Use the timeout when querying Elasticsearch

[mpchadwick]

Description

Sets a timeout when querying Elasticsearch. Without a timeout the following can happen...

• For whatever reason Elasticsearch becomes REALLY slow to respond to a bunch of queries (on one site I've seen it taking like 900 seconds in New Relic)
• Lots of PHP processes wait A LONG TIME for these responses to come back from Elasticsearch.
• Build up of PHP processes cause entire site to go down due to high load average, php-fpm max children, etc, etc

If the timeout is exceeded the user will get a 503, but at least it won't bring the site down. Anyway, if it's waiting more than the timeout (default 15 seconds) it's a pretty awful user experience already at that point...

Fixed Issues (if relevant)

N/A

Manual testing scenarios

Here's how I tested...

1. Create a dummy php server that sleeps for 60 seconds and returns nothing[1]
2. Run that on port 9201 [2]
3. Update the Magento Elasticseach settings to point to php instance running on port 9201
4. Visit any category page

[1]

Assuming Magento is querying index magento2-3-develop_product_1

$ tree
.
└── magento2-3-develop_product_1
    └── document
        └── _search
            └── index.php

3 directories, 1 file
$ cat magento2-3-develop_product_1/document/_search/index.php
<?php

sleep(60);

[2]

$ php -S localhost:9201

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[mpchadwick]

@magento-engcom-team give me test instance

[magento-engcom-team]

Hi @mpchadwick. Thank you for your request.\nUnfortunately, I can only deploy instances for 2.2-develop and 2.3-develop base branches

[mpchadwick]

@magento-engcom-team give me new test instance

[magento-engcom-team]

Hi @mpchadwick. Thank you for your request.\nUnfortunately, I can only deploy instances for 2.2-develop and 2.3-develop base branches

[magento-engcom-team]

Hi @mpchadwick. Thank you for your contribution.
We will aim to release these changes as part of 2.3.0.
Please check the release notes for final confirmation.