Charon/docs/plans/current_spec.md

CrowdSec Hub Presets Sync & Apply Plan (feature/beta-release)

Current State (what exists today)

• Backend: backend/internal/api/handlers/crowdsec_handler.go exposes ListPresets (returns curated list from backend/internal/crowdsec/presets.go) and a stubbed PullAndApplyPreset that only validates slug and returns preview or HTTP 501 when apply=true. No real hub sync or apply.
• Backend uses CommandExecutor for cscli decisions only; no hub pull/install logic and no cache/backups beyond file write backups in WriteFile and import flow.
• Frontend: frontend/src/pages/CrowdSecConfig.tsx calls pullAndApplyCrowdsecPreset then falls back to local writeCrowdsecFile apply. Preset catalog merges backend list with frontend/src/data/crowdsecPresets.ts. Errors 501/404 are surfaced as info to keep local apply working. Overview toggle/start/stop already wired to startCrowdsec/stopCrowdsec.
• Docs: docs/cerberus.md still notes CrowdSec integration is a placeholder; no hub sync described.

Goal

Implement real CrowdSec Hub preset sync + apply on backend (using cscli or direct hub index) with caching, validation, backups, rollback, and wire the UI to new endpoints so operators can preview/apply hub items with clear status/errors.

Backend Plan (handlers, helpers, storage)

1. Route adjustments (gin group under /admin/crowdsec in backend/internal/api/handlers/crowdsec_handler.go):
   • Replace stub endpoint with POST /admin/crowdsec/presets/pull → fetch hub item and cache; returns metadata + preview + cache key/etag.
   • Add POST /admin/crowdsec/presets/apply → apply previously pulled item by cache key/slug; performs backup + cscli install + optional restart.
   • Keep GET /admin/crowdsec/presets but include hub/etag info and whether cached locally.
   • Optional: GET /admin/crowdsec/presets/cache/:slug → raw preview/download for UI.
2. Hub sync helper (new backend/internal/crowdsec/hub_sync.go):
   • Provide type HubClient interface { FetchIndex(ctx) (HubIndex, error); FetchPreset(ctx, slug) (PresetBundle, error) } with real impl using either: a) cscli hub list -o json and cscli hub update + cscli hub install <item> (preferred if cscli present), or b) direct fetch of https://hub.crowdsec.net/ or GitHub raw .index.json + tarball download.
   • Validate downloads: size limits, tarball path traversal guard, checksum/etag compare, basic YAML validation.
3. Caching (new backend/internal/crowdsec/hub_cache.go):
   • Cache pulled bundles under ${DataDir}/hub_cache/<slug>/ with index metadata (etag, fetched_at, source URL) and preview YAML.
   • Expose LoadCachedPreset(slug) and StorePreset(slug, bundle); evict stale on TTL (configurable, default 24h) or when etag changes.
4. Apply flow (extend handler):
   • Pull: fetch index, resolve slug, download bundle to cache, return preview + warnings (missing cscli, requires restart, etc.).
   • Apply: before modify, run backupDir := DataDir + ".backup." + timestamp (mirror current write/import backups). Then: a) If cscli available: cscli hub update, cscli hub install <slug> (or collection path), maybe cscli decisions list sanity check. Use CommandExecutor with context timeout. b) If cscli absent: extract bundle into DataDir with sanitized paths; preserve permissions. c) Write audit record to DB table crowdsec_preset_events (new model in backend/internal/models).
   • On failure: restore backup (rename back), surface error + backup path.
5. Status and restart:
   • After apply, optionally call h.Executor.Stop/Start if running to reload config; or cscli service reload when available. Return reload_performed flag.
6. Validation & security hardening:
   • Enforce Cerberus enablement check (isCerberusEnabled) on all new routes.
   • Path sanitization with filepath.Clean, limit tar extraction to DataDir, reject symlinks/abs paths.
   • Timeouts on all external calls; default 10s pull, 15s apply.
   • Log with context: slug, etag, source, backup path; redact secrets.
7. Migration of curated list:
   • Keep curated presets in backend/internal/crowdsec/presets.go but add Source: "hub" for hub-backed items and include RequiresHub true when not bundled.
   • ListPresets should merge curated + live hub index when available, mark availability per slug (cached, remote-only, local-bundled).

Frontend Plan (API wiring + UX)

1. API client updates in frontend/src/api/presets.ts:
   • Replace pullAndApplyCrowdsecPreset with pullCrowdsecPreset({ slug }) and applyCrowdsecPreset({ slug, cache_key }); include response typing for preview/status/errors.
   • Add getCrowdsecPresetCache(slug) if backend exposes cache preview.
2. CrowdSec config page frontend/src/pages/CrowdSecConfig.tsx:
   • Use new mutations: pull to show preview + metadata (etag, fetched_at, source); disable local fallback unless backend says apply_supported=false.
   • Show status strip (success/error) and backup path from apply response; surface reload flag and errors inline.
   • Gate preset actions when Cerberus disabled; show tooltip if hub unreachable.
   • Keep local backup + manual file apply as last-resort only when backend explicitly returns 501/NotImplemented.
3. Overview page frontend/src/pages/Security.tsx:
   • No UI change except error surfacing when start/stop fails due to hub apply requiring reload; show toast from handler message.
4. Import page frontend/src/pages/ImportCrowdSec.tsx:
   • Add note linking to presets apply so users prefer presets over raw package imports.

Hub Fetch/Validate/Apply Flow (detailed)

1. Pull
   • Handler: CrowdsecHandler.PullPreset(ctx) (new) calls HubClient.FetchPreset → HubCache.StorePreset → returns {preset, preview_yaml, etag, cache_key, fetched_at}.
   • If hub unavailable, return 503 with message; UI shows retry/cached copy option.
2. Apply
   • Handler: CrowdsecHandler.ApplyPreset(ctx) loads cache by slug/cache_key → backupCurrentConfig() → InstallPreset() (cscli or manual) → optional restart → returns {status:"applied", backup, reloaded:true/false}.
   • On error: restore backup, include {status:"failed", backup, error}.
3. Caching & rollback
   • Cache directory per slug with checksum file; TTL enforced on pull; apply uses cached bundle unless force_refetch flag.
   • Backups stored with timestamp; keep last N (configurable). Provide restoration note in response for UI.
4. Validation
   • Tarball extraction guard: reject absolute paths, .., symlinks; limit total size.
   • YAML sanity: parse key scenario/collection files to ensure readable; log warning not blocker unless parse fails.
   • Require explicit apply=true separate from pull; no implicit apply on pull.

Security Considerations

• Only allow these endpoints when Cerberus enabled and user authenticated to admin scope.
• Use CommandExecutor to shell out to cscli; restrict PATH and working dir; do not pass user-controlled args without whitelist.
• Network egress: if hub URL configurable, validate scheme is https and host is allowlisted (crowdsec official or configured mirror).
• Rate limit pull/apply (simple in-memory token bucket) to avoid abuse.
• Logging: include slug and etag, omit file contents; redact download URLs if they contain tokens (unlikely).

Required Tests

• Backend unit/integration:
  • backend/internal/api/handlers/crowdsec_handler_test.go: success and error cases for PullPreset (hub reachable/unreachable, invalid slug), ApplyPreset (cscli success, cscli missing fallback, apply fails and restores backup), ListPresets merging cached hub entries.
  • backend/internal/crowdsec/hub_sync_test.go: parse index JSON, validate tar extraction guards, TTL eviction.
  • backend/internal/crowdsec/hub_cache_test.go: store/load/evict logic and checksum verification.
  • backend/internal/api/handlers/crowdsec_exec_test.go: ensure executor timeouts/commands constructed for cscli hub calls.
• Frontend unit/UI:
  • frontend/src/pages/tests/CrowdSecConfig.test.tsx: pull shows preview, apply success shows backup path/reload flag, hub failure falls back to cached/local message, Cerberus disabled disables actions.
  • frontend/src/api/tests/presets.test.ts: client hits new endpoints and maps response.
  • frontend/src/pages/tests/Security.test.tsx: start/stop toasts remain correct when apply errors bubble.

Docs Updates

• Update docs/cerberus.md CrowdSec section with new hub preset flow, backup/rollback notes, and requirement for cscli availability when using hub.
• Update docs/features.md to list “CrowdSec Hub presets sync/apply (admin)” and mention offline curated fallback.
• Add short troubleshooting entry in docs/troubleshooting/crowdsec.md (new) for hub unreachable, checksum mismatch, or cscli missing.

Migration Notes

• Existing curated presets remain but are marked as bundled; UI should continue to show them even if hub unreachable.
• Stub endpoint POST /admin/crowdsec/presets/pull/apply is replaced by separate pull and apply; frontend must switch to new API paths before backend removal to avoid 404.
• Backward compatibility: keep returning 501 from old endpoint until frontend merged; remove once new routes live and tested.