unkin-agent
2b37986218
Small Go tool + distroless container used as a K8s initContainer to block an app until its database (Postgres/MySQL) is reachable. Env-var configured (WAITFORDB_* + libpq PG* fallback), configurable timeout/interval, redacted logs, exit codes. Woodpecker CI publishes docker-internal/waitfordb on tag.
32 lines
783 B
Go
32 lines
783 B
Go
package driver
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import (
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"context"
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"database/sql"
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)
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// sqlPinger runs the liveness query against a database/sql handle. It is shared
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// by every engine whose Go driver plugs into database/sql.
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type sqlPinger struct {
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db *sql.DB
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}
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func openSQL(driverName, dsn string) (*sqlPinger, error) {
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db, err := sql.Open(driverName, dsn)
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if err != nil {
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return nil, err
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}
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// A readiness check only ever needs one connection; keep the pool tiny so a
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// failed attempt does not leave idle half-open connections behind.
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db.SetMaxOpenConns(1)
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db.SetMaxIdleConns(0)
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return &sqlPinger{db: db}, nil
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}
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func (p *sqlPinger) Ping(ctx context.Context) error {
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var one int
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return p.db.QueryRowContext(ctx, "SELECT 1").Scan(&one)
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}
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func (p *sqlPinger) Close() error { return p.db.Close() }
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