Henry
20308a2d16
Co-authored-by: nova28 <17953305+nova28@users.noreply.github.com> Co-authored-by: Carlos Florencio <carlosmflorencio@gmail.com>
52 lines
2.1 KiB
Go
52 lines
2.1 KiB
Go
package db
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import (
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"context"
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"database/sql"
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"errors"
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"fmt"
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"github.com/jmoiron/sqlx"
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)
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// pgxDriverName mirrors dialect.PGX. Inlined rather than importing
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// internal/db/dialect: that package's own test binary imports internal/db,
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// so internal/db importing dialect back would create a build cycle for
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// dialect's tests.
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const pgxDriverName = "pgx"
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// ErrTaskRowNotFound is returned by LockTaskRowInTx when the named task row
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// does not exist.
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var ErrTaskRowNotFound = errors.New("task row not found")
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// LockTaskRowInTx takes the shared row lock on tasks(id) that serializes any
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// writer able to affect a task-scoped gate condition (session, environment,
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// running-executor, workspace-folder, workspace-group-membership, and the
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// task row's own fields) against every other such writer and against the
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// task row's own concurrent readers of that state.
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//
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// On PostgreSQL this is a real `SELECT ... FOR UPDATE`, held for the
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// lifetime of tx. On SQLite it is a deliberate no-op: the writer pool
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// (OpenSQLite) is capped at one connection, so a single open write
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// transaction already excludes every other write against the same
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// database for its whole lifetime — there is no second writer connection
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// that could interleave. This mirrors the two-primitive split already used
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// by the task-cleanup barrier (task/repository/sqlite/task_cleanup_barrier.go):
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// a caller across a package boundary (this function is shared by both the
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// task and office repositories, which write to the same tasks table using
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// the same underlying writer handle) gets the identical guarantee without
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// duplicating the dialect branch at every call site.
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func LockTaskRowInTx(ctx context.Context, tx *sqlx.Tx, driverName, taskID string) error {
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if driverName != pgxDriverName {
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return nil
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}
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var locked string
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if err := tx.QueryRowContext(ctx, tx.Rebind(`SELECT id FROM tasks WHERE id = ? FOR UPDATE`), taskID).Scan(&locked); err != nil {
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if errors.Is(err, sql.ErrNoRows) {
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return fmt.Errorf("%w: %s", ErrTaskRowNotFound, taskID)
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}
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return fmt.Errorf("lock task row: %w", err)
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}
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return nil
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}
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