是否可以获取每个日志输出的行号和文件？
例如：
var winston = require('winston');
winston.log('info', 'some message!'); // this is at line 4 of myfile.js
应在日志文件中指定“某些消息”来自 myFile.js 第 4 行。
【问题讨论】：
您可以将文件名传递为label，您可以从callingModule中获取文件名。
创建logger.js 文件和类似代码
var winston = require('winston');
var getLabel = function (callingModule) {
var parts = callingModule.filename.split('/');
return parts[parts.length - 2] + '/' + parts.pop();
};
module.exports = function (callingModule) {
return new winston.Logger({
transports: [
new winston.transports.Console({
label: getLabel(callingModule),
json: false,
timestamp: true,
depth:true,
colorize:true
})
]
});
};
现在这里是你的测试文件
var logger = require('./logger')(module);
function test() {
logger.info('test logger');
}
test();
如果你运行测试文件，输出看起来像
2017-07-08T07:15:20.671Z - info: [utils/test.js] test logger
【讨论】：
出于性能问题，温斯顿没有计划这样做。详情请check here。
我试过https://github.com/baryon/tracer，但效果不好，例如行号有时不正确。
【讨论】：
我在某处找到了这段代码，是的，但它正在工作。在新的winston.js 中使用它，然后在任何文件中都需要它。
var winston = require('winston')
var path = require('path')
var PROJECT_ROOT = path.join(__dirname, '..')
var appRoot = require('app-root-path');
const options = {
file: {
level: 'info',
filename: `${appRoot}/logs/app.log`,
handleExceptions: true,
json: true,
maxsize: 5242880, // 5MB
maxFiles: 5,
colorize: false,
timestamp: true
},
console: {
level: 'debug',
handleExceptions: true,
json: true,
colorize: true,
timestamp: true
}
};
var logger = new winston.Logger({
transports: [
new winston.transports.File(options.file),
new winston.transports.Console(options.console)
],
exitOnError: false // do not exit on handled exceptions
});
logger.stream = {
write: function (message) {
logger.info(message)
}
}
// A custom logger interface that wraps winston, making it easy to instrument
// code and still possible to replace winston in the future.
module.exports.debug = module.exports.log = function () {
logger.debug.apply(logger, formatLogArguments(arguments))
}
module.exports.info = function () {
logger.info.apply(logger, formatLogArguments(arguments))
}
module.exports.warn = function () {
logger.warn.apply(logger, formatLogArguments(arguments))
}
module.exports.error = function () {
logger.error.apply(logger, formatLogArguments(arguments))
}
module.exports.stream = logger.stream
/**
* Attempts to add file and line number info to the given log arguments.
*/
function formatLogArguments (args) {
args = Array.prototype.slice.call(args)
var stackInfo = getStackInfo(1)
if (stackInfo) {
// get file path relative to project root
var calleeStr = '(' + stackInfo.relativePath + ':' + stackInfo.line + ')'
if (typeof (args[0]) === 'string') {
args[0] = calleeStr + ' ' + args[0]
} else {
args.unshift(calleeStr)
}
}
return args
}
/**
* Parses and returns info about the call stack at the given index.
*/
function getStackInfo (stackIndex) {
// get call stack, and analyze it
// get all file, method, and line numbers
var stacklist = (new Error()).stack.split('\n').slice(3)
// stack trace format:
// http://code.google.com/p/v8/wiki/JavaScriptStackTraceApi
// do not remove the regex expresses to outside of this method (due to a BUG in node.js)
var stackReg = /at\s+(.*)\s+\((.*):(\d*):(\d*)\)/gi
var stackReg2 = /at\s+()(.*):(\d*):(\d*)/gi
var s = stacklist[stackIndex] || stacklist[0]
var sp = stackReg.exec(s) || stackReg2.exec(s)
if (sp && sp.length === 5) {
return {
method: sp[1],
relativePath: path.relative(PROJECT_ROOT, sp[2]),
line: sp[3],
pos: sp[4],
file: path.basename(sp[2]),
stack: stacklist.join('\n')
}
}
}
来源：https://gist.github.com/transitive-bullshit/39a7edc77c422cbf8a18
【讨论】：
我还创建了一个gist for the following code：
const { format } = require('winston');
const { combine, colorize, timestamp, printf } = format;
/**
* /**
* Use CallSite to extract filename and number, for more info read: https://v8.dev/docs/stack-trace-api#customizing-stack-traces
* @param numberOfLinesToFetch - optional, when we want more than one line back from the stacktrace
* @returns {string|null} filename and line number separated by a colon, if numberOfLinesToFetch > 1 we'll return a string
* that represents multiple CallSites (representing the latest calls in the stacktrace)
*
*/
const getFileNameAndLineNumber = function getFileNameAndLineNumber (numberOfLinesToFetch = 1) {
const oldStackTrace = Error.prepareStackTrace;
const boilerplateLines = line => line &&
line.getFileName() &&
(line.getFileName().indexOf('<My Module Name>') &&
(line.getFileName().indexOf('/node_modules/') < 0));
try {
// eslint-disable-next-line handle-callback-err
Error.prepareStackTrace = (err, structuredStackTrace) => structuredStackTrace;
Error.captureStackTrace(this);
// we need to "peel" the first CallSites (frames) in order to get to the caller we're looking for
// in our case we're removing frames that come from logger module or from winston
const callSites = this.stack.filter(boilerplateLines);
if (callSites.length === 0) {
// bail gracefully: even though we shouldn't get here, we don't want to crash for a log print!
return null;
}
const results = [];
for (let i = 0; i < numberOfLinesToFetch; i++) {
const callSite = callSites[i];
let fileName = callSite.getFileName();
fileName = fileName.includes(BASE_DIR_NAME) ? fileName.substring(BASE_DIR_NAME.length + 1) : fileName;
results.push(fileName + ':' + callSite.getLineNumber());
}
return results.join('\n');
} finally {
Error.prepareStackTrace = oldStackTrace;
}
};
function humanReadableFormatter ({ level, message, ...metadata }) {
const filename = getFileNameAndLineNumber();
return `[${level}] [${filename}] ${message} ${JSON.stringify(metadata)}`;
}
const logger = winston.createLogger({
transports: [
new winston.transports.Console({
level: 'info',
handleExceptions: true,
humanReadableUnhandledException: true,
json: false,
colorize: { all: true },
stderrLevels: ['error', 'alert', 'critical', 'bizAlert'],
format: combine(
colorize(),
timestamp(),
humanReadableFormatter,
),
})
]
});
我使用的是winston 2.x（但同样的解决方案也适用于winston 3.x）和that's the way我正在记录调用者的文件名和行号：
重要：注意嵌入代码cmets！
/**
* Use CallSite to extract filename and number
* @returns {string} filename and line number separated by a colon
*/
const getFileNameAndLineNumber = () => {
const oldStackTrace = Error.prepareStackTrace;
try {
// eslint-disable-next-line handle-callback-err
Error.prepareStackTrace = (err, structuredStackTrace) => structuredStackTrace;
Error.captureStackTrace(this);
// in this example I needed to "peel" the first 10 CallSites in order to get to the caller we're looking for, hence the magic number 11
// in your code, the number of stacks depends on the levels of abstractions you're using, which mainly depends on winston version!
// so I advise you to put a breakpoint here and see if you need to adjust the number!
return this.stack[11].getFileName() + ':' + this.stack[11].getLineNumber();
} finally {
Error.prepareStackTrace = oldStackTrace;
}
};
以及（简化版）格式化函数：
function humanReadableFormatter ({level, message}) {
const filename = getFileNameAndLineNumber();
return `[${level}] ${filename} ${message}`;
}
然后声明传输使用格式化程序：
new winston.transports.Console({
level: 'info',
handleExceptions: true,
humanReadableUnhandledException: true,
json: false,
colorize: 'level',
stderrLevels: ['warn', 'error', 'alert'],
formatter: humanReadableFormatter,
})
要了解有关 prepareStackTrace 的更多信息，请阅读：https://v8.dev/docs/stack-trace-api#customizing-stack-traces
【讨论】：
const boilerplateLines = line => line && line.getFileName() &&(line.getFileName().indexOf('<My Module Name>') && (line.getFileName().indexOf('/node_modules/') < 0);
.indexOf('/node_modules/') < 0)); Missing )
你可以对字符串进行操作
console.log(new Error().stack.split('\n')[1].slice(7));
获取行号和文件路径以及函数名。
输出看起来像
AutomationFramework._this.parsingLogic (/Users/user_name/Desktop/something/some-file.js:49:25)
【讨论】：