[ISSUE] Fix: Wildcard Stats Key Behavior Changes

[xuannam230201]

[ISSUE]: Wildcard Stats Key Behavior Changes

Problem

Previously, when value_to_metric logic was added (in my another PR), the wildcard stats key behavior was accidentally changed. Wildcard patterns without value_to_metric or share_threshold were generating stats keys without the wildcard value pattern (e.g., test-domain.wild instead of test-domain.wild_foo*). This broke backward compatibility for wildcard configurations.

Additionally, when share_threshold was implemented, stats keys for wildcard patterns with share_threshold were also not including the wildcard pattern with * (e.g., test-domain.files instead of test-domain.files_files/*), which was inconsistent with the expected behavior for wildcard stats.

Note: The lack of unit tests for wildcard stats keys made it difficult to detect this behavioral change. Adding comprehensive unit tests can help avoid such issues in the future.

Solution

The code now preserves the original wildcard stats behavior while properly handling share_threshold and value_to_metric flags according to the following rules:

1. No value_to_metric OR detailed_metric: Stats key includes wildcard pattern with * (e.g., test-domain.wild_foo*)
2. value_to_metric OR detailed_metric: Stats key includes actual runtime value (e.g., test-domain.wild_foo1)
3. share_threshold: true: Stats key always includes wildcard pattern with *, regardless of other flags (e.g., test-domain.wild_foo*)

This change ensures that:

1. When a wildcard is matched and neither value_to_metric nor share_threshold is enabled, the stats key includes the wildcard pattern (e.g., foo*) instead of just the key name (original behavior).
2. When share_threshold is enabled, the stats key consistently includes the wildcard pattern with * (e.g., test-domain.files_files/*), maintaining consistency with wildcard stats behavior.

Test Coverage

Added & Updated comprehensive unit tests to prevent future regressions.

[xuannam230201]

Hi @collin-lee , this issue was introduced in my another PR (this line and this line). As a result, I create this PR to address this issue (to maintain backward compatibility for metrics of wild card). Could you please help to take a look at this?

Thanks in advance!

[xuannam230201]

Remove these codes because each time this.statsManager.NewStats is called, logger prints debug log "Creating stats..." once. As a result, with current code, each request makes logger log that twice.

FullKey is automatically assigned to stat.string when rateLimit is initialized; as a result, remove the assignment (redundant).

[xuannam230201]

Refactor the logic to include value in stats. It's not necessary to repeat:

valueToMetricFullKey.WriteString(entry.Key)
valueToMetricFullKey.WriteString("_")
valueToMetricFullKey.WriteString(...)

several times in this logic