From 86c255dfeabc60b0ef46ff78bc487c61c9548c79 Mon Sep 17 00:00:00 2001
From: Alex Auvolat <alex@adnab.me>
Date: Wed, 11 Jan 2023 22:44:21 +0100
Subject: Less spam on stdout

---
 src/dns_config.rs |  2 +-
 src/main.rs       | 15 +++++++++++----
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/src/dns_config.rs b/src/dns_config.rs
index 1356fc7..0697270 100644
--- a/src/dns_config.rs
+++ b/src/dns_config.rs
@@ -19,7 +19,7 @@ const CNAME_TARGET_METADATA_TAG: &str = "cname_target";
 
 // ---- Extract DNS config from Consul catalog ----
 
-#[derive(Debug)]
+#[derive(Debug, Eq, PartialEq, Default)]
 pub struct DnsConfig {
     pub entries: HashMap<DnsEntryKey, DnsEntryValue>,
 }
diff --git a/src/main.rs b/src/main.rs
index 77c8b16..24193f7 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -129,6 +129,8 @@ async fn dump_config_on_change(
     mut rx_dns_config: watch::Receiver<Arc<dns_config::DnsConfig>>,
     mut must_exit: watch::Receiver<bool>,
 ) {
+    let mut prev_dns_config = Arc::new(dns_config::DnsConfig::default());
+
     while !*must_exit.borrow() {
         select!(
             c = rx_dns_config.changed() => {
@@ -138,11 +140,16 @@ async fn dump_config_on_change(
             }
             _ = must_exit.changed() => continue,
         );
-        println!("---- DNS CONFIGURATION ----");
-        for (k, v) in rx_dns_config.borrow().entries.iter() {
-            println!("   {} {}", k, v);
+
+        let new_dns_config = rx_dns_config.borrow_and_update().clone();
+        if new_dns_config != prev_dns_config {
+            println!("---- DNS CONFIGURATION ----");
+            for (k, v) in rx_dns_config.borrow().entries.iter() {
+                println!("   {} {}", k, v);
+            }
+            println!();
         }
-        println!();
+        prev_dns_config = new_dns_config;
     }
 }
 
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