storj/private/dbutil/pgutil/schema.go
paul cannon bbdb351e5e all: use jackc/pgx in place of lib/pq
What:

Use the github.com/jackc/pgx postgresql driver in place of
github.com/lib/pq.

Why:

github.com/lib/pq has some problems with error handling and context
cancellations (i.e. it might even issue queries or DML statements more
than once! see https://github.com/lib/pq/issues/939). The
github.com/jackx/pgx library appears not to have these problems, and
also appears to be better engineered and implemented (in particular, it
doesn't use "exceptions by panic"). It should also give us some
performance improvements in some cases, and even more so if we can use
it directly instead of going through the database/sql layer.

Change-Id: Ia696d220f340a097dee9550a312d37de14ed2044
2020-07-13 15:54:41 +00:00

92 lines
2.5 KiB
Go

// Copyright (C) 2019 Storj Labs, Inc.
// See LICENSE for copying information.
// Package pgutil contains utilities for postgres
package pgutil
import (
"context"
"crypto/rand"
"database/sql"
"encoding/hex"
"net/url"
"strings"
)
// CreateRandomTestingSchemaName creates a random schema name string.
func CreateRandomTestingSchemaName(n int) string {
data := make([]byte, n)
_, err := rand.Read(data)
if err != nil {
panic(err)
}
return hex.EncodeToString(data)
}
// ConnstrWithSchema adds schema to a connection string
func ConnstrWithSchema(connstr, schema string) string {
if strings.Contains(connstr, "?") {
connstr += "&options="
} else {
connstr += "?options="
}
return connstr + url.QueryEscape("--search_path="+QuoteIdentifier(schema))
}
// ParseSchemaFromConnstr returns the name of the schema parsed from the
// connection string if one is provided
func ParseSchemaFromConnstr(connstr string) (string, error) {
url, err := url.Parse(connstr)
if err != nil {
return "", err
}
queryValues := url.Query()
// this is the Proper™ way to encode search_path in a pg connection string
options := queryValues["options"]
for _, option := range options {
if strings.HasPrefix(option, "--search_path=") {
return UnquoteIdentifier(option[len("--search_path="):]), nil
}
}
// this is another way we've used before; supported brokenly as a kludge in github.com/lib/pq
schema := queryValues["search_path"]
if len(schema) > 0 {
return UnquoteIdentifier(schema[0]), nil
}
return "", nil
}
// QuoteSchema quotes schema name for
func QuoteSchema(schema string) string {
return QuoteIdentifier(schema)
}
// Execer is for executing sql
type Execer interface {
ExecContext(ctx context.Context, query string, args ...interface{}) (sql.Result, error)
}
// CreateSchema creates a schema if it doesn't exist.
func CreateSchema(ctx context.Context, db Execer, schema string) (err error) {
for try := 0; try < 5; try++ {
_, err = db.ExecContext(ctx, `CREATE SCHEMA IF NOT EXISTS `+QuoteSchema(schema)+`;`)
// Postgres `CREATE SCHEMA IF NOT EXISTS` may return "duplicate key value violates unique constraint".
// In that case, we will retry rather than doing anything more complicated.
//
// See more in: https://stackoverflow.com/a/29908840/192220
if IsConstraintError(err) {
continue
}
return err
}
return err
}
// DropSchema drops the named schema
func DropSchema(ctx context.Context, db Execer, schema string) error {
_, err := db.ExecContext(ctx, `DROP SCHEMA `+QuoteSchema(schema)+` CASCADE;`)
return err
}