Trim metrics summary reports to user-specified time range

[harp-intel]

This pull request introduces a new feature for trimming metrics to a specific time range and refactors the metrics codebase to use integer timestamps consistently. It also improves usability and robustness in the metrics reporting and summary generation. The most important changes are grouped below:

New Feature: Time Range Trimming for Metrics

• Added a new metrics trim subcommand, allowing users to generate summary reports for a specific time interval using either absolute timestamps or relative offsets. This is documented in the README.md with usage examples and output details.
• Implemented filterByTimeRange methods for both MetricCollection and MetricGroup, enabling filtering of metrics rows to a specified time range. The summary generation pipeline now supports time-based trimming via summarizeMetricsWithTrim. [1] [2]

Timestamp Refactor

• Changed the internal representation of timestamps from float64 to int throughout the metrics codebase, including struct fields, parsing logic, aggregation, and tests, ensuring consistency and simplifying time-based operations. [1] [2] [3] [4] [5] [6]

Usability Improvements

• The metrics command now displays available subcommands in its help output, making it easier for users to discover and use features like trimming.

Robustness and Error Handling

• Added an Initialized method to the Metadata struct and updated the JSON marshaling logic to output null if metadata is uninitialized, preventing errors in downstream report generation.

Frontend/Reporting Enhancements

• Updated the HTML report templates to safely handle cases where system_info or metadata may be undefined, preventing runtime errors in the interactive report. [1] [2]

[Copilot]

Pull request overview

This pull request introduces a new metrics trim subcommand for filtering metrics to specific time ranges and refactors timestamp handling from float64 to int throughout the metrics codebase. This allows users to analyze specific portions of collected metrics data by excluding unwanted phases like setup or teardown.

Key changes:

• Added metrics trim subcommand with support for absolute timestamps and relative time offsets
• Refactored all timestamp representations from float64 to int for consistency
• Enhanced HTML report templates with null-safety checks for metadata

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
cmd/metrics/trim.go	New trim subcommand implementation with time range validation and filtering logic
cmd/metrics/summary.go	Added summarizeMetricsWithTrim function and filterByTimeRange methods; refactored timestamp type from float64 to int
cmd/metrics/summary_test.go	Updated test fixtures to use integer timestamps instead of float64
cmd/metrics/metadata.go	Added Initialized() method and null-handling in JSON marshaling
cmd/metrics/metrics.go	Enhanced usage output to display available subcommands
cmd/metrics/resources/base.html	Added null-safety checks for system_info and metadata in template
README.md	Documented the new trim feature with usage examples