Implements a Pion Go B2BUA media server sidecar that sits between Meta's
WhatsApp Cloud API and the agent's browser, enabling call persistence
across page reloads, server-side recording, multi-participant support,
audio injection, and AI integration readiness.
Go Media Server (enterprise/media-server/):
- Pion WebRTC v4 B2BUA with Peer A (Meta) and Peer B (Agent) connections
- Real-time OGG/Opus recording with crash recovery
- Audio bridge with multi-peer fan-out and AudioConsumer plugin interface
- Audio injection from OGG files with loop support for hold music
- Session manager with graceful shutdown and orphaned recording recovery
- HTTP API with Bearer token auth, health checks, and metrics
Rails Integration:
- Whatsapp::MediaServerClient HTTP client for Go sidecar communication
- Dual-mode CallService: legacy browser-direct and server-relay paths
- Media server callback controller for agent disconnect/recording/terminate
- CallRecordingFetchJob: downloads OGG from Go server to ActiveStorage/S3
- CallCleanupJob: sweeps stale ringing and in-progress calls
- New endpoints: active, agent_answer, reconnect, join, play_audio
- DB migration: media_session_id column with indexes
Frontend:
- Dual-mode composable auto-detecting legacy vs server-relay
- handleAgentOffer() for receiving SDP from media server
- useCallReconnection composable for page reload recovery
- Removed terminateCallOnUnload in server-relay mode
- Simplified outbound call flow in ConversationHeader
- New ActionCable event: whatsapp_call.agent_offer
Documentation:
- Server-side WebRTC architecture spec (1505 lines)
- Implementation plan with 119 trackable checklist items
- Feature spec, PR breakdown, and relay architecture docs
Replace the WhatsappCall model with the unified Call model introduced
in feat/voice-call-model (PR #14026), enabling multi-provider support
(Twilio + WhatsApp) under a single data model.
Key changes:
- Delete WhatsappCall model and its 3 migrations (whatsapp_calls table)
- Enhance Call model with WhatsApp-specific helpers (sdp_offer,
ice_servers, recording_url, direction_label, ringing?, in_progress?)
- Update all backend services, controller, and jobs to use Call model
- Map statuses: accepted→in_progress, rejected→failed, missed→no_answer,
ended→completed
- Map directions: inbound→incoming, outbound→outgoing (enums)
- Rename call_id column to provider_call_id, always set provider: :whatsapp
- Add authorization check on initiate action
- Add race condition guard in outbound call_connect webhook handler
- Consolidate direction_label helper into Call model (DRY)
- Update frontend data key from waCallId to callId in VoiceCall bubble
- Remove whatsapp_calls table from schema.rb, fix missing started_at
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
