From 9909bf3217f171b9831413a1b1be07583677e621 Mon Sep 17 00:00:00 2001
From: Maarten Mulders <mthmulders@users.noreply.github.com>
Date: Thu, 2 May 2024 11:38:31 +0200
Subject: [PATCH] fix: Improve error logging in case of connection failure
 (#367)

Closes #363.
---
 src/main/java/it/mulders/mcs/search/SearchClient.java   | 4 ++++
 src/test/java/it/mulders/mcs/search/SearchClientIT.java | 1 +
 2 files changed, 5 insertions(+)

diff --git a/src/main/java/it/mulders/mcs/search/SearchClient.java b/src/main/java/it/mulders/mcs/search/SearchClient.java
index 3fe2bc4e..a7840081 100644
--- a/src/main/java/it/mulders/mcs/search/SearchClient.java
+++ b/src/main/java/it/mulders/mcs/search/SearchClient.java
@@ -4,6 +4,7 @@
 import it.mulders.mcs.common.SearchResponseBodyHandler;
 
 import java.io.IOException;
+import java.net.ConnectException;
 import java.net.URI;
 import java.net.http.HttpClient;
 import java.net.http.HttpRequest;
@@ -32,6 +33,9 @@ public Result<SearchResponse> search(final SearchQuery query) {
         try {
             return client.send(request, new SearchResponseBodyHandler())
                     .body();
+        } catch (ConnectException e) {
+            // The JDK HTTP client throws a ConnectException without a message, we can do better.
+            return new Result.Failure<>(new ConnectException("Can't resolve " + hostname));
         } catch (IOException | InterruptedException e) {
             return new Result.Failure<>(e);
         }
diff --git a/src/test/java/it/mulders/mcs/search/SearchClientIT.java b/src/test/java/it/mulders/mcs/search/SearchClientIT.java
index 5fc58d37..c7b781d3 100644
--- a/src/test/java/it/mulders/mcs/search/SearchClientIT.java
+++ b/src/test/java/it/mulders/mcs/search/SearchClientIT.java
@@ -129,6 +129,7 @@ void should_gracefully_handle_connection_failure() {
 
             assertThat(result).isInstanceOf(Result.Failure.class);
             assertThat(result.cause()).isInstanceOf(ConnectException.class);
+            assertThat(result.cause().getLocalizedMessage()).contains("localhost:21");
         }
     }
 }
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