From ccf64a853421085c890ef2794843bf3992404fae Mon Sep 17 00:00:00 2001
From: whyrusleeping <why@ipfs.io>
Date: Tue, 23 Jun 2020 14:34:15 -0700
Subject: [PATCH] add the real code

---
 journal/journal.go | 142 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 142 insertions(+)
 create mode 100644 journal/journal.go

diff --git a/journal/journal.go b/journal/journal.go
new file mode 100644
index 000000000..faf0fff9d
--- /dev/null
+++ b/journal/journal.go
@@ -0,0 +1,142 @@
+package journal
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+	"sync"
+	"time"
+
+	logging "github.com/ipfs/go-log"
+	"golang.org/x/xerrors"
+)
+
+func InitializeSystemJournal(dir string) error {
+	if err := os.MkdirAll(dir, 0755); err != nil {
+		return err
+	}
+	j, err := OpenFSJournal(dir)
+	if err != nil {
+		return err
+	}
+	currentJournal = j
+	return nil
+}
+
+func Add(sys string, val interface{}) {
+	currentJournal.AddEntry(sys, val)
+}
+
+var log = logging.Logger("journal")
+
+var currentJournal Journal
+
+type Journal interface {
+	AddEntry(system string, obj interface{})
+	Close() error
+}
+
+// fsJournal is a basic journal backed by files on a filesystem
+type fsJournal struct {
+	fi    *os.File
+	fSize int64
+
+	lk sync.Mutex
+
+	journalDir string
+
+	incoming         chan *JournalEntry
+	journalSizeLimit int64
+
+	closing chan struct{}
+}
+
+func OpenFSJournal(dir string) (*fsJournal, error) {
+	fsj := &fsJournal{
+		journalDir:       dir,
+		incoming:         make(chan *JournalEntry, 32),
+		journalSizeLimit: 1 << 30,
+		closing:          make(chan struct{}),
+	}
+
+	if err := fsj.rollJournalFile(); err != nil {
+		return nil, err
+	}
+
+	go fsj.runLoop()
+
+	return fsj, nil
+}
+
+type JournalEntry struct {
+	System    string
+	Timestamp time.Time
+	Val       interface{}
+}
+
+func (fsj *fsJournal) putEntry(je *JournalEntry) error {
+	b, err := json.Marshal(je)
+	if err != nil {
+		return err
+	}
+	n, err := fsj.fi.Write(append(b, '\n'))
+	if err != nil {
+		return err
+	}
+
+	fsj.fSize += int64(n)
+
+	if fsj.fSize >= fsj.journalSizeLimit {
+		fsj.rollJournalFile()
+	}
+
+	return nil
+}
+
+func (fsj *fsJournal) rollJournalFile() error {
+	if fsj.fi != nil {
+		fsj.fi.Close()
+	}
+
+	nfi, err := os.Create(filepath.Join(fsj.journalDir, fmt.Sprintf("lotus-journal-%d.ndjson", time.Now().Unix())))
+	if err != nil {
+		return xerrors.Errorf("failed to open journal file: %w", err)
+	}
+
+	fsj.fi = nfi
+	fsj.fSize = 0
+	return nil
+}
+
+func (fsj *fsJournal) runLoop() {
+	for {
+		select {
+		case je := <-fsj.incoming:
+			if err := fsj.putEntry(je); err != nil {
+				log.Errorw("failed to write out journal entry", "entry", je, "err", err)
+			}
+		case <-fsj.closing:
+			fsj.fi.Close()
+			return
+		}
+	}
+}
+
+func (fsj *fsJournal) AddEntry(system string, obj interface{}) {
+	je := &JournalEntry{
+		System:    system,
+		Timestamp: time.Now(),
+		Val:       obj,
+	}
+	select {
+	case fsj.incoming <- je:
+	case <-fsj.closing:
+		log.Warnw("journal closed but tried to log event", "entry", je)
+	}
+}
+
+func (fsj *fsJournal) Close() error {
+	close(fsj.closing)
+	return nil
+}