fix(distance): max_depth, compute min_certs_for_referee

distance-oracle/src/lib.rs

@@ -8,7 +8,7 @@ use subxt::storage::StorageKey;
 
 pub struct Settings {
     pub evaluation_result_dir: PathBuf,
-    pub min_certs_for_referee: u32,
+    pub max_depth: u32,
     pub rpc_url: String,
 }
 
@@ -16,7 +16,7 @@ impl Default for Settings {
     fn default() -> Self {
         Self {
             evaluation_result_dir: PathBuf::from("/tmp/duniter/chains/gdev/distance"),
-            min_certs_for_referee: 2,
+            max_depth: 5,
             rpc_url: String::from("ws://127.0.0.1:9944"),
         }
     }
@@ -145,6 +145,10 @@ pub async fn run(settings: Settings) {
         members.insert(idty_id_from_storage_key(&member_idty), 0);
     }
 
+    let min_certs_for_referee = (members.len() as f32)
+        .powf(1. / (settings.max_depth as f32))
+        .ceil() as u32;
+
     // idty -> received certs
     let mut received_certs = HashMap::<IdtyIndex, Vec<IdtyIndex>>::new();
 
@@ -160,7 +164,7 @@ pub async fn run(settings: Settings) {
     while let Some((receiver, issuers)) = certs_iter.next().await.unwrap() {
         let receiver = idty_id_from_storage_key(&receiver);
         // Update members' issued certs count
-        if issuers.len() as u32 >= settings.min_certs_for_referee {
+        if issuers.len() as u32 >= min_certs_for_referee {
             for (issuer, _removable_on) in issuers.iter() {
                 if let Some(issued_certs) = members.get_mut(issuer) {
                     *issued_certs += 1;
@@ -181,7 +185,7 @@ pub async fn run(settings: Settings) {
 
     // Only retain referees
     // TODO benchmark: can it be faster? (maybe using drain_filter)
-    members.retain(|_idty, issued_certs| *issued_certs >= settings.min_certs_for_referee);
+    members.retain(|_idty, issued_certs| *issued_certs >= min_certs_for_referee);
     let referees = members;
 
     let evaluation: Vec<Perbill> = evaluation_pool
@@ -190,12 +194,7 @@ pub async fn run(settings: Settings) {
         .into_par_iter()
         .map(|(idty, _)| {
             Perbill::from_rational(
-                distance_rule(
-                    &received_certs,
-                    &referees,
-                    settings.min_certs_for_referee,
-                    idty,
-                ),
+                distance_rule(&received_certs, &referees, settings.max_depth, idty),
                 referees.len() as u32,
             )
         })

distance-oracle/src/main.rs

@@ -4,8 +4,9 @@ use clap::Parser;
 struct Cli {
     #[clap(short = 'd', long, default_value = "/tmp/duniter/chains/gdev/distance")]
     evaluation_result_dir: String,
-    #[clap(short = 'c', long, default_value = "2")]
-    min_certs_for_referee: u32,
+    /// Maximum depth to explore the WoT graph for referees
+    #[clap(short = 'D', long, default_value = "5")]
+    max_depth: u32,
     #[clap(short = 'u', long, default_value = "ws://127.0.0.1:9944")]
     rpc_url: String,
 }
@@ -16,7 +17,7 @@ async fn main() {
 
     distance_oracle::run(distance_oracle::Settings {
         evaluation_result_dir: cli.evaluation_result_dir.into(),
-        min_certs_for_referee: cli.min_certs_for_referee,
+        max_depth: cli.max_depth,
         rpc_url: cli.rpc_url,
     })
     .await;

docs/user/distance.md

@@ -18,10 +18,14 @@ It will be available at `./target/release/distance-oracle`. Move it to somewhere
 
 Add this line to your cron with the command `crontab -e`: (add option `-u <user>` to edit another user's cron)
 
-    4,24,44 * * * * /absolute/path/to/distance-oracle
+    4,24,44 * * * * nice -n 2 /absolute/path/to/distance-oracle
 
 The precise hours don't matter so you can pick random values, but it should run at least one time per hour, and running it more often decreases the risk of problem in case of missing blocks or temporary network failure.
 
 If the evaluation ran successfully in a session, the next runs in the same session won't re-evaluate the same data.
 
-No additional configuration is needed for Duniter.
+The `nice -n 2` lowers the oracle's priority, so that Duniter has the priority even when the oracle wants to use all the cores.
+
+### Additional Duniter configuration
+
+Duniter should keep states at least one session old, that it 600 blocks (while 256 is the default). Use the option `--state-pruning 600` if your node is not already an archive (`--state-pruning archive`).

end2end-tests/tests/common/mod.rs

@@ -264,8 +264,6 @@ pub fn spawn_distance_oracle(distance_oracle_binary_path: &str, duniter_rpc_port
                 &format!("ws://127.0.0.1:{duniter_rpc_port}"),
                 "-d",
                 "/tmp/duniter-cucumber/chains/gdev/distance",
-                "-c",
-                "2",
             ]
             .iter(),
         )

end2end-tests/tests/cucumber_tests.rs

@@ -514,7 +514,7 @@ async fn should_have_distance_ok(world: &mut DuniterWorld, who: String) -> Resul
         .unwrap();
 
     if world
-        .read(&gdev::storage().distance().distance_ok_identities(&idty_id))
+        .read(&gdev::storage().distance().distance_ok_identities(idty_id))
         .await?
         .unwrap()
     {