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| /**
* Module dependencies
*/
var _ = require('lodash');
var async = require('async');
var getRelations = require('../../../utils/getRelations');
/**
* Try and synchronize the underlying physical-layer schema
* to work with our app's collections. (i.e. models)
*
* @param {Function} cb
*/
module.exports = function(cb) {
var self = this;
// Refuse to run this migration strategy in production.
Iif (process.env.NODE_ENV === 'production') {
return cb(new Error('`migrate: "alter"` strategy is not supported in production, please change to `migrate: "safe"`.'));
}
// Find any junctionTables that reference this collection
var relations = getRelations({
schema: self.query.waterline.schema,
parentCollection: self.collection
});
var backupData;
// Check that collection exists--
self.describe(function afterDescribe(err, attrs) {
Iif (err) return cb(err);
// if it doesn't go ahead and add it and get out
if (!attrs) return self.define(cb);
var collectionName = _.find(self.query.waterline.schema, {tableName: self.collection}).identity;
// Create a mapping of column names -> attribute names
var columnNamesMap = _.reduce(self.query.waterline.schema[collectionName].definition, function(memo, val, key) {
// If the attribute has a custom column name, use it as the key for the mapping
if (val.columnName) {
memo[val.columnName] = key;
// Otherwise just use the attribute name
} else {
memo[key] = key;
}
return memo;
}, {});
// Transform column names into attribute names using the columnNamesMap,
// removing attributes that no longer exist (they will be dropped)
attrs = _.compact(_.keys(attrs).map(function(key) {
return columnNamesMap[key];
}));
//
// TODO:
// Take a look and see if anything important has changed.
// If it has (at all), we still have to follow the naive strategy below,
// but it will at least save time in the general case.
// (because it really sucks to have to wait for all of this to happen
// every time you initialize Waterline.)
//
//
// OK so we have to fix up the schema and migrate the data...
//
// ... we'll let Waterline do it for us.
//
// Load all data from this collection into memory.
// If this doesn't work, crash to avoid corrupting any data.
// (see `waterline/lib/adapter/ddl/README.md` for more info about this)
//
// Make sure we only select the existing keys for the schema.
// The default "find all" will select each attribute in the schema, which
// now includes attributes that haven't been added to the table yet, so
// on SQL databases the query will fail with "unknown field" error.
//
var hasSchema = self.query.hasSchema;
// If we have a schema, make sure we only select the existing keys for the schema.
// The default "find all" will select each attribute in the schema, which
// now includes attributes that haven't been added to the table yet, so
// on SQL databases the query will fail with "unknown field" error.
//
// If we don't have a schema then we need to select all the values to make
// sure we don't lose data in the process.
var queryCriteria;
if (hasSchema) {
queryCriteria = {select: attrs};
} else {
queryCriteria = {};
}
self.find(queryCriteria, function(err, existingData) {
Iif (err) {
//
// TODO:
// If this was a memory error, log a more useful error
// explaining what happened.
//
return cb(err);
}
//
// From this point forward, we must be very careful.
//
backupData = _.cloneDeep(existingData, function dealWithBuffers(val) {
if (val instanceof Buffer) {
return val.slice();
}
});
// Check to see if there is anything obviously troublesome
// that will cause the drop and redefinition of our schemaful
// collections to fail.
// (i.e. violation of uniqueness constraints)
var attrs = self.query.waterline.collections[self.identity]._attributes;
var pk = self.query.waterline.collections[self.identity].primaryKey;
var attrsAsArray = _.reduce(_.cloneDeep(attrs), function(memo, attrDef, attrName) {
attrDef.name = attrName;
memo.push(attrDef);
return memo;
}, []);
var uniqueAttrs = _.where(attrsAsArray, {unique: true});
async.each(uniqueAttrs, function(uniqueAttr, each_cb) {
var uniqueData = _.uniq(_.pluck(existingData, uniqueAttr.name));
// Remove any unique values who have their values set to undefined or null
var cleansedExistingData = _.filter(existingData, function(val) {
return [undefined, null].indexOf(val[uniqueAttr.name]) < 0;
});
// Remove any undefined or null values from the unique data
var cleansedUniqueData = _.filter(uniqueData, function(val) {
return [undefined, null].indexOf(val) < 0;
});
Iif (cleansedUniqueData.length < cleansedExistingData.length) {
// Some existing data violates a new uniqueness constraint
var prompt = require('prompt');
prompt.start();
console.log(
'One or more existing records in your database violate ' +
'a new uniqueness constraint\n' +
'on `' + uniqueAttr.name + '` ' +
'in your `' + self.identity + '` model.');
console.log();
console.log('Should we automatically remove duplicates?');
console.log();
console.log('** WARNING: DO NOT TYPE "y" IF YOU ARE WORKING WITH PRODUCTION DATA **');
// var laptimer = setInterval(function beepbeepbeepbeep(){
// process.stdout.write('\u0007');
// }, 1500);
prompt.get(['y/n'], function(err, results) {
// clearInterval(laptimer);
if (err) return each_cb(err);
var wasConfirmedByUser = _.isString(results['y/n']) && results['y/n'].match(/y/);
if (wasConfirmedByUser) {
// Wipe out duplicate records in `backupData` and continue
// to perform the automigration
var diff = _.difference(existingData, _.uniq(existingData, false, uniqueAttr.name));
var destroyCriteria = {};
destroyCriteria[pk] = _.pluck(diff, pk);
// console.log(diff, '\n', destroyCriteria);
backupData = _.remove(backupData, function(datum) {
return !_.contains(destroyCriteria[pk], datum[pk]);
});
return each_cb();
// console.log(backupData);
// throw new Error();
// self.query.waterline.collections[self.collection].destroy(destroyCriteria).exec(each_cb);
} else return each_cb(new Error('Auto-migration aborted. Please migrate your data manually and then try this again.'));
});
} else return each_cb();
}, function afterAsyncEach(err) {
Iif (err) return cb(err);
// Now we'll drop the collection.
self.drop(relations, function(err) {
Iif (err) return uhoh(err, backupData, cb);
// Now we'll redefine the collection.
self.define(function(err) {
Iif (err) return uhoh(err, backupData, cb);
// Now we'll create the `backupData` again,
// being careful not to run any lifecycle callbacks
// and disable automatic updating of `createdAt` and
// `updatedAt` attributes:
//
// ((((TODO: actually be careful about said things))))
//
self.createEach(backupData, function(err) {
Iif (err) return uhoh(err, backupData, cb);
// Done.
return cb();
});
}); // </define>
}); // </drop>
}); // </find>
});
//
// The old way-- (doesn't always work, and is way more
// complex than we should spend time on for now)
//
// || || || || || ||
// \/ \/ \/ \/ \/ \/
//
// Otherwise, if it *DOES* exist, we'll try and guess what changes need to be made
// self.alter(function(err) {
// if (err) return cb(err);
// cb();
// });
});
};
/**
* uh oh.
*
* If we can't persist the data again, we'll log an error message, then
* stream the data to stdout as JSON to make sure that it gets persisted
* SOMEWHERE at least.
*
* (this is another reason this automigration strategy cannot be used in
* production currently..)
*
* @param {[type]} err [description]
* @param {[type]} backupData [description]
* @param {Function} cb [description]
* @return {[type]} [description]
*/
function uhoh(err, backupData, cb) {
console.error('Waterline encountered a fatal error when trying to perform the `alter` auto-migration strategy.');
console.error('In a couple of seconds, the data (cached in memory) will be logged to stdout.');
console.error('(a failsafe put in place to preserve development data)');
console.error();
console.error('In the mean time, here\'s the error:');
console.error();
console.error(err);
console.error();
console.error();
setTimeout(function() {
console.error('================================');
console.error('Data backup:');
console.error('================================');
console.error('');
console.log(backupData);
return cb(err);
}, 1200);
}
|