YAMLpp is dynamic, self-generating YAML

YAMLpp is dynamic, self-generating YAML

YAMLpp introduces a pre-processor that adds dynamic capabilities to YAML, addressing the pain of static configuration files. For example, a single http://dev.company.local URL repeated across files requires manual updates, risking errors during environment transitions.

Why This Matters

YAML’s static nature creates friction in dynamic environments. Manual search/replace is error-prone, templating engines like Jinja risk syntax errors, and alternatives like Jsonnet introduce new toolchains. YAMLpp resolves this by embedding macros directly into YAML, preserving editor support and avoiding external dependencies.

Key Insights

• “Static YAML forces repetitive updates, increasing maintenance costs.”
• “YAMLpp uses .context and .if constructs to generate dynamic output.”
• “YAMLpp is implemented in Python with a test suite (pytest).”

Working Example

.context:
  name: "World"
  message: "Hello {{ name }}!"

.context:
  .platform: dev
  server:
    .if: "(platform, {{ prod }})"
    .then:
      url: prod.machine.local
    .else:
      url: dev.machine.local

Practical Applications

• Use Case: Kubernetes deployment configs with environment-specific variables
• Pitfall: Overusing nested constructs may reduce readability for teams unfamiliar with YAMLpp

References:

• https://dev.to/fralau/yamlpp-is-dynamicself-generating-yaml-2cb8

---