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/*
** Zabbix
** Copyright (C) 2001-2021 Zabbix SIA
**
** This program is free software; you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 2 of the License, or
** (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
** GNU General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with this program; if not, write to the Free Software
** Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
**/
package postgres
import (
"context"
"crypto/tls"
"database/sql"
"fmt"
"net"
"net/url"
"path/filepath"
"strings"
"sync"
"time"
"github.com/jackc/pgx/v4/pgxpool"
"github.com/jackc/pgx/v4/stdlib"
"github.com/omeid/go-yarn"
"zabbix.com/pkg/log"
"zabbix.com/pkg/tlsconfig"
"zabbix.com/pkg/uri"
"zabbix.com/pkg/zbxerr"
)
const MinSupportedPGVersion = 100000
type PostgresClient interface {
Query(ctx context.Context, query string, args ...interface{}) (rows *sql.Rows, err error)
QueryByName(ctx context.Context, queryName string, args ...interface{}) (rows *sql.Rows, err error)
QueryRow(ctx context.Context, query string, args ...interface{}) (row *sql.Row, err error)
QueryRowByName(ctx context.Context, queryName string, args ...interface{}) (row *sql.Row, err error)
PostgresVersion() int
}
// PGConn holds pointer to the Pool of Postgres Instance.
type PGConn struct {
client *sql.DB
callTimeout time.Duration
ctx context.Context
lastTimeAccess time.Time
version int
queryStorage *yarn.Yarn
}
var errorQueryNotFound = "query %q not found"
// Query wraps pgxpool.Query.
func (conn *PGConn) Query(ctx context.Context, query string, args ...interface{}) (rows *sql.Rows, err error) {
rows, err = conn.client.QueryContext(ctx, query, args...)
if ctxErr := ctx.Err(); ctxErr != nil {
err = ctxErr
}
return
}
// QueryByName executes a query from queryStorage by its name and returns a singe row.
func (conn *PGConn) QueryByName(ctx context.Context, queryName string, args ...interface{}) (rows *sql.Rows, err error) {
if sql, ok := (*conn.queryStorage).Get(queryName + sqlExt); ok {
normalizedSQL := strings.TrimRight(strings.TrimSpace(sql), ";")
return conn.Query(ctx, normalizedSQL, args...)
}
return nil, fmt.Errorf(errorQueryNotFound, queryName)
}
// QueryRow wraps pgxpool.QueryRow.
func (conn *PGConn) QueryRow(ctx context.Context, query string, args ...interface{}) (row *sql.Row, err error) {
row = conn.client.QueryRowContext(ctx, query, args...)
if ctxErr := ctx.Err(); ctxErr != nil {
err = ctxErr
}
return
}
// QueryRowByName executes a query from queryStorage by its name and returns a singe row.
func (conn *PGConn) QueryRowByName(ctx context.Context, queryName string, args ...interface{}) (row *sql.Row, err error) {
if sql, ok := (*conn.queryStorage).Get(queryName + sqlExt); ok {
normalizedSQL := strings.TrimRight(strings.TrimSpace(sql), ";")
return conn.QueryRow(ctx, normalizedSQL, args...)
}
return nil, fmt.Errorf(errorQueryNotFound, queryName)
}
// GetPostgresVersion exec SQL query to retrieve the version of PostgreSQL server we are currently connected to.
func getPostgresVersion(ctx context.Context, conn *sql.DB) (version int, err error) {
err = conn.QueryRowContext(ctx, `select current_setting('server_version_num');`).Scan(&version)
return
}
// PostgresVersion returns the version of PostgreSQL server we are currently connected to.
func (conn *PGConn) PostgresVersion() int {
return conn.version
}
// updateAccessTime updates the last time a connection was accessed.
func (conn *PGConn) updateAccessTime() {
conn.lastTimeAccess = time.Now()
}
// ConnManager is a thread-safe structure for manage connections.
type ConnManager struct {
sync.Mutex
connMutex sync.Mutex
connections map[uri.URI]*PGConn
keepAlive time.Duration
connectTimeout time.Duration
callTimeout time.Duration
Destroy context.CancelFunc
queryStorage yarn.Yarn
}
// NewConnManager initializes connManager structure and runs Go Routine that watches for unused connections.
func NewConnManager(keepAlive, connectTimeout, callTimeout,
hkInterval time.Duration, queryStorage yarn.Yarn) *ConnManager {
ctx, cancel := context.WithCancel(context.Background())
connMgr := &ConnManager{
connections: make(map[uri.URI]*PGConn),
keepAlive: keepAlive,
connectTimeout: connectTimeout,
callTimeout: callTimeout,
Destroy: cancel, // Destroy stops originated goroutines and closes connections.
queryStorage: queryStorage,
}
go connMgr.housekeeper(ctx, hkInterval)
return connMgr
}
// closeUnused closes each connection that has not been accessed at least within the keepalive interval.
func (c *ConnManager) closeUnused() {
c.connMutex.Lock()
defer c.connMutex.Unlock()
for uri, conn := range c.connections {
if time.Since(conn.lastTimeAccess) > c.keepAlive {
conn.client.Close()
delete(c.connections, uri)
log.Debugf("[%s] Closed unused connection: %s", pluginName, uri.Addr())
}
}
}
// closeAll closes all existed connections.
func (c *ConnManager) closeAll() {
c.connMutex.Lock()
for uri, conn := range c.connections {
conn.client.Close()
delete(c.connections, uri)
}
c.connMutex.Unlock()
}
// housekeeper repeatedly checks for unused connections and closes them.
func (c *ConnManager) housekeeper(ctx context.Context, interval time.Duration) {
ticker := time.NewTicker(interval)
for {
select {
case <-ctx.Done():
ticker.Stop()
c.closeAll()
return
case <-ticker.C:
c.closeUnused()
}
}
}
// create creates a new connection with given credentials.
func (c *ConnManager) create(uri uri.URI, details tlsconfig.Details) (*PGConn, error) {
c.connMutex.Lock()
defer c.connMutex.Unlock()
if _, ok := c.connections[uri]; ok {
// Should never happen.
panic("connection already exists")
}
ctx := context.Background()
host := uri.Host()
port := uri.Port()
if uri.Scheme() == "unix" {
socket := uri.Addr()
host = filepath.Dir(socket)
ext := filepath.Ext(filepath.Base(socket))
if len(ext) <= 1 {
return nil, fmt.Errorf("incorrect socket: %q", socket)
}
port = ext[1:]
}
dbname, err := url.QueryUnescape(uri.GetParam("dbname"))
if err != nil {
return nil, err
}
dsn := fmt.Sprintf("host=%s port=%s dbname=%s user=%s",
host, port, dbname, uri.User())
if uri.Password() != "" {
dsn += " password=" + uri.Password()
}
client, err := createTLSClient(dsn, c.connectTimeout, details)
if err != nil {
return nil, err
}
serverVersion, err := getPostgresVersion(ctx, client)
if err != nil {
return nil, err
}
if serverVersion < MinSupportedPGVersion {
return nil, fmt.Errorf("postgres version %d is not supported", serverVersion)
}
c.connections[uri] = &PGConn{
client: client,
callTimeout: c.callTimeout,
version: serverVersion,
lastTimeAccess: time.Now(),
ctx: ctx,
queryStorage: &c.queryStorage,
}
log.Debugf("[%s] Created new connection: %s", pluginName, uri.Addr())
return c.connections[uri], nil
}
func createTLSClient(dsn string, timeout time.Duration, details tlsconfig.Details) (*sql.DB, error) {
config, err := pgxpool.ParseConfig(dsn)
if err != nil {
return nil, err
}
config.ConnConfig.DialFunc = func(ctx context.Context, network, addr string) (net.Conn, error) {
d := net.Dialer{}
ctxTimeout, cancel := context.WithTimeout(context.Background(), timeout)
defer cancel()
conn, err := d.DialContext(ctxTimeout, network, addr)
return conn, err
}
config.ConnConfig.TLSConfig, err = getTLSConfig(details)
if err != nil {
return nil, err
}
return stdlib.OpenDB(*config.ConnConfig), nil
}
func getTLSConfig(details tlsconfig.Details) (*tls.Config, error) {
switch details.TlsConnect {
case "required":
return &tls.Config{InsecureSkipVerify: true}, nil
case "verify_ca":
return tlsconfig.CreateConfig(details, true)
case "verify_full":
return tlsconfig.CreateConfig(details, false)
}
return nil, nil
}
// get returns a connection with given uri if it exists and also updates lastTimeAccess, otherwise returns nil.
func (c *ConnManager) get(uri uri.URI) *PGConn {
c.connMutex.Lock()
defer c.connMutex.Unlock()
if conn, ok := c.connections[uri]; ok {
conn.updateAccessTime()
return conn
}
return nil
}
// GetConnection returns an existing connection or creates a new one.
func (c *ConnManager) GetConnection(uri uri.URI, details tlsconfig.Details) (conn *PGConn, err error) {
c.Lock()
defer c.Unlock()
conn = c.get(uri)
if conn == nil {
conn, err = c.create(uri, details)
}
if err != nil {
err = zbxerr.ErrorConnectionFailed.Wrap(err)
}
return
}
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