From 3e5f476dff8ff503f40f0048da9c1ae566be7d4e Mon Sep 17 00:00:00 2001
From: Oleksandr Ieremeev <yeremeyev.alexander@gmail.com>
Date: Sun, 19 Aug 2018 16:40:32 +0300
Subject: [PATCH] Extend logs page (some previous logs, timestamp or rows)

---
 handlers/dashboard.go | 19 ++++++++++-------
 source/tmpl/logs.html |  2 +-
 utils/log.go          | 34 ++++++++++++++++++++++++------
 utils/logRow.go       | 49 +++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 89 insertions(+), 15 deletions(-)
 create mode 100644 utils/logRow.go

diff --git a/handlers/dashboard.go b/handlers/dashboard.go
index a726f48a..49495eff 100644
--- a/handlers/dashboard.go
+++ b/handlers/dashboard.go
@@ -80,7 +80,15 @@ func LogsHandler(w http.ResponseWriter, r *http.Request) {
 		http.Redirect(w, r, "/", http.StatusSeeOther)
 		return
 	}
-	ExecuteResponse(w, r, "logs.html", nil)
+	utils.LockLines.Lock()
+	logs := make([]string, 0)
+	len := len(utils.LastLines)
+	// We need string log lines from end to start.
+	for i := len - 1; i >= 0; i-- {
+		logs = append(logs, utils.LastLines[i].FormatForHtml()+"\r\n")
+	}
+	utils.LockLines.Unlock()
+	ExecuteResponse(w, r, "logs.html", logs)
 }
 
 func LogsLineHandler(w http.ResponseWriter, r *http.Request) {
@@ -88,12 +96,7 @@ func LogsLineHandler(w http.ResponseWriter, r *http.Request) {
 		w.WriteHeader(http.StatusInternalServerError)
 		return
 	}
-	switch v := utils.LastLine.(type) {
-	case string:
-		w.Write([]byte(v))
-	case error:
-		w.Write([]byte(v.Error()))
-	case []byte:
-		w.Write(v)
+	if lastLine := utils.GetLastLine(); lastLine != nil {
+		w.Write([]byte(lastLine.FormatForHtml()))
 	}
 }
diff --git a/source/tmpl/logs.html b/source/tmpl/logs.html
index 4e32b505..b999babe 100644
--- a/source/tmpl/logs.html
+++ b/source/tmpl/logs.html
@@ -22,7 +22,7 @@
 
     <div class="col-12">
 
-        <textarea id="live_logs" class="form-control" rows="40" readonly></textarea>
+        <textarea id="live_logs" class="form-control" rows="40" readonly>{{range .}}{{.}}{{end}}</textarea>
 
     </div>
 
diff --git a/utils/log.go b/utils/log.go
index 4f077f04..781e2c6a 100644
--- a/utils/log.go
+++ b/utils/log.go
@@ -23,13 +23,15 @@ import (
 	"os"
 	"os/signal"
 	"syscall"
+	"sync"
 )
 
 var (
-	logFile  *os.File
-	fmtLogs  *log.Logger
-	ljLogger *lumberjack.Logger
-	LastLine interface{}
+	logFile   *os.File
+	fmtLogs   *log.Logger
+	ljLogger  *lumberjack.Logger
+	LastLines []*LogRow
+	LockLines sync.Mutex
 )
 
 func createLog(dir string) error {
@@ -69,6 +71,7 @@ func InitLogs() error {
 	fmtLogs = log.New(logFile, "", log.Ldate|log.Ltime)
 	log.SetOutput(ljLogger)
 	rotate()
+	LastLines = make([]*LogRow, 0)
 	return err
 }
 
@@ -84,7 +87,7 @@ func rotate() {
 }
 
 func Log(level int, err interface{}) error {
-	LastLine = err
+	pushLastLine(err)
 	var outErr error
 	switch level {
 	case 5:
@@ -119,6 +122,25 @@ func Http(r *http.Request) string {
 	msg := fmt.Sprintf("%v (%v) | IP: %v", r.RequestURI, r.Method, r.Host)
 	fmtLogs.Printf("WEB: %v\n", msg)
 	fmt.Printf("WEB: %v\n", msg)
-	LastLine = msg
+	pushLastLine(msg)
 	return msg
 }
+
+func pushLastLine(line interface{}) {
+	LockLines.Lock()
+	defer LockLines.Unlock()
+	LastLines = append(LastLines, NewLogRow(line))
+	// We want to store max 1000 lines in memory (for /logs page).
+	for len(LastLines) > 1000 {
+		LastLines = LastLines[1:]
+	}
+}
+
+func GetLastLine() *LogRow {
+	LockLines.Lock()
+	defer LockLines.Unlock()
+	if len(LastLines) > 0 {
+		return LastLines[len(LastLines) - 1]
+	}
+	return nil
+}
diff --git a/utils/logRow.go b/utils/logRow.go
new file mode 100644
index 00000000..207c8a4b
--- /dev/null
+++ b/utils/logRow.go
@@ -0,0 +1,49 @@
+// Statup
+// Copyright (C) 2018.  Hunter Long and the project contributors
+// Written by Hunter Long <info@socialeck.com> and the project contributors
+//
+// https://github.com/hunterlong/statup
+//
+// The licenses for most software and other practical works are designed
+// to take away your freedom to share and change the works.  By contrast,
+// the GNU General Public License is intended to guarantee your freedom to
+// share and change all versions of a program--to make sure it remains free
+// software for all its users.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package utils
+
+import (
+	"time"
+	"fmt"
+)
+
+type LogRow struct {
+	Date	time.Time
+	Line	interface{}
+}
+
+func NewLogRow(line interface{}) (logRow *LogRow) {
+	logRow = new(LogRow)
+	logRow.Date = time.Now()
+	logRow.Line = line
+	return
+}
+
+func (o *LogRow) LineAsString() string {
+	switch v := o.Line.(type) {
+	case string:
+		return v
+	case error:
+		return v.Error()
+	case []byte:
+		return string(v)
+	}
+	return ""
+}
+
+func (o *LogRow) FormatForHtml() string {
+	return fmt.Sprintf("%s: %s", o.Date.Format("2006-01-02 15:04:05"), o.LineAsString())
+}