Change provider options callback signature to return error code

The callback now returns an error code and takes a reference to
provider options string.

Author: Daniele Sciascia

include/wsrep/provider.hpp

@@ -518,12 +518,12 @@ namespace wsrep
          * @param provider_options_cb Callback to get initial provider options
          * @param thread_service Optional thread service implementation.
          */
-        static std::unique_ptr<provider>
-        make_provider(wsrep::server_state&, const std::string& provider_spec,
-                      const std::function<std::string(const provider_options&)>&
-                          provider_options_cb,
-                      const wsrep::provider::services& services
-                      = wsrep::provider::services());
+        static std::unique_ptr<provider> make_provider(
+            wsrep::server_state&, const std::string& provider_spec,
+            const std::function<int(const provider_options&, std::string&)>&
+                provider_options_cb,
+            const wsrep::provider::services& services
+            = wsrep::provider::services());
 
     protected:
         wsrep::server_state& server_state_;

include/wsrep/server_state.hpp

@@ -296,11 +296,12 @@ namespace wsrep
          *
          * @return Zero on success, non-zero on error.
          */
-        int load_provider(const std::string& provider,
-                          const std::function<std::string(
-                              const provider_options&)>& provider_options_cb,
-                          const wsrep::provider::services& services
-                          = wsrep::provider::services());
+        int load_provider(
+            const std::string& provider,
+            const std::function<int(const provider_options&, std::string&)>&
+                provider_options_cb,
+            const wsrep::provider::services& services
+            = wsrep::provider::services());
 
         /**
          * Load WSRep provider.
@@ -321,7 +322,11 @@ namespace wsrep
                           = wsrep::provider::services())
         {
             return load_provider(
-                provider, [options](const provider_options&) { return options; },
+                provider,
+                [options](const provider_options&, std::string& option_string) {
+                  option_string.append(options);
+                  return 0;
+                },
                 services);
         }
 

src/provider.cpp

@@ -29,7 +29,7 @@
 
 std::unique_ptr<wsrep::provider> wsrep::provider::make_provider(
     wsrep::server_state& server_state, const std::string& provider_spec,
-    const std::function<std::string(const provider_options&)>&
+    const std::function<int(const provider_options&, std::string&)>&
         provider_options_cb,
     const wsrep::provider::services& services)
 {
@@ -41,19 +41,23 @@ std::unique_ptr<wsrep::provider> wsrep::provider::make_provider(
     }
     catch (const wsrep::runtime_error& e)
     {
-        provider_options opts;
+        provider_options options;
+        std::string options_string;
         wsrep::log_error() << "Failed to create a new provider '"
                            << provider_spec << "'"
-                           << " with options '" << provider_options_cb(opts)
+                           << " with options '"
+                           << provider_options_cb(options, options_string)
                            << "': " << e.what();
     }
     catch (...)
     {
-        provider_options opts;
+        provider_options options;
+        std::string options_string;
         wsrep::log_error() << "Caught unknown exception when trying to "
                            << "create a new provider '"
                            << provider_spec << "'"
-                           << " with options '" << provider_options_cb(opts);
+                           << " with options '"
+                           << provider_options_cb(options, options_string);
     }
     return 0;
 }

src/server_state.cpp

@@ -500,7 +500,7 @@ static int apply_toi(wsrep::provider& provider,
 
 int wsrep::server_state::load_provider(
     const std::string& provider_spec,
-    const std::function<std::string(const provider_options&)>&
+    const std::function<int(const provider_options&, std::string&)>&
         provider_options_cb,
     const wsrep::provider::services& services)
 {

src/wsrep_provider_v26.cpp

@@ -778,7 +778,7 @@ void wsrep::wsrep_provider_v26::deinit_services()
 wsrep::wsrep_provider_v26::wsrep_provider_v26(
     wsrep::server_state& server_state,
     const std::string& provider_spec,
-    const std::function<std::string(provider_options&)>& provider_options_cb,
+    const std::function<int(provider_options&, std::string&)>& provider_options_cb,
     const wsrep::provider::services& services)
     : provider(server_state)
     , wsrep_()
@@ -798,8 +798,6 @@ wsrep::wsrep_provider_v26::wsrep_provider_v26(
     }
 
     init_services(services);
-    provider_options options;
-    config_service_v2_fetch(wsrep_, &options);
 
     struct wsrep_init_args init_args;
     memset(&init_args, 0, sizeof(init_args));
@@ -808,8 +806,6 @@ wsrep::wsrep_provider_v26::wsrep_provider_v26(
     init_args.node_address = server_state_.address().c_str();
     init_args.node_incoming = server_state_.incoming_address().c_str();
     init_args.data_dir = server_state_.working_dir().c_str();
-    const auto& provider_options = provider_options_cb(options);
-    init_args.options = provider_options.c_str();
     init_args.proto_ver = server_state.max_protocol_version();
     init_args.state_id = &state_id;
     init_args.state = 0;
@@ -823,6 +819,16 @@ wsrep::wsrep_provider_v26::wsrep_provider_v26(
     init_args.sst_donate_cb = &sst_donate_cb;
     init_args.synced_cb = &synced_cb;
 
+    provider_options options;
+    config_service_v2_fetch(wsrep_, &options);
+
+    std::string provider_options;
+    if (provider_options_cb(options, provider_options))
+    {
+        throw wsrep::runtime_error("Failed to initialize wsrep provider options");
+    }
+    init_args.options = provider_options.c_str();
+
     if (wsrep_->init(wsrep_, &init_args) != WSREP_OK)
     {
         throw wsrep::runtime_error("Failed to initialize wsrep provider");

src/wsrep_provider_v26.hpp

@@ -33,9 +33,10 @@ namespace wsrep
     public:
         void init_services(const wsrep::provider::services& services);
         void deinit_services();
-        wsrep_provider_v26(wsrep::server_state&, const std::string&,
-                           const std::function<std::string(provider_options&)>&,
-                           const wsrep::provider::services& services);
+        wsrep_provider_v26(
+            wsrep::server_state&, const std::string&,
+            const std::function<int(provider_options&, std::string&)>&,
+            const wsrep::provider::services& services);
         ~wsrep_provider_v26() WSREP_OVERRIDE;
         enum wsrep::provider::status
         connect(const std::string&, const std::string&, const std::string&,

test/mock_server_state.hpp

@@ -263,7 +263,8 @@ namespace wsrep
         {
             set_provider_factory(
                 [&](wsrep::server_state&, const std::string&,
-                    const std::function<std::string(const wsrep::provider_options&)>&,
+                    const std::function<int(const wsrep::provider_options&,
+                                            std::string&)>&,
                     const wsrep::provider::services&)
                 {
                     // The provider object is destroyed upon server state