记录NodeJS
作为nodejs的前身，我编写了如下的测试代码。但是内存越来越大，有时没有任何输出（通过多种方式改变它）。
有2个着名的日志记录模块，log4js和winston。以log4js为例。
1。 main.js
(function(){
"use strict";
let log4js = require("./log4js-config.js");
let logger = log4js.getLogger("log4js_main");
for(let i = 0; i < 10000000 ; i++){
logger.log("info", "info message " + i + ".");
}
})();
2。 log4js-config.js
module.exports = (function(){
"use strict";
let Log4js = require("log4js");
Log4js.configure(
{
"appenders" : [
{ "type" : "logLevelFilter"
,"level" : "ALL"
,"appender" : {
"type" : "console"
}
}
,{ "type" : "logLevelFilter"
,"level" : "ALL"
,"appender" : {
"type" : "dateFile"
,"filename" : "./logs/log4js_date"
,"pattern" : "-yyyyMMdd.log"
,"alwaysIncludePattern" : false
,"maxLogSize" : 209715200
,"_maxLogSize" : "200M = 200 * 1024 * 1024 = 209715200"
,"category" : "log4js.dateFile"
}
}
,{ "type" : "logLevelFilter"
,"level" : "ALL"
,"appender" : {
"type" : "file"
,"filename" : "./logs/log4js_size.log"
,"maxLogSize" : 209715200
,"_maxLogSize" : "200M = 200 * 1024 * 1024 = 209715200"
,"alwaysIncludePattern" : false
,"backups" : 10
,"category" : "log4js.file"
}
}
]
,"replaceConsole" : true
}
);
return Log4js;
})();
当循环次数很小时，虽然内存增加了 从来没有倒下，它运作良好。但是，当时代被设定得更多 超过10,000,000，它会失败并提示如下：
...
[2015-12-14 11:23:12.480] [INFO] log4js_main - info message 2525074.
[2015-12-14 11:23:12.480] [INFO] log4js_main - info message 2525075.
[2015-12-14 11:23:12.480] [INFO] log4js_main - info message 2525076.
[2015-12-14 11:23:12.480] [INFO] log4js_main - info message 2525077.
[2015-12-14 11:23:12.480] [INFO] log4js_main - info message 2525078.
[2015-12-14 11:23:12.480] [INFO] log4js_main - info message 2525079.
[2015-12-14 11:23:12.480] [INFO] log4js_main - info message 2525080.
[2015-12-14 11:23:12.480] [INFO] log4js_main - info message 2525081.
[2015-12-14 11:23:12.480] [INFO] log4js_main - info message 2525082.
<--- Last few GCs --->
420299 ms: Scavenge 1399.0 (1457.4) -> 1399.0 (1457.4) MB, 2.3 / 0 ms (+ 0.0 ms in 1 steps since l
ast GC) [allocation failure] [incremental marking delaying mark-sweep].
421110 ms: Mark-sweep 1399.0 (1457.4) -> 1399.0 (1457.4) MB, 814.3 / 0 ms (+ 15.0 ms in 2 steps si
nce start of marking, biggest step 15.0 ms) [last resort gc].
421937 ms: Mark-sweep 1399.0 (1457.4) -> 1399.0 (1457.4) MB, 828.6 / 0 ms [last resort gc].
<--- JS stacktrace --->
==== JS stack trace =========================================
Security context: 0000019446CE3AD1 <JS Object>
1: nextTick [node.js:~491] [pc=0000037DBBD17738] (this=0000012811B14929 <a process with map 0000
02F23C011991>,callback=0000017AB4E49C01 <JS Function afterWrite (SharedFunctionInfo 000002DC70230AF1
)>)
2: arguments adaptor frame: 5->1
3: onwrite(aka onwrite) [_stream_writable.js:~315] [pc=0000037DBB93CC17] (this=0000019446C04189
<undefined>,stream=000000727BB2BEE1 <a WriteStream wit...
FATAL ERROR: CALL_AND_RETRY_LAST Allocation failed - process out of memory
PS
作为我在stackoverflow.com的第一个问题，我想分享一些事情 困扰了我很久。所以谈到这个问题。
答案 0 :(得分：2)
<强> TL;博士
有必要让记录器有机会进行I / O工作 setImmediate（）并使用event而不是＆＃39; for＆＃39;做循环，或者它 将内容保留在内存中并因内存不足而死亡。
根本原因
这是由the event loop mechanisms of nodejs， bool ev_run（循环，int标志）引起的，它需要一个任务 来自观察者的每次按此顺序：
idle -> I/O -> check
＆＃39; ＆＃39;和＆＃39; process.nextTick（）＆＃39;是空闲的观察者，所以 记录器没有机会进行基础I / O工作。它 导致内存耗尽。
<强>解决方案
因此，我们需要让记录器有机会完成基础工作。
main.js for log4js
(function(){
"use strict";
const WORK_DONE_EVENT_NAME = "work-done";
const WORK_TIMES = 100 * 1000 * 1000;
let evem = new (require("events").EventEmitter)();
// Explicitly listening on the event.
evem.on(WORK_DONE_EVENT_NAME, function(){
// setImmediate: after I/O operations
setImmediate(doWork);
});
let log4js = require("./log4js-config.js");
let logger = log4js.getLogger("log4js_main");
let idx = 0;
function doWork(){
idx++;
if(idx >= WORK_TIMES){
console.timeEnd(WORK_DONE_EVENT_NAME);
return;
}
logger.info(idx);
setImmediate(function(){
evem.emit(WORK_DONE_EVENT_NAME);
});
}
console.time(WORK_DONE_EVENT_NAME);
doWork();
})();
log4js-config.js（保持不变）
win.main.js
(function(){
"use strict";
const WORK_DONE_EVENT_NAME = "work-done";
const WORK_TIMES = 100 * 1000 * 1000;
let evem = new (require("events").EventEmitter)();
let logger = require("./winston-config");
// Explicitly listening on the event.
evem.on(WORK_DONE_EVENT_NAME, function(){
// setImmediate: after I/O operations
setImmediate(doWork);
});
let idx = 0;
function doWork(){
idx++;
if(idx >= WORK_TIMES){
console.timeEnd(WORK_TIMES);
return;
}
logger.silly(idx, function(err, level, msg, meta){
if(err){
throw err;
}
evem.emit(WORK_DONE_EVENT_NAME);
});
}
console.time(WORK_TIMES);
doWork();
})();
<强>温斯顿 - config.js
module.exports = (function(){
"use strict";
let Winston = require("winston");
let WinstonDailyRotateFile = require("winston-daily-rotate-file");
let transports = [
new (Winston.transports.Console)({
"colorize" : true
,"timestamp" : true
,"showLevel": true
,"level" : "silly"
})
,new (Winston.transports.File)({
"name" : "winston-file"
,"filename" : "./logs/winston_size.log"
,"maxsize" : 209715200
, "_maxsize" : "200M = 200 * 1024 * 1024 = 209715200"
,"maxFiles" : 1024
,"timestamp" : true
,"showLevel": true
,"level": "silly"
})
,new (WinstonDailyRotateFile)({
"name" : "winston-daily-file"
,"filename" : "./logs/winston_date"
,"datePattern" : "-yyyyMMdd.log"
,"maxsize" : 209715200
, "_maxsize" : "200M = 200 * 1024 * 1024 = 209715200"
,"maxFiles" : 10
,"timestamp" : true
,"level": "silly"
})
];
let logger = new (Winston.Logger)({
"transports" : transports
});
return logger;
})();