[j0sh]

Support sync and async on_payment_session callbacks in call_runner and expose LivePaymentSession.manifest_id for payment attribution. Invoke the callback for each new session.

Validate segCreds when parsing signer responses and remove redundant caller checks. Cover callback ordering, failures, and cancellation.

[eliteprox]

Still reviewing the error handling and payment status reporting, but here is one nit

[eliteprox]

Overall changes lgtm and test fine. Added one more suggestion to call_runner.

For context, we're using the on_payment_session callback with manifest_id in builder-core to confirm if payment was sent for the job.

[Copilot]

🟢 Approval recommended

Static review identified no blocking issues in callback handling or signer validation, and the added tests cover the key failure paths; tests were not executed.

No open issues 🎉

What changed in this PR

Adds payment-session notifications to runner calls, allowing callers to attribute payments using the session’s manifest ID.

Changes:

• Supports synchronous and asynchronous callbacks for each new payment session, before dispatching the paid request.
• Exposes LivePaymentSession.manifest_id and centralizes segCreds validation in signer-response parsing.
• Adds tests for callback ordering, failures, cancellation, and manifest attribution.

File	Description
tests/​test_live_runner.py	Tests callback sequencing, error propagation, and cancellation.
tests/​test_live_payment_session.py	Verifies the exposed manifest ID.
src/​livepeer_gateway/​remote_signer.py	Adds the manifest property and validates segment credentials centrally.
src/​livepeer_gateway/​live_runner.py	Implements payment-session callbacks and removes redundant validation.
src/​livepeer_gateway/​__init__.py	Exports the callback type.
CHANGELOG.md	Documents the new callback and manifest property.

_{Review effort: Balanced}

[eliteprox]

Once await payment_session.get_payment() returns on line 851, the remote signer has already persisted the ticket and debited the caller's allocation, but call_runner only surfaces that payment_session through on_payment_session. This makes it hard to match job attempts that recorded cost by successfully signing, but failing on job start attempt, leading to regression in billing accuracy.

Would you be open to accumulating each signed payment_session into a list immediately after get_payment() succeeds (before awaiting on_payment_session) and attaching payment_sessions: tuple[LivePaymentSession, ...] = () (or manifest_ids: tuple[str, ...] = ()) to LiveRunnerCallResult, LiveRunnerCallStream, and LivepeerGatewayError? That way consumers recording a job attempt can read every signed manifest_id and whether payment was sent (bool(payment_sessions)) directly from the returned result or caught error, while keeping on_payment_session for callers that want to persist pre-dispatch state (more context in NE-Build-Track/livepeer-builder-core#33 (comment)). This way we're not relying on a callback hook for the manifest_id.

• On LiveRunnerCallResult (lines 161–173) and LiveRunnerCallStream (lines 176–196), payment_session is cleared to None when payment_type == "fixed" (line 892 and line 939), and when multiple 402 challenges are signed across retries (as in test_reports_each_successful_session_before_dispatch), only the last payment_session and session_id are retained on the return value.
• When the paid runner request subsequently raises a non-402 LivepeerHTTPError (line 944), fails JSON decoding (lines 923–930), or exhausts challenge retries (line 951), the raised LivepeerGatewayError carries none of the sessions signed during the attempt.

[j0sh]

What regression in billing accuracy?

Is there a reason this needs to be built into the API? Can accomplish the same with

payment_sessions = []
await call_runner(
    ...,
    on_payment_session=payment_sessions.append,
)

[Copilot]

🟢 Approval recommended

Static review found no blocking issues in callback handling, signer validation, or the accompanying tests; tests were not executed.

No open issues 🎉

_{Review effort: Balanced}