fix: ensure database commits complete before HTTP responses #722
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Use scope="function" for database dependencies to prevent race conditions where DIRAC queries data immediately after DiracX writes it. With the default scope="request", commits were happening after sending responses, causing intermittent "No sandbox matches the requirements" errors. Introduced DBDepends helper using functools.partial to consistently apply scope="function" to all database dependencies (AuthDB, JobDB, JobLoggingDB, PilotAgentsDB, SandboxMetadataDB, TaskQueueDB, JobParametersDB). This ensures transaction commits complete before HTTP responses are sent, eliminating timing-based race conditions in DIRAC-DiracX interactions.
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Problem
When DIRAC calls DiracX endpoints that write to the database and then immediately queries the same data, intermittent "No sandbox matches the requirements" errors occur due to a race condition.
Root Cause
With FastAPI's default
scope="request"for dependencies:This causes DIRAC to query before the data is committed, resulting in race condition failures.
Solution
Changed all database dependencies to use
scope="function"which ensures:Changes
DBDependshelper usingfunctools.partial(Depends, scope="function")This prevents timing-based race conditions in all DIRAC-DiracX database interactions.
Testing
This fix addresses the production issue where sandbox uploads were intermittently failing with "No sandbox matches the requirements" errors immediately after successful DiracX uploads.