feat: add transaction support

[achrinza]

Blocked by #634
Replaces #626

Signed-off by: Sergey Nosenko [email protected]
Signed-off-by: Rifa Achrinza [email protected]

Checklist

• DCO (Developer Certificate of Origin) signed in all commits
• npm test passes on your machine
• New tests added or existing tests modified to cover all changes
• Code conforms with the style guide
• Commit messages are following our guidelines

[marioestradarosa]

@darknos thanks for the PR and sorry for the inconvenience. Many developers are waiting for your new feature to be published 👍 .

[darknos]

any updates?

[dhmlau]

I'm not familiar with the code but the changes look reasonable to me.
As a nitpick, I wonder if we want to add some debug statement in there, like what we did in the postgresql connector. When debugging a transaction issue long time ago for that connector, it does help to have debug turned on and have something printed out. But this could be out of scope for this PR. Thanks.

UPDATED: meant to include this link: https://github.com/loopbackio/loopback-connector-postgresql/blob/master/lib/transaction.js

[marioestradarosa]

I wonder if we want to add some debug statement in there, like what we did in the postgresql connector.

The postgreSQL connector only print debug isolation level, begin, rollback & commit and those should be printed out from here instead loopback-datasource-juggler as a centralized location.

[achrinza]

@dhmlau I propose merging this PR first, then adding the debug statement later if needed.

[marioestradarosa]

@dhmlau I propose merging this PR first, then adding the debug statement later if needed.

I believe that the debug print outs should be placed in the loopback-datasource-juggler not on every connector. The reason why is because this debug printings are general and can be caught in the loopback-datasource-juggler . We are duplicating code and effort.

[dhmlau]

Agreed to land this PR first and add the debug info as a separate PR. Thanks.