LNKD

Simple linked YAML documents.

A simple utility for linking YAML documents. For Python >=3.6.

Getting started

You can install lnkd with:

pip install lnkd

Why does it exist?

If you work with cloud technologies, YAML is part of your day job. It's often great for managing complex service configurations, but it's also not uncommon to get YAML files many hundreds of lines long. Some of the more advanced features of YAML -- such as merge tags make this process a little easier,but not always ideal.

Long story short, this little package is the offshoot of an afternoon roaming the interwebs trying to figure out how best to link YAML files across multiple local and remote locations and stitch them together nicely. It is not the only way of doing this, and it's also almost certainly not the best way of doing it. In fact, it will make it very easy to create a lot of anti-patterns, and by default your YAML parser is unlikely to get on well with the new tag. Adding new syntax is dangerous. You've been warned.

Anyway, it's here on the off-chance someone wants to avoid an afternoon of trawling Stack Overflow.

Right, so how does it look?

You now get the !@ tag to add to your YAML. Here's how it works:

Say we've a big ol' config file. Here we'll pretend it's a docker-compose file:

# service.yaml
version: '3'
services:
    client:
        !@ client.yaml

And we store our client service config in a file client.yaml:

# client.yaml
build:
    image: python:3.6-alpine
    environment:
        POSTGRES_USER: admin
        POSTGRES_PASSWORD: 1234
        POSTGRES_DB: accounts

If we then run:

lnkd service.yaml --output docker-compose.yaml

We'd get:

# docker-compose.yaml
version: '3'
services:
    client:
        build:
            image: python:3.6-alpine
            environment:
              POSTGRES_USER: admin
              POSTGRES_PASSWORD: 1234
              POSTGRES_DB: accounts

And that's pretty much it. You can use these components programmatically to load and build your YAML structures too.

Programmatic usage

Want to use these capabilities directly in your Python code? No problem, you can use them like:

import yaml
import lnkd

with open("service.yaml", "r") as file:
    data = yaml.load(file, Loader=lnkd.LinkedLoader)

You'll get the linked data as a dictionary.

Notes

• If you can, use anchors and aliases instead. If you haven't heard of these before, Atlassian have written a short example.
• This package implements only custom tags. It does not enable shared anchors and aliases across files.