weatherreporter/docs/internal/reporttemplate.md

Report Template Internals

internal/reporttemplate embeds and renders the repository's native Markdown templates. The current template IDs are daily, today, tomorrow, and hourly. The template files, partials, and complete render-context field reference are maintained in report templates.

Assets and lookup

The package embeds top-level templates and shared partials. Template returns the requested embedded template and fails with the requested ID when it is unknown or unreadable.

Generated-text schemas and Promptkit definitions are owned by internal/promptassets; report-template owns Markdown source only. Report definitions select IDs, while generated-text internals verifies the supported schema/template pairing.

Rendering

Render loads the top-level template, creates a text/template with helper functions and missingkey=error, parses the template, parses every shared partial, and executes the result against the typed render context. This makes missing context fields, bad template syntax, unreadable partials, and execution failures actionable with template or partial context.

Top-level templates decide which shared partials they invoke. The current partials cover daypart forecast variants, alert digest, and precipitation timing. Template code receives curated typed contexts rather than raw data packages or complete fact bundles, and it must not reimplement weather selection or generated-text validation. Context construction rejects report-identity disagreements before template execution. Every generated-prose insertion uses the plainText helper. It retains ordinary prose and paragraph breaks but renders Markdown/HTML syntax, code indentation, and control characters as safe text, so the repository templates remain the sole owners of report structure.

Boundaries and verification

This package does not collect weather data, build modules, validate generated text, construct contexts, resolve report definitions, write state, execute Promptkit, or upload reports. It produces Markdown bytes for application orchestration to persist.

Focused tests cover template lookup, rendering, partial behavior, daypart fallbacks, missing keys, and malformed context:

go test ./internal/reporttemplate

Embedded templates stay as separate files and shared fragments stay under the partial directory. Generated-text schemas are embedded separately by internal/promptassets and describe prose slots rather than deterministic weather facts.