Adds a RabbitMQ backend as an alternative to Pulsar, selectable via
PUBSUB_BACKEND=rabbitmq. Both backends implement the same PubSubBackend
protocol — no application code changes needed to switch.
RabbitMQ topology:
- Single topic exchange per topicspace (e.g. 'tg')
- Routing key derived from queue class and topic name
- Shared consumers: named queue bound to exchange (competing, round-robin)
- Exclusive consumers: anonymous auto-delete queue (broadcast, each gets
every message). Used by Subscriber and config push consumer.
- Thread-local producer connections (pika is not thread-safe)
- Push-based consumption via basic_consume with process_data_events
for heartbeat processing
Consumer model changes:
- Consumer class creates one backend consumer per concurrent task
(required for pika thread safety, harmless for Pulsar)
- Consumer class accepts consumer_type parameter
- Subscriber passes consumer_type='exclusive' for broadcast semantics
- Config push consumer uses consumer_type='exclusive' so every
processor instance receives config updates
- handle_one_from_queue receives consumer as parameter for correct
per-connection ack/nack
LibrarianClient:
- New shared client class replacing duplicated librarian request-response
code across 6+ services (chunking, decoders, RAG, etc.)
- Uses stream-document instead of get-document-content for fetching
document content in 1MB chunks (avoids broker message size limits)
- Standalone object (self.librarian = LibrarianClient(...)) not a mixin
- get-document-content marked deprecated in schema and OpenAPI spec
Serialisation:
- Extracted dataclass_to_dict/dict_to_dataclass to shared
serialization.py (used by both Pulsar and RabbitMQ backends)
Librarian queues:
- Changed from flow class (persistent) back to request/response class
now that stream-document eliminates large single messages
- API upload chunk size reduced from 5MB to 3MB to stay under broker
limits after base64 encoding
Factory and CLI:
- get_pubsub() handles 'rabbitmq' backend with RabbitMQ connection params
- add_pubsub_args() includes RabbitMQ options (host, port, credentials)
- add_pubsub_args(standalone=True) defaults to localhost for CLI tools
- init_trustgraph skips Pulsar admin setup for non-Pulsar backends
- tg-dump-queues and tg-monitor-prompts use backend abstraction
- BaseClient and ConfigClient accept generic pubsub config
The metadata field (list of triples) in the pipeline Metadata class
was redundant. Document metadata triples already flow directly from
librarian to triple-store via emit_document_provenance() - they don't
need to pass through the extraction pipeline.
Additionally, chunker and PDF decoder were overwriting metadata to []
anyway, so any metadata passed through the pipeline was being
discarded.
Changes:
- Remove metadata field from Metadata dataclass
(schema/core/metadata.py)
- Update all Metadata instantiations to remove metadata=[]
parameter
- Remove metadata handling from translators (document_loading,
knowledge)
- Remove metadata consumption from extractors (ontology, agent)
- Update gateway serializers and import handlers
- Update all unit, integration, and contract tests
Tech spec
BlobStore (trustgraph-flow/trustgraph/librarian/blob_store.py):
- get_stream() - yields document content in chunks for streaming retrieval
- create_multipart_upload() - initializes S3 multipart upload, returns
upload_id
- upload_part() - uploads a single part, returns etag
- complete_multipart_upload() - finalizes upload with part etags
- abort_multipart_upload() - cancels and cleans up
Cassandra schema (trustgraph-flow/trustgraph/tables/library.py):
- New upload_session table with 24-hour TTL
- Index on user for listing sessions
- Prepared statements for all operations
- Methods: create_upload_session(), get_upload_session(),
update_upload_session_chunk(), delete_upload_session(),
list_upload_sessions()
- Schema extended with UploadSession, UploadProgress, and new
request/response fields
- Librarian methods: begin_upload, upload_chunk, complete_upload,
abort_upload, get_upload_status, list_uploads
- Service routing for all new operations
- Python SDK with transparent chunked upload:
- add_document() auto-switches to chunked for files > 10MB
- Progress callback support (on_progress)
- get_pending_uploads(), get_upload_status(), abort_upload(),
resume_upload()
- Document table: Added parent_id and document_type columns with index
- Document schema (knowledge/document.py): Added document_id field for
streaming retrieval
- Librarian operations:
- add-child-document for extracted PDF pages
- list-children to get child documents
- stream-document for chunked content retrieval
- Cascade delete removes children when parent is deleted
- list-documents filters children by default
- PDF decoder (decoding/pdf/pdf_decoder.py): Updated to stream large
documents from librarian API to temp file
- Librarian service (librarian/service.py): Sends document_id instead of
content for large PDFs (>2MB)
- Deprecated tools (load_pdf.py, load_text.py): Added deprecation
warnings directing users to tg-add-library-document +
tg-start-library-processing
Remove load_pdf and load_text utils
Move chunker/librarian comms to base class
Updating tests
