neigbours by transport

5 files changed, 43 insertions, 2 deletions

diff --git a/docs/measurements.md b/docs/measurements.md
index 81ca0fc..cff7add 100644
--- a/docs/measurements.md
+++ b/docs/measurements.md
@@ -98,6 +98,7 @@ or caught up over many small messages.
 | `topology.view.stable` | `stable_members` | Members whose registry entry says `stable`. |
 | `topology.view.neighbours` | `neighbours` | Current neighbours: peers this node keeps alive and syncs with on its own. At least `k` (links chosen by either end count); well above `k` on a stable member that many others chose, bounded at about 8 × k. |
 | `topology.view.stableNeighbours` | `stable_neighbours` | Of those, stable members. |
+| `topology.view.neighboursByTransport` | `neighbours_on{transport}` | Of those, by this node's transports (address schemes): the ones the member list gives an address on it. One on two transports counts on both; one it gives none for (not listed yet, or only connecting out), on none. About `k` on each ([`peers.md`](peers.md)); few on one means that transport reaches the swarm through few members. |
 | `topology.view.ownTree.members` | `own_tree_members` | Other members in this node's own writer's tree: what its writes go along ([`peers.md`](peers.md)), as this node computes it (what members beyond its neighbours reach is taken from the member list's graph). |
 | `topology.view.ownTree.depth`, `.meanDepth` | `own_tree_depth`, `own_tree_mean_depth` | The most hops along it from this node to one of them, and the mean. |
 | `topology.view.ownTree.offTree` | `own_tree_off_members` | Members it doesn't reach: no member they reach comes before them, they are below one such, or the member list's graph doesn't connect them to this node. They get its writes by announcement. |
diff --git a/docs/openapi.yaml b/docs/openapi.yaml
index 3d74746..db73ede 100644
--- a/docs/openapi.yaml
+++ b/docs/openapi.yaml
@@ -2069,7 +2069,7 @@ components:
               oneOf:
                 - type: 'null'
                 - type: object
-                  required: [members, reachable, stable, neighbours, stableNeighbours, ownTree]
+                  required: [members, reachable, stable, neighbours, stableNeighbours, neighboursByTransport, ownTree]
                   properties:
                     members:
                       type: integer
@@ -2083,6 +2083,11 @@ components:
                       type: integer
                     stableNeighbours:
                       type: integer
+                    neighboursByTransport:
+                      type: object
+                      additionalProperties:
+                        type: integer
+                      description: Neighbours the member list gives an address on each of this node's transports (address schemes); one on two counts on both.
                     ownTree:
                       description: This node's own writer's tree; null while it isn't in the member list's graph.
                       oneOf:
diff --git a/src/api/stats.rs b/src/api/stats.rs
index 3851ef7..306b6a2 100644
--- a/src/api/stats.rs
+++ b/src/api/stats.rs
@@ -187,6 +187,8 @@ struct TopologyView {
     stable: usize,
     neighbours: usize,
     stable_neighbours: usize,
+    /// Neighbours by our transports (`topology::Summary`).
+    neighbours_by_transport: std::collections::BTreeMap<String, usize>,
     /// Our own writer's tree (`swarm::tree::own_shape`); absent while we aren't in the
     /// member list's graph.
     own_tree: Option<OwnTree>,
@@ -382,6 +384,7 @@ pub(crate) async fn collect(state: &AppState, list: &PeerListResponse) -> StatsR
                 stable: s.stable,
                 neighbours: s.neighbours,
                 stable_neighbours: s.stable_neighbours,
+                neighbours_by_transport: s.neighbours_by_transport,
                 own_tree,
             }),
         },
diff --git a/src/api/stats/prometheus.rs b/src/api/stats/prometheus.rs
index db3cef3..ffe6593 100644
--- a/src/api/stats/prometheus.rs
+++ b/src/api/stats/prometheus.rs
@@ -713,6 +713,18 @@ pub(super) fn render(stats: &StatsResponse, list: &PeerListResponse) -> String {
             "Current neighbours with the stable tier.",
             view.stable_neighbours as f64,
         );
+        out.family(
+            "neighbours_on",
+            "gauge",
+            "Current neighbours with an address on one of this node's transports, by transport.",
+        );
+        for (transport, neighbours) in &view.neighbours_by_transport {
+            out.sample(
+                "neighbours_on",
+                &[("transport", transport)],
+                *neighbours as f64,
+            );
+        }
         if let Some(tree) = &view.own_tree {
             out.single(
                 "own_tree_members",
diff --git a/src/swarm/topology/mod.rs b/src/swarm/topology/mod.rs
index afa13ee..37b2f71 100644
--- a/src/swarm/topology/mod.rs
+++ b/src/swarm/topology/mod.rs
@@ -117,7 +117,7 @@ pub(crate) fn is_full_mesh(state: &AppState) -> bool {
 }
 
 /// The current view in numbers, once known.
-#[derive(Debug, Clone, Copy)]
+#[derive(Debug, Clone)]
 pub(crate) struct Summary {
     /// Registered members, us included.
     pub(crate) members: usize,
@@ -126,6 +126,10 @@ pub(crate) struct Summary {
     pub(crate) stable: usize,
     pub(crate) neighbours: usize,
     pub(crate) stable_neighbours: usize,
+    /// For each of our transports (address scheme), the neighbours the member list
+    /// gives an address on it: one on two transports counts on both, one it gives none
+    /// for (not listed yet, or only connecting out) on none.
+    pub(crate) neighbours_by_transport: BTreeMap<String, usize>,
 }
 
 pub(crate) fn summary(state: &AppState) -> Option<Summary> {
@@ -148,6 +152,22 @@ pub(crate) fn summary(state: &AppState) -> Option<Summary> {
                 .iter()
                 .filter(|m| view.stable.contains(*m))
                 .count(),
+            neighbours_by_transport: view
+                .local_transports
+                .iter()
+                .map(|transport| {
+                    let on_it = view
+                        .neighbours
+                        .iter()
+                        .filter(|m| {
+                            view.transports
+                                .get(*m)
+                                .is_some_and(|theirs| theirs.contains(transport))
+                        })
+                        .count();
+                    (transport.clone(), on_it)
+                })
+                .collect(),
         })
 }