131 lines
2.6 KiB
Go
131 lines
2.6 KiB
Go
package adapter
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import (
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"database/sql"
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"fmt"
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"time"
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)
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/*
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DBAdapter
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Automatically creates connections for each database URL.
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Executes queries on the specified database.
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Closes connections older than ConnectionLiveTime
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*/
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type DBAdapter struct {
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Type string
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MaxAttempts int
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ConnectionLiveTime int
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dbs *DBMap
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}
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type DBMap struct {
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Connections map[string]*sql.DB
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ConnectionAttempts map[string]int
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ConnectionTime map[string]int64
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}
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func (a *DBAdapter) Open(url string) (*sql.DB, error) {
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defer a.CleanUp()
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if a.MaxAttempts == 0 {
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a.MaxAttempts = 6
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}
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if a.ConnectionLiveTime == 0 {
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a.ConnectionLiveTime = 120
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}
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if a.dbs == nil {
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a.dbs = &DBMap{
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Connections: make(map[string]*sql.DB),
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ConnectionAttempts: make(map[string]int),
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ConnectionTime: make(map[string]int64),
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}
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}
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connections := a.dbs.Connections
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attempts := a.dbs.ConnectionAttempts
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lastHits := a.dbs.ConnectionTime
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lastHits[url] = time.Now().Unix()
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if _, ok := connections[url]; !ok {
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connections[url], _ = sql.Open(a.Type, url)
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} else {
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err := connections[url].Ping()
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if err != nil {
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connections[url] = nil
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attempts[url]++
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time.Sleep(time.Duration(5) * time.Second)
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if attempts[url] > a.MaxAttempts {
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return nil, fmt.Errorf(
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`failed to connect to "%s", after %v attempts`,
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url,
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a.MaxAttempts,
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)
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}
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return a.Open(url)
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}
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}
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attempts[url] = 0
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return connections[url], nil
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}
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func (a *DBAdapter) GetDB(url string) *sql.DB {
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if a.dbs == nil {
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return nil
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}
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return a.dbs.Connections[url]
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}
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func (a *DBAdapter) Close() {
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for url, db := range a.dbs.Connections {
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db.Close()
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delete(a.dbs.Connections, url)
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delete(a.dbs.ConnectionAttempts, url)
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delete(a.dbs.ConnectionTime, url)
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}
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a.dbs = nil
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}
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func (a *DBAdapter) CleanUp() {
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if a.dbs == nil {
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return
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}
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lastHits := a.dbs.ConnectionTime
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liveTime := a.ConnectionLiveTime
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for url, db := range a.dbs.Connections {
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if time.Now().Unix()-lastHits[url] > int64(liveTime) {
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db.Close()
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delete(a.dbs.Connections, url)
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delete(a.dbs.ConnectionAttempts, url)
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delete(a.dbs.ConnectionTime, url)
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}
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}
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}
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func (a *DBAdapter) Query(req Query) (*sql.Rows, error) {
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db, err := a.Open(req.Db)
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if err != nil {
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return nil, err
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}
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sfmt, err := db.Prepare(req.Expression)
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if err != nil {
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return nil, err
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}
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return sfmt.Query(req.Data...)
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}
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func (a *DBAdapter) Exec(req Query) (sql.Result, error) {
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db, err := a.Open(req.Db)
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if err != nil {
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return nil, err
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}
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sfmt, err := db.Prepare(req.Expression)
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if err != nil {
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return nil, err
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}
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return sfmt.Exec(req.Data...)
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}
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