Fix MCP gateway ACL check for multi-replica deployments - #8243
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The EMQX authz callback is load-balanced across forge replicas, but checkMcpTopic compared the topic's platformId against the answering replica's own randomly-minted id. With more than one replica this denied ff/v1/mcp/... request publishes and response subscriptions whenever the callback landed on a different replica, surfacing as intermittent 504s from /mcp. The platformId is a routing address, not an identity claim - the client is already authenticated as forge_platform - so validate its shape (UUID) instead of its identity.
Steve-Mcl
enabled auto-merge (squash)
August 24, 2026 10:59
cstns
approved these changes
Aug 24, 2026
Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## main #8243 +/- ##
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+ Coverage 75.94% 76.09% +0.14%
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Files 445 445
Lines 23990 23991 +1
Branches 6404 6404
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+ Hits 18220 18255 +35
+ Misses 5770 5736 -34
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Description
The EMQX authz callback is load-balanced across forge replicas, but checkMcpTopic compared the topic's platformId against the answering replica's own randomly-minted id. With more than one replica this denied ff/v1/mcp/... request publishes and response subscriptions whenever the callback landed on a different replica, surfacing as intermittent 504s from /mcp.
The platformId is a routing address, not an identity claim - the client is already authenticated as forge_platform - so validate its shape (UUID) instead of its identity.
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