Marcelo Schmidt
9 years ago
parent
6d7cbbd18a
commit
5735ff2b37
@ -0,0 +1,276 @@ |
||||
/* |
||||
Adds migration capabilities. Migrations are defined like: |
||||
|
||||
Migrations.add({ |
||||
up: function() {}, //*required* code to run to migrate upwards
|
||||
version: 1, //*required* number to identify migration order
|
||||
down: function() {}, //*optional* code to run to migrate downwards
|
||||
name: 'Something' //*optional* display name for the migration
|
||||
}); |
||||
|
||||
The ordering of migrations is determined by the version you set. |
||||
|
||||
To run the migrations, set the MIGRATE environment variable to either |
||||
'latest' or the version number you want to migrate to. Optionally, append |
||||
',exit' if you want the migrations to exit the meteor process, e.g if you're |
||||
migrating from a script (remember to pass the --once parameter). |
||||
|
||||
e.g: |
||||
MIGRATE="latest" mrt # ensure we'll be at the latest version and run the app |
||||
MIGRATE="latest,exit" mrt --once # ensure we'll be at the latest version and exit |
||||
MIGRATE="2,exit" mrt --once # migrate to version 2 and exit |
||||
|
||||
Note: Migrations will lock ensuring only 1 app can be migrating at once. If |
||||
a migration crashes, the control record in the migrations collection will |
||||
remain locked and at the version it was at previously, however the db could |
||||
be in an inconsistant state. |
||||
*/ |
||||
|
||||
// since we'll be at version 0 by default, we should have a migration set for
|
||||
// it.
|
||||
var DefaultMigration = {version: 0, up: function(){}}; |
||||
|
||||
Migrations = { |
||||
_list: [DefaultMigration], |
||||
options: { |
||||
// false disables logging
|
||||
log: true, |
||||
// null or a function
|
||||
logger: null, |
||||
// enable/disable info log "already at latest."
|
||||
logIfLatest: true, |
||||
// migrations collection name
|
||||
collectionName: "migrations" |
||||
}, |
||||
config: function(opts) { |
||||
this.options = _.extend({}, this.options, opts); |
||||
}, |
||||
} |
||||
|
||||
/* |
||||
Logger factory function. Takes a prefix string and options object |
||||
and uses an injected `logger` if provided, else falls back to |
||||
Meteor's `Log` package. |
||||
Will send a log object to the injected logger, on the following form: |
||||
message: String |
||||
level: String (info, warn, error, debug) |
||||
tag: 'Migrations' |
||||
*/ |
||||
function createLogger(prefix) { |
||||
check(prefix, String); |
||||
|
||||
// Return noop if logging is disabled.
|
||||
if(Migrations.options.log === false) { |
||||
return function() {}; |
||||
} |
||||
|
||||
return function(level, message) { |
||||
check(level, Match.OneOf('info', 'error', 'warn', 'debug')); |
||||
check(message, String); |
||||
|
||||
var logger = Migrations.options && Migrations.options.logger; |
||||
|
||||
if(logger && _.isFunction(logger)) { |
||||
|
||||
logger({ |
||||
level: level, |
||||
message: message, |
||||
tag: prefix |
||||
}); |
||||
|
||||
} else { |
||||
Log[level]({ message: prefix + ': ' + message }); |
||||
} |
||||
} |
||||
} |
||||
|
||||
var log; |
||||
|
||||
Meteor.startup(function () { |
||||
var options = Migrations.options; |
||||
|
||||
// collection holding the control record
|
||||
Migrations._collection = new Mongo.Collection(options.collectionName); |
||||
|
||||
log = createLogger('Migrations'); |
||||
|
||||
['info', 'warn', 'error', 'debug'].forEach(function(level) { |
||||
log[level] = _.partial(log, level); |
||||
}); |
||||
|
||||
if (process.env.MIGRATE) |
||||
Migrations.migrateTo(process.env.MIGRATE); |
||||
}); |
||||
|
||||
// Add a new migration:
|
||||
// {up: function *required
|
||||
// version: Number *required
|
||||
// down: function *optional
|
||||
// name: String *optional
|
||||
// }
|
||||
Migrations.add = function(migration) { |
||||
if (typeof migration.up !== 'function') |
||||
throw new Meteor.Error('Migration must supply an up function.'); |
||||
|
||||
if (typeof migration.version !== 'number') |
||||
throw new Meteor.Error('Migration must supply a version number.'); |
||||
|
||||
if (migration.version <= 0) |
||||
throw new Meteor.Error('Migration version must be greater than 0'); |
||||
|
||||
// Freeze the migration object to make it hereafter immutable
|
||||
Object.freeze(migration); |
||||
|
||||
this._list.push(migration); |
||||
this._list = _.sortBy(this._list, function(m) {return m.version;}); |
||||
} |
||||
|
||||
// Attempts to run the migrations using command in the form of:
|
||||
// e.g 'latest', 'latest,exit', 2
|
||||
// use 'XX,rerun' to re-run the migration at that version
|
||||
Migrations.migrateTo = function(command) { |
||||
if (_.isUndefined(command) || command === '' || this._list.length === 0) |
||||
throw new Error("Cannot migrate using invalid command: " + command); |
||||
|
||||
if (typeof command === 'number') { |
||||
var version = command; |
||||
} else { |
||||
var version = command.split(',')[0]; |
||||
var subcommand = command.split(',')[1]; |
||||
} |
||||
|
||||
if (version === 'latest') { |
||||
this._migrateTo(_.last(this._list).version); |
||||
} else { |
||||
this._migrateTo(parseInt(version), (subcommand === 'rerun')); |
||||
} |
||||
|
||||
// remember to run meteor with --once otherwise it will restart
|
||||
if (subcommand === 'exit') |
||||
process.exit(0); |
||||
} |
||||
|
||||
// just returns the current version
|
||||
Migrations.getVersion = function() { |
||||
return this._getControl().version; |
||||
} |
||||
|
||||
// migrates to the specific version passed in
|
||||
Migrations._migrateTo = function(version, rerun) { |
||||
var self = this; |
||||
var control = this._getControl(); // Side effect: upserts control document.
|
||||
var currentVersion = control.version; |
||||
|
||||
if (lock() === false) { |
||||
log.info('Not migrating, control is locked.'); |
||||
return; |
||||
} |
||||
|
||||
if (rerun) { |
||||
log.info('Rerunning version ' + version); |
||||
migrate('up', version); |
||||
log.info('Finished migrating.'); |
||||
unlock(); |
||||
return; |
||||
} |
||||
|
||||
if (currentVersion === version) { |
||||
if (Migrations.options.logIfLatest) { |
||||
log.info('Not migrating, already at version ' + version); |
||||
} |
||||
unlock(); |
||||
return; |
||||
} |
||||
|
||||
var startIdx = this._findIndexByVersion(currentVersion); |
||||
var endIdx = this._findIndexByVersion(version); |
||||
|
||||
// log.info('startIdx:' + startIdx + ' endIdx:' + endIdx);
|
||||
log.info('Migrating from version ' + this._list[startIdx].version |
||||
+ ' -> ' + this._list[endIdx].version); |
||||
|
||||
// run the actual migration
|
||||
function migrate(direction, idx) { |
||||
var migration = self._list[idx]; |
||||
|
||||
if (typeof migration[direction] !== 'function') { |
||||
unlock(); |
||||
throw new Meteor.Error('Cannot migrate ' + direction + ' on version ' |
||||
+ migration.version); |
||||
} |
||||
|
||||
function maybeName() { |
||||
return migration.name ? ' (' + migration.name + ')' : ''; |
||||
} |
||||
|
||||
log.info('Running ' + direction + '() on version ' |
||||
+ migration.version + maybeName()); |
||||
|
||||
migration[direction](migration); |
||||
} |
||||
|
||||
// Returns true if lock was acquired.
|
||||
function lock() { |
||||
// This is atomic. The selector ensures only one caller at a time will see
|
||||
// the unlocked control, and locking occurs in the same update's modifier.
|
||||
// All other simultaneous callers will get false back from the update.
|
||||
return self._collection.update( |
||||
{_id: 'control', locked: false}, {$set: {locked: true, lockedAt: new Date()}} |
||||
) === 1; |
||||
} |
||||
|
||||
// Side effect: saves version.
|
||||
function unlock() { |
||||
self._setControl({locked: false, version: currentVersion}); |
||||
} |
||||
|
||||
if (currentVersion < version) { |
||||
for (var i = startIdx;i < endIdx;i++) { |
||||
migrate('up', i + 1); |
||||
currentVersion = self._list[i + 1].version; |
||||
} |
||||
} else { |
||||
for (var i = startIdx;i > endIdx;i--) { |
||||
migrate('down', i); |
||||
currentVersion = self._list[i - 1].version; |
||||
} |
||||
} |
||||
|
||||
unlock(); |
||||
log.info('Finished migrating.'); |
||||
} |
||||
|
||||
// gets the current control record, optionally creating it if non-existant
|
||||
Migrations._getControl = function() { |
||||
var control = this._collection.findOne({_id: 'control'}); |
||||
|
||||
return control || this._setControl({version: 0, locked: false}); |
||||
} |
||||
|
||||
// sets the control record
|
||||
Migrations._setControl = function(control) { |
||||
// be quite strict
|
||||
check(control.version, Number); |
||||
check(control.locked, Boolean); |
||||
|
||||
this._collection.update({_id: 'control'}, |
||||
{$set: {version: control.version, locked: control.locked}}, {upsert: true}); |
||||
|
||||
return control; |
||||
} |
||||
|
||||
// returns the migration index in _list or throws if not found
|
||||
Migrations._findIndexByVersion = function(version) { |
||||
for (var i = 0;i < this._list.length;i++) { |
||||
if (this._list[i].version === version) |
||||
return i; |
||||
} |
||||
|
||||
throw new Meteor.Error('Can\'t find migration version ' + version); |
||||
} |
||||
|
||||
//reset (mainly intended for tests)
|
||||
Migrations._reset = function() { |
||||
this._list = [{version: 0, up: function(){}}]; |
||||
this._collection.remove({}); |
||||
} |
||||
@ -0,0 +1,22 @@ |
||||
Package.describe({ |
||||
name: 'rocketchat:migrations', |
||||
version: '0.0.1', |
||||
summary: '', |
||||
git: '' |
||||
}); |
||||
|
||||
Package.onUse(function(api) { |
||||
api.versionsFrom('1.0'); |
||||
|
||||
api.use('rocketchat:lib'); |
||||
api.use('rocketchat:version'); |
||||
api.use('coffeescript'); |
||||
|
||||
api.addFiles('migrations.js', 'server'); |
||||
|
||||
api.export('Migrations', 'server'); |
||||
}); |
||||
|
||||
Package.onTest(function(api) { |
||||
|
||||
}); |
||||
Loading…
Reference in new issue