gowerline

Because Python is hard and I've always wanted to write my segments in Go.

What is this ?

This is a deamon that generates and returns Powerline segments as described in the docs. This project has 2 parts:

• The daemon that runs your go code and exposes an HTTP API
• The powerline compatible code that glues it with the powerline-daemon

Quick install

You can grab the latest version of gowerline by running the following (needs curl, jq, tar and wget)

curl -sSfL https://raw.githubusercontent.com/thomas-maurice/gowerline/master/install.sh | bash

Then install the latest version of the python extension by running

pip install -U gowerline

How does it work ?

This is a pluggable segment generating system. Essentially a very simple powerline "segment" in the sense of the python class, will call a Go server that will be in charge of generating the actual segments. It allows you to generate data that would be too long to generate if it had to be called every time you pop a shell, for instance do API calls to your favourite stock ticker or for example check the validity of an auth token every other minute.

Available plugins

Every plugin has a README.md file at the root of their directory detailing what they do and how they work

Plugin name	Plugin description
Bash	Renders segments that are the result of bash commands ran on a schedule
Finnhub	Displays financial infos about a stock ticker (or many!) that you are interested in
Vault	Gives you information about your current Hashicorp Vault token (display name, validity TTL & co)
Colourenv	Renders environment variables in your terminal with different colourschemes depending on values (useful to not wreck production by mistake)
Network	Displays information about how your network connexion is doing

How does it work (on my system) ?

You have two parts to it:

• The powerline extension, that bridges between poweline and the Go server
• The Go server that will bridge between the python extension and the plugins.

Essentially, everytime you open a prompt, Powerline will call the various extensions of the server to fetch segments to render, it's as simple as this.

How do I install it ?

$ make install # Will install the python extension and the go binary
$ make install-systemd # Will install the userland systemd service to start the server
$ make install-full # will do both
# this will remove it
$ make uninstall

You might also need to pip install -r requirements.txt

How do I use it ?

Add the segment to powerline

This will use the time plugin. In your powerline theme, add the following:

{
    "function": "gowerline.gowerline.gwl",
    "priority": 10,
    "args": {
        "function": "time"
    }
}

Every plugin exposes one or more function that you have to reference in your powerline config. This will effectively be passed down to the Go code, as long as every other variable you add in this JSON.

The Gowerline config itself lives in ~/.gowerline/server.yaml

debug: false
listen:
  # use port to listen over HTTP, this is
  # not the recommended, use the socket instead
  # port: 6666
  unix: ~/.gowerline/server.sock
plugins:
  - name: time
    config:
    # no config needed
  - name: network
    config:
      ipService: https://checkip.amazonaws.com/
  - name: finnhub
    # toggle to true to actually load the plugin
    disabled: true
    config:
      token: YOUR_FINHUB_TOKEN
      tickers:
        - CFLT
        - AAPL
        - FB
  - name: vault
    config:
    # no config needed
  - name: colourenv
    config:
      variables:
        ENV:
          - regex: stag
            highlightGroup: "information:priority"
          - regex: devel
            highlightGroup: "information:regular"
          - regex: prod
            highlightGroup: "warning:regular"
  - name: bash
    config:
      commands:
        date:
          cmd: "date"
          interval: 30
          highlightGroup: "information:regular"
        kubeContext:
          cmd: "kubectl config get-contexts --no-headers | grep '*' | awk '{ print $3 }'"
          interval: 5
          highlightGroup: "gwl:kube_context"

The command line

The gowerline binary is also a commandline tool that allows you to interract with the server. You need to add the binary to your path like so:

export PATH=${PATH}:${HOME}/.gowerline/bin

You can list plugins and get help about a specific plugin like so:

$ gowerline plugin list
+-----------+--------------------------------+--------------------------------+---------+
|   NAME    |          DESCRIPTION           |             AUTHOR             | VERSION |
+-----------+--------------------------------+--------------------------------+---------+
| bash      | Executes bash commands on      | Thomas Maurice                 | 0.0.1   |
|           | a schedule and returns the     | <thomas@maurice.fr>            |         |
|           | result                         |                                |         |
| colourenv | Displays the content of env    | Thomas Maurice                 | 0.0.1   |
|           | vars with colours depending on | <thomas@maurice.fr>            |         |
|           | matched regexes                |                                |         |
| finnhub   | Returns information about the  | Thomas Maurice                 | 0.0.1   |
|           | stock price of certain tickers | <thomas@maurice.fr>            |         |
| network   | Gather information about your  | Thomas Maurice                 | devel   |
|           | network connectivity           | <thomas@maurice.fr>            |         |
| time      | Shows time, it is a debug      | Thomas Maurice                 | 0.0.1   |
|           | segment                        | <thomas@maurice.fr>            |         |
| vault     | Gathers information about      | Thomas Maurice                 | 0.0.1   |
|           | the current Vault token and    | <thomas@maurice.fr>            |         |
|           | formats the result             |                                |         |
+-----------+--------------------------------+--------------------------------+---------+

You can also get help about a specific plugin, it will tell you what functions ship with a plugin and the arguments to include in your powerline json config:

./bin/gowerline-v0.0.3-15-2d4a3be-dirty-thomas_linux_amd64 plugin functions bash
+---------------+--------------------------------+----------+----------------------------+
| FUNCTION NAME |          DESCRIPTION           | ARGUMENT |       ARGUMENT HELP        |
+---------------+--------------------------------+----------+----------------------------+
| bash          | Runs bash functions at regular |          |                            |
|               | intervals and displays the     |          |                            |
|               | output                         |          |                            |
|               |                                | cmd      | Name of the command to run |
+---------------+--------------------------------+----------+----------------------------+

You can also test what is going to be returned, instead of messing with a cURL command:

./bin/gowerline-v0.0.3-15-2d4a3be-dirty-thomas_linux_amd64 plugin run-function bash -a cmd=kubeContext -o json 
[
  {
    "contents": "kubernetes",
    "highlight_groups": [
      "gwl:kube_context",
      "information:regular"
    ]
  }
]

How do I extend it ?

Go have a look at the example plugin. It should be easy to understand. Feel free to copy it in the plugins/ directory and fill in the blanks.

The Makefile is designed so that if you run make plugins your new source will be picked up and compiled to bin/plugins/<plugin>

The plugins are complied as Go plugins (essentialy .so libraries) that are loaded by the main daemon.