This adds logging to the read & write operations to the telemetry state
file. In particular,
- for read, no error is logged if the state file doesn't exist, which is
expected to happen when the user is new. An error is logged otherwise
(e.g. file format error, errors when reading an existing file like
permission issue).
- for write, any error in the path will be logged.
This commit also puts the instantiation of the `Persistence` object out
of the `ClearcutLogger` object to avoid circular dependency.
This PR implements the persistence layer for the telemetry system. It
introduces `FilePersistence` for local state management and integrates
it with `ClearcutLogger` to support "Daily Active" metric. I have
decided not to send `first_time_installation` events since we can deduce
them from `daily active` events where the `days_since_last_active` will
be `-1` for that case.
**Implementation Roadmap:**
This is the third in a series of PRs designed to implement the telemetry
system:
1. **CLI & Opt-out Mechanism
([Merged](https://github.com/ChromeDevTools/chrome-devtools-mcp/pull/757)):**
* Added `--usage-statistics` flag and transparency logging.
2. **Logger Scaffolding & Integration
([Merged](https://github.com/ChromeDevTools/chrome-devtools-mcp/pull/758)):**
* **`ClearcutLogger`**: Implemented the main logging entry point.
* **One-way Data Flow**: Integrated `logToolInvocation` and
`logServerStart` hooks into `main.ts` to capture events.
* **`ClearcutSender`**: Introduced a transport abstraction.
* **Type Definitions**: Added TypeScript definitions for the telemetry
Protocol Buffer messages.
3. **Persistence Layer (This PR):**
* **`FilePersistence`**: Implemented a local file-based state manager to
persist the `lastActive` timestamp.
* **Daily Active Logic**: Integrated persistence into `ClearcutLogger`
to automatically detect and log `daily_active` events (with
`days_since_last_active` calculation) via `logDailyActiveIfNeeded`.
4. **Watchdog Process Architecture (Next):**
* Move `ClearcutSender` execution to a dedicated watchdog process to
ensure reliable event transmission even during abrupt server shutdowns.
5. **Transport, Batching & Retries (Next):**
* Finalize `ClearcutSender` with actual HTTP transport logic, including
event batching and exponential backoff retries.
yulunz