79 lines
1.5 KiB
Go
79 lines
1.5 KiB
Go
package dbwait
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import (
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"context"
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"database/sql"
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"fmt"
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"net/url"
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"os"
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"time"
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)
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func Wait(databaseURL *url.URL, period time.Duration, timeout time.Duration) error {
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var err error
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var sqlDB *sql.DB
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switch databaseURL.Scheme {
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case "oracle":
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sqlDB, err = sql.Open("oracle", databaseURL.String())
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if err != nil {
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return err
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}
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case "postgres":
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sqlDB, err = sql.Open("postgres", databaseURL.String())
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if err != nil {
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return err
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}
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}
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defer func() { _ = sqlDB.Close() }()
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ctx, cancel := context.WithTimeout(context.Background(), timeout)
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defer cancel()
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ticker := time.NewTicker(time.Nanosecond)
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<-ticker.C
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LOOP:
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for {
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select {
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case <-ctx.Done():
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return ctx.Err()
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case <-ticker.C:
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queryCtx, queryCancel := context.WithTimeout(ctx, period)
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defer queryCancel()
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switch databaseURL.Scheme {
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case "oracle":
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row := sqlDB.QueryRowContext(queryCtx, "SELECT 1 FROM dual")
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var n int
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err := row.Scan(&n)
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if err != nil {
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fmt.Fprintf(os.Stderr, "%s: %s\n", time.Now().String(), err.Error())
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ticker.Reset(period)
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continue LOOP
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}
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if n != 1 {
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fmt.Fprintf(os.Stderr, "%s: Returned value not 1\n", time.Now().String())
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ticker.Reset(period)
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continue LOOP
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}
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return nil
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case "postgres":
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row := sqlDB.QueryRowContext(queryCtx, "SELECT 1 AS ROW")
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err := row.Err()
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switch {
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case err == nil:
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return nil
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default:
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fmt.Fprintf(os.Stderr, "%s: %s\n", time.Now().String(), err.Error())
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ticker.Reset(period)
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continue LOOP
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}
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}
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}
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}
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}
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