WSv2 egress relays upstream events verbatim without the HTTP-path
namespace restore, so flattening requests that take the WSv2 branch
would surface flattened tool names the client cannot match. Resolve
the WS transport decision before flattening and skip flattening only
when the request will actually go WSv2 (passthrough accounts return
via HTTP before the WSv2 branch and still flatten).
Also check all type assertions in responses_namespace_test.go to
satisfy golangci-lint errcheck.
Resolve conflict in openai_gateway_passthrough.go streaming path: keep
main's normalizeCompletedImageGenerationStatus normalization ahead of
this branch's namespace restore block, mirroring the established order
in openai_gateway_response_handling.go.
The snapshot taken before dispatching the OAuth response handler still used
raw c.Writer.Size(), while handleOpenAIImagesOAuthResponseError compares it
against the keepalive-adjusted size. From the second failover round on, the
previous round's heartbeat bytes made the raw snapshot positive while the
adjusted size stayed -1, so a retryable upstream error was misjudged as
'response already written': the failover was swallowed and the client got a
committed 200 with a whitespace-only body.
Snapshot now uses OpenAIImagesJSONKeepaliveAdjustedWrittenSize, matching the
comparison side. Regression test simulates a prior-round heartbeat before
ForwardImages and asserts the retryable error still converts to
UpstreamFailoverError (verified red without the fix, green with it).
Codex/OpenAI upstream switched from a WebSocket pool to HTTP/2. The
outbound H2 transport set neither ReadIdleTimeout nor ResponseHeaderTimeout
(the OpenAI profile forces ResponseHeaderTimeout=0), so a pooled H2
connection silently killed by a proxy/NAT becomes a "dead connection":
both ends believe it is alive and a request assigned to it hangs until the
OS TCP retransmit timeout (minutes) before the first byte — observed as an
8m37s TTFT with an eventual 200. Occasional (only when a request lands on a
dead pooled conn) and across all groups (shared OpenAI transport); worse on
larger idle pools.
Explicitly configure http2 on the openai_h2 transport and enable active
PING health checks (ReadIdleTimeout=15s, PingTimeout=15s) so dead
connections are detected and evicted at the source, instead of relying on
ResponseHeaderTimeout as an after-the-fact backstop. Scoped to the
openai_h2 path only; Claude/Gemini (default) and h1 modes are untouched.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Wesley Liddick