tailscale installed according to the official documentation, it is also necessary to install curl at either 7.40.0 or above, which is when the --unix-socket flag was introduced. You can check your version of curl with the --version flag:

$ curl --version
curl 7.85.0 (x86_64-redhat-linux-gnu) libcurl/7.85.0 OpenSSL/3.0.9 zlib/1.2.12 brotli/1.0.9 libidn2/2.3.4 libpsl/0.21.1 (+libidn2/2.3.3) libssh/0.10.5/openssl/zlib nghttp2/1.51.0
Release-Date: 2022-08-31
Protocols: dict file ftp ftps gopher gophers http https imap imaps ldap ldaps mqtt pop3 pop3s rtsp scp sftp smb smbs smtp smtps telnet tftp 
Features: alt-svc AsynchDNS brotli GSS-API HSTS HTTP2 HTTPS-proxy IDN IPv6 Kerberos Largefile libz NTLM NTLM_WB PSL SPNEGO SSL threadsafe TLS-SRP UnixSockets

If curl or Tailscale isn't installed or tailscaled isn't running, then installing and configuring this segment will have no effect.

Installation

Using Pip:

pip install powerline-tailscale

Configuration

Only three highlight groups are necessary to be defined in order for powerline-tailscale to work. These can be set up in ~/.config/powerline/colorschemes/default.json. You are free to choose any colors you want.

{
  "name": "Default",
    "groups": {
      "tailscale":                 { "fg": "white", "bg": "gray2","attrs": [] },
      "tailscale_exitnode":        { "fg": "white", "bg": "steelblue","attrs": [] },
      "tailscale:divider":         { "fg": "white", "bg": "steelblue", "attrs": [] }
    }
}

After that, add the segment's configuration by modifying the relevant Powerline theme. If you are using the default, then in ~/.config/powerline/themes/shell/default.json:

{
  "function": "powerline_tailscale.tailscale",
    "args": {
      "show_profile_name": true,
      "show_exit_node_status": false,
      "show_exit_node": true
  }
}

Now, just reload Powerline using powerline-daemon --replace.

Options

• show_profile_name shows either:
  • "logged out" if tailscaled is running, but no account is logged in;
  • "default" if no profile is created, i.e. the log-in hasn't been done with tailscale login --nickname=<name>;
  • or the name of the profile itself;
• show_exit_node_status shows a boolean "exit node (y)" or "exit node (n)" depending on whether connected to an exit node through tailscale up --exit-node="<IP>"
• show_exit_node shows the actual IP address of the exit node as given to tailscale up --exit-node="<IP>"
  • the show_exit_node_status option needs to be set to false when this option is set to true
  • if not connected to an exit node, then "exit node (n)" is shown

Disabling

By default the segment will always be displayed, but you may wish to toggle it instead. This can be done through a Bash function, which unsets or sets an environment variable that the segment reads:

function plts() {
  if [[ $POWERLINE_TAILSCALE = "0" ]]; then
    unset POWERLINE_TAILSCALE
  else
    export POWERLINE_TAILSCALE=0
  fi
}

You can add this function to your ~/.bashrc file, source it using source ~/.bashrc, and then toggle the segment using plts or whatever you chose for the name of the function. This function name can also be Tab-completed.

If you want to start your shell sessions without having this segment, then add export POWERLINE_TAILSCALE="0" somewhere in ~/.bashrc.