Better error handling in Proxy Resolver.

src/Disks/S3/ProxyResolverConfiguration.cpp

@@ -7,6 +7,11 @@
 #include <Poco/Net/HTTPResponse.h>
 #include <common/logger_useful.h>
 
+namespace DB::ErrorCodes
+{
+    extern const int BAD_ARGUMENTS;
+}
+
 namespace DB::S3
 {
 ProxyResolverConfiguration::ProxyResolverConfiguration(const Poco::URI & endpoint_, String proxy_scheme_, unsigned proxy_port_)
@@ -30,13 +35,16 @@ Aws::Client::ClientConfigurationPerRequest ProxyResolverConfiguration::getConfig
     Aws::Client::ClientConfigurationPerRequest cfg;
     try
     {
-        /// It should be just empty GET / request.
+        /// It should be just empty GET request.
-        Poco::Net::HTTPRequest request(Poco::Net::HTTPRequest::HTTP_1_1);
+        Poco::Net::HTTPRequest request(Poco::Net::HTTPRequest::HTTP_GET, endpoint.getPath(), Poco::Net::HTTPRequest::HTTP_1_1);
         session->sendRequest(request);
 
         Poco::Net::HTTPResponse response;
         auto & response_body_stream = session->receiveResponse(response);
 
+        if (response.getStatus() != Poco::Net::HTTPResponse::HTTP_OK)
+            throw Exception("Proxy resolver returned not OK status: " + response.getReason(), ErrorCodes::BAD_ARGUMENTS);
+
         String proxy_host;
         /// Read proxy host as string from response body.
         Poco::StreamCopier::copyToString(response_body_stream, proxy_host);

src/Disks/S3/ProxyResolverConfiguration.h

@@ -6,7 +6,7 @@ namespace DB::S3
 {
 /**
  * Proxy configuration where proxy host is obtained each time from specified endpoint.
- * For each request to S3 it makes GET request to specified endpoint and reads proxy host from a response body.
+ * For each request to S3 it makes GET request to specified endpoint URL and reads proxy host from a response body.
  * Specified scheme and port added to obtained proxy host to form completed proxy URL.
  */
 class ProxyResolverConfiguration : public ProxyConfiguration

tests/integration/test_s3_with_proxy/configs/config.d/storage_conf.xml

@@ -18,12 +18,12 @@
                 <secret_access_key>minio123</secret_access_key>
                 <proxy>
                     <!--
-                        At each interaction with S3 resolver sends empty GET / request to specified endpoint to obtain proxy host.
+                        At each interaction with S3 resolver sends empty GET request to specified endpoint URL to obtain proxy host.
                         Proxy host is returned as string in response body.
                         Then S3 client uses proxy URL formed as proxy_scheme://proxy_host:proxy_port to make request.
                     -->
                     <resolver>
-                        <endpoint>http://resolver:8080</endpoint>
+                        <endpoint>http://resolver:8080/hostname</endpoint>
                         <proxy_scheme>http</proxy_scheme>
                         <proxy_port>8888</proxy_port>
                     </resolver>

tests/integration/test_s3_with_proxy/proxy-resolver/resolver.py

@@ -2,7 +2,7 @@ import bottle
 import random
 
 
-@bottle.route('/')
+@bottle.route('/hostname')
 def index():
     if random.randrange(2) == 0:
         return 'proxy1'