New Integration ProxySQL

[FlorianVeaux]

ProxySQL is a new integration, originally implemented here

This PR is based on this implementation but a few changes are to be noted.
To show the full diff, you can use this permalink

Implementation-wise

1. Most of the query logic was removed to rely on the QueryManager util. This util is used in other database like integrations and allows us to abstract a lot of technicalities to focus only on how to connect and execute queries against the database. The rest is handled by the QueryManager.
2. The version of ProxySQL is now collected.
3. A new service check called proxysql.backend.connect is emitted for each mysql backend that proxysql knows about. The value of the service check is based on the availability of the given backend.
4. The integration uses a configuration spec so that the conf.yaml.example is generated automatically.
5. Updated docs to reflect it is a default integration now
6. Added SSL support

Metric-wise

1. Most of time related metrics (like proxysql.query_processor_time_ms) that means the number of time spent doing a given thing are converted into temporal_percent (i.e proxysql.query_processor_time_pct) that represent the amount of time spent in that state as a percentage of total time. This is generally easier to work with.
2. Added proxysql.uptime
3. Made query_cache metrics a rate
4. Updated the metadata.csv to use gauge instead of rate everywhere. When the agent submits a rate, the backend type for that metric is a gauge
5. Kept a single slite3_memory metric under the name proxysql.memory.sqlite3_memory_bytes

[codecov]

Codecov Report

Merging #6144 into master will increase coverage by 2.33%.
The diff coverage is 90.04%.

Impacted Files	Coverage Δ
proxysql/datadog_checks/proxysql/ssl_utils.py	34.78% <34.78%> (ø)
proxysql/datadog_checks/proxysql/proxysql.py	90.90% <90.90%> (ø)
proxysql/tests/test_proxysql.py	97.56% <97.56%> (ø)
proxysql/datadog_checks/proxysql/__about__.py	100.00% <100.00%> (ø)
proxysql/datadog_checks/proxysql/__init__.py	100.00% <100.00%> (ø)
proxysql/datadog_checks/proxysql/queries.py	100.00% <100.00%> (ø)
proxysql/tests/common.py	100.00% <100.00%> (ø)
proxysql/tests/conftest.py	100.00% <100.00%> (ø)
mesos_slave/datadog_checks/mesos_slave/__init__.py
...g_checks_base/datadog_checks/base/stubs/tagging.py
... and 844 more

[l0k0ms]

G2G doc wise after the small nits are integrated :)

[therve]

Looks great! Some minor comments, mostly a doc discrepancy.

[ofek]

Awesome!!!

[ofek]

For when we have multiple test files, may want to do this now #6117 (comment)

[FlorianVeaux]

But as a fixture you need to set an extra param in each test function.
In that case there is a single test file, but even with multiple, we could import the helper method from somewhere and I think it's cleaner to have a single import than updating every test signature.

[ofek]

by that logic, what's the point of fixtures for config?

[FlorianVeaux]

I think a fixture is useful if you execute code in it. You read a file maybe, or you do a deepcopy of an integration config. By that mean, it abstracts a lot of complexity in your test, you just use the result of that fixture as a parameter of your tests.

If the result of your fixture is a static function that you could define what's the point? Seems more complex (the test runs the code of the fixture, gets the result, put in in an argument of the test, then you call that argument (because the result of that fixture was a function itself)....) than simply defining the function statically.

[ofek]

Excellent!

[pkatiushyn]

Hello, this does not seem to work with ProxySQL user specified in admin-stats_credentials.

2020-04-30 12:16:00 UTC | CORE | ERROR | (pkg/collector/python/datadog_agent.go:116 in LogMessage) | proxysql:5f743655467150c0 | (core.py:68) | Error querying stats_mysql_global: (1045, u'ProxySQL Admin Error: no such table: stats.stats_mysql_global')
2020-04-30 12:16:00 UTC | CORE | WARN | (pkg/collector/python/datadog_agent.go:118 in LogMessage) | proxysql:5f743655467150c0 | (proxysql.py:83) | Failed to fetch records from query: `SELECT variable_value FROM main.global_variables WHERE variable_name='admin-version'`.

[tabacco]

For users in admin-stats_credentials, the 'stats' database is named 'main'. Also, there's no way for stats users to get the proxysql version.

[pkatiushyn]

It's just my suggestion. I think it's not secure to use admin user for monitoring and I think it is possible to use user specified in admin-stats_credentials.
ProxySQL version probably can be obtained from shell proxysql -v.