Add support for custom provider implementation

- Add a set_provider_factory() method to server_state to allow
  injecting provider factory which will be called when the
  provider is loaded.

Other related changes:
- Implement to_string() helper method for id class.
- Fix id ostream operator human readable id printing.
- Pass victim client_service as an argument to provider::bf_abort()
  to allow passing victim context to custom provider.
- Implement prev() helper method for seqno class.
- Make server_state recover_streaming_appliers_if_not_recovered()
  public. In some recovery scenarios the method must be called outside
  of server_state internal code paths.
- Add storage_service requires_globals() method. The storage service
  implementation may override this to return false if changing to
  storage service context does not require store/reset globals.
- Change view final() to also require that the view status is not
  primary for the view to be final. Also change the method name to
  is_final() to avoid confusion with C++ final identifier.
- Fixes to server state handling in disconnecting and disconnected
  states.

Co-authored-by: Denis Protivensky <[email protected]>

Author: temeo

.gitignore

@@ -13,3 +13,6 @@ wsrep-API/libwsrep_api_v26.a
 
 # Gcov generated files
 *.dgcov
+
+# Test logs
+wsrep-lib_test.log

include/wsrep/client_state.hpp

@@ -582,7 +582,8 @@ namespace wsrep
          * @param lock Lock to protect client state.
          * @param bf_seqno Seqno of the BF aborter.
          */
-        int bf_abort(wsrep::unique_lock<wsrep::mutex>& lock, wsrep::seqno bf_seqno);
+        int bf_abort(wsrep::unique_lock<wsrep::mutex>& lock,
+                     wsrep::seqno bf_seqno);
         /**
          * Wrapper to bf_abort() call, grabs lock internally.
          */
@@ -593,7 +594,8 @@ namespace wsrep
          * should be called by the TOI operation which needs to
          * BF abort a transaction.
          */
-        int total_order_bf_abort(wsrep::unique_lock<wsrep::mutex>& lock, wsrep::seqno bf_seqno);
+        int total_order_bf_abort(wsrep::unique_lock<wsrep::mutex>& lock,
+                                 wsrep::seqno bf_seqno);
 
         /**
          * Wrapper to total_order_bf_abort(), grabs lock internally.

include/wsrep/id.hpp

@@ -93,6 +93,11 @@ namespace wsrep
         {
             return undefined_;
         }
+
+        /**
+         * Return id in string representation.
+         */
+        std::string to_string() const;
     private:
         static const wsrep::id undefined_;
         native_type data_;

include/wsrep/provider.hpp

@@ -29,6 +29,7 @@
 
 #include <cstring>
 
+#include <memory>
 #include <string>
 #include <vector>
 #include <ostream>
@@ -47,7 +48,7 @@ namespace wsrep
     class tls_service;
     class allowlist_service;
     class event_service;
-
+    class client_service;
     class stid
     {
     public:
@@ -283,7 +284,6 @@ namespace wsrep
             static const int streaming = (1 << 15);
             static const int snapshot = (1 << 16);
             static const int nbo = (1 << 17);
-
             /** decipher capability bitmask */
             static std::string str(int);
         };
@@ -375,6 +375,7 @@ namespace wsrep
          */
         virtual enum status bf_abort(wsrep::seqno bf_seqno,
                                      wsrep::transaction_id victim_trx,
+                                     wsrep::client_service& victim_ctx,
                                      wsrep::seqno& victim_seqno) = 0;
         virtual enum status rollback(wsrep::transaction_id) = 0;
         virtual enum status commit_order_enter(const wsrep::ws_handle&,
@@ -407,6 +408,7 @@ namespace wsrep
          * Leave total order isolation critical section
          */
         virtual enum status leave_toi(wsrep::client_id,
+                                      const wsrep::ws_meta& ws_meta,
                                       const wsrep::mutable_buffer& err) = 0;
 
         /**
@@ -509,11 +511,12 @@ namespace wsrep
          * @param provider_options Initial options to provider
          * @param thread_service Optional thread service implementation.
          */
-        static provider* make_provider(wsrep::server_state&,
-                                       const std::string& provider_spec,
-                                       const std::string& provider_options,
-                                       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::string& provider_options,
+            const wsrep::provider::services& services
+            = wsrep::provider::services());
 
     protected:
         wsrep::server_state& server_state_;

include/wsrep/seqno.hpp

@@ -51,6 +51,11 @@ namespace wsrep
             return (seqno_ == -1);
         }
 
+        wsrep::seqno prev() const
+        {
+            return seqno{seqno_ - 1};
+        }
+
         bool operator<(seqno other) const
         {
             return (seqno_ < other.seqno_);

include/wsrep/server_state.hpp

@@ -92,7 +92,9 @@
 #include "compiler.hpp"
 #include "xid.hpp"
 
+#include <memory>
 #include <deque>
+#include <functional>
 #include <vector>
 #include <string>
 #include <map>
@@ -188,8 +190,6 @@ namespace wsrep
             rm_sync
         };
 
-        virtual ~server_state();
-
         wsrep::encryption_service* encryption_service()
         { return encryption_service_; }
 
@@ -299,6 +299,17 @@ namespace wsrep
                           const wsrep::provider::services& services
                           = wsrep::provider::services());
 
+        using provider_factory_func =
+            std::function<decltype(wsrep::provider::make_provider)>;
+
+        /**
+         * Set provider factory method.
+         *
+         * @param Factory method to create a provider.
+         */
+        void set_provider_factory(const provider_factory_func&);
+
+        /** Unload/unset provider. */
         void unload_provider();
 
         bool is_provider_loaded() const { return provider_ != 0; }
@@ -310,12 +321,8 @@ namespace wsrep
          *
          * @throw wsrep::runtime_error if provider has not been loaded
          *
-         * @todo This should not be virtual. However, currently there
-         *       is no mechanism for tests and integrations to provide
-         *       their own provider implementations, so this is kept virtual
-         *       for time being.
          */
-        virtual wsrep::provider& provider() const
+        wsrep::provider& provider() const
         {
             if (provider_ == 0)
             {
@@ -529,6 +536,19 @@ namespace wsrep
             return init_initialized_;
         }
 
+        /** Recover streaming appliers if not already recoverd yet.
+         *
+         * This method recovers streaming appliers from streaming log.
+         * It must be called before starting to apply events after
+         * connecting to the cluster.
+         *
+         * @param lock Lock object holding server_state mutex.
+         * @param service Either client or high priority service.
+         */
+        template <class C>
+        void recover_streaming_appliers_if_not_recovered(
+            wsrep::unique_lock<wsrep::mutex>& lock, C& service);
+
         /**
          * This method will be called by the provider when
          * a remote write set is being applied. It is the responsibility
@@ -618,6 +638,7 @@ namespace wsrep
             , streaming_appliers_()
             , streaming_appliers_recovered_()
             , provider_()
+            , provider_factory_(wsrep::provider::make_provider)
             , name_(name)
             , id_(wsrep::id::undefined())
             , incoming_address_(incoming_address)
@@ -645,11 +666,7 @@ namespace wsrep
         // Interrupt all threads which are waiting for state
         void interrupt_state_waiters(wsrep::unique_lock<wsrep::mutex>&);
 
-        // Recover streaming appliers if not already recoverd
-        template <class C>
-        void recover_streaming_appliers_if_not_recovered(
-            wsrep::unique_lock<wsrep::mutex>&, C&);
-
+      private:
         // Close SR transcations whose origin is outside of current
         // cluster view.
         void close_orphaned_sr_transactions(
@@ -702,7 +719,8 @@ namespace wsrep
                          wsrep::high_priority_service*> streaming_appliers_map;
         streaming_appliers_map streaming_appliers_;
         bool streaming_appliers_recovered_;
-        wsrep::provider* provider_;
+        std::unique_ptr<wsrep::provider> provider_;
+        provider_factory_func provider_factory_;
         std::string name_;
         wsrep::id id_;
         std::string incoming_address_;

include/wsrep/storage_service.hpp

@@ -92,6 +92,17 @@ namespace wsrep
 
         virtual void store_globals() = 0;
         virtual void reset_globals() = 0;
+
+        /**
+         * Return true if the implementation requires storing
+         * and restoring global state. Return true by default
+         * since this is the original behavior. Stateless
+         * implementations may override.
+         */
+        virtual bool requires_globals() const {
+            return true;
+        }
+
     };
 }
 

include/wsrep/transaction.hpp

@@ -200,9 +200,11 @@ namespace wsrep
         void after_applying();
 
         bool bf_abort(wsrep::unique_lock<wsrep::mutex>& lock,
-                      wsrep::seqno bf_seqno);
+                      wsrep::seqno bf_seqno,
+                      wsrep::client_service&);
         bool total_order_bf_abort(wsrep::unique_lock<wsrep::mutex>&,
-                                  wsrep::seqno bf_seqno);
+                                  wsrep::seqno bf_seqno,
+                                  wsrep::client_service&);
 
         void clone_for_replay(const wsrep::transaction& other);
 

include/wsrep/view.hpp

@@ -117,9 +117,9 @@ namespace wsrep
         /**
          * Return true if the view is final
          */
-        bool final() const
+        bool is_final() const
         {
-            return (members_.empty() && own_index_ == -1);
+            return (status_ != status::primary && members_.empty() && own_index_ == -1);
         }
 
         /**

src/client_state.cpp

@@ -511,7 +511,7 @@ int wsrep::client_state::bf_abort(wsrep::unique_lock<wsrep::mutex>& lock,
 {
     assert(lock.owns_lock());
     assert(mode_ == m_local || transaction_.is_streaming());
-    auto ret = transaction_.bf_abort(lock, bf_seqno);
+    auto ret = transaction_.bf_abort(lock, bf_seqno, client_service_);
     assert(lock.owns_lock());
     return ret;
 }
@@ -527,7 +527,7 @@ int wsrep::client_state::total_order_bf_abort(
 {
     assert(lock.owns_lock());
     assert(mode_ == m_local || transaction_.is_streaming());
-    auto ret = transaction_.total_order_bf_abort(lock, bf_seqno);
+    auto ret = transaction_.total_order_bf_abort(lock, bf_seqno, client_service_);
     assert(lock.owns_lock());
     return ret;
 }
@@ -585,7 +585,7 @@ wsrep::client_state::poll_enter_toi(
             // Successfully entered TOI, but the provider reported failure.
             // This may happen for example if certification fails.
             // Leave TOI before proceeding.
-            if (provider().leave_toi(id_, wsrep::mutable_buffer()))
+            if (provider().leave_toi(id_, poll_meta, wsrep::mutable_buffer()))
             {
                 wsrep::log_warning()
                     << "Failed to leave TOI after failure in "
@@ -689,10 +689,12 @@ int wsrep::client_state::leave_toi_local(const wsrep::mutable_buffer& err)
 {
     debug_log_state("leave_toi_local: enter");
     assert(toi_mode_ == m_local);
-    leave_toi_common();
 
+    auto ret = (provider().leave_toi(id_, toi_meta_, err) == provider::success ? 0 : 1);
+    leave_toi_common();
     debug_log_state("leave_toi_local: leave");
-    return (provider().leave_toi(id_, err) == provider::success ? 0 : 1);
+
+    return ret;
 }
 
 void wsrep::client_state::leave_toi_mode()
@@ -809,7 +811,7 @@ int wsrep::client_state::end_nbo_phase_one(const wsrep::mutable_buffer& err)
     assert(mode_ == m_nbo);
     assert(in_toi());
 
-    enum wsrep::provider::status status(provider().leave_toi(id_, err));
+    enum wsrep::provider::status status(provider().leave_toi(id_, toi_meta_, err));
     wsrep::unique_lock<wsrep::mutex> lock(mutex_);
     int ret;
     switch (status)
@@ -910,7 +912,7 @@ int wsrep::client_state::end_nbo_phase_two(const wsrep::mutable_buffer& err)
     assert(toi_mode_ == m_local);
     assert(in_toi());
     enum wsrep::provider::status status(
-        provider().leave_toi(id_, err));
+        provider().leave_toi(id_, toi_meta_, err));
     wsrep::unique_lock<wsrep::mutex> lock(mutex_);
     int ret;
     switch (status)

src/config_service_v1.cpp

@@ -151,6 +151,11 @@ int wsrep::config_service_v1_fetch(wsrep::provider& provider,
                                    wsrep::provider_options* options)
 {
     struct wsrep_st* wsrep = (struct wsrep_st*)provider.native();
+    if (wsrep == nullptr)
+    {
+        // Not a provider which was loaded via wsrep-API
+        return 0;
+    }
     if (config_service_v1_probe(wsrep->dlh))
     {
         wsrep::log_warning() << "Provider does not support config service v1";

src/id.cpp

@@ -50,13 +50,23 @@ wsrep::id::id(const std::string& str)
     }
 }
 
+std::string wsrep::id::to_string() const
+{
+  std::ostringstream os;
+  os << *this;
+  return os.str();
+}
+
 std::ostream& wsrep::operator<<(std::ostream& os, const wsrep::id& id)
 {
     const char* ptr(static_cast<const char*>(id.data()));
     size_t size(id.size());
-    if (static_cast<size_t>(std::count_if(ptr, ptr + size, ::isalnum)) == size)
+    if (static_cast<size_t>(
+            std::count_if(ptr, ptr + size,
+                          [](char c) { return (::isalnum(c) || c == '\0'); }))
+        == size)
     {
-        return (os << std::string(ptr, size));
+        return (os << std::string(ptr, ::strnlen(ptr, size)));
     }
     else
     {

src/provider.cpp

@@ -26,16 +26,16 @@
 #include <cassert>
 #include <memory>
 
-wsrep::provider* wsrep::provider::make_provider(
+std::unique_ptr<wsrep::provider> wsrep::provider::make_provider(
     wsrep::server_state& server_state,
     const std::string& provider_spec,
     const std::string& provider_options,
     const wsrep::provider::services& services)
 {
     try
     {
-        return new wsrep::wsrep_provider_v26(
-            server_state, provider_options, provider_spec, services);
+        return std::unique_ptr<wsrep::provider>(new wsrep::wsrep_provider_v26(
+            server_state, provider_options, provider_spec, services));
     }
     catch (const wsrep::runtime_error& e)
     {
@@ -120,7 +120,6 @@ std::string wsrep::provider::capability::str(int caps)
     WSREP_PRINT_CAPABILITY(streaming,            "STREAMING");
     WSREP_PRINT_CAPABILITY(snapshot,             "READ_VIEW");
     WSREP_PRINT_CAPABILITY(nbo,                  "NBO");
-
 #undef WSREP_PRINT_CAPABILITY
 
     if (caps)