Jonathan
35 lines
899 B
Python
35 lines
899 B
Python
import psycopg
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def claim_next(conn: psycopg.Connection) -> str | None:
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"""Atomically claim the oldest queued job. Returns its id or None."""
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with conn.cursor() as cur:
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cur.execute(
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"""
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SELECT id FROM "Job"
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WHERE state = 'requested'
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ORDER BY "createdAt" ASC
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FOR UPDATE SKIP LOCKED
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LIMIT 1
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"""
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)
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row = cur.fetchone()
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if row is None:
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conn.rollback()
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return None
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job_id = row[0]
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cur.execute(
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"""
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UPDATE "Job"
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SET state = 'matching',
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"currentStage" = 'match',
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"claimedAt" = now(),
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attempts = attempts + 1,
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"updatedAt" = now()
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WHERE id = %s
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""",
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(job_id,),
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)
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conn.commit()
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return job_id
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