Update logging logic to allow writing to log files

src/logging.js

 /**
  * Custom logging to create more useful output.
+ * Simply include this file at the top of other files to get extra logging logic.
  */
 
 // System Imports.
 const chalk = require('chalk');
+const fs = require('fs');
 const path = require('path');
 
+// User Imports.
+const getCurrentDate = require('./helper_functions.js');
+
 
 /**
  * Essentially "upgrades" default Javascript console output to be more informative.
@@ -25,39 +30,159 @@ const path = require('path');
         Error.prepareStackTrace = originalPrepareStackTrace;
         let relativeFileName = path.relative(process.cwd(), callee.getFileName());
 
-
-        // This is where we actually prepend to our provided log text.
+        // Generate and log our text to console/file.
+        let prefix = '';
+        let console_string = '';
+        let log_string = '';
         if (methodName == 'debug') {
-            // Prepend text for DEBUG level.
-            var prefix = ` ${chalk.green('[DEBUG]')} [${relativeFileName} ${callee.getLineNumber()}] `;
+            // Handling for DEBUG level.
+
+            // Generate and print Console text.
+            prefix = ` ${chalk.green('[DEBUG]')} [${relativeFileName} ${callee.getLineNumber()}] `;
+            console_string = prefix.concat(firstArgument, ...otherArguments);
+            originalLoggingMethod(console_string);
+
+            // Generate and print Log File text.
+            prefix = `${getCurrentDate()} [DEBUG] [${relativeFileName} ${callee.getLineNumber()}] `;
+            log_string = prefix.concat(firstArgument, ...otherArguments, '\n');
+            write_to_file(log_string, 'debug');
 
         } else if (methodName == 'info') {
-            // Prepend text for INFO level.
-            var prefix = ` ${chalk.blue('[INFO]')}  [${relativeFileName} ${callee.getLineNumber()}] `;
+            // Handling for INFO level.
+
+            // Generate and print Console text.
+            prefix = ` ${chalk.blue('[INFO]')} [${relativeFileName} ${callee.getLineNumber()}] `;
+            console_string = prefix.concat(firstArgument, ...otherArguments);
+            originalLoggingMethod(console_string);
+
+            // Generate and print Log File text.
+            prefix = `${getCurrentDate()} [INFO] [${relativeFileName} ${callee.getLineNumber()}] `;
+            log_string = prefix.concat(firstArgument, ...otherArguments, '\n');
+            write_to_file(log_string, 'info');
 
         } else if (methodName == 'warning' || methodName == 'warn') {
-            // Prepend text for WARNING level.
-            var prefix = ` ${chalk.yellow('[WARN]')}  [${relativeFileName} ${callee.getLineNumber()}] `;
+            // Handling for WARNING level.
+
+            // Generate and print Console text.
+            prefix = ` ${chalk.yellow('[WARN]')} [${relativeFileName} ${callee.getLineNumber()}] `;
+            console_string = prefix.concat(firstArgument, ...otherArguments);
+            originalLoggingMethod(console_string);
+
+            // Generate and print Log File text.
+            prefix = `${getCurrentDate()} [WARN] [${relativeFileName} ${callee.getLineNumber()}] `;
+            log_string = prefix.concat(firstArgument, ...otherArguments, '\n');
+            write_to_file(log_string, 'warn');
 
         } else if (methodName == 'error' || methodName == 'err') {
             // Prepend text for ERROR level.
-            var prefix = ` ${chalk.red('[ERROR]')} [${relativeFileName} ${callee.getLineNumber()}] `;
+
+            // Generate and print Console text.
+            prefix = ` ${chalk.red('[ERROR]')} [${relativeFileName} ${callee.getLineNumber()}] `;
+            console_string = prefix.concat(firstArgument, ...otherArguments);
+            originalLoggingMethod(console_string);
+
+            // Generate and print Log File text.
+            prefix = `${getCurrentDate()} [ERROR] [${relativeFileName} ${callee.getLineNumber()}] `;
+            log_string = prefix.concat(firstArgument, ...otherArguments, '\n');
+            write_to_file(log_string, 'error');
 
         } else if (methodName == 'log') {
             //  LOG level does not get prepend text.
-            var prefix = ' ';
+            prefix = ' ';
+            console_string = prefix.concat(firstArgument, ...otherArguments);
+            originalLoggingMethod(console_string);
 
         } else {
             // Fallback prepend text for all other cases.
-            var prefix = ` [${methodName}] [${relativeFileName} ${callee.getLineNumber()}] `;
+            prefix = ` [${methodName}] [${relativeFileName} ${callee.getLineNumber()}] `;
+            console_string = prefix.concat(firstArgument, ...otherArguments);
+            originalLoggingMethod(console_string);
         }
 
-
-        // More magic to generate the console output.
-        if (typeof firstArgument === 'string') {
-            originalLoggingMethod(prefix + firstArgument, ...otherArguments);
-        } else {
-            originalLoggingMethod(prefix, firstArgument, ...otherArguments);
-        }
     };
 });
+
+
+/**
+ * Writes provided string to log files.
+ */
+function write_to_file(log_string, level) {
+    let directory = './logging/';
+    let file_location = './logging/info.log';
+    let log_level = 0;
+
+    // Get appropriate level of logger. Based off of Python log levels.
+    // https://docs.python.org/3/library/logging.html
+    if (level == 'error') {
+        log_level = 40;
+    } else if (level == 'warn') {
+        log_level = 30;
+    } else if (level == 'info') {
+        log_level = 20;
+    } else if (level == 'debug') {
+        log_level = 10;
+    }
+    console.log('Log Level: ' + log_level);
+
+    // Attempt to create logging folder.
+    fs.mkdir(directory, err => {
+        // Ignore "dir already exists" errors. Raise all others.
+        if (err && err.code != 'EEXIST') {
+            throw err;
+        }
+    });
+
+    // Attempt to write to appropriate files, based on logging level.
+    if (log_level >= 40) {
+        // Error level logging or higher.
+        fs.appendFile(directory.concat('error.log'), log_string, (err) => {
+            if (err) {
+                console.log(err);
+                throw err;
+            }
+        });
+    }
+    if (log_level >= 30) {
+        // Warning level logging or higher.
+        fs.appendFile(directory.concat('warn.log'), log_string, (err) => {
+            if (err) {
+                console.log(err);
+                throw err;
+            }
+        });
+    }
+    if (log_level >= 20) {
+        // Info level logging or higher.
+        fs.appendFile(directory.concat('info.log'), log_string, (err) => {
+            if (err) {
+                console.log(err);
+                throw err;
+            }
+        });
+    }
+    if (log_level >= 10) {
+        // Debug level logging or higher.
+        fs.appendFile(directory.concat('debug.log'), log_string, (err) => {
+            if (err) {
+                console.log(err);
+                throw err;
+            }
+        });
+    }
+}
+
+
+/**
+ * Simple test to make sure all loging levels work as expected.
+ * Should convert this to a proper unit test at a later date.
+ */
+function testLogLevels() {
+    console.debug('Debug level test');
+    console.info('Info level test.');
+    console.warn('Warn level test.');
+    console.error('Error level test.');
+    console.log('Log/default level test.');
+}
+
+
+module.exports = testLogLevels;