forked from arp242/goatcounter
/
session.go
275 lines (234 loc) · 6.53 KB
/
session.go
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// Copyright © 2019 Martin Tournoij – This file is part of GoatCounter and
// published under the terms of a slightly modified EUPL v1.2 license, which can
// be found in the LICENSE file or at https://license.goatcounter.com
package goatcounter
import (
"context"
"crypto/sha256"
"database/sql"
"fmt"
"sync"
"time"
"zgo.at/errors"
"zgo.at/goatcounter/cfg"
"zgo.at/zdb"
"zgo.at/zhttp"
"zgo.at/zlog"
"zgo.at/zstd/zsync"
)
type Session struct {
ID int64 `db:"id"`
Site int64 `db:"site"`
Hash []byte `db:"hash"`
CreatedAt time.Time `db:"created_at"`
LastSeen time.Time `db:"last_seen"`
}
type Salt struct {
mu sync.Mutex
current string
previous string
CycleEvery time.Duration
firstRefresh sync.Once
}
var Salts = Salt{
CycleEvery: 4 * time.Hour,
}
func (s *Salt) Set(current, previous string) {
s.mu.Lock()
s.current = current
s.previous = previous
s.mu.Unlock()
}
func (s *Salt) Clear() {
s.mu.Lock()
s.current = ""
s.previous = ""
s.firstRefresh = sync.Once{}
s.mu.Unlock()
}
func (s *Salt) Get(ctx context.Context) (current, previous string) {
if s.current == "" || s.previous == "" {
s.firstRefresh.Do(func() {
err := s.Refresh(ctx)
if err != nil {
panic(err)
}
})
}
if s.current == "" {
panic("Salt.Get: s.current is empty")
}
if s.previous == "" {
panic("Salt.Get: s.previous is empty")
}
return s.current, s.previous
}
func (s *Salt) Refresh(ctx context.Context) error {
var newsalt []struct {
Salt string `db:"salt"`
CreatedAt time.Time `db:"created_at"`
}
err := zdb.TX(ctx, func(ctx context.Context, db zdb.DB) error {
err := db.SelectContext(ctx, &newsalt,
`select salt, created_at from session_salts order by previous asc`)
if err != nil {
return err
}
if len(newsalt) == 0 { // First run
_, err = db.ExecContext(ctx, `insert into session_salts (previous, salt, created_at)
values (0, $1, $2), (1, $3, $4)`,
zhttp.Secret256(), Now().Format(zdb.Date), zhttp.Secret256(), Now().Format(zdb.Date))
if err != nil {
return err
}
goto get
}
if s.current == "" { // Server restart
goto get
}
if newsalt[1].CreatedAt.Add(s.CycleEvery).After(Now()) {
return nil
}
_, err = db.ExecContext(ctx, `delete from session_salts where previous=1`)
if err != nil {
return err
}
_, err = db.ExecContext(ctx, `update session_salts set previous=1 where previous=0`)
if err != nil {
return err
}
_, err = db.ExecContext(ctx, `insert into session_salts (previous, salt, created_at) values (0, $1, $2)`,
zhttp.Secret256(), Now())
if err != nil {
return err
}
get:
newsalt = newsalt[0:0]
err = db.SelectContext(ctx, &newsalt, `select salt from session_salts order by previous asc`)
if err != nil {
return err
}
s.Set(newsalt[0].Salt, newsalt[1].Salt)
return nil
})
if err != nil {
return errors.Errorf("salt.Refresh: %w", err)
}
return nil
}
// hasPath reports if this session has already visited a path.
func (s *Session) hasPath(ctx context.Context, path string) (bool, error) {
if s.ID == 0 {
return false, errors.Errorf("Session.hasPath: s.ID is 0")
}
var r uint8
err := zdb.MustGet(ctx).GetContext(ctx, &r, `/* Session.hasPath */
select 1 from session_paths where session=$1 and lower(path) = lower($2) limit 1`,
s.ID, path)
if zdb.ErrNoRows(err) {
return false, nil
}
return true, errors.Wrap(err, "Session.hasPath")
}
// GetOrCreate gets the session by hash, creating a new one if it doesn't exist
// yet.
func (s *Session) GetOrCreate(ctx context.Context, path, ua, remoteAddr string) (firstVisit bool, err error) {
return s.getOrCreate(ctx, path, ua, remoteAddr, 0)
}
var hashOnce zsync.Once
func (s *Session) getOrCreate(ctx context.Context, path, ua, remoteAddr string, r int) (firstVisit bool, err error) {
if r > 10 {
zlog.Module("session").Fields(zlog.F{
"remoteAddr": remoteAddr,
"ua": ua,
"siteID": MustGetSite(ctx).ID,
}).Printf("recurse > 10")
return false, nil
}
db := zdb.MustGet(ctx)
site := MustGetSite(ctx)
now := Now()
curSalt, prevSalt := Salts.Get(ctx)
h := sha256.New()
h.Write([]byte(fmt.Sprintf("%d%s%s%s", site.ID, ua, remoteAddr, curSalt)))
hash := h.Sum(nil)
err = db.GetContext(ctx, s, `select * from sessions where site=$1 and hash=$2`, site.ID, hash)
if zdb.ErrNoRows(err) { // Try previous salt.
h := sha256.New()
h.Write([]byte(fmt.Sprintf("%d%s%s%s", site.ID, ua, remoteAddr, prevSalt)))
prevHash := h.Sum(nil)
err = db.GetContext(ctx, s, `select * from sessions where site=$1 and hash=$2`, site.ID, prevHash)
if err == nil {
hash = prevHash
}
}
switch err {
default:
return false, errors.Wrap(err, "Session.GetOrCreate")
case nil:
_, err := db.ExecContext(ctx, `update sessions
set last_seen=$1 where site=$2 and hash=$3`,
now.Format(zdb.Date), site.ID, hash)
if err != nil {
zlog.Errorf("Session.getOrCreate: update: %w", err)
}
has, err := s.hasPath(ctx, path)
if err != nil {
zlog.Errorf("Session.getOrCreate: %w", err)
return false, nil
}
if !has {
_, err = db.ExecContext(ctx, `
insert into session_paths (session, path) values ($1, $2)`,
s.ID, path)
if err != nil {
zlog.Errorf("Session.getOrCreate: insert path: %w", err)
}
}
return !has, nil
case sql.ErrNoRows:
var err error
hh := fmt.Sprintf("%x", hash)
ran := hashOnce.Do(hh, func() {
s.Site = site.ID
s.Hash = hash
s.CreatedAt = now
s.LastSeen = now
err = s.create(ctx, path)
})
if !ran {
time.Sleep(50 * time.Millisecond)
return s.getOrCreate(ctx, path, ua, remoteAddr, r+1)
}
if err != nil {
return false, err
}
go func() {
time.Sleep(10 * time.Second)
hashOnce.Forget(hh)
}()
return true, nil
}
}
func (s *Session) create(ctx context.Context, path string) error {
query := `insert into sessions (site, hash, created_at, last_seen) values ($1, $2, $3, $4)`
args := []interface{}{s.Site, s.Hash, s.CreatedAt.Format(zdb.Date), s.LastSeen.Format(zdb.Date)}
db := zdb.MustGet(ctx)
if cfg.PgSQL {
err := db.GetContext(ctx, &s.ID, query+" returning id", args...)
if err != nil {
return errors.Wrap(err, "Session.create: insert")
}
} else {
res, err := db.ExecContext(ctx, query, args...)
if err != nil {
return errors.Errorf("Session.create: insert: %w", err)
}
s.ID, err = res.LastInsertId()
if err != nil {
return errors.Errorf("Session.create: lastInsertID: %w", err)
}
}
_, err := db.ExecContext(ctx, `insert into session_paths (session, path) values ($1, $2)`, s.ID, path)
return errors.Wrap(err, "Session.create: insert path")
}