Implemented logging mechanism (#785)

gpt4all-chat/CMakeLists.txt

@@ -71,6 +71,7 @@ qt_add_executable(chat
     localdocs.h localdocs.cpp localdocsmodel.h localdocsmodel.cpp
     llm.h llm.cpp
     server.h server.cpp
+    logger.h logger.cpp
     sysinfo.h
 )
 

gpt4all-chat/logger.cpp

@@ -0,0 +1,61 @@
+#include "logger.h"
+
+#include <QFile>
+#include <QDebug>
+#include <QStandardPaths>
+#include <QDateTime>
+
+class MyLogger: public Logger { };
+Q_GLOBAL_STATIC(MyLogger, loggerInstance)
+Logger *Logger::globalInstance()
+{
+    return loggerInstance();
+}
+
+Logger::Logger()
+{
+    // Get log file dir
+    auto dir = QStandardPaths::writableLocation(QStandardPaths::AppLocalDataLocation);
+    // Remove old log file
+    QFile::remove(dir+"/log-prev.txt");
+    QFile::rename(dir+"/log.txt", dir+"/log-prev.txt");
+    // Open new log file
+    m_file.setFileName(dir+"/log.txt");
+    if (!m_file.open(QIODevice::NewOnly | QIODevice::WriteOnly | QIODevice::Text)) {
+        qWarning() << "Failed to open log file, logging to stdout...";
+        m_file.open(stdout, QIODevice::WriteOnly | QIODevice::Text);
+    }
+    // On success, install message handler
+    qInstallMessageHandler(Logger::messageHandler);
+}
+
+void Logger::messageHandler(QtMsgType type, const QMessageLogContext &, const QString &msg)
+{
+    auto logger = globalInstance();
+    // Get message type as string
+    QString typeString;
+    switch (type) {
+    case QtDebugMsg:
+        typeString = "Debug";
+        break;
+    case QtInfoMsg:
+        typeString = "Info";
+        break;
+    case QtWarningMsg:
+        typeString = "Warning";
+        break;
+    case QtCriticalMsg:
+        typeString = "Critical";
+        break;
+    case QtFatalMsg:
+        typeString = "Fatal";
+        break;
+    default:
+        typeString = "???";
+    }
+    // Get time and date
+    auto timestamp = QDateTime::currentDateTime().toString();
+    // Write message
+    logger->m_file.write(QString("[%1] (%2): %4\n").arg(typeString, timestamp, msg).toStdString().c_str());
+    logger->m_file.flush();
+}

gpt4all-chat/logger.h

@@ -0,0 +1,18 @@
+#ifndef LOGGER_H
+#define LOGGER_H
+#include <QFile>
+
+class Logger
+{
+    QFile m_file;
+
+    static void messageHandler(QtMsgType type, const QMessageLogContext &context, const QString &msg);
+
+public:
+    static Logger *globalInstance();
+
+    explicit Logger();
+    friend class MyLogger;
+};
+
+#endif // LOGGER_H

gpt4all-chat/main.cpp

@@ -10,6 +10,7 @@
 #include "download.h"
 #include "network.h"
 #include "config.h"
+#include "logger.h"
 
 int main(int argc, char *argv[])
 {
@@ -19,6 +20,8 @@ int main(int argc, char *argv[])
     QCoreApplication::setApplicationVersion(APP_VERSION);
     QSettings::setDefaultFormat(QSettings::IniFormat);
 
+    Logger::globalInstance();
+
     QGuiApplication app(argc, argv);
     QQmlApplicationEngine engine;
     qmlRegisterSingletonInstance("llm", 1, 0, "LLM", LLM::globalInstance());