transactions multi-table MVP

[ckhsponge]

This is a first attempt at dynamodb transactions that can span tables. Create, update, upsert and delete are supported. See README_transact.md for examples of the proposed API.

Tests have not yet been implemented.

[ckhsponge]

@andrykonchin I made some updates to the transaction API and now there is no longer a mess of hashes being passed around. Your feedback would be appreciated. Some minor cleanup and tests are still needed.

[codecov[bot]]

Codecov Report

Attention: 6 lines in your changes are missing coverage. Please review.

Comparison is base (4520343) 90.32% compared to head (a5b7640) 90.89%.

Files	Patch %	Lines
lib/dynamoid/transaction_write/update_upsert.rb	90.62%	3 Missing :warning:
lib/dynamoid/transaction_write/update.rb	88.23%	2 Missing :warning:
lib/dynamoid/transaction_write/action.rb	98.46%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #688 +/- ## ========================================== + Coverage 90.32% 90.89% +0.56% ========================================== Files 62 71 +9 Lines 3154 3414 +260 ========================================== + Hits 2849 3103 +254 - Misses 305 311 +6 ```

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[ckhsponge]

@andrykonchin Another round of feedback would be appreciated. I believe all issues were covered although adding block support for updates is something that could still be done. This might be a cleaner place to add add() expressions.

I'd like to get to a v1 candidate at some point with unit tests included.

[ckhsponge]

@andrykonchin Thanks for the feedback. There are now proper delete and destroys. Upsert is working like an upsert as well.

[andrykonchin]

Looks good so we can move on and and add specs.

[ckhsponge]

@andrykonchin There's now a collection of specs for the transaction writes. Can you run them on github or give me permission to run them?

What else is needed to get v1 released?

Thanks!

[andrykonchin]

The new specs look good, but I would prefer to have more granular test cases that check only one aspect of a method behaviour (ideally only one check/assert per case)

[ckhsponge]

The new specs look good, but I would prefer to have more granular test cases that check only one aspect of a method behaviour (ideally only one check/assert per case)

Yeah, I usually put 4 or 5 syntax checks in each case. I'll split those out.

[ckhsponge]

@andrykonchin Thanks for the specs review. What are your thoughts on this one? https://github.com/Dynamoid/dynamoid/pull/688#discussion_r1436639724

[andrykonchin]

A failing spec is fixed on master.

[ckhsponge]

@andrykonchin update() and upsert() no longer allow a key to be specified separate from the attributes. A key must always be included in the model or in the attributes. This simplifies the method signatures and makes them consistent with the other transaction actions.

I believe I covered all your feedback on the specs so another round of review would be good. Thanks!!!

[ckhsponge]

@andrykonchin More tests were added for rollbacks and callbacks. Instance usage tests for upsert were removed.

[ckhsponge]

I removed the named parameter for options. This simplifies the brackets for expected usage e.g.:

save!( instance, skip_callbacks: true)
create!( klass, name: 'hi')
create!( klass, {name: 'hi'}, {skip_callbacks: true})

instead of:

save!( instance, options: {skip_callbacks: true})
create!( klass, {name: 'hi'})
create!( klass, {name: 'hi'}, options: {skip_callbacks: true})

[ckhsponge]

@andrykonchin I believe all feedback has been addressed and further review would be appreciated.

[ckhsponge]

@andrykonchin Anything blocking this? Thanks.

[andrykonchin]

Could you please fix Rubocop issues (related to the changes only - there are some existing issues on master - I will address them myself) and squash all the working commits into one or more atomic ones?

[andrykonchin]

I want to release a new version without transactions now and release transactions in the next version. The last release was a year ago and I was already asked for new version.

[ckhsponge]

@andrykonchin I squashed the commits and I believe Rubocops will pass. Anything else I need to do? There are Codeclimate complexity issues.

[andrykonchin]

Merged! :tada: Great work!

[ckhsponge]

That's great news! Thanks for the support.