Executing services methods using transaction, implementation of issue #91 #113

pnakibar · 2017-08-23T02:20:42Z

My solution to the issue #91 .
Pretty much a naive implementation due to not knowing the internals of knex.

Easy to use, simply import the newly created hooks and add them to the hooks of the service you want to use it (usually in global hooks) and then the feathers-knex deal with using the transaction.

Usage:

// Application hooks that run for every service
import { transactionHooks as transaction } from 'feathers-knex';

const logger = require('./hooks/logger');

module.exports = {
  before: {
    all: [transaction.start({ dbServiceName: 'knexClient' })],
    find: [],
    get: [],
    create: [],
    update: [],
    patch: [],
    remove: []
  },

  after: {
    all: [logger(), transaction.end()],
    find: [],
    get: [],
    create: [],
    update: [],
    patch: [],
    remove: []
  },

  error: {
    all: [transaction.rollback(), logger()],
    find: [],
    get: [],
    create: [],
    update: [],
    patch: [],
    remove: []
  }
};

Looking forward to some feedback on the code!

RobIsHere · 2017-08-23T19:24:35Z

Great! I'm looking on your solution because I need the same functionality. Put a nested json to a rest service and store it in diverse tables using a all-or-nothing transaction.

One small quesition: Is it possible to use hook.service instead of hook.app.get(dbServiceName) in transaction start?
(Docs here suggest it could work: https://docs.feathersjs.com/api/hooks.html#hook-objects)

This would remove the need for the service name parameter - which is likely to be forgotten, when you rename a service during refactoring later on.

daffl

This is great, thank you for doing this! I made a couple of comments/questions.

Ideally, we'd also want to test this functionality somehow (e.g. having two services, one called in a hook with the transaction, throwing an error and making sure both are rolled back). It looks like SQLite supports transactions so you should be able to just run tests via npm test.

daffl · 2017-08-23T21:43:35Z

src/index.js


 const debug = require('debug')('feathers-knex');
+const debugTransaction = require('debug')('feathers-knex-transaction');


We usually only use one debug per module.

daffl · 2017-08-23T21:43:50Z

src/index.js

+  db (params = {}) {
+    if (params.transaction) {
+      const { trx, id } = params.transaction;
+      debugTransaction('ran %s with transaction %s', this.table, id);


I'd change this to just debug

daffl · 2017-08-23T21:44:57Z

src/index.js

@@ -169,6 +176,7 @@ class Service {
  }

  find (params) {
+    debug('method find of service %s called', this.table);


Should be removed for consistency (we might want to add more debug statements to all database adapters but that would be a different issue).

daffl · 2017-08-23T21:46:40Z

src/transaction-hooks.js

@@ -0,0 +1,42 @@
+const debug = require('debug')('feathers-knex-transaction');


We may want to rename this file to just hooks and call the methods transactionStart, transactionEnd and transactionRollback and export it as init.hooks instead of https://github.com/feathersjs/feathers-knex/pull/113/files#diff-1fdf421c05c1140f6d71444ea2b27638R339

Alternatively we could also export it as export default { transaction: { start, end, rollback } } and use it as hooks.transaction.start etc.

daffl · 2017-08-23T21:50:28Z

src/transaction-hooks.js

+  debug('started transaction system with %s service', dbServiceName);
+  return (hook) =>
+    new Promise(resolve =>
+      hook.app.get(dbServiceName).transaction(trx => {


Can you try if hook.service.Model works here? I think it should (because it is the same thing really).

pnakibar · 2017-08-24T16:21:49Z

@daffl should I remove the debug from the transaction-hooks.js file (now called hooks.js)?

daffl · 2017-08-24T16:29:59Z

@pnakibar Sorry, I meant one debug per file (in the hooks case probably called debug('feathers-knex/hooks')).

pnakibar · 2017-08-24T16:32:49Z

It's alright!
The module are a bit redundant in the javascript IMO anyways ;)

Just submitted a new PR with the requested changes.

daffl · 2017-08-24T16:40:31Z

Awesome, looks great! Any chance to add some tests or would you like me to try and add those?

pnakibar · 2017-08-24T16:41:48Z

The new app.hooks.js:

// Application hooks that run for every service
import * as feathersKnex from 'feathers-knex';

const { hooks: { transaction } } = feathersKnex;

const logger = require('./hooks/logger');

module.exports = {
  before: {
    all: [transaction.start({ dbServiceName: 'knexClient' })],
    find: [],
    get: [],
    create: [],
    update: [],
    patch: [],
    remove: []
  },

  after: {
    all: [logger(), transaction.end()],
    find: [],
    get: [],
    create: [],
    update: [],
    patch: [],
    remove: []
  },

  error: {
    all: [transaction.rollback(), logger()],
    find: [],
    get: [],
    create: [],
    update: [],
    patch: [],
    remove: []
  }
};

pnakibar · 2017-08-24T16:42:27Z

@daffl if you could, it would be awesome!
I struggled a bit to understand the test suit...

daffl · 2017-08-24T16:43:04Z

Also, we have to update https://docs.feathersjs.com/api/databases/knexjs.html with a section for transaction support once this is released.

pnakibar · 2017-08-24T16:46:48Z

Also, the options object to the start hook could be better. I will try to improve it once I write the docs!

daffl · 2017-08-24T16:51:41Z

I don't think the option is necessary. Did you try hook.service.Model instead of hook.app.get(dbServiceName) in https://github.com/feathersjs/feathers-knex/pull/113/files#diff-95b96dc34a5bf5b035b35940dd2d2d60R8?

pnakibar · 2017-08-24T16:54:05Z

Will try it, my concern was with using two database adapters.

pnakibar · 2017-08-24T18:27:31Z

@daffl tried it. Was a bit unsuccessful, since not all my services have the service.Model, and some of them interact with a database.

RobIsHere · 2017-08-24T19:37:20Z

Thank you all for your great work! This is going on so fast, it's amazing!

Maybe you could allow the developer to pass his own Model. Or use the default, if he doesn't.
Would something like this work?


const start = (options) => {
  const Model = options.Model || hook.service.Model; // changed here

  debug('started transaction system'); // changed here
  return (hook) =>
    new Promise(resolve =>
      Model.transaction(trx => {  // changed here
        const id = Date.now();
        hook.params.transaction = {
          trx,
          id
        };
        debug('started a new transaction %s', id);
        return resolve(hook);
      })
    );
};

The parameter name "Model" is already used for passing the db instance at knex db service init. Also if you just need some db instance, exposing only this instead of a whole service could decouple things.

Just thinking about this...

daffl · 2017-08-24T19:48:09Z

The Model for Knex is basically just the main Knex client connection instance (see here).

I can't think of a case where this would change throughout a transaction (and I don't think transactions across different databases are possible at the Knex level).

pnakibar · 2017-08-31T21:42:55Z

@daffl is it still ok to merge the pull request?

daffl · 2017-09-02T05:30:56Z

Sorry, for some reason I dropped the ball on this. Merged. Will add some tests and let you know when it's released.

daffl · 2017-09-03T00:02:00Z

Released as v2.8.0

pnakibar added 4 commits August 22, 2017 23:11

created transaction hooks

9e54d4b

added interaction with params.transaction to the service

0b24673

fixed styling in transaction-hooks

2340af0

added createQuery new default value for params

d93e023

pnakibar changed the title ~~Using transactions, implementation of issue #91~~ Executing services methods using transaction, implementation of issue #91 Aug 23, 2017

daffl requested changes Aug 23, 2017

View reviewed changes

pnakibar added 5 commits August 24, 2017 13:16

removed debugTransaction from index.js

3193907

removed debug from find method

cc20e68

changed transaction-hooks.js to hooks.js

36e47d9

exporting transaction hooks as a object name transaction

7f21598

importing as transaction as hooks and exporting as init.hooks

0794b15

pnakibar added 2 commits August 24, 2017 13:23

updated hooks.js with applied linter differences

0981f11

fixed import hooks to the correct file

f9d2c53

daffl approved these changes Aug 24, 2017

View reviewed changes

updated docs

2fcab2d

daffl merged commit c8b4481 into feathersjs-ecosystem:master Sep 2, 2017

daffl mentioned this pull request Sep 2, 2017

Finalize transaction hooks and functionality, add to tests #114

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Executing services methods using transaction, implementation of issue #91 #113

Executing services methods using transaction, implementation of issue #91 #113

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daffl commented Sep 3, 2017


		const debug = require('debug')('feathers-knex');
		const debugTransaction = require('debug')('feathers-knex-transaction');

		@@ -0,0 +1,42 @@
		const debug = require('debug')('feathers-knex-transaction');

Executing services methods using transaction, implementation of issue #91 #113

Executing services methods using transaction, implementation of issue #91 #113

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