623505b9c8
Eight items were still open at the end of M1: two integration tests that had only been run by hand, and six known gaps. Recurrence overrides now reach Google. Google addresses an exception through the series rather than as an event of its own, so the master is sent first and each override is then matched to its instance by original start time and patched. Matching needs the two sides' spellings reduced to one key: iCalendar writes a zoned local time, Google an absolute offset. An override matching no occurrence is counted rather than forced — that means a stale RECURRENCE-ID left behind by an edited RRULE, and inventing an event for it would put something in the calendar the series does not contain. Reading one component apart from another needed a view `properties` cannot give: it flattens every VEVENT together, which is right for the UID a series shares and wrong for an override, whose SUMMARY and the master's are then indistinguishable. `Calendar::events` splits them. A TZID now travels with the VTIMEZONE that defines it, derived from the zone's own transition table as the yearly rule it implies. This changes the content hash of every zoned recurring event, so the first cycle after this re-pushes them. A Google authorisation is filed under the account it was granted for rather than the endpoint that asked for it, so two endpoints on one account no longer need a login each. The account is read from the primary calendar's id, which needs no scope beyond the calendar one already granted. Authorisations written by the previous scheme are still honoured, and move across at the next login. An unreachable Google endpoint no longer ends the cycle — one lapsed token used to stop the CalDAV side too. It is named, only the aggregates depending on it stand down, and the run exits non-zero so a partial cycle cannot pass for success. The CalDAV leg cannot be narrowed the same way: pimsync is one process covering every pair, so a failure does not say which pair it belongs to. `--dry-run` now pulls for real, into a throwaway copy of the local mirrors and through a pimsync configuration that only ever reads from a server. What it reports is measured against the calendars as they are now rather than against whatever the last real cycle left behind. `calcalist prune` reports local mirrors of endpoints the configuration no longer names, and removes them under --force. The integration tests run against a real Radicale server and a real iCal feed: convergence and idempotence, the dry run, prune, and the scheduling rule asserted on the bytes that actually reached the server. The plan asked for an SMTP sink for that last one; Radicale implements no RFC 6638 scheduling, so a quiet SMTP port would have proved nothing about the transform. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
60 lines
4.9 KiB
Markdown
60 lines
4.9 KiB
Markdown
# Calcalist
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## Idea
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Small Rust based commandline tool with utility systemd service file that can aggregate and sync events between CalDAV/Google Calendar/iCal. Users who have a Google Calendar can create a new calendar that syncs events from several CalDAV calendars. CalDAV users can sync several Google Calendars into one calendar. This should be doable both ways, so the aggregating calendar needs to be able to distinguish where its events came from and also have a way to create new events that get synced to the correct source. In addition iCal feeds can also be aggregated but they remain one way only.
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Configuration via a simple web interface. Configuration is saved in a portable toml file that can be easily migrated.
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## Architecture
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Every endpoint — sources and aggregate targets alike — is mirrored to a local vdir, so the aggregation engine works purely on local files.
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- `pimsync` is driven as a one-shot subprocess for the CalDAV and WebCal legs. Its daemon mode is unusable here: it would race the reconciler over the same vdir files, so calcalist owns scheduling.
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- The Google leg is calcalist's own, via the Calendar REST API. pimsync cannot reach Google — it has no REST storage, and its config exposes only HTTP Basic auth, which Google's CalDAV endpoint has rejected since 2025-03-14.
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- Sync state (event mappings, hashes, sync tokens) lives in a JSON sidecar under `$XDG_STATE_HOME/calcalist/`, never in the portable config.
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- Secrets are never stored in the config either. Credentials come from `*_command` fields that are executed to fetch them.
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- A Google authorisation is filed under the account it was granted for, not the endpoint that asked for it, so every endpoint on that account shares it. An endpoint names its `account` only when calcalist is logged in to more than one.
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## Sync semantics
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| Question | Behaviour |
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|---|---|
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| Provenance | Aggregate UIDs derived as `blake3(aggregate_id, source_id, source_uid)`; the state file is a cache, not a single point of failure |
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| Routing new events | A `@endpoint-id` line in the description, or a matching category, picks the source; otherwise the aggregate's `default_sink`. A hint naming an invalid sink is refused, never redirected to the default |
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| Conflicts | Source wins — the origin calendar is authoritative |
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| Deletion | Propagates to the source, guarded by a mass-deletion threshold |
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| Attendees (mirroring) | Kept verbatim on a Google target; demoted to inert data on a CalDAV target |
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| Attendees (routing) | Preserved — the sink server sends real invitations, which is intended |
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| Alarms | Always preserved, with no option to strip them |
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| Retargeting | `sync` refuses on target drift; `aggregate retarget` performs it deliberately |
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| Recurrence | A series and its exceptions share one file. Google addresses an exception through the series, so the master is sent first and each override is matched to its instance by original start time and patched |
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| Unreachable endpoints | Named in the report; only the aggregates depending on them stand down, and the run exits non-zero |
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| Dry runs | Pull for real, into a throwaway copy of the local mirrors and through a read-only pimsync configuration. Nothing outside the copy is written |
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The governing rule behind the attendee handling: **writes to an aggregate must never emit scheduling mail; writes to a source schedule normally.** Google can be told not to notify, so attendees survive intact there. CalDAV offers no portable way to suppress RFC 6638 scheduling, so inertness is achieved structurally by dropping the live properties instead.
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Alarms are never stripped because the whole point of the tool is that a user subscribes to one calendar rather than several — so the duplicate-notification problem that stripping would guard against does not arise, while stripping would silently destroy every reminder in the one calendar the user actually watches.
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## Development
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Use devbox for dependency management and scripts. Use jj for version control (colocated with git).
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- `devbox run fmt` — format.
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- `devbox run check` — format check, clippy with warnings denied, and tests. This is the gate; jj has no commit step to hang a hook off, since the working copy is itself a commit.
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- `devbox run test` — tests only.
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Keep `/target` in `.gitignore`: jj snapshots the working copy on every command, with no staging step.
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## Coding style
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- Simple, readable, idiomatic.
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- Explicit types for public APIs and important fields.
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- Prefer immutable data structures.
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- No global mutable state.
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- No speculative features or dependencies.
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- Keep functions short and single-purpose; extract helpers to avoid nesting.
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- File and module naming: `snake_case.rs`. Types and traits: `PascalCase`. Functions, variables and fields: `snake_case`. Constants: `SCREAMING_SNAKE_CASE`.
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- Run `devbox run check` before describing a change.
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- Comment only when intent is not obvious from the code.
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- Prefer composition and traits over deep type hierarchies.
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