Convert RST to YAML

Why Convert RST to YAML?

Converting reStructuredText (RST) documents to YAML format is valuable when you need to extract structured data from documentation for use in configuration files, CI/CD pipelines, or DevOps tooling. YAML's human-readable syntax and wide adoption in the DevOps ecosystem make it an ideal target format.

YAML has become the de facto standard for configuration in modern software development. Docker Compose, Kubernetes, Ansible, GitHub Actions, and countless other tools use YAML. Converting RST documentation that describes configurations to YAML creates directly usable configuration files.

The conversion is particularly useful for teams that document their infrastructure and configuration in RST for Sphinx-based documentation systems. By converting to YAML, the documented configuration can be directly applied, ensuring documentation and actual configuration stay synchronized.

YAML's support for complex nested structures, arrays, and multiple data types makes it suitable for representing the hierarchical data often found in technical documentation. Field lists, tables, and structured content in RST map naturally to YAML's key-value and list structures.

Key Benefits of Converting RST to YAML:

• DevOps Ready: Use in Docker, Kubernetes, Ansible, and CI/CD tools
• Human Readable: Clean, indentation-based syntax
• Configuration Files: Generate usable config from documentation
• Nested Data: Support for complex hierarchical structures
• Comments: YAML preserves explanatory comments
• Type Support: Strings, numbers, booleans, arrays, objects
• Universal Parsing: Libraries available for every language

Practical Examples

Example 1: Application Configuration

Input RST file (config.rst):

Application Configuration
=========================

Server Settings
---------------

:host: 0.0.0.0
:port: 8080
:debug: false

Database
--------

:driver: postgresql
:host: localhost
:port: 5432
:name: myapp_db

Output YAML file (config.yaml):

# Application Configuration

server_settings:
  host: "0.0.0.0"
  port: 8080
  debug: false

database:
  driver: postgresql
  host: localhost
  port: 5432
  name: myapp_db

Example 2: CI/CD Pipeline Definition

Input RST file (pipeline.rst):

CI Pipeline
===========

Build Stage
-----------

* Install dependencies
* Run linter
* Run unit tests

Deploy Stage
------------

* Build Docker image
* Push to registry
* Deploy to staging

Output YAML file (pipeline.yaml):

# CI Pipeline

stages:
  build:
    steps:
      - Install dependencies
      - Run linter
      - Run unit tests

  deploy:
    steps:
      - Build Docker image
      - Push to registry
      - Deploy to staging

Example 3: Kubernetes-style Manifest

Input RST file (service.rst):

Service Definition
==================

Metadata
--------

:name: web-service
:namespace: production

Specification
-------------

:replicas: 3
:port: 80
:targetPort: 8080

Environment Variables
---------------------

* LOG_LEVEL=info
* MAX_CONNECTIONS=100

Output YAML file (service.yaml):

# Service Definition

metadata:
  name: web-service
  namespace: production

spec:
  replicas: 3
  port: 80
  targetPort: 8080

env:
  - name: LOG_LEVEL
    value: info
  - name: MAX_CONNECTIONS
    value: "100"

Frequently Asked Questions (FAQ)

Q: What is YAML?

A: YAML (YAML Ain't Markup Language) is a human-readable data serialization format. It uses indentation to represent structure (similar to Python) and is widely used for configuration files in DevOps tools like Docker, Kubernetes, Ansible, and CI/CD platforms.

Q: What RST content converts best to YAML?

A: Field lists (:key: value), definition lists, and structured tables convert naturally to YAML key-value pairs and nested structures. Lists become YAML sequences. Headers can become nested mapping keys. Prose text is less suitable for YAML.

Q: How are data types handled?

A: The converter attempts to infer types: "true"/"false" become booleans, numbers become integers or floats, and dates are parsed when recognizable. Use quotes to force string type. YAML 1.2 has strict rules about type inference.

Q: Can I use the output with Docker Compose?

A: If your RST documents Docker service configurations, the YAML output can be a starting point for docker-compose.yml. You'll need to ensure the structure matches Docker Compose's expected format, which may require manual adjustment.

Q: What about Kubernetes manifests?

A: Similar to Docker, documented Kubernetes configurations can convert to YAML manifest format. The output provides the data structure; you may need to add Kubernetes-specific fields like apiVersion and kind to create valid manifests.

Q: How do I validate YAML syntax?

A: Use online validators like YAML Lint, or command-line tools like yamllint. Python's PyYAML or ruamel.yaml will raise exceptions on invalid YAML. IDE extensions provide real-time validation with syntax highlighting.

Q: What's the difference between YAML and JSON?

A: YAML is more human-readable (no quotes for most strings, uses indentation instead of braces), supports comments, and is a superset of JSON (valid JSON is valid YAML 1.2). YAML is preferred for configuration; JSON for APIs and data interchange.

Q: Can I convert YAML back to RST?

A: Yes, using custom scripts or templates. Read YAML with PyYAML and generate RST field lists or tables. This is useful for generating documentation from configuration files, ensuring docs stay synchronized with actual config.