Python: add agent-framework-hosting-invocations channel#5640
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eavanvalkenburg wants to merge 6 commits intomicrosoft:feature/python-hostingfrom
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Python: add agent-framework-hosting-invocations channel#5640eavanvalkenburg wants to merge 6 commits intomicrosoft:feature/python-hostingfrom
eavanvalkenburg wants to merge 6 commits intomicrosoft:feature/python-hostingfrom
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New ``agent-framework-hosting`` package implementing ADR 0026 / SPEC-002:
the channel-neutral host that lets a single ``Agent`` (or ``Workflow``)
fan out across multiple wire protocols ("channels") behind one Starlette
ASGI app.
Surface (re-exported from ``agent_framework_hosting``):
- ``AgentFrameworkHost`` — wraps a hostable target, mounts channels onto
an ASGI app, owns per-isolation-key ``AgentSession`` reuse, threads
request context (``response_id`` / ``previous_response_id``) into
context providers via an ``ExitStack`` of ``bind_request_context``
calls, and exposes an opt-in Hypercorn ``serve()`` helper (extra
``[serve]``).
- ``Channel`` protocol + ``ChannelContribution`` — the surface a channel
package implements (routes, lifespans, identity hooks, …).
- ``ChannelRequest`` / ``ChannelSession`` / ``ChannelIdentity`` /
``ChannelPush`` / ``ChannelCommand[Context]`` / ``ChannelRunHook`` /
``ChannelStreamTransformHook`` / ``DeliveryReport`` /
``HostedRunResult`` / ``ResponseTarget`` / ``ResponseTargetKind`` /
``apply_run_hook`` — channel-side dataclasses + helpers.
- ``IsolationKeys`` + ``ISOLATION_HEADER_USER`` / ``..._CHAT`` +
``get/set/reset_current_isolation_keys`` — the host's ASGI middleware
reads the ``x-agent-{user,chat}-isolation-key`` headers off each
inbound request and exposes them to the agent stack via a
``ContextVar`` so storage-side providers (e.g.
``FoundryHostedAgentHistoryProvider``) can apply per-tenant
partitioning without channels having to forward anything.
Includes 45 unit tests covering the host, channel contributions,
isolation contextvar, and shared types. Registers the package in
``python/pyproject.toml`` ``[tool.uv.sources]`` and adds the matching
pyright ``executionEnvironments`` entry for tests.
Hypercorn is an optional dependency (``[serve]`` extra); the soft import
in ``serve()`` is annotated for pyright since it isn't on the default
install.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Source-code changes - _suppress_already_consumed: narrow contract — RuntimeError now logs at WARNING with exc_info; non-RuntimeError still logs at exception(). Docstring clarifies that any non-clean teardown is observable. - _BoundResponseStream: add aclose() and route __await__ through get_final_response() so the binding is always released — fixes contextvar leak when channels abandon the stream or use the await-the-stream convenience. - Lifespan: aggregate startup/shutdown callback errors; every callback runs, all failures are logged with their qualname, and the first error is re-raised so Starlette still aborts boot. - _build_run_kwargs: switch session-cache write to dict.setdefault so concurrent racers cannot orphan a session if create_session ever yields. - _deliver_response: introduce DeliveryReport.failed for push outages vs explicit "no link" drops; an outage no longer triggers an originating fallback so the channel can decide degraded behaviour. Test additions - tests/test_isolation.py (new): full coverage of IsolationKeys, the contextvar helpers, header constants, and end-to-end ASGI middleware lift / reset / passthrough. - tests/test_host.py: TestBindRequestContext, TestBoundResponseStream (aclose / __await__ / __getattr__ forwarding / double-close idempotency), TestWrapInputListMessages (list[Message] LAST precedence), TestLifespanAggregation (startup + shutdown). - tests/test_types.py: TestApplyRunHook (sync/async/None), and TestDeliveryReport (new failed field). - Updated test_push_exception_marks_skipped -> test_push_exception_lands_in_failed_no_fallback to match the new delivery contract. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
moonbox3
reviewed
May 7, 2026
- Refactor workflow checkpoint restoration into shared helpers (_restore_workflow_checkpoint for blocking; the streaming sibling drains the rehydration stream) so the blocking and streaming paths rehydrate identically — clarifies the previously inline _maybe_restore by hoisting the pattern next to the blocking call site. - Document that blocking workflow output is text-only by design; richer modalities ride the streaming AgentResponseUpdate channel, which preserves all content parts. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
These review comments were filed on PR-4 (microsoft#5640) but target lines that live in the hosting-core package (PR-2 / microsoft#5638), so the fixes land here and PR-4's stack will pick them up on rebase. - _suppress_already_consumed: narrow the RuntimeError catch to the two documented benign messages (`Inner stream not available`, `Event loop is closed`); any other RuntimeError now logs at ERROR with a full traceback so executor bugs / runner-context state errors / checkpoint RuntimeErrors during the post-run flush no longer masquerade as benign cleanup noise. Still no propagation (we're in an async-generator finally during teardown) — see the docstring. - _restore_workflow_checkpoint{,_streaming}: log a WARNING when a non-None latest checkpoint drains to zero events, so a stale or partially-written checkpoint_id surfaces as an operator signal instead of a silent state-loss. (The `deliver_response` "no destinations resolvable" vs "every destination errored" concern raised in 3198268038 is already addressed by the existing `failed` vs `skipped` distinction surfaced through `DeliveryReport.failed` — see lines 1080-1102 and the `DeliveryReport` docstring.) Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
New ``agent-framework-hosting-invocations`` package implementing the "Invocations" HTTP channel for the Hosting framework -- a lightweight JSON-over-HTTP shape (``POST /invocations``) for callers that want a single request/response without committing to the full OpenAI Responses envelope. Mounts onto an ``AgentFrameworkHost`` like any other channel. Surface (re-exported from ``agent_framework_hosting_invocations``): - ``InvocationsChannel`` -- concrete ``Channel`` implementation. Owns the Starlette route, parses inbound JSON into a ``ChannelRequest`` (``input`` / ``session`` / ``metadata`` / ``options``), runs the optional ``ChannelRunHook``, calls back into the ``ChannelContext`` to invoke the agent target, and returns a flat JSON envelope (or an SSE stream when ``stream=true``). - 8 unit tests covering route wiring, isolation-key passthrough, hook composition, sync vs streaming paths, and ack-only behaviour for non-originating ``DeliveryReport``s. Registers the package in ``python/pyproject.toml`` ``[tool.uv.sources]`` and adds the matching pyright ``executionEnvironments`` entry. Independent of PR-3 (Responses); both depend only on PR-2 (Hosting core). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
- expand `_stream` docstring to call out the HTTP-200 + `event: error` SSE contract (status committed before generator runs; hard failures surface as the first SSE frame, not an HTTP code) - split chunked text on full-line terminators via `splitlines()` so embedded `\r` / `\r\n` no longer leak into `data:` framing on the wire, breaking EventSource consumers - on `get_final_response()` failure, emit `event: error` instead of silently swallowing — finalize is what triggers history-provider persistence on the agent side, so a 5xx / disk-full / context-provider error must reach the client - add tests covering `stream_transform_hook` (rewrite, drop, async), CRLF-in-chunk framing, and the finalize-error → no-`[DONE]` contract Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Motivation and Context
Implements §7 ("Built-in channels — Invocations") of SPEC-002 (merged via #5549). Pairs with
ResponsesChannelto make anAgentFrameworkHostruntime-compatible with the Foundry Hosted Agents platform (per ADR §11).Description
Adds the new
agent-framework-hosting-invocationspackage (python/packages/hosting-invocations/) with:InvocationsChannel— mountsPOST /invocations/invoke(configurable), accepts the host-native JSON envelope used by Foundry Hosted Agents, and routes to the host's target.Stack
PR-4 of 9. Depends on #PR-2 (
feat/hosting-core). Independent of PR-3.Contribution Checklist