be-technical-interview-rust/CHANGES.md

Backend internal interview (rust)

CHANGES: fixed branch

• Moving from HashMap to BTreeMap to preseve loading lines order, nevertheless still looks very cumbersome.
• Fix lines parser in Maps metrics and in aggregated_metrics to be handled properly.
• Fix unwrap / expect for obvious reasons, add simple error message via map_err, unwrap_or_else and closure function.
• Fix some source code lines order, output format and conversions.
• Change some iterators to functional mode.
• Separate tasks to independent funtions for better isolation, less responsibilities and help on tests handling.
• Adding output_path to help on result output options.
• Adding elapsed time to show how many millisecods took each metric file and total processing.
• Create type alias to make so long Map types more readable.
• Create a MetricLine struct to make parser easier (a lot of work should be done but requires full refactoring).
• Adding input_2.txt to process multiple metrics in parallel (done via std::threads), collect result properly via channels (std:mpsc) and show then properly.
• Create a generate_metrics to process each metric file and to be used in test_expected_metrics
• Following unit tests are implemented:
  • test_load_input test load input file input.txt.
  • test_invalid_line_value test use invalid value in line parsing.
  • test_invalid_line test use invlid value in line parsing.
  • test_expected_metrics test load input data from input.txt compare with output_expected.txt.

Note

Code simply works as expected trying to be preserve initial approach and not too much disruptive changes.
It is able to process multiple metrics in parallel (input.txt and input_2.txt).
A full refactoring has to be done for better quality, maintenance and be more readable. (Structs, implementaitions, settings for multiple inputs, etc).

Next round in: Improve branch