Add full_server_name support as template variable to sqlserver template config key

[joelmarcotte]

This pull request introduces support for a new $full_server_name variable in the SQL Server integration for the template config key, which represents the full server name as returned by @@SERVERNAME. The changes include updates to constants, configuration templates, caching mechanisms, and tests to incorporate this new field.

Enhancements to SQL Server Integration:

Support for full_server_name:

• Added STATIC_INFO_FULL_SERVERNAME as a new constant in sqlserver/datadog_checks/sqlserver/const.py to represent the full server name.
• Updated the example configuration file (sqlserver/datadog_checks/sqlserver/data/conf.yaml.example) to include full_server_name as a new template option for identifying SQL Server instances.

Updates to Static Information Cache:

• Modified load_static_information in sqlserver/datadog_checks/sqlserver/sqlserver.py to cache the full_server_name value.
• Updated database_identifier in sqlserver/datadog_checks/sqlserver/sqlserver.py to use STATIC_INFO_FULL_SERVERNAME when applicable.
• When a servername is present, make sure the instancename fallsback to '' if its value is None to avoid seeing None in the output.

Test Coverage:

• Enhanced unit tests in sqlserver/tests/test_unit.py to validate full_server_name functionality, including its usage in templates and caching. [1] [2]

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.45%. Comparing base (824902a) to head (449dac0).
Report is 15 commits behind head on master.

Additional details and impacted files

Flag	Coverage Δ
activemq	?
cassandra	?
confluent_platform	?
hive	?
hivemq	?
hudi	?
ignite	?
jboss_wildfly	?
kafka	?
presto	?
solr	?
sqlserver	91.14% <100.00%> (+4.49%)	⬆️
tomcat	?
weblogic	?

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[sethsamuel]

This example exists to show how to use tags, why is it changed?

[joelmarcotte]

Many users will simply wonder what's the best variable to use to name their sqlserver instance. For sqlserver the default should be $full_server_name in my opinion (if users are willing to diverge from the actual default of $resolved_hostname).

[sethsamuel]

Nit: let's be consistent of if it's server_name or servername

[joelmarcotte]

I thought I was being consistent here, since servername above is one word, yet its template variable is $server_name.

[joelmarcotte]

So the static variable is full_servername and the actual template variable is full_server_name

Review from sethsamuel is dismissed. Related teams and files:

• database-monitoring-agent
  • sqlserver/assets/configuration/spec.yaml
  • sqlserver/datadog_checks/sqlserver/data/conf.yaml.example