From a11ed03031cb59b412950d62960fc27cf919e2bf Mon Sep 17 00:00:00 2001
From: Alex Auvolat <alex@adnab.me>
Date: Thu, 2 Feb 2023 16:24:30 +0100
Subject: Avoid sending useless changes to downstream listener

---
 Cargo.toml             |  2 +-
 examples/watch_test.rs |  3 ++-
 src/catalog.rs         | 25 ++++++++++++++-----------
 3 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index b844a1f..3f967b4 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -2,7 +2,7 @@
 name = "df-consul"
 description = "Deuxfleurs' async Rust bindings for (a subset of) the Consul HTTP API"
 authors = [ "Alex Auvolat <alex@adnab.me>" ]
-version = "0.3.2"
+version = "0.3.3"
 edition = "2021"
 license = "MIT"
 repository = "https://git.deuxfleurs.fr/Deuxfleurs/df-consul"
diff --git a/examples/watch_test.rs b/examples/watch_test.rs
index d4d48a0..c697a53 100644
--- a/examples/watch_test.rs
+++ b/examples/watch_test.rs
@@ -22,6 +22,7 @@ async fn main() {
         if watch.changed().await.is_err() {
             break;
         }
-        println!("\n{:?}", watch.borrow_and_update());
+        //println!("\n{:?}", watch.borrow_and_update());
+        println!("changed, {} values", watch.borrow_and_update().len());
     }
 }
diff --git a/src/catalog.rs b/src/catalog.rs
index cad7f5b..042f745 100644
--- a/src/catalog.rs
+++ b/src/catalog.rs
@@ -22,7 +22,7 @@ use crate::{Consul, WithIndex};
 
 /// Node summary, as specified in response to "list nodes" API calls in
 /// <https://developer.hashicorp.com/consul/api-docs/catalog#list-nodes>
-#[derive(Serialize, Deserialize, Debug, Clone)]
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq)]
 #[serde(rename_all = "PascalCase")]
 pub struct Node {
     pub node: String,
@@ -31,7 +31,7 @@ pub struct Node {
 }
 
 /// One of the services returned in a CatalogNode
-#[derive(Serialize, Deserialize, Debug, Clone)]
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq)]
 #[serde(rename_all = "PascalCase")]
 pub struct Service {
     pub service: String,
@@ -42,7 +42,7 @@ pub struct Service {
 
 /// Full node info, as specified in response to "retrieve map of services for a node" API call in
 /// <https://developer.hashicorp.com/consul/api-docs/catalog#retrieve-map-of-services-for-a-node>
-#[derive(Serialize, Deserialize, Debug)]
+#[derive(Serialize, Deserialize, Debug, PartialEq, Eq)]
 #[serde(rename_all = "PascalCase")]
 pub struct CatalogNode {
     pub node: Node,
@@ -55,7 +55,7 @@ pub type ServiceList = HashMap<String, Vec<String>>;
 
 /// Node serving a service, as specified in response to "list nodes for a service" API call in
 /// <https://developer.hashicorp.com/consul/api-docs/catalog#list-nodes-for-service>
-#[derive(Serialize, Deserialize, Debug)]
+#[derive(Serialize, Deserialize, Debug, PartialEq, Eq)]
 #[serde(rename_all = "PascalCase")]
 pub struct ServiceNode {
     pub node: String,
@@ -70,7 +70,7 @@ pub struct ServiceNode {
 /// Node serving a service with health info,
 /// as specified in response to "list service instances for a service" health API call in
 /// <https://developer.hashicorp.com/consul/api-docs/health#list-service-instances-for-service>
-#[derive(Serialize, Deserialize, Debug, Clone)]
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq)]
 #[serde(rename_all = "PascalCase")]
 pub struct HealthServiceNode {
     pub node: Node,
@@ -79,7 +79,7 @@ pub struct HealthServiceNode {
 }
 
 /// A health check as returned in HealthServiceNode
-#[derive(Serialize, Deserialize, Debug, Clone)]
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq)]
 #[serde(rename_all = "PascalCase")]
 pub struct HealthCheck {
     pub node: String,
@@ -244,7 +244,14 @@ async fn do_watch_all_service_health(
                 match watch_res {
                     Ok(nodes) => {
                         let index = nodes.index();
-                        services.insert(service.clone(), nodes.into_inner().into());
+
+                        let nodes =  nodes.into_inner();
+                        if services.get(&service).as_ref().map(|n| &n[..]) != Some(&nodes[..]) {
+                            services.insert(service.clone(), nodes.into());
+                            if tx.send(services.clone()).is_err() {
+                                break;
+                            }
+                        }
 
                         let consul = &consul;
                         service_watchers.push(Box::pin(async move {
@@ -252,10 +259,6 @@ async fn do_watch_all_service_health(
                                 .map_err(|e| (1, e));
                             (service, res)
                         }));
-
-                        if tx.send(services.clone()).is_err() {
-                            break;
-                        }
                     }
                     Err((err_count, e)) => {
                         warn!("Error getting service {}: {} ({} consecutive errors)", service, e, err_count);
-- 
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