Subscription ops discovered via services/list + services/schema now
register a StreamingHandler (HandlerKind::Stream) that calls
CallConnection::subscribe_with_payload and forwards the remote stream
end-to-end (ADR-049 §8). Query/Mutation ops keep the existing
make_forwarding_handler (HandlerKind::Once).
- Add CallConnection::subscribe_with_payload(payload) mirroring
call_with_payload so the forwarding handler can populate forwarded_for
(ADR-032) + auth_token on the subscription payload. subscribe() now
delegates to subscribe_with_payload.
- Add make_streaming_forwarding_handler() in from_call.rs using
make_streaming_handler + futures::stream::once(...).flatten() to await
subscribe_with_payload then forward its stream.
- Branch build_bundles on spec.op_type (already parsed by rebuild_spec_for).
- Reuse build_forwarded_payload — no new payload-construction code.
- composition_authority: None, scoped_env: None for FromCall streaming
leaves (same as Query/Mutation FromCall leaves).
- Abort cascade (ADR-016 §6) already wired via PendingRequestMap in
subscribe_with_payload.
Closes the gap where a from_call-imported Subscription truncated to the
first value.
Add the foundational types for ADR-049 streaming handlers:
- StreamingHandler, ResponseStream type aliases and HandlerKind enum
(Once | Stream) in registration.rs, with make_streaming_handler() helper
- CallError::invalid_operation_type() in wire.rs (sixth protocol code,
retryable: false)
- HandlerRegistration.handler flipped from Handler to HandlerKind;
HandlerRegistration::new() now takes HandlerKind
- OperationRegistryBuilder absorbs wrapping: with_local/with_leaf/
with_leaf_provenance wrap raw Handler in HandlerKind::Once for
Query/Mutation; new with_local_streaming/with_leaf_streaming take a
StreamingHandler and wrap in HandlerKind::Stream for Subscription.
Builder validates kind matches spec.op_type (mismatch = startup error)
- OperationRegistry::register() returns Result<(), String> with a clear
mismatch message; all call sites updated to handle the Result
- invoke() matches on HandlerKind: Once -> existing path; Stream ->
INVALID_OPERATION_TYPE error envelope (guards against silent
truncation; invoke_streaming() added in a downstream task)
- OverlayOperationEnv::invoke_with_policy matches on HandlerKind:
Once -> dispatch; Stream -> INVALID_OPERATION_TYPE (composition is
request/response-only)
- Migrated every HandlerRegistration::new() construction site (~95)
to wrap raw Handler in HandlerKind::Once(handler); the builder sites
are handled by the builder-absorbs-wrapping change
- Updated two websocket subscription tests that relied on Subscription
ops dispatching via invoke() to expect INVALID_OPERATION_TYPE
- Added unit tests for invoke/register validation and
make_streaming_handler
The #2 gap in alknet-call: discovers the remote peer's External operations
via services/list + services/schema and registers them in the connection's
Layer 2 overlay as FromCall-provenance leaves with forwarding handlers. The
discovery mechanism was already implemented in registry/discovery.rs;
from_call is the client-side consumer of that API.
src/client/from_call.rs:
- from_call(connection, FromCallConfig) -> Result<Vec<HandlerRegistration>,
AdapterError>. Calls services/list then services/schema for each op,
rebuilds OperationSpec from the schema JSON (parsing op_type, visibility,
error_schemas, access_control), constructs a forwarding handler that calls
the remote op via CallConnection::call(), and returns FromCall-provenance
bundles (composition_authority: None, scoped_env: None, empty capabilities,
remote_safe: false per ADR-028 §4).
- FromCallConfig { namespace_prefix: Option<String>, operation_filter:
Option<HashSet<String>> } with builder methods.
- v1 defaults (two-way doors recorded in client-and-adapters.md):
- error-on-collision (DC-3/OQ-28): applying the (possibly empty) prefix
produces a name already seen -> AdapterError::Conflict, not silent
overwrite.
- auto-on-reconnect (DC-2/OQ-27): the overlay is per-connection (Layer 2,
ADR-024), so re-import on reconnect is naturally scoped; the assembly
layer calls from_call immediately after connect().
- Forwarding handler captures an Arc<CallConnection> and, on invocation,
calls the remote op and returns its ResponseEnvelope. The
parent_request_id participates in the cross-node abort cascade
(ADR-016 §6) — if the parent is aborted, the cascade reaches this handler
which sends call.aborted to the remote node; cross-node abort is
transparent.
- Trust is transitive (recorded in spec): a from_call-imported op executes
the remote node's code; scoped_env bounds which ops are reachable, not
what they do.
OperationContext.internal is now pub (was pub(crate)) so downstream
consumers (assembly layer, integration tests) can construct contexts for
overlay-env dispatch.
Tests (207 lib + 2 integration):
- Unit: rebuild_spec name/prefix/op_type/visibility/error_schemas/acl;
unknown op_type -> SchemaParse; missing op_type -> SchemaParse;
FromCallConfig builder; from_call against a mock connection returns
DiscoveryFailed (no transport); FromCall provenance + leaf fields + remote_safe false.
- Integration (tests/two_node_call.rs): from_call over a real QUIC loopback
— CallClient connects, from_call discovers server/echo, registers the
bundle in the overlay, and the forwarding handler round-trips an input
through the overlay env to the remote op and back.
clippy + fmt + test all green.
Refs: tasks/call/client/from-call.md
Refs: docs/architecture/decisions/017-call-protocol-client-and-adapter-contract.md §3, §6
Refs: docs/architecture/crates/call/client-and-adapters.md §from_call
