diff --git a/server/src/logging.ts b/server/src/logging.ts
new file mode 100644
index 0000000..16db54b
--- /dev/null
+++ b/server/src/logging.ts
@@ -0,0 +1,183 @@
+/**
+ * Logging utilities
+ * copy from vscode-cmake-tools
+ */
+
+import * as node_fs from 'fs';
+import * as path from 'path';
+
+/** Logging levels */
+export enum LogLevel {
+    Debug,
+    Info,
+    Warning,
+    Error,
+    Off,
+}
+
+type LogLevelKey = 'debug' | 'info' | 'warning' | 'error' | 'off';
+
+/**
+ * Get the name of a logging level
+ * @param level A logging level
+ */
+function levelName(level: LogLevel): LogLevelKey {
+    switch (level) {
+        case LogLevel.Debug:
+            return 'debug';
+        case LogLevel.Info:
+            return 'info';
+        case LogLevel.Warning:
+            return 'warning';
+        case LogLevel.Error:
+            return 'error';
+        case LogLevel.Off:
+            return 'off';
+    }
+}
+
+/**
+ * Determine if logging is enabled for the given LogLevel
+ * @param level The log level to check
+ */
+function levelEnabled(level: LogLevel): boolean {
+    // const strlevel = vscode.workspace.getConfiguration('cmake').get<LogLevelKey>('loggingLevel', 'info');
+    const strLevel = extSettings.loggingLevel;
+    switch (strLevel) {
+        case 'debug':
+            return level >= LogLevel.Debug;
+        case 'info':
+            return level >= LogLevel.Info;
+        case 'warning':
+            return level >= LogLevel.Warning;
+        case 'error':
+            return level >= LogLevel.Error;
+        case 'off':
+            return level >= LogLevel.Off;
+        default:
+            console.error('Invalid logging level in settings.json');
+            return true;
+    }
+}
+
+export interface Stringable {
+    toString(): string;
+    toLocaleString(): string;
+}
+
+let _LOGGER: NodeJS.WritableStream;
+
+export function logFilePath(): string {
+    return path.join(paths.dataDir, 'log.txt');
+}
+
+async function _openLogFile() {
+    if (!_LOGGER) {
+        const fpath = logFilePath();
+        await mkdir_p(path.dirname(fpath));
+        if (await exists(fpath)) {
+            _LOGGER = node_fs.createWriteStream(fpath, { flags: 'r+' });
+        } else {
+            _LOGGER = node_fs.createWriteStream(fpath, { flags: 'w' });
+        }
+    }
+    return _LOGGER;
+}
+
+/**
+ * Manages and controls logging
+ */
+class SingletonLogger {
+    private readonly _logStream = _openLogFile();
+
+    private _log(level: LogLevel, ...args: Stringable[]) {
+
+        if (!levelEnabled(level)) {
+            return;
+        }
+
+        const user_message = args.map(a => a.toString()).join(' ');
+        const prefix = new Date().toISOString() + ` [${levelName(level)}]`;
+        const raw_message = `${prefix} ${user_message}`;
+        switch (level) {
+            // case LogLevel.Trace:
+            case LogLevel.Debug:
+            case LogLevel.Info:
+                // case LogLevel.Note:
+                if (process.env['CMT_QUIET_CONSOLE'] !== '1') {
+                    console.info('[cmake-intellisence]', raw_message);
+                }
+                break;
+            case LogLevel.Warning:
+                console.warn('[cmake-intellisence]', raw_message);
+                break;
+            case LogLevel.Error:
+                console.error('[cmake-intellisence]', raw_message);
+                break;
+        }
+        // Write to the logfile asynchronously.
+        this._logStream.then(strm => strm.write(raw_message + '\n')).catch(e => {
+            console.error('Unhandled error while writing cmake-intellisence log file', e);
+        });
+    }
+
+    debug(...args: Stringable[]) {
+        this._log(LogLevel.Debug, ...args);
+    }
+
+    info(...args: Stringable[]) {
+        this._log(LogLevel.Info, ...args);
+    }
+
+    warning(...args: Stringable[]) {
+        this._log(LogLevel.Warning, ...args);
+    }
+
+    error(...args: Stringable[]) {
+        this._log(LogLevel.Error, ...args);
+    }
+
+    private static _inst: SingletonLogger | null = null;
+
+    static instance(): SingletonLogger {
+        if (SingletonLogger._inst === null) {
+            SingletonLogger._inst = new SingletonLogger();
+        }
+        return SingletonLogger._inst;
+    }
+}
+
+export class Logger {
+    constructor(readonly _tag: string) { }
+    get tag() {
+        return `[${this._tag}]`;
+    }
+
+    debug(...args: Stringable[]) {
+        SingletonLogger.instance().debug(this.tag, ...args);
+    }
+
+    info(...args: Stringable[]) {
+        SingletonLogger.instance().info(this.tag, ...args);
+    }
+
+    warning(...args: Stringable[]) {
+        SingletonLogger.instance().warning(this.tag, ...args);
+    }
+
+    error(...args: Stringable[]) {
+        SingletonLogger.instance().error(this.tag, ...args);
+    }
+
+    static logTestName(suite?: string, test?: string) {
+        SingletonLogger.instance().info('-----------------------------------------------------------------------');
+        SingletonLogger.instance().info(`Beginning test: ${suite ?? 'unknown suite'} - ${test ?? 'unknown test'}`);
+    }
+}
+
+export function createLogger(tag: string) {
+    return new Logger(tag);
+}
+
+import paths, { mkdir_p, exists } from './paths';
+import { extSettings } from './settings';
diff --git a/server/src/paths.ts b/server/src/paths.ts
new file mode 100644
index 0000000..589f7a8
--- /dev/null
+++ b/server/src/paths.ts
@@ -0,0 +1,191 @@
+/**
+ * This module defines important directories and paths to the extension
+ * copy from vscode-cmake-tools
+ */
+
+import * as path from 'path';
+import * as fs from 'fs';
+import * as util from 'util';
+
+const promisify = util.promisify;
+export const stat = promisify(fs.stat);
+export const mkdir = promisify(fs.mkdir);
+
+/**
+ * Try and stat() a file/folder. If stat() fails for *any reason*, returns `null`.
+ * @param filePath The file to try and stat()
+ */
+export async function tryStat(filePath: fs.PathLike): Promise<fs.Stats | null> {
+    try {
+        return await stat(filePath);
+    } catch (_e) {
+        // Don't even bother with the error. Any number of things might have gone
+        // wrong. Probably one of: Non-existing file, bad permissions, bad path.
+        return null;
+    }
+}
+
+export async function exists(filePath: string): Promise<boolean> {
+    const stat = await tryStat(filePath);
+    return stat !== null;
+}
+
+/**
+ * Creates a directory and all parent directories recursively. If the file
+ * already exists, and is not a directory, just return.
+ * @param fspath The directory to create
+ */
+export async function mkdir_p(fspath: string): Promise<void> {
+    const parent = path.dirname(fspath);
+    if (!await exists(parent)) {
+        await mkdir_p(parent);
+    } else {
+        if (!(await stat(parent)).isDirectory()) {
+            throw new Error(`cannot.create.path', 'Cannot create ${fspath}: ${fspath} is a non-directory`);
+        }
+    }
+    if (!await exists(fspath)) {
+        await mkdir(fspath);
+    } else {
+        if (!(await stat(fspath)).isDirectory()) {
+            throw new Error(`cannot.create.directory', 'Cannot create directory ${fspath}. It exists, and is not a directory!`);
+        }
+    }
+}
+
+class WindowsEnvironment {
+    get AppData(): string | undefined {
+        return process.env['APPDATA'];
+    }
+
+    get LocalAppData(): string | undefined {
+        return process.env['LOCALAPPDATA'];
+    }
+
+    get AllUserProfile(): string | undefined {
+        return process.env['ProgramData'];
+    }
+
+    get ComSpec(): string {
+        let comSpec = process.env['ComSpec'];
+
+        if (undefined === comSpec) {
+            comSpec = this.SystemRoot! + '\\system32\\cmd.exe';
+        }
+
+        return comSpec;
+    }
+
+    get HomeDrive(): string | undefined {
+        return process.env['HOMEDRIVE'];
+    }
+
+    get HomePath(): string | undefined {
+        return process.env['HOMEPATH'];
+    }
+
+    get ProgramFilesX86(): string | undefined {
+        return process.env['ProgramFiles(x86)'];
+    }
+
+    get ProgramFiles(): string | undefined {
+        return process.env['ProgramFiles'];
+    }
+
+    get SystemDrive(): string | undefined {
+        return process.env['SystemDrive'];
+    }
+
+    get SystemRoot(): string | undefined {
+        return process.env['SystemRoot'];
+    }
+
+    get Temp(): string | undefined {
+        return process.env['TEMP'];
+    }
+}
+
+/**
+ * Directory class.
+ */
+class Paths {
+    private _ninjaPath?: string;
+
+    readonly windows: WindowsEnvironment = new WindowsEnvironment();
+
+    /**
+     * The current user's home directory
+     */
+    get userHome(): string {
+        if (process.platform === 'win32') {
+            return path.join(process.env['HOMEDRIVE'] || 'C:', process.env['HOMEPATH'] || 'Users\\Public');
+        } else {
+            return process.env['HOME'] || process.env['PROFILE']!;
+        }
+    }
+
+    /**
+     * The user-local data directory. This is where user-specific persistent
+     * application data should be stored.
+     */
+    get userLocalDir(): string {
+
+        if (process.platform === 'win32') {
+            return this.windows.LocalAppData!;
+        } else {
+            const xdg_dir = process.env['XDG_DATA_HOME'];
+            if (xdg_dir) {
+                return xdg_dir;
+            }
+            const home = this.userHome;
+            return path.join(home, '.local/share');
+        }
+    }
+
+    get userRoamingDir(): string {
+        if (process.platform === 'win32') {
+            return this.windows.AppData!;
+        } else {
+            const xdg_dir = process.env['XDG_CONFIG_HOME'];
+            if (xdg_dir) {
+                return xdg_dir;
+            }
+            const home = this.userHome;
+            return path.join(home, '.config');
+        }
+    }
+
+    /**
+     * The directory where CMake Tools should store user-specific persistent
+     * data.
+     */
+    get dataDir(): string {
+        return path.join(this.userLocalDir, 'cmake-intellisence');
+    }
+
+    /**
+     * The "roaming" directory where CMake Tools stores roaming configuration
+     * data.
+     */
+    get roamingDataDir(): string {
+        return path.join(this.userRoamingDir, 'cmake-intellisence');
+    }
+
+    /**
+     * Get the platform-specific temporary directory
+     */
+    get tmpDir(): string {
+        if (process.platform === 'win32') {
+            return this.windows.Temp!;
+        } else {
+            return '/tmp';
+        }
+    }
+
+    get ninjaPath() {
+        return this._ninjaPath;
+    }
+}
+
+const paths = new Paths();
+export default paths;
diff --git a/server/src/server.ts b/server/src/server.ts
index e4146a5..b45b68b 100644
--- a/server/src/server.ts
+++ b/server/src/server.ts
@@ -29,6 +29,7 @@ import { getTokenBuilder, getTokenModifiers, getTokenTypes, SemanticListener, to
 import { extSettings } from './settings';
 import { DefinationListener, incToBaseDir, refToDef, topScope } from './symbolTable/goToDefination';
 import { getFileContext } from './utils';
+import { createLogger } from './logging';
 
 type Word = {
     text: string,
@@ -47,6 +48,7 @@ export const connection = createConnection(ProposedFeatures.all);
 // Create a simple text document manager.
 export const documents: TextDocuments<TextDocument> = new TextDocuments(TextDocument);
 
+export const logger = createLogger('server');
 
 connection.onInitialize(async (params: InitializeParams) => {
     initParams = params;
@@ -312,6 +314,7 @@ connection.onDefinition((params: DefinitionParams) => {
         if (refToDef.has(wordPos)) {
             resolve(refToDef.get(wordPos));
         } else {
+            logger.warning(`can't find defination, word: ${word.text}, wordPos: ${wordPos}`);
             return null;
         }
     });
@@ -481,6 +484,7 @@ function getProposals(word: string, kind: CompletionItemKind, dataSource: string
 // Make the text document manager listen on the connection
 // for open, change and close text document events
 documents.listen(connection);
+logger.info('listen on connection');
 
 // Listen on the connection
 connection.listen();
diff --git a/server/src/utils.ts b/server/src/utils.ts
index 60dea40..54d8d2f 100644
--- a/server/src/utils.ts
+++ b/server/src/utils.ts
@@ -7,7 +7,7 @@ import antlr4 from './parser/antlr4/index.js';
 import InputStream from './parser/antlr4/InputStream';
 import CMakeLexer from "./parser/CMakeLexer";
 import CMakeParser from "./parser/CMakeParser";
-import { documents } from './server';
+import { documents, logger } from './server';
 
 export function getFileContext(uri: URI) {
     const document = documents.get(uri.toString());
@@ -28,6 +28,8 @@ export function getSubCMakeListsUri(baseDir: URI, subDir: string): URI {
     const subCMakeListsUri: URI = Utils.joinPath(baseDir, subDir, 'CMakeLists.txt');
     if (existsSync(subCMakeListsUri.fsPath)) {
         return subCMakeListsUri;
+    } else {
+        logger.error('getSubCMakeListsUri:', subCMakeListsUri.fsPath, 'not exist');
     }
 
     return null;
@@ -37,6 +39,8 @@ export function getIncludeFileUri(baseDir: URI, includeFileName: string): URI {
     const incFileUri: URI = Utils.joinPath(baseDir, includeFileName);
     if (existsSync(incFileUri.fsPath)) {
         return incFileUri;
+    } else {
+        logger.error('getIncludeFileUri:', incFileUri.fsPath, 'not exist');
     }
 
     const cmakePath: string = which('cmake');
@@ -50,6 +54,8 @@ export function getIncludeFileUri(baseDir: URI, includeFileName: string): URI {
     if (existsSync(resPath)) {
         // return pathToFileURL(resPath).toString();
         return URI.file(resPath);
+    } else {
+        logger.error('getIncludeFileUri:', resPath, 'not exist');
     }
 
     return null;