/
sql.go
127 lines (111 loc) · 3.14 KB
/
sql.go
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package history
import (
"database/sql"
"errors"
"os"
)
var (
// ErrNoSchemaDefinedForDriver is the error for when you've used a driver
// with no schema defined. Programmer error.
ErrNoSchemaDefinedForDriver = errors.New("schema not defined for driver")
qlSchema = `CREATE TABLE IF NOT EXISTS history
(namespace string NOT NULL,
service string NOT NULL,
message string NOT NULL,
stamp time NOT NULL)`
schemaByDriver = map[string]string{
"ql": qlSchema,
"ql-mem": qlSchema,
"postgres": `CREATE TABLE IF NOT EXISTS history
(namespace text NOT NULL,
service text NOT NULL,
message text NOT NULL,
stamp timestamp with time zone NOT NULL)`,
}
)
// A history DB that uses a SQL database
type sqlHistoryDB struct {
driver *sql.DB
schema string
}
func NewSQL(driver, datasource string) (DB, error) {
db, err := sql.Open(driver, datasource)
if err != nil {
return nil, err
}
historyDB := &sqlHistoryDB{
driver: db,
schema: schemaByDriver[driver],
}
if historyDB.schema == "" {
return nil, ErrNoSchemaDefinedForDriver
}
return historyDB, historyDB.ensureTables()
}
func (db *sqlHistoryDB) queryEvents(query string, params ...interface{}) ([]Event, error) {
eventRows, err := db.driver.Query(query, params...)
if err != nil {
return nil, err
}
defer eventRows.Close()
events := []Event{}
for eventRows.Next() {
var event Event
eventRows.Scan(&event.Service, &event.Msg, &event.Stamp)
events = append(events, event)
}
if err = eventRows.Err(); err != nil {
return nil, err
}
return events, nil
}
func (db *sqlHistoryDB) AllEvents(namespace string) ([]Event, error) {
return db.queryEvents(`SELECT service, message, stamp
FROM history
WHERE namespace = $1
ORDER BY service, stamp DESC`, namespace)
}
func (db *sqlHistoryDB) EventsForService(namespace, service string) ([]Event, error) {
return db.queryEvents(`SELECT service, message, stamp
FROM history
WHERE namespace = $1 AND service = $2
ORDER BY stamp DESC`, namespace, service)
}
func (db *sqlHistoryDB) LogEvent(namespace, service, msg string) error {
tx, err := db.driver.Begin()
if err != nil {
return err
}
_, err = tx.Exec(`INSERT INTO history
(namespace, service, message, stamp)
VALUES ($1, $2, $3, now())`, namespace, service, msg)
if err == nil {
err = tx.Commit()
}
return err
}
func (db *sqlHistoryDB) ensureTables() (err error) {
// ql requires a temp directory, but will apparently not create it
// if it doesn't exist; and that can be the case when run inside a
// container.
os.Mkdir(os.TempDir(), 0777)
tx, err := db.driver.Begin()
if err != nil {
return err
}
// cznic/ql has its own idea of types; this will need to be
// adapted for other DB drivers.
// http://godoc.org/github.com/cznic/ql#hdr-Types
_, err = tx.Exec(db.schema)
if err != nil {
return err
}
err = tx.Commit()
if err != nil {
return err
}
return nil
}
func (db *sqlHistoryDB) Close() error {
return db.driver.Close()
}