feat(logging): Add configurable rate limit for logging

[sergeymatov]

Introduce --tracing-rate-limit BURST:REPLENISH_PER_SECOND. if omitted, logging is unchanged and no throttling is applied. Initialize tracing explicitly from main() so CLI-provided throttle settings are applied before startup logs.

[Copilot]

Pull request overview

Adds an optional CLI-configured tracing/logging rate limiter so lower-severity logs (info/debug/trace) can be throttled while keeping warn/error unthrottled, and ensures tracing is initialized early enough for startup logs to respect CLI settings.

Changes:

• Add --tracing-rate-limit BURST:REPLENISH_PER_SECOND parsing + config plumbing in args.
• Add TracingControl::init_with_rate_limit(...) and integrate tracing-throttle in tracectl.
• Initialize tracing from dataplane::main() before emitting startup logs / applying tracing commands.

Reviewed changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
tracectl/src/lib.rs	Re-export TracingRateLimitConfig from tracectl.
tracectl/src/control.rs	Introduce rate-limit config + initialization path using OnceLock and tracing-throttle.
tracectl/Cargo.toml	Add tracing-throttle dependency.
dataplane/src/main.rs	Initialize tracing with optional rate limit before startup logs and tracing command processing.
args/src/lib.rs	Add TracingRateLimit type, FromStr parser, CLI flag, and config section field.
Cargo.toml	Add workspace dependency for tracing-throttle (and minor formatting change).
Cargo.lock	Lockfile updates to include tracing-throttle and transitive dependency changes.

[Copilot]

Pull request overview

Adds an optional CLI-configurable tracing/logging rate limit and ensures tracing is initialized early in dataplane so startup logs honor the CLI settings.

Changes:

• Add --tracing-rate-limit BURST:REPLENISH_PER_SECOND parsing and plumbing into runtime configuration.
• Extend tracectl tracing initialization to optionally apply a throttle layer for INFO/DEBUG/TRACE (leaving WARN/ERROR unthrottled).
• Initialize tracing from dataplane::main() before emitting startup logs.

Reviewed changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
tracectl/src/lib.rs	Re-export TracingRateLimitConfig for downstream initialization.
tracectl/src/control.rs	Introduce rate-limit config + OnceLock init, and wire in tracing-throttle for lower-severity logs.
tracectl/Cargo.toml	Add tracing-throttle dependency.
dataplane/src/main.rs	Initialize tracing earlier and pass CLI-provided rate-limit config.
args/src/lib.rs	Add TracingRateLimit type, CLI flag, config propagation, and parsing tests.
Cargo.toml	Add workspace dependency on tracing-throttle.
Cargo.lock	Lockfile updates for new dependency (and transitive bumps).

Comments suppressed due to low confidence (1)

args/src/lib.rs:1616

confidence: 10
tags: [logic]

`args/src/lib.rs` defines `#[cfg(test)] mod tests` twice at the same module scope, which will not compile (duplicate module name). Merge the new `TracingRateLimit` tests into the existing `mod tests` block (or rename one of the modules).

#[test]
fn tracing_rate_limit_parses_valid_values() {
    let rate_limit = TracingRateLimit::from_str("10:20").unwrap();
    assert_eq!(rate_limit.burst, 10);
    assert_eq!(rate_limit.replenish_per_second, 20);
}
#[test]
fn tracing_rate_limit_rejects_missing_separator() {
    let err = TracingRateLimit::from_str("10").unwrap_err();
    assert_eq!(err, "Bad syntax: missing :");
}
#[test]
fn tracing_rate_limit_rejects_non_numeric_values() {
    let err = TracingRateLimit::from_str("abc:20").unwrap_err();
    assert!(err.starts_with("Bad burst value:"));
    let err = TracingRateLimit::from_str("10:def").unwrap_err();
    assert!(err.starts_with("Bad replenish-per-second value:"));
}
#[test]
fn tracing_rate_limit_rejects_zero_values() {
    let err = TracingRateLimit::from_str("0:20").unwrap_err();
    assert_eq!(err, "Burst must be greater than 0");
    let err = TracingRateLimit::from_str("10:0").unwrap_err();
    assert_eq!(err, "Replenish-per-second must be greater than 0");
}

}

</details>

[sergeymatov]

This comment can be ignored

[mvachhar]

How hard is it to write a test to cover this instead of telling copilot to go away?

[mvachhar]

(And can AI write the test with some guidance?)