headless_zip.js

/*******************************************************************************
 * Copyright 2016 IBM Corp.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *******************************************************************************/

var fs = require('fs')
var path = require('path')
var JSZip = require("jszip");

var dirToWriteTo;
var filesToKeep = 10;
var filesWritten = [];

function onError(err) {
	console.error('Headless Zip: an error occurred:', err)
}

function deleteDir(directory) {
	// Delete temporary directory
	if(fs.existsSync(directory)) {
		fs.readdirSync(directory).forEach(function(file,index){
			var fileName = path.join(directory, file)
			fs.unlinkSync(fileName)
		})
		fs.rmdirSync(directory);
	}
}

function deleteFile(filename) {
	fs.unlink(filename)
}

module.exports.setHeadlessOutputDir = function setHeadlessOutputDir(dir) {
	dirToWriteTo = dir;
}

module.exports.setFilesToKeep = function setFilesToKeep(numFiles) {
	filesToKeep = numFiles;
}

function timestamp() {
	var date = new Date(Date.now())
	var timestamp = pad(date.getDate().toString()) + pad((date.getMonth() + 1).toString()) + date.getFullYear().toString().substr(2,3) + '_'
		+ pad(date.getHours().toString()) + pad(date.getMinutes().toString()) + pad(date.getSeconds().toString()) + '_'
		+ process.pid
	return timestamp
}

function pad(numberString) {
	// pads a single digit number with a leading 0
	if(numberString.length == 1) {
		return '0' + numberString
	}
	return numberString
}

module.exports.headlessZip = function headlessZip(dirToZip) {
	var outputFileName;
	if(dirToWriteTo) {
		outputFileName = path.join(dirToWriteTo, 'nodeappmetrics' + timestamp() + '.hcd')
	} else {
		outputFileName = 'nodeappmetrics' + timestamp() + '.hcd'
	}

	filesWritten.push(outputFileName)
	if(filesWritten.length > filesToKeep) {
		var earliest = filesWritten.shift()
		deleteFile(earliest)
	}

	if(fs.existsSync(dirToZip)) {
		var zip = new JSZip();
		var files = fs.readdirSync(dirToZip)
		for (var i = 0, len = files.length; i < len; i++) {
			zip.file(files[i], fs.readFileSync(path.join(dirToZip, files[i])), {compression : "DEFLATE"})
		}
		fs.writeFileSync(outputFileName, zip.generate({type:"nodebuffer", compression:'DEFLATE'}));
		deleteDir(dirToZip)
	}
}

module.exports.tryZipOnExit = function tryZipOnExit() {
	var outputDir = dirToWriteTo;
	if(!outputDir) {
		ouputDir = process.cwd().toString()
	}
	if(fs.existsSync(outputDir)) {
		var files = fs.readdirSync(outputDir);
		// Search for temporary output directory using pattern matching
		for (var i = 0, len = files.length; i < len; i++) {
			if(/tmp_(\w+)/.test(files[i].toString())) {
				var dirToZip = path.join(outputDir, files[i])
				this.headlessZip(dirToZip)
				return;
			}
		}
	}
}