Cody Rose
101 lines
2.7 KiB
Go
101 lines
2.7 KiB
Go
package jdbc
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import (
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"context"
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"errors"
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"fmt"
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"github.com/lib/pq"
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"strings"
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)
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type postgresJDBC struct {
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conn string
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params map[string]string
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}
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func (s *postgresJDBC) ping(ctx context.Context) pingResult {
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// It is crucial that we try to build a connection string ourselves before using the one we found. This is because
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// if the found connection string doesn't include a username, the driver will attempt to connect using the current
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// user's name, which will fail in a way that looks like a determinate failure, thus terminating the waterfall. In
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// contrast, when we build a connection string ourselves, if there's no username, we try 'postgres' instead, which
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// actually has a chance of working.
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return ping(ctx, "postgres", isPostgresErrorDeterminate,
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buildPostgresConnectionString(s.params, true),
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buildPostgresConnectionString(s.params, false),
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s.conn,
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"postgres://"+s.conn)
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}
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func isPostgresErrorDeterminate(err error) bool {
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// Postgres codes from https://www.postgresql.org/docs/current/errcodes-appendix.html
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if pqErr, isPostgresError := err.(*pq.Error); isPostgresError {
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switch pqErr.Code {
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case "28P01":
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// Invalid username/password
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return true
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case "3D000":
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// Unknown database
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return false // "Indeterminate" so that other connection variations will be tried
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case "3F000":
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// Unknown schema
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return false // "Indeterminate" so that other connection variations will be tried
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}
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}
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return false
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}
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func joinKeyValues(m map[string]string, sep string) string {
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var data []string
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for k, v := range m {
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if v == "" {
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continue
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}
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data = append(data, fmt.Sprintf("%s=%s", k, v))
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}
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return strings.Join(data, sep)
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}
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func parsePostgres(subname string) (jdbc, error) {
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// expected form: //HOST/DB?key=value&key=value
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hostAndDB, paramString, _ := strings.Cut(subname, "?")
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if !strings.HasPrefix(hostAndDB, "//") {
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return nil, errors.New("expected host to start with //")
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}
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hostAndDB = strings.TrimPrefix(hostAndDB, "//")
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host, database, _ := strings.Cut(hostAndDB, "/")
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params := map[string]string{
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"host": host,
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"dbname": database,
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}
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for _, param := range strings.Split(paramString, "&") {
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key, val, _ := strings.Cut(param, "=")
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params[key] = val
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}
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return &postgresJDBC{subname[2:], params}, nil
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}
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func buildPostgresConnectionString(params map[string]string, includeDbName bool) string {
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data := map[string]string{
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// default user
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"user": "postgres",
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}
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for key, val := range params {
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if key == "host" {
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if h, p, found := strings.Cut(val, ":"); found {
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data["host"] = h
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data["port"] = p
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continue
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}
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}
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if key == "dbname" && !includeDbName {
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continue
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}
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data[key] = val
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}
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return joinKeyValues(data, " ")
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}
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