Building Block View

Whitebox Overall System

Element	Responsibility	Code
main	Go requires a main func as the application’s entry point.
api gateway	An HTTP server with a fixed set of routes, called from the public website. Dispatches to the domain layer and returns plain HTML to the static site (or other formats, via a technical API still in planning).	internal/api
domain	Core functionality: coordinates the various subsystems and collects results.
types	A few data types and structures shared by other parts, extracted from the domain to avoid circular dependencies.
github	Wrapper for the public GitHub GraphQL API. Queries repository info — open issues, bugs, pull requests — for each site.
database	Wrapper for Turso, an SQLite clone running in the cloud, chosen to avoid operating a dedicated database.
fly.io	Wrapper for the fly.io API, used to find the server region the application runs in. Not to be confused with the deployment concept in section 7.

Availability Monitoring

Availability probing is triggered externally by cron-job.org calling POST /api/probe on a 15-minute schedule with a bearer token (see the availability-monitoring decision in section 9).

The API gateway dispatches the request to internal/probe, which measures all monitored properties concurrently, performs 2-of-3 failure confirmation, records results in Turso, and alerts Slack if any site is down.

internal/availability is the read/write and computation layer: internal/probe writes transitions, daily rollups, and heartbeats through it; internal/api reads it to compute the status tokens, verdict, and 30-day history shown on the pages.

Runtime storage uses three Turso tables:

• status_snapshot — state transitions (site, status, changed_at, response_ms, detail, monitor_id as vantage).
• status_bucket — daily downtime rollups per site (site, bucket_start, bucket_kind='day', downtime_minutes, outage_count).
• probe_run — run heartbeat log (run_at, vantage, sites_checked, duration_ms).