Ilia Denisov
8881214213
Mechanical, behaviour-preserving removal of Stage N / TODO-N / phase (RN) references from comments, doc-comments, service READMEs, the current-state docs (ARCHITECTURE, FUNCTIONAL+_ru, TESTING, UI_DESIGN), config-file comments, and the .fbs/.proto schema comments. PLAN.md / PRERELEASE.md / CLAUDE.md keep the stage history. - Rename the only stage-named identifiers: registerStage8 -> registerSocialOps, registerStage11 -> registerLinkOps (gateway transcode). - Split stage6_test.go: TestEmailLoginFlow -> email_test.go, TestGuestAutoMatchLeavesNoStats (+ provisionGuest) -> account_test.go. - Regenerated proto bindings (push.pb.go, telegram_grpc.pb.go) from the de-staged .proto comments; FB Go/TS bindings unchanged (flatc strips schema comments). go build/vet/gofmt clean across modules; integration typecheck and pnpm check green.
228 lines
15 KiB
Markdown
228 lines
15 KiB
Markdown
# backend
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Internal-only domain service for the Scrabble platform (module `scrabble/backend`).
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It owns identity/sessions, accounts, the lobby, game runtime, robot, chat, history
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and administration. Its only network consumers are the `gateway` and the platform
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side-services; it is never exposed publicly.
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The backend provides the foundation: configuration, the HTTP listener with the
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`/api/v1` route-group skeleton and probes, the Postgres pool with embedded goose
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migrations, OpenTelemetry wiring, an in-memory session cache, and the durable
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accounts / identities / sessions data model. The session and account REST
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endpoints live in the `gateway`; the backend ships the store/service layer they
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call.
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`internal/engine` is the in-process bridge to the `scrabble-solver`
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library: a versioned dictionary registry, a deterministic tile bag, and a pure
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rules `Game` (legal plays, passes, exchanges, resignations and end-condition
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detection) that emits dictionary-independent move records. It is a library only;
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the game domain wires it into the process.
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`internal/game` is the game domain over the engine. Active games are
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event-sourced: a `games` row plus an append-only decoded move journal, with the
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live `engine.Game` kept warm in a cache and rebuilt by replay on a miss. It
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provides create, the play/pass/exchange/resign transitions, an unlimited
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score/legality preview, the hint (per-game allowance plus a profile wallet), the
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word-check tool with complaint capture, per-player game state, history and GCG
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export, per-account statistics on finish, and a background turn-timeout sweeper
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that auto-resigns overdue turns (honouring each player's daily away window). Like
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the engine it is a service/store layer; the HTTP surface lives in the `gateway`.
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The lobby and social fabric. `internal/lobby` holds an in-memory
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matchmaking pool (FIFO per variant, pairs two humans into an auto-match) and
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friend-game invitations (invite → accept, starting a 2–4 player game once every
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invitee accepts). `internal/social` owns the friend graph (request/accept),
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per-user blocks, and per-game chat with nudges folded in as a message kind; chat
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messages are length-capped, content-filtered (no links/emails/phone numbers,
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including obfuscated forms) and stored with the sender's IP. `internal/account`
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gains profile editing and the email confirm-code flow (a `Mailer` seam: SMTP or a
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development log mailer). The engine now also handles **multi-player drop-out**: in
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a 3–4 player game a resignation or timeout drops that seat and the rest play on
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(the tile disposition is a per-game setting), the game ending when one active seat
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remains. As before this is a service/store layer — chat and nudges are persisted
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but their live delivery, and all REST endpoints, live in the `gateway`; the
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services are exposed via `Server` accessors for those handlers.
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The robot opponent (`internal/robot`). A pool of durable accounts —
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each a `kind='robot'` identity, provisioned at startup with chat and friend
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requests blocked — backs human-like, per-language composed names. A background driver plays the
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robot's moves through the public game API as an ordinary seated player (so only
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`internal/engine` imports the solver): it decides once per game whether to play to
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win (≈ 40%), targets a small score margin, and times its moves with a move-number-aware
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right-skewed delay (quick openings, long endgames), a night-sleep window anchored to the opponent's timezone, and nudge
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behaviour — all derived deterministically from the game seed, so it keeps no extra
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state. The matchmaker now substitutes a pooled robot (matching the game's language) after a 10-second wait and
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exposes `Poll` so a waiting player can collect the started game — it is the **stream-down
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fallback**: while the client is streaming, the live match-found push (enriched with the recipient's
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initial game state) drives it instead.
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The backend opens to the edge. The route groups gain their first
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handlers (`internal/server/handlers_*.go`): gateway-only session endpoints under
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`/api/v1/internal` (Telegram/guest/email login → mint, resolve, revoke) and a
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slice of authenticated `/api/v1/user` operations (profile, submit play, game
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state, lobby enqueue/poll, chat). The social/account/history operations under
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`/api/v1/user`: `friends/*` (request/respond/cancel/unfriend,
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list/incoming, the one-time `code` issue/redeem), `blocks/*`, `invitations/*`
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(create/accept/decline/cancel/list), `PUT profile`, `email/{request,confirm}`,
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`stats`, and `games/:id/gcg` (finished-only). The `internal/notify` hub feeds a
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second listener — `internal/pushgrpc`, a gRPC server (`BACKEND_GRPC_ADDR`) streaming
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live events (your-turn, opponent-moved, chat, nudge, match-found, notify) to the
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gateway. The gateway-only `POST /api/v1/internal/push-target` (a user's
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Telegram `external_id`, language and `notifications_in_app_only` flag) lets the gateway
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route out-of-app push to the Telegram connector; the Telegram login
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seeds a new account's language and display name from the launch fields, and the
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`accounts.notifications_in_app_only` flag (default true).
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`accounts.is_guest` marks an ephemeral guest — a durable row
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with no identity, excluded from statistics. The server-rendered
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**admin console** at `/_gm` (`internal/adminconsole` + `internal/server/handlers_admin_console.go`;
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the gateway fronts it with Basic-Auth and a same-origin guard protects its POSTs), the
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**complaint resolution** lifecycle (the `complaints` `disposition`/`resolution_note`/
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`resolved_at`/`applied_in_version` columns + the `status` CHECK) feeding a dictionary-change
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pipeline, dictionary **hot-reload** from `BACKEND_DICT_DIR/<version>/`
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(`engine.OpenWithVersions` / `Registry.LoadAvailable`), and operator **broadcasts** via a
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backend Telegram-connector client (`internal/connector`, `BACKEND_CONNECTOR_ADDR`) — each
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broadcast picks the delivering bot by an operator-chosen language. `accounts.service_language`
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holds the language tag of the bot a Telegram
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user last signed in through, written on every login and returned by
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`/internal/push-target` (falling back to `preferred_language`) so out-of-app push routes
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to the right bot. The shared wire contracts live in the sibling [`../pkg`](../pkg) module.
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**Account linking & merge** (`/api/v1/user/link/*`). `internal/link`
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orchestrates it: an email confirm-code or a gateway-validated Telegram identity is
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attached to the current account, and when the identity already has its own account
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the two are merged in one transaction (`internal/accountmerge`) — stats and the hint
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wallet summed, `paid_account` ORed, identities/games/chat/complaints transferred,
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friends/blocks de-duplicated, the secondary kept as a `merged_into` tombstone (so a
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shared finished game's foreign keys hold); a shared **active** game blocks the merge.
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The current account is primary, except a guest initiator whose linked identity has a
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durable owner — then the durable account wins and a fresh session is minted for it.
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The `accounts.paid_account`/`merged_into`/`merged_at` columns back this. This supersedes the
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former `email.bind.*` edge surface (the `RequestCode`/`ConfirmCode` primitives stay).
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Rate-limit observability: the gateway posts its periodic rejection
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summaries to `POST /api/v1/internal/ratelimit/report`; `internal/ratewatch` keeps a
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bounded in-memory episode window for the console's **Throttled** page and applies the
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conservative auto-flag — an account sustaining `BACKEND_HIGHRATE_FLAG_THRESHOLD`
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rejected calls within `BACKEND_HIGHRATE_FLAG_WINDOW` gets the soft, reversible
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`accounts.flagged_high_rate_at` marker (set-once; a badge in the user list and a
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**Clear** action on the user card; never an automatic ban).
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## Package layout
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```
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cmd/backend/ # entrypoint: telemetry -> db+migrate -> registry -> cache -> game+sweeper -> robot pool+driver -> lobby+social -> server
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cmd/jetgen/ # dev tool: regenerate go-jet code from a throwaway container
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internal/config/ # env configuration (composes postgres + telemetry + game config)
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internal/telemetry/ # OpenTelemetry providers + per-request timing middleware
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internal/postgres/ # pgx-over-database/sql pool (otelsql), goose migrations
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migrations/ # embedded *.sql (goose), schema `backend`
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jet/ # generated go-jet models + table builders (committed)
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internal/account/ # durable accounts + platform/email identities (store) + email/identity link primitives
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internal/accountmerge/ # single-transaction merge of a secondary account into a primary
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internal/link/ # link/merge orchestrator over account + accountmerge + session
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internal/session/ # opaque tokens, sessions store, write-through cache, service (incl. RevokeAllForAccount)
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internal/server/ # gin engine, route groups, X-User-ID middleware, probes
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internal/engine/ # in-process scrabble-solver bridge: registry, bag, Game, replay
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internal/game/ # game domain: lifecycle, journal+cache, hint, word-check, GCG, sweeper
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internal/social/ # friend graph, per-user blocks, per-game chat + nudge, content filter
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internal/lobby/ # in-memory matchmaking pool (+ robot substitution) + friend-game invitations
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internal/robot/ # human-like robot opponent: account pool, seed-derived strategy, move driver
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internal/adminconsole/ # server-rendered admin console (Go templates + embedded CSS, view models), served at /_gm
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internal/connector/ # backend gRPC client to the Telegram connector (operator broadcasts)
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internal/ratewatch/ # gateway rate-limit reports: episode window for the console + the high-rate auto-flag
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```
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## Configuration (environment)
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| Variable | Default | Notes |
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| --- | --- | --- |
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| `BACKEND_HTTP_ADDR` | `:8080` | HTTP (REST) listen address. |
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| `BACKEND_GRPC_ADDR` | `:9090` | gRPC listen address for the live-event push stream to the gateway. |
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| `BACKEND_LOG_LEVEL` | `info` | `debug` / `info` / `warn` / `error`. |
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| `BACKEND_POSTGRES_DSN` | — | **Required.** pgx/libpq URL; must pin `search_path=backend`. |
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| `BACKEND_POSTGRES_MAX_OPEN_CONNS` | `25` | Pool max open connections. |
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| `BACKEND_POSTGRES_MAX_IDLE_CONNS` | `5` | Pool max idle connections. |
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| `BACKEND_POSTGRES_CONN_MAX_LIFETIME` | `30m` | Max connection lifetime. |
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| `BACKEND_POSTGRES_OPERATION_TIMEOUT` | `5s` | Connect attempt + `/readyz` ping bound. |
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| `BACKEND_SERVICE_NAME` | `scrabble-backend` | OpenTelemetry `service.name`. |
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| `BACKEND_OTEL_TRACES_EXPORTER` | `none` | `none`, `stdout` or `otlp` (gRPC; endpoint from the standard `OTEL_EXPORTER_OTLP_*`). |
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| `BACKEND_OTEL_METRICS_EXPORTER` | `none` | `none`, `stdout` or `otlp`. |
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| `BACKEND_DICT_DIR` | — | **Required.** Directory of committed `.dawg` dictionaries. |
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| `BACKEND_DICT_VERSION` | `v1` | Dictionary version new games pin. |
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| `BACKEND_GAME_TIMEOUT_SWEEP_INTERVAL` | `1m` | How often the turn-timeout sweeper runs. |
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| `BACKEND_GAME_CACHE_TTL` | `24h` | Idle window before a live game is evicted from cache. |
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| `BACKEND_LOBBY_ROBOT_WAIT` | `10s` | Auto-match wait before a robot is substituted for a missing human. |
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| `BACKEND_LOBBY_REAPER_INTERVAL` | `1s` | How often the substitution reaper scans for over-waited players. |
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| `BACKEND_ROBOT_DRIVE_INTERVAL` | `30s` | How often the robot driver scans for due robot turns. |
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| `BACKEND_SMTP_HOST` | — | Email relay host. **Empty selects the development log mailer** (the confirm-code is logged, not sent). |
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| `BACKEND_SMTP_PORT` | `587` | Email relay port. |
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| `BACKEND_SMTP_USERNAME` | — | SMTP user; empty relays without authentication. |
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| `BACKEND_SMTP_PASSWORD` | — | SMTP password. |
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| `BACKEND_SMTP_FROM` | `no-reply@localhost` | Envelope/From address for confirm-codes. |
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| `BACKEND_CONNECTOR_ADDR` | — | Telegram connector gRPC address for admin-console operator broadcasts. Empty disables broadcasts. |
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| `BACKEND_GUEST_REAP_INTERVAL` | `1h` | How often the abandoned-guest reaper sweeps. |
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| `BACKEND_GUEST_RETENTION` | `720h` | Account age past which a guest with no game seat is deleted. |
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| `BACKEND_HIGHRATE_FLAG_THRESHOLD` | `1000` | Gateway-reported rejected calls within the window past which an account is soft-flagged. |
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| `BACKEND_HIGHRATE_FLAG_WINDOW` | `10m` | The rolling window those rejections accumulate over. |
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## Run
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```sh
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docker run -d --name scrabble-pg -e POSTGRES_PASSWORD=dev -p 5432:5432 postgres:17-alpine
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# DAWGs: extract the dictionary release artifact (or point at a local scrabble-solver/dawg):
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mkdir -p /tmp/dawg && curl -fsSL https://gitea.iliadenisov.ru/developer/scrabble-dictionary/releases/download/v1.0.0/scrabble-dawg-v1.0.0.tar.gz | tar xz -C /tmp/dawg
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BACKEND_POSTGRES_DSN='postgres://postgres:dev@localhost:5432/postgres?search_path=backend&sslmode=disable' \
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BACKEND_DICT_DIR=/tmp/dawg \
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GOPRIVATE='gitea.iliadenisov.ru/*' \
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go run ./cmd/backend
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```
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On boot the backend opens the pool, creates the `backend` schema if needed,
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applies the embedded migrations, loads the dictionaries into the engine registry
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(a hard dependency — a missing dictionary aborts the boot), warms the session
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cache and starts the game turn-timeout sweeper. `GET /healthz` reports liveness;
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`GET /readyz` reports 200 only when the database answers and the session cache is
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warmed.
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## Migrations & generated code
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Migrations are plain goose SQL under `internal/postgres/migrations` (sequential
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`NNNNN_name.sql`), embedded and applied at startup. The incremental history was
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squashed into a single `00001_baseline.sql` before the first production deploy
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(there was no production data); new schema changes append as `00002_*` onward.
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After changing the schema,
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regenerate the committed go-jet code (needs Docker):
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```sh
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go run ./cmd/jetgen # rewrites internal/postgres/jet against a temp container
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```
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## Engine & dictionaries
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`internal/engine` consumes `scrabble-solver` in-process as a **published, versioned
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module** (`gitea.iliadenisov.ru/developer/scrabble-solver`, pinned in `go.mod`). Set
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`GOPRIVATE=gitea.iliadenisov.ru/*` so go fetches it directly from this Gitea (skipping
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the public proxy/checksum DB); no sibling checkout or `go.work` replace is needed (for
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local solver co-development you may add a temporary replace — see `go.work`).
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`github.com/iliadenisov/dafsa` (the DAWG loader) is a direct dependency. The dictionaries
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(`en_sowpods.dawg`, `ru_scrabble.dawg`, `ru_erudit.dawg`) ship as a **release artifact**
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from the [`scrabble-dictionary`](https://gitea.iliadenisov.ru/developer/scrabble-dictionary)
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repo (one semver per set); the engine loads them by `(variant, dict_version)` from
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`BACKEND_DICT_DIR`. The backend loads them at startup as a hard dependency
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(a missing dictionary aborts the boot).
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## Tests
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```sh
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go test -count=1 ./... # unit tests (no Docker)
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go test -tags=integration -count=1 -p=1 ./... # Postgres-backed (needs Docker)
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```
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Integration tests are guarded by the `integration` build tag and run against a
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throwaway `postgres:17-alpine` container; they fail loudly when Docker is absent
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rather than skipping. The `internal/engine` tests load the DAWGs from
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`BACKEND_DICT_DIR` (CI sets it to the extracted dictionary release artifact; locally it
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defaults to a `scrabble-solver/dawg` sibling checkout) and fail loudly when that directory
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is absent. `GOPRIVATE=gitea.iliadenisov.ru/*` is needed for go to fetch the pinned solver
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module.
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