feat(metrics): disable metrics flush via environment variables

[anafalcao]

Issue number:
#2996

Summary

Add environment variable POWERTOOLS_METRICS_DISABLED to control metrics emission, allowing developers to disable metrics during testing and local development.
The behavior remains unchanged when POWERTOOLS_METRICS_DISABLED is not set or is set to a falsy value.
If POWERTOOLS_DEV is enabled, it also stops sending metrics.
The POWERTOOLS_METRICS_DISABLED environment variable takes precedence over POWERTOOLS_DEV.

Changes

• Added support for POWERTOOLS_METRICS_DISABLED environment variable.
• When set to a truthy value (true, True, TRUE, 1), metrics collection will be disabled.
• Works for Amazon CloudWatch and Datadog providers.
• Updated documentation to reflect the new functionality.
• • POWERTOOLS_DEV includes disabling metrics as default, but can be overwritten by POWERTOOLS_METRICS_DISABLED

User experience

os.environ["POWERTOOLS_METRICS_DISABLED"] = "true"
metrics = Metrics(namespace="TestApplication")
metrics.add_metric(name="test", unit="Count", value=1)
result = metrics.flush_metrics()  # Returns empty as it's disabled

OR

os.environ["POWERTOOLS_DEV"] = "true"
metrics = Metrics(namespace="TestApplication")
metrics.add_metric(name="test", unit="Count", value=1)
result = metrics.flush_metrics()  # Returns empty as it's disabled

Checklist

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• Meet tenets criteria
• I have performed a self-review of this change
• Changes have been tested
• Changes are documented
• PR title follows conventional commit semantics

Is this a breaking change?

RFC issue number:

Checklist:

• Migration process documented
• Implement warnings (if it can live side by side)

Acknowledgment

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Disclaimer: We value your time and bandwidth. As such, any pull requests created on non-triaged issues might not be successful.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.25%. Comparing base (1ca05a2) to head (762e67b).
Report is 2 commits behind head on develop.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #6046   +/-   ##
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  Coverage    96.25%   96.25%           
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  Files          234      234           
  Lines        11057    11068   +11     
  Branches       803      805    +2     
========================================
+ Hits         10643    10654   +11     
  Misses         327      327           
  Partials        87       87           

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[leandrodamascena]

Hello @anafalcao! Super nice PR with a code/design very well written!

I think the only thing missing is the part where you don't flush the metrics when it disabled. 🚀

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[dreamorosi]

Good work!