Logs support.

Added /logs endpoint with basic logger and LoggerAdapter.

src/Adapters/Logger/FileLoggerAdapter.js

@@ -0,0 +1,225 @@
+// Logger
+//
+// Wrapper around Winston logging library with custom query
+// 
+// expected log entry to be in the shape of:
+// {"level":"info","message":"{ '0': 'Your Message' }","timestamp":"2016-02-04T05:59:27.412Z"}
+//
+import { LoggerAdapter } from './LoggerAdapter';
+import winston from 'winston';
+import fs from 'fs';
+import { Parse } from 'parse/node';
+
+const MILLISECONDS_IN_A_DAY = 24 * 60 * 60 * 1000;
+const CACHE_TIME = 1000 * 60;
+
+let LOGS_FOLDER = './logs/';
+
+if (typeof process !== 'undefined' && process.env.NODE_ENV === 'test') {
+  LOGS_FOLDER = './test_logs/'
+}
+
+let currentDate = new Date();
+
+let simpleCache = {
+  timestamp: null,
+  from: null,
+  until: null,
+  order: null,
+  data: [],
+  level: 'info',
+};
+
+// returns Date object rounded to nearest day
+let _getNearestDay = (date) => {
+  return new Date(date.getFullYear(), date.getMonth(), date.getDate());
+}
+
+// returns Date object of previous day
+let _getPrevDay = (date) => {
+  return new Date(date - MILLISECONDS_IN_A_DAY);
+}
+
+// returns the iso formatted file name
+let _getFileName = () => {
+  return _getNearestDay(currentDate).toISOString()
+}
+
+// check for valid cache when both from and util match.
+// cache valid for up to 1 minute
+let _hasValidCache = (from, until, level) => {
+  if (String(from) === String(simpleCache.from) &&
+    String(until) === String(simpleCache.until) &&
+    new Date() - simpleCache.timestamp < CACHE_TIME &&
+    level === simpleCache.level) {
+    return true;
+  }
+  return false;
+}
+
+// renews transports to current date
+let _renewTransports = ({infoLogger, errorLogger, logsFolder}) => {
+  if (infoLogger) {
+    infoLogger.add(winston.transports.File, {
+      filename: logsFolder + _getFileName() + '.info',
+      name: 'info-file',
+      level: 'info'
+    });
+  }
+  if (errorLogger) {
+    errorLogger.add(winston.transports.File, {
+      filename: logsFolder + _getFileName() + '.error',
+      name: 'error-file',
+      level: 'error'
+    });
+  }
+};
+
+// check that log entry has valid time stamp based on query
+let _isValidLogEntry = (from, until, entry) => {
+  var _entry = JSON.parse(entry),
+    timestamp = new Date(_entry.timestamp);
+  return timestamp >= from && timestamp <= until
+    ? true
+    : false
+};
+
+// ensure that file name is up to date
+let _verifyTransports = ({infoLogger, errorLogger, logsFolder}) => {
+  if (_getNearestDay(currentDate) !== _getNearestDay(new Date())) {
+    currentDate = new Date();
+    if (infoLogger) {
+      infoLogger.remove('info-file');
+    } 
+    if (errorLogger) {
+      errorLogger.remove('error-file');
+    }
+    _renewTransports({infoLogger, errorLogger, logsFolder});
+  }
+}
+
+export class FileLoggerAdapter extends LoggerAdapter {
+  constructor(options = {}) {
+    super();
+
+    this._logsFolder = options.logsFolder || LOGS_FOLDER;
+
+    // check logs folder exists
+    if (!fs.existsSync(this._logsFolder)) {
+      fs.mkdirSync(this._logsFolder);
+    }
+
+    this._errorLogger = new (winston.Logger)({
+      exitOnError: false,
+      transports: [
+        new (winston.transports.File)({
+          filename: this._logsFolder + _getFileName() + '.error',
+          name: 'error-file',
+          level: 'error'
+        })
+      ]
+    });
+
+    this._infoLogger = new (winston.Logger)({
+      exitOnError: false,
+      transports: [
+        new (winston.transports.File)({
+          filename: this._logsFolder + _getFileName() + '.info',
+          name: 'info-file',
+          level: 'info'
+        })
+      ]
+    });
+  }
+
+  info() {
+    _verifyTransports({infoLogger: this._infoLogger, logsFolder: this._logsFolder});
+    return this._infoLogger.info.apply(undefined, arguments);    
+  }
+
+  error() {
+    _verifyTransports({errorLogger: this._errorLogger, logsFolder: this._logsFolder});
+    return this._errorLogger.error.apply(undefined, arguments);
+  }
+
+  // custom query as winston is currently limited
+  query(options, callback) {
+    if (!options) {
+      options = {};
+    }
+    // defaults to 7 days prior
+    let from = options.from || new Date(Date.now() - (7 * MILLISECONDS_IN_A_DAY));
+    let until = options.until || new Date();
+    let size = options.size || 10;
+    let order = options.order || 'desc';
+    let level = options.level || 'info';
+    let roundedUntil = _getNearestDay(until);
+    let roundedFrom = _getNearestDay(from);
+
+    if (_hasValidCache(roundedFrom, roundedUntil, level)) {
+      let logs = [];
+      if (order !== simpleCache.order) {
+        // reverse order of data
+        simpleCache.data.forEach((entry) => {
+          logs.unshift(entry);
+        });
+      } else {
+        logs = simpleCache.data;
+      }
+      callback(logs.slice(0, size));
+      return;
+    }
+
+    let curDate = roundedUntil;
+    let curSize = 0;
+    let method = order === 'desc' ? 'push' : 'unshift';
+    let files = [];
+    let promises = [];
+
+    // current a batch call, all files with valid dates are read
+    while (curDate >= from) {
+      files[method](this._logsFolder + curDate.toISOString() + '.' + level);
+      curDate = _getPrevDay(curDate);
+    }
+
+    // read each file and split based on newline char.
+    // limitation is message cannot contain newline
+    // TODO: strip out delimiter from logged message
+    files.forEach(function(file, i) {
+      let promise = new Parse.Promise();
+      fs.readFile(file, 'utf8', function(err, data) {
+        if (err) {
+          promise.resolve([]);
+        }  else {
+          let results = data.split('\n').filter((value) => {
+            return value.trim() !== '';
+          });
+          promise.resolve(results);
+        }
+      });
+      promises[method](promise);
+    });
+
+    Parse.Promise.when(promises).then((results) => {
+      let logs = [];
+      results.forEach(function(logEntries, i) {
+        logEntries.forEach(function(entry) {
+          if (_isValidLogEntry(from, until, entry)) {
+            logs[method](JSON.parse(entry));
+          }
+        });
+      });
+      simpleCache = {
+        timestamp: new Date(),
+        from: roundedFrom,
+        until: roundedUntil,
+        data: logs,
+        order,
+        level,
+      };
+      callback(logs.slice(0, size));
+    });
+  }
+}
+
+export default FileLoggerAdapter;

src/Adapters/Logger/LoggerAdapter.js

@@ -0,0 +1,17 @@
+// Logger Adapter
+//
+// Allows you to change the logger mechanism
+//
+// Adapter classes must implement the following functions:
+// * info(obj1 [, obj2, .., objN])
+// * error(obj1 [, obj2, .., objN])
+// * query(options, callback)
+// Default is FileLoggerAdapter.js
+
+export class LoggerAdapter {
+  info() {}
+  error() {}
+  query(options, callback) {}
+}
+
+export default LoggerAdapter;