get_consensus_weights

vanguards_rs::control

Function get_consensus_weights 

Source 
pub fn get_consensus_weights(
    consensus_filename: &Path,
) -> Result<HashMap<String, i64>>
Expand description

Parses consensus bandwidth weights from a cached-microdesc-consensus file.

Bandwidth weights are used by Tor clients to select relays proportionally to their contribution to the network. These weights are essential for the bandwidth-weighted guard selection algorithm.

§Weight Keys

Common weight keys include:

KeyDescription
WggWeight for Guard-flagged nodes in guard position
WgmWeight for Guard-flagged nodes in middle position
WmmWeight for non-flagged nodes in middle position
WmeWeight for Exit-flagged nodes in middle position
WeeWeight for Exit-flagged nodes in exit position

§Arguments

  • consensus_filename - Path to the cached-microdesc-consensus file

§Returns

A HashMap mapping weight keys (e.g., “Wmm”) to their integer values (typically in range 0-10000, representing parts per 10000).

§Errors

Returns Error::Consensus if:

  • The file cannot be opened or read
  • No bandwidth-weights line is found in the file

§File Format

The function looks for a line starting with bandwidth-weights followed by space-separated key=value pairs:

bandwidth-weights Wbd=0 Wbe=0 Wbg=4194 Wbm=10000 ...

§Example

use std::path::Path;
use vanguards_rs::control::get_consensus_weights;

let weights = get_consensus_weights(Path::new("/var/lib/tor/cached-microdesc-consensus"))?;

if let Some(wmm) = weights.get("Wmm") {
    println!("Middle position weight: {}", wmm);
}

§See Also