Yaml Tag Extensions

Quick Guide

pip install YamlTagExtensions

Tags supported

!VARIABLE

# variables.yaml
country: Atlantis
name: Jane Doe

# deployment.yaml
conn_string: my_amazing_conn_string_xxxxxxxxxxxxxx

Use the tag to initialize settings / variables that needs to be accessed in the yaml.

The !variable / !VARIABLE / !Variable can be invoked as follows.
This approach requires to end the document using ---
Use yaml.load_all feature if this approach is chosen.

!VARIABLES
- '../test/resources/variable_loader/deployment.yaml'
- '../test/resources/variable_loader/variables.yaml'
---
person:
  name: Jane Doe
  country: !$ '.variables.country'

Assign a key before defining the !Variables.

Ending the document is not necessary, and yaml.load can be used.

setup: !VARIABLES
  - '../test/resources/variable_loader/deployment.yaml'
  - '../test/resources/variable_loader/variables.yaml'

!$

Use this tag to access the !Variables set into the loader context.

To access country value from variables.yaml

person:
  name: Jane Doe
  country: !$ '.variables.country' # .<file_name>.<attribute>

Also allows fetching of nested values / attributes.

Env variables can also be accessed using !$ detected by the presence of .env prefix in the fetch string.

database: !$ '.env.DATABASE_NAME' # .env.<attribute>

!FILE

Read a file and attach it as verbatim to a desired YAML location.
The read uses smart-open pkg for type resolution.

  my_file_contents: !FILE
    path: resources/file_loader/sample_file.txt

!TEMPLATE

Leverage the power of templating with Jinja2 + YAML.
Create a Jinja2 template / Yaml with Jinja2 syntax's, to create reusable configurations that render a YAML dynamically.

simple_job:
  database_name: DB
  table_name: person
  sql:
    - !TEMPLATE
      path: "resources/j2_loader/insert_into_template.j2"
      params:
        name: John Doe
        age: 30
        country: Wakanda
    - !Template
      path: "resources/j2_loader/insert_into_template.j2"
      params:
        name: !$ '.variables.name'
        age: 28
        country: !$ '.variables.country'

# insert_into_template.j2
insert_into:
  name: {{ name | upper }}
  age: {{ age }}
  country: {{ country }}

Rendered YAML

simple_job:
  database_name: DB
  table_name: person
  sql:
    - insert_into:
        age: 30
        country: Wakanda
        name: JOHN DOE
    - insert_into:
        age: 28
        country: Atlantis
        name: JANE DOE

Initialize and load yaml using YTE

import yaml
from YamlTagExtensions.core import yte_loader

yaml.load_all(
    open('<PATH TO THE YAML FILE>'),
    Loader=yte_loader
)

import yaml
from YamlTagExtensions.core import yte_loader

yaml.load(
    open('<PATH TO THE YAML FILE>'),
    Loader=yte_loader
)