backups: take a pattern instead of interval secs

part of #699

src/backups.js

@@ -9,7 +9,6 @@ exports = module.exports = {
     get: get,
 
     startBackupTask: startBackupTask,
-    ensureBackup: ensureBackup,
 
     restore: restore,
 
@@ -57,6 +56,7 @@ var addons = require('./addons.js'),
     BoxError = require('./boxerror.js'),
     collectd = require('./collectd.js'),
     constants = require('./constants.js'),
+    CronJob = require('cron').CronJob,
     crypto = require('crypto'),
     database = require('./database.js'),
     DataLayout = require('./datalayout.js'),
@@ -143,8 +143,8 @@ function testConfig(backupConfig, callback) {
 
     if (backupConfig.format !== 'tgz' && backupConfig.format !== 'rsync') return callback(new BoxError(BoxError.BAD_FIELD, 'unknown format', { field: 'format' }));
 
-    // remember to adjust the cron ensureBackup task interval accordingly
-    if (backupConfig.intervalSecs < 6 * 60 * 60) return callback(new BoxError(BoxError.BAD_FIELD, 'Interval must be atleast 6 hours', { field: 'intervalSecs' }));
+    const job = safe.safeCall(function () { return new CronJob(backupConfig.schedulePattern); });
+    if (!job) return callback(new BoxError(BoxError.BAD_FIELD, 'Invalid schedule pattern', { field: 'schedulePattern' }));
 
     if ('password' in backupConfig) {
         if (typeof backupConfig.password !== 'string') return callback(new BoxError(BoxError.BAD_FIELD, 'password must be a string', { field: 'password' }));
@@ -1227,31 +1227,6 @@ function startBackupTask(auditSource, callback) {
     });
 }
 
-function ensureBackup(auditSource, callback) {
-    assert.strictEqual(typeof auditSource, 'object');
-
-    debug('ensureBackup: %j', auditSource);
-
-    getByIdentifierAndStatePaged(exports.BACKUP_IDENTIFIER_BOX, exports.BACKUP_STATE_NORMAL, 1, 1, function (error, backups) {
-        if (error) {
-            debug('Unable to list backups', error);
-            return callback(error);
-        }
-
-        settings.getBackupConfig(function (error, backupConfig) {
-            if (error) return callback(error);
-
-            if (backups.length !== 0 && (new Date() - new Date(backups[0].creationTime) < (backupConfig.intervalSecs - 3600) * 1000)) { // adjust 1 hour
-                debug('Previous backup was %j, no need to backup now', backups[0]);
-                return callback(null);
-            }
-
-            startBackupTask(auditSource, callback);
-        });
-    });
-}
-
-// backups must be descending in creationTime
 function applyBackupRetentionPolicy(backups, policy, referencedBackupIds) {
     assert(Array.isArray(backups));
     assert.strictEqual(typeof policy, 'object');