node-bunyan-lite/lib/bunyan.js

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/*
* Copyright (c) 2012 Trent Mick. All rights reserved.
*
* The bunyan logging library for node.js.
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*/
var VERSION = '0.15.0';
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// Bunyan log format version. This becomes the 'v' field on all log records.
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// `0` is until I release a version '1.0.0' of node-bunyan. Thereafter,
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// starting with `1`, this will be incremented if there is any backward
// incompatible change to the log record format. Details will be in
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// 'CHANGES.md' (the change log).
var LOG_VERSION = 0;
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var xxx = function xxx(s) { // internal dev/debug logging
var args = ['XX' + 'X: '+s].concat(Array.prototype.slice.call(arguments, 1));
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console.error.apply(this, args);
};
var xxx = function xxx() {}; // uncomment to turn of debug logging
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var os = require('os');
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var fs = require('fs');
var util = require('util');
var assert = require('assert');
try {
var dtrace = require('trentm-dtrace-provider');
} catch (e) {
dtrace = null;
}
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var EventEmitter = require('events').EventEmitter;
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//---- Internal support stuff
function objCopy(obj) {
if (obj === null) {
return null;
} else if (Array.isArray(obj)) {
return obj.slice();
} else {
var copy = {};
Object.keys(obj).forEach(function (k) {
copy[k] = obj[k];
});
return copy;
}
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}
var format = util.format;
if (!format) {
// If node < 0.6, then use its `util.format`:
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// <https://github.com/joyent/node/blob/master/lib/util.js#L22>:
var inspect = util.inspect;
var formatRegExp = /%[sdj%]/g;
format = function format(f) {
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if (typeof (f) !== 'string') {
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var objects = [];
for (var i = 0; i < arguments.length; i++) {
objects.push(inspect(arguments[i]));
}
return objects.join(' ');
}
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var i = 1;
var args = arguments;
var len = args.length;
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var str = String(f).replace(formatRegExp, function (x) {
if (i >= len)
return x;
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switch (x) {
case '%s': return String(args[i++]);
case '%d': return Number(args[i++]);
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case '%j': return JSON.stringify(args[i++], safeCycles());
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case '%%': return '%';
default:
return x;
}
});
for (var x = args[i]; i < len; x = args[++i]) {
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if (x === null || typeof (x) !== 'object') {
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str += ' ' + x;
} else {
str += ' ' + inspect(x);
}
}
return str;
};
}
/**
* Gather some caller info 3 stack levels up.
* See <http://code.google.com/p/v8/wiki/JavaScriptStackTraceApi>.
*/
function getCaller3Info() {
var obj = {};
var saveLimit = Error.stackTraceLimit;
var savePrepare = Error.prepareStackTrace;
Error.stackTraceLimit = 3;
Error.captureStackTrace(this, getCaller3Info);
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Error.prepareStackTrace = function (_, stack) {
var caller = stack[2];
obj.file = caller.getFileName();
obj.line = caller.getLineNumber();
var func = caller.getFunctionName();
if (func)
obj.func = func;
};
this.stack;
Error.stackTraceLimit = saveLimit;
Error.prepareStackTrace = savePrepare;
return obj;
}
/**
* Warn about an bunyan processing error.
*
* If file/line are given, this makes an attempt to warn on stderr only once.
*
* @param msg {String} Message with which to warn.
* @param file {String} Optional. File path relevant for the warning.
* @param line {String} Optional. Line number in `file` path relevant for
* the warning.
*/
function _warn(msg, file, line) {
assert.ok(msg);
var key;
if (file && line) {
key = file + ':' + line;
if (_warned[key]) {
return;
}
_warned[key] = true;
}
process.stderr.write(msg + '\n');
}
var _warned = {};
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//---- Levels
var TRACE = 10;
var DEBUG = 20;
var INFO = 30;
var WARN = 40;
var ERROR = 50;
var FATAL = 60;
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var levelFromName = {
'trace': TRACE,
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'debug': DEBUG,
'info': INFO,
'warn': WARN,
'error': ERROR,
'fatal': FATAL
};
// Dtrace probes.
var dtp = undefined;
var probes = dtrace && {};
/**
* Resolve a level number, name (upper or lowercase) to a level number value.
*
* @api public
*/
function resolveLevel(nameOrNum) {
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var level = (typeof (nameOrNum) === 'string'
? levelFromName[nameOrNum.toLowerCase()]
: nameOrNum);
if (! (TRACE <= level && level <= FATAL)) {
throw new Error('invalid level: ' + nameOrNum);
}
return level;
}
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//---- Logger class
/**
* Create a Logger instance.
*
* @param options {Object} See documentation for full details. At minimum
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* this must include a 'name' string key. Configuration keys:
* - `streams`: specify the logger output streams. This is an array of
* objects with these fields:
* - `type`: The stream type. See README.md for full details.
* Often this is implied by the other fields. Examples are
* "file", "stream" and "raw".
* - `level`: Defaults to "info".
* - `path` or `stream`: The specify the file path or writeable
* stream to which log records are written. E.g.
* `stream: process.stdout`.
* - `closeOnExit` (boolean): Optional. Default is true for a
* "file" stream when `path` is given, false otherwise.
* See README.md for full details.
* - `level`: set the level for a single output stream (cannot be used
* with `streams`)
* - `stream`: the output stream for a logger with just one, e.g.
* `process.stdout` (cannot be used with `streams`)
* - `serializers`: object mapping log record field names to
* serializing functions. See README.md for details.
* - `src`: Boolean (default false). Set true to enable 'src' automatic
* field with log call source info.
* All other keys are log record fields.
*
* An alternative *internal* call signature is used for creating a child:
* new Logger(<parent logger>, <child options>[, <child opts are simple>]);
*
* @param _childSimple (Boolean) An assertion that the given `_childOptions`
* (a) only add fields (no config) and (b) no serialization handling is
* required for them. IOW, this is a fast path for frequent child
* creation.
*/
function Logger(options, _childOptions, _childSimple) {
xxx('Logger start:', options)
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if (! this instanceof Logger) {
return new Logger(options, _childOptions);
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}
// Input arg validation.
var parent;
if (_childOptions !== undefined) {
parent = options;
options = _childOptions;
if (! parent instanceof Logger) {
throw new TypeError('invalid Logger creation: do not pass a second arg');
}
}
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if (!options) {
throw new TypeError('options (object) is required');
}
if (!parent) {
if (!options.name) {
throw new TypeError('options.name (string) is required');
}
} else {
if (options.name) {
throw new TypeError('invalid options.name: child cannot set logger name');
}
}
if (options.stream && options.streams) {
throw new TypeError('cannot mix "streams" and "stream" options');
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}
if (options.streams && !Array.isArray(options.streams)) {
throw new TypeError('invalid options.streams: must be an array')
}
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if (options.serializers && (typeof (options.serializers) !== 'object' ||
Array.isArray(options.serializers))) {
throw new TypeError('invalid options.serializers: must be an object')
}
EventEmitter.call(this);
// Fast path for simple child creation.
if (parent && _childSimple) {
// `_isSimpleChild` is a signal to stream close handling that this child
// owns none of its streams.
this._isSimpleChild = true;
this._level = parent._level;
this.streams = parent.streams;
this.serializers = parent.serializers;
this.src = parent.src;
var fields = this.fields = {};
var parentFieldNames = Object.keys(parent.fields);
for (var i = 0; i < parentFieldNames.length; i++) {
var name = parentFieldNames[i];
fields[name] = parent.fields[name];
}
var names = Object.keys(options);
for (var i = 0; i < names.length; i++) {
var name = names[i];
fields[name] = options[name];
}
return;
}
// Null values.
var self = this;
if (parent) {
this._level = parent._level;
this.streams = [];
for (var i = 0; i < parent.streams.length; i++) {
var s = objCopy(parent.streams[i]);
s.closeOnExit = false; // Don't own parent stream.
this.streams.push(s);
}
this.serializers = objCopy(parent.serializers);
this.src = parent.src;
this.fields = objCopy(parent.fields);
if (options.level) {
this.level(options.level);
}
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} else {
this._level = Number.POSITIVE_INFINITY;
this.streams = [];
this.serializers = null;
this.src = false;
this.fields = {};
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}
if (!dtp && dtrace) {
dtp = dtrace.createDTraceProvider('bunyan');
for (var level in levelFromName) {
var probe;
probes[levelFromName[level]] = probe =
dtp.addProbe('log-' + level, 'char *');
// Explicitly add a reference to dtp to prevent it from being GC'd
probe.dtp = dtp;
}
dtp.enable();
}
// Helpers
function addStream(s) {
s = objCopy(s);
// Implicit 'type' from other args.
var type = s.type;
if (!s.type) {
if (s.stream) {
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s.type = 'stream';
} else if (s.path) {
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s.type = 'file'
}
}
s.raw = (s.type === 'raw'); // PERF: Allow for faster check in `_emit`.
if (s.level) {
s.level = resolveLevel(s.level);
} else if (options.level) {
s.level = resolveLevel(options.level);
} else {
s.level = INFO;
}
if (s.level < self._level) {
self._level = s.level;
}
switch (s.type) {
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case 'stream':
if (!s.closeOnExit) {
s.closeOnExit = false;
}
break;
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case 'file':
if (!s.stream) {
s.stream = fs.createWriteStream(s.path,
{flags: 'a', encoding: 'utf8'});
s.stream.on('error', function (err) {
self.emit('error', err, s);
});
if (!s.closeOnExit) {
s.closeOnExit = true;
}
} else {
if (!s.closeOnExit) {
s.closeOnExit = false;
}
}
break;
case 'raw':
if (!s.closeOnExit) {
s.closeOnExit = false;
}
break;
default:
throw new TypeError('unknown stream type "' + s.type + '"');
}
self.streams.push(s);
}
function addSerializers(serializers) {
if (!self.serializers) {
self.serializers = {};
}
Object.keys(serializers).forEach(function (field) {
var serializer = serializers[field];
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if (typeof (serializer) !== 'function') {
throw new TypeError(format(
'invalid serializer for "%s" field: must be a function', field));
} else {
self.serializers[field] = serializer;
}
});
}
// Handle *config* options (i.e. options that are not just plain data
// for log records).
if (options.stream) {
addStream({
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type: 'stream',
stream: options.stream,
closeOnExit: false,
level: (options.level ? resolveLevel(options.level) : INFO)
});
} else if (options.streams) {
options.streams.forEach(addStream);
} else if (parent && options.level) {
this.level(options.level);
} else if (!parent) {
addStream({
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type: 'stream',
stream: process.stdout,
closeOnExit: false,
level: (options.level ? resolveLevel(options.level) : INFO)
});
}
if (options.serializers) {
addSerializers(options.serializers);
}
if (options.src) {
this.src = true;
}
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xxx('Logger: ', self)
// Fields.
// These are the default fields for log records (minus the attributes
// removed in this constructor). To allow storing raw log records
// (unrendered), `this.fields` must never be mutated. Create a copy for
// any changes.
var fields = objCopy(options);
delete fields.stream;
delete fields.level;
delete fields.streams;
delete fields.serializers;
delete fields.src;
if (this.serializers) {
this._applySerializers(fields);
}
if (!fields.hostname) {
fields.hostname = os.hostname();
}
if (!fields.pid) {
fields.pid = process.pid;
}
Object.keys(fields).forEach(function (k) {
self.fields[k] = fields[k];
});
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}
util.inherits(Logger, EventEmitter);
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/**
* Create a child logger, typically to add a few log record fields.
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*
* This can be useful when passing a logger to a sub-component, e.g. a
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* 'wuzzle' component of your service:
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*
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* var wuzzleLog = log.child({component: 'wuzzle'})
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* var wuzzle = new Wuzzle({..., log: wuzzleLog})
*
* Then log records from the wuzzle code will have the same structure as
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* the app log, *plus the component='wuzzle' field*.
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*
* @param options {Object} Optional. Set of options to apply to the child.
* All of the same options for a new Logger apply here. Notes:
* - The parent's streams are inherited and cannot be removed in this
* call. Any given `streams` are *added* to the set inherited from
* the parent.
* - The parent's serializers are inherited, though can effectively be
* overwritten by using duplicate keys.
* - Can use `level` to set the level of the streams inherited from
* the parent. The level for the parent is NOT affected.
* @param simple {Boolean} Optional. Set to true to assert that `options`
* (a) only add fields (no config) and (b) no serialization handling is
* required for them. IOW, this is a fast path for frequent child
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* creation. See 'tools/timechild.js' for numbers.
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*/
Logger.prototype.child = function (options, simple) {
return new Logger(this, options || {}, simple);
}
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/* BEGIN JSSTYLED */
/**
* Close this logger.
*
* This closes streams (that it owns, as per 'endOnClose' attributes on
* streams), etc. Typically you **don't** need to bother calling this.
Logger.prototype.close = function () {
if (this._closed) {
return;
}
if (!this._isSimpleChild) {
self.streams.forEach(function (s) {
if (s.endOnClose) {
xxx('closing stream s:', s);
s.stream.end();
s.endOnClose = false;
}
});
}
this._closed = true;
}
*/
/* END JSSTYLED */
/**
* Get/set the level of all streams on this logger.
*
* Get Usage:
* // Returns the current log level (lowest level of all its streams).
* log.level() -> INFO
*
* Set Usage:
* log.level(INFO) // set all streams to level INFO
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* log.level('info') // can use 'info' et al aliases
*/
Logger.prototype.level = function level(value) {
if (value === undefined) {
return this._level;
}
var newLevel = resolveLevel(value);
var len = this.streams.length;
for (var i = 0; i < len; i++) {
this.streams[i].level = newLevel;
}
this._level = newLevel;
}
/**
* Get/set the level of a particular stream on this logger.
*
* Get Usage:
* // Returns an array of the levels of each stream.
* log.levels() -> [TRACE, INFO]
*
* // Returns a level of the identified stream.
* log.levels(0) -> TRACE // level of stream at index 0
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* log.levels('foo') // level of stream with name 'foo'
*
* Set Usage:
* log.levels(0, INFO) // set level of stream 0 to INFO
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* log.levels(0, 'info') // can use 'info' et al aliases
* log.levels('foo', WARN) // set stream named 'foo' to WARN
*
* Stream names: When streams are defined, they can optionally be given
* a name. For example,
* log = new Logger({
* streams: [
* {
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* name: 'foo',
* path: '/var/log/my-service/foo.log'
* level: 'trace'
* },
* ...
*
* @param name {String|Number} The stream index or name.
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* @param value {Number|String} The level value (INFO) or alias ('info').
* If not given, this is a 'get' operation.
* @throws {Error} If there is no stream with the given name.
*/
Logger.prototype.levels = function levels(name, value) {
if (name === undefined) {
assert.equal(value, undefined);
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return this.streams.map(
function (s) { return s.level });
}
var stream;
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if (typeof (name) === 'number') {
stream = this.streams[name];
if (stream === undefined) {
throw new Error('invalid stream index: ' + name);
}
} else {
var len = this.streams.length;
for (var i = 0; i < len; i++) {
var s = this.streams[i];
if (s.name === name) {
stream = s;
break;
}
}
if (!stream) {
throw new Error(format('no stream with name "%s"', name));
}
}
if (value === undefined) {
return stream.level;
} else {
var newLevel = resolveLevel(value);
stream.level = newLevel;
if (newLevel < this._level) {
this._level = newLevel;
}
}
}
/**
* Apply registered serializers to the appropriate keys in the given fields.
*
* Pre-condition: This is only called if there is at least one serializer.
*
* @param fields (Object) The log record fields.
* @param keys (Array) Optional array of keys to which to limit processing.
*/
Logger.prototype._applySerializers = function (fields, keys) {
var self = this;
// Mapping of keys to potentially serialize.
var applyKeys = fields;
if (keys) {
applyKeys = {};
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for (var i = 0; i < keys.length; i++) {
applyKeys[keys[i]] = true;
}
}
xxx('_applySerializers: applyKeys', applyKeys);
// Check each serializer against these (presuming number of serializers
// is typically less than number of fields).
Object.keys(this.serializers).forEach(function (name) {
if (applyKeys[name]) {
xxx('_applySerializers; apply to "%s" key', name)
try {
fields[name] = self.serializers[name](fields[name]);
} catch (err) {
_warn(format('bunyan: ERROR: This should never happen. '
+ 'This is a bug in <https://github.com/trentm/node-bunyan> or '
+ 'in this application. Exception from "%s" Logger serializer: %s',
name, err.stack || err));
fields[name] = format('(Error in Bunyan log "%s" serializer '
+ 'broke field. See stderr for details.)', name);
}
}
});
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}
/**
* A log record is a 4-tuple:
* [<default fields object>,
* <log record fields object>,
* <level integer>,
* <msg args array>]
* For Perf reasons, we only render this down to a single object when
* it is emitted.
*/
Logger.prototype._mkRecord = function (fields, level, msgArgs) {
var recFields = (fields ? objCopy(fields) : null);
return [this.fields, recFields, level, msgArgs];
}
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/**
* Emit a log record.
*
* @param rec {log record}
* @param noemit {Boolean} Optional. Set to true to skip emission
* and just return the JSON string.
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*/
Logger.prototype._emit = function (rec, noemit) {
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var i;
// Lazily determine if this Logger has non-"raw" streams. If there are
// any, then we need to stringify the log record.
if (this.haveNonRawStreams === undefined) {
this.haveNonRawStreams = false;
for (i = 0; i < this.streams.length; i++) {
if (!this.streams[i].raw) {
this.haveNonRawStreams = true;
break;
}
}
}
// Stringify the object. Attempt to warn/recover on error.
var str;
if (noemit || this.haveNonRawStreams) {
str = JSON.stringify(rec, safeCycles()) + '\n';
}
if (noemit)
return str;
var level = rec.level;
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for (i = 0; i < this.streams.length; i++) {
var s = this.streams[i];
if (s.level <= level) {
xxx('writing log rec "%s" to "%s" stream (%d <= %d): %j',
rec.msg, s.type, s.level, level, rec);
s.stream.write(s.raw ? rec : str);
}
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};
return str;
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}
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/**
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* Build a log emitter function for level minLevel. I.e. this is the
* creator of `log.info`, `log.error`, etc.
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*/
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function mkLogEmitter(minLevel) {
return function () {
var log = this;
function mkRecord(args) {
if (args[0] instanceof Error) {
// `log.<level>(err, ...)`
fields = {err: errSerializer(args[0])};
if (args.length === 1) {
msgArgs = [fields.err.message];
} else {
msgArgs = Array.prototype.slice.call(args, 1);
}
} else if (typeof (args[0]) === 'string') { // `log.<level>(msg, ...)`
fields = null;
msgArgs = Array.prototype.slice.call(args);
} else if (Buffer.isBuffer(args[0])) { // `log.<level>(buf, ...)`
// Almost certainly an error, show `inspect(buf)`. See bunyan issue #35.
fields = null;
msgArgs = Array.prototype.slice.call(args);
msgArgs[0] = util.inspect(msgArgs[0]);
} else { // `log.<level>(fields, msg, ...)`
fields = args[0];
msgArgs = Array.prototype.slice.call(args, 1);
}
// Build up the record object.
var rec = objCopy(log.fields);
var level = rec.level = minLevel;
var recFields = (fields ? objCopy(fields) : null);
if (recFields) {
if (log.serializers) {
log._applySerializers(recFields);
}
Object.keys(recFields).forEach(function (k) {
rec[k] = recFields[k];
});
}
rec.msg = format.apply(log, msgArgs);
if (!rec.time) {
rec.time = (new Date());
}
// Get call source info
if (log.src && !rec.src) {
rec.src = getCaller3Info()
}
rec.v = LOG_VERSION;
return rec;
};
var fields = null;
var msgArgs = arguments;
var str = null;
var rec = null;
if (arguments.length === 0) { // `log.<level>()`
return (this._level <= minLevel);
} else if (this._level > minLevel) {
/* pass through */
} else {
rec = mkRecord(msgArgs);
str = this._emit(rec);
}
probes && probes[minLevel].fire(function () {
return [ str ||
(rec && log._emit(rec, true)) ||
log._emit(mkRecord(msgArgs), true) ];
});
}
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}
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/**
* The functions below log a record at a specific level.
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*
* Usages:
* log.<level>() -> boolean is-trace-enabled
* log.<level>(<Error> err, [<string> msg, ...])
* log.<level>(<string> msg, ...)
* log.<level>(<object> fields, <string> msg, ...)
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*
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* where <level> is the lowercase version of the log level. E.g.:
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*
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* log.info()
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*
* @params fields {Object} Optional set of additional fields to log.
* @params msg {String} Log message. This can be followed by additional
* arguments that are handled like
* [util.format](http://nodejs.org/docs/latest/api/all.html#util.format).
*/
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Logger.prototype.trace = mkLogEmitter(TRACE);
Logger.prototype.debug = mkLogEmitter(DEBUG);
Logger.prototype.info = mkLogEmitter(INFO);
Logger.prototype.warn = mkLogEmitter(WARN);
Logger.prototype.error = mkLogEmitter(ERROR);
Logger.prototype.fatal = mkLogEmitter(FATAL);
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//---- Standard serializers
// A serializer is a function that serializes a JavaScript object to a
// JSON representation for logging. There is a standard set of presumed
// interesting objects in node.js-land.
Logger.stdSerializers = {};
// Serialize an HTTP request.
Logger.stdSerializers.req = function req(req) {
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if (!req || !req.connection)
return req;
return {
method: req.method,
url: req.url,
headers: req.headers,
remoteAddress: req.connection.remoteAddress,
remotePort: req.connection.remotePort
};
// Trailers: Skipping for speed. If you need trailers in your app, then
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// make a custom serializer.
//if (Object.keys(trailers).length > 0) {
// obj.trailers = req.trailers;
//}
};
// Serialize an HTTP response.
Logger.stdSerializers.res = function res(res) {
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if (!res || !res.statusCode)
return res;
return {
statusCode: res.statusCode,
header: res._header
}
};
/*
* This function dumps long stack traces for exceptions having a cause()
* method. The error classes from
* [verror](https://github.com/davepacheco/node-verror) and
* [restify v2.0](https://github.com/mcavage/node-restify) are examples.
*
* Based on `dumpException` in
* https://github.com/davepacheco/node-extsprintf/blob/master/lib/extsprintf.js
*/
function getFullErrorStack(ex)
{
var ret = ex.stack || ex.toString();
if (ex.cause && typeof(ex.cause) === 'function') {
var cex = ex.cause();
if (cex) {
ret += '\nCaused by: ' + getFullErrorStack(cex);
}
}
return (ret);
}
// Serialize an Error object
// (Core error properties are enumerable in node 0.4, not in 0.6).
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var errSerializer = Logger.stdSerializers.err = function err(err) {
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if (!err || !err.stack)
return err;
var obj = {
message: err.message,
name: err.name,
stack: getFullErrorStack(err)
}
Object.keys(err).forEach(function (k) {
if (err[k] !== undefined) {
obj[k] = err[k];
}
});
return obj;
};
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// A JSON stringifier that handles cycles safely.
// Usage: JSON.stringify(obj, safeCycles())
function safeCycles() {
var seen = [];
return function(key, val) {
if (!val || typeof val !== 'object') {
return val;
}
if (seen.indexOf(val) !== -1) {
return '[Circular]';
}
seen.push(val);
return val;
};
}
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/**
* RingBuffer is a Writable Stream that just stores the last N records in
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* memory.
*
* @param options {Object}, with the following fields:
*
* - limit: number of records to keep in memory
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*/
function RingBuffer(options) {
this.limit = options && options.limit ? options.limit : 100;
this.writable = true;
this.records = [];
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EventEmitter.call(this);
}
util.inherits(RingBuffer, EventEmitter);
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RingBuffer.prototype.write = function (record) {
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if (!this.writable)
throw (new Error('RingBuffer has been ended already'));
this.records.push(record);
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if (this.records.length > this.limit)
this.records.shift();
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return (true);
};
RingBuffer.prototype.end = function () {
if (arguments.length > 0)
this.write.apply(this, Array.prototype.slice.call(arguments));
this.writable = false;
};
RingBuffer.prototype.destroy = function () {
this.writable = false;
this.emit('close');
};
RingBuffer.prototype.destroySoon = function () {
this.destroy();
};
//---- Exports
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module.exports = Logger;
module.exports.TRACE = TRACE;
module.exports.DEBUG = DEBUG;
module.exports.INFO = INFO;
module.exports.WARN = WARN;
module.exports.ERROR = ERROR;
module.exports.FATAL = FATAL;
module.exports.resolveLevel = resolveLevel;
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module.exports.VERSION = VERSION;
module.exports.LOG_VERSION = LOG_VERSION;
module.exports.createLogger = function createLogger(options) {
return new Logger(options);
};
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module.exports.RingBuffer = RingBuffer;
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// Useful for custom `type == "raw"` streams that may do JSON stringification
// of log records themselves. Usage:
// var str = JSON.stringify(rec, bunyan.safeCycles());
module.exports.safeCycles = safeCycles;