Crate zerodds_opcua_bridge 

zerodds-opcua-bridge — the OMG DDS-OPCUA Gateway 1.0 as a daemon on zerodds-dcps.

Crate zerodds-opcua-bridge. Safety classification: STANDARD.

The four no_std + alloc OPC-UA crates (zerodds_opcua_gateway, zerodds_opcua_uacp, zerodds_opcua_server, zerodds_opcua_pubsub) implement the OMG DDS-OPCUA Gateway 1.0 type system and AddressSpace mapping, the Part 6 opc.tcp framing and SecureChannel, the Part 4 Client/Server service set, and the Part 14 (UADP) PubSub wire stack — as libraries, with no DDS runtime, no network listener loop and no configuration file. This crate is the part that was missing: a running process.

What the daemon does

• DDS → OPC UA (Gateway 1.0 §9): DDS topics — named in daemon::config’s opcua.gateway_config (the Spec §10 XML this daemon reads via zerodds_opcua_gateway::xml::parse_gateway_config) — appear in this daemon’s own opc.tcp zerodds_opcua_server::Server AddressSpace: one ObjectNode per DDS domain, one per topic, and one Variable per sample field, kept live by a DDS reader pump (address_space_build). A write to a ua_to_dds_connection node from any OPC-UA client goes back into DDS.
• OPC UA → DDS (Gateway 1.0 §8): the servers named in opcua.client.servers are browsed and subscribed as an OPC-UA client (ua_client); their monitored nodes are written into the configured DDS topics.
• Part 14 PubSub: the opcua.pubsub.connections named in the config run a zerodds_opcua_pubsub::daemon::Publisher/zerodds_opcua_pubsub::daemon::Subscriber pair per connection over UDP multicast (pubsub_glue), publishing DataSets built from DDS topics and writing received DataSets back into DDS.

Types are resolved through the reflective layer ([zerodds-dcps::serialized_type::SerializedTypeSupport], fed by a CompleteTypeObject this daemon builds from an operator-supplied .idl file — idl) rather than a compiled Rust type, the same primitive crates/xrce-agent’s daemon and crates/routing-service use for a topic whose Rust type is not linked in.

Module map

• dynamic_type / dynamic_value — zerodds_types::dynamic ↔ the OPC-UA gateway’s own symbolic type/value model (zerodds_opcua_gateway::dds_to_ua::walker::DdsType / zerodds_opcua_gateway::data_value::Variant).
• idl — compiles an operator-supplied .idl file and builds the [zerodds-dcps::serialized_type::SerializedTypeSupport] for a named type in it.
• dds_bridge — the DDS-side port: participant/topic/reader/writer registration against a real [zerodds-dcps::runtime::DcpsRuntime], plus SEDP-discovered topic enumeration.
• address_space_build — Gateway 1.0 §9.3 AddressSpace materialization (DomainNode/TopicNode/instance nodes) over a live DDS reader.
• ua_client — the OPC-UA client side of Gateway 1.0 §8.
• pubsub_glue — the Part 14 UADP Publisher/Subscriber wiring.
• daemon — the process itself: CLI, YAML config, SIGHUP/SIGTERM, systemd Type=notify, observability.

Feature daemon (default-on) gates the whole crate: the reflective type layer, the DDS port, the AddressSpace/PubSub glue and the process itself. Without it the crate is empty — there is no other consumer of these modules; unlike the four library crates it wires together, this one is the product, not a component.

Modules

address_space_build

Gateway 1.0 §9.3 AddressSpace materialization: DDS Domain → Object node, DDS Topic → Object node, DDS sample → the Variable hierarchy zerodds_opcua_gateway::address_space::build_sample_instance already computes symbolically, turned into real zerodds_opcua_server::address_space::NodeMetas + HasComponent references and kept live by crate::dynamic_value::flatten.

daemon

The zerodds-opcua-bridged process: CLI, YAML config, SIGHUP/SIGTERM, systemd Type=notify, observability.

dds_bridge

The DDS side of the daemon: one DcpsRuntime per configured domain, raw-byte reader/writer registration via DcpsRuntime::register_user_ reader_kind/register_user_writer_kind — the same primitive crates/xrce-agent’s daemon and crates/routing-service use for a topic with no compiled Rust type — and a SerializedTypeSupport per topic, built by crate::idl from the operator’s own .idl file.

dynamic_type

zerodds_types::dynamic::DynamicType → DdsType, the lightweight type tree zerodds_opcua_gateway::dds_to_ua::walker walks (Gateway 1.0 §9.2).

dynamic_value

zerodds_types::dynamic::DynamicData ↔ a flat, path-named list of Variants.

idl

Compiles an operator-supplied .idl file into a model this daemon can resolve DDS types from, and builds the [zerodds-dcps::serialized_type::SerializedTypeSupport] a topic named in the config needs to decode/encode its samples without a compiled Rust type.

pubsub_glue

Part 14 UADP wiring: a Publisher per configured DDS-topic-to-DataSet mapping (DDS → PubSub) and a Subscriber per DataSet-to-DDS-topic mapping (PubSub → DDS), both driven by the same crate::dynamic_value::flatten/crate::dynamic_value::unflatten pair the AddressSpace side uses.

ua_client

Gateway 1.0 §8 (OPC UA → DDS): browses and subscribes a configured foreign OPC-UA server as a client (zerodds_opcua_server::client::Client over zerodds_opcua_server::client::tcp::TcpTransport) and writes the monitored nodes’ values into DDS.