loopback/common/models/checkpoint.js

78 lines
1.5 KiB
JavaScript

/**
* Module Dependencies.
*/
var PersistedModel = require('../../lib/loopback').PersistedModel
, loopback = require('../../lib/loopback')
, assert = require('assert');
/**
* Properties
*/
var properties = {
seq: {type: Number},
time: {type: Date, default: Date},
sourceId: {type: String}
};
/**
* Options
*/
var options = {
};
/**
* Checkpoint list entry.
*
* @property id {Number} the sequencial identifier of a checkpoint
* @property time {Number} the time when the checkpoint was created
* @property sourceId {String} the source identifier
*
* @class
* @inherits {PersistedModel}
*/
var Checkpoint = module.exports = PersistedModel.extend('Checkpoint', properties, options);
/**
* Get the current checkpoint id
* @callback {Function} callback
* @param {Error} err
* @param {Number} checkpointId The current checkpoint id
*/
Checkpoint.current = function(cb) {
var Checkpoint = this;
this.find({
limit: 1,
order: 'seq DESC'
}, function(err, checkpoints) {
if(err) return cb(err);
var checkpoint = checkpoints[0];
if(checkpoint) {
cb(null, checkpoint.seq);
} else {
Checkpoint.create({seq: 0}, function(err, checkpoint) {
if(err) return cb(err);
cb(null, checkpoint.seq);
});
}
});
}
Checkpoint.beforeSave = function(next, model) {
if(!model.getId() && model.seq === undefined) {
model.constructor.current(function(err, seq) {
if(err) return next(err);
model.seq = seq + 1;
next();
});
} else {
next();
}
}