Merge pull request #6 from panlei-coder/fix_learner_bug

fix: fixed a bug on supporting learners and added an interface for acquiring Learners
arana-db · Jun 13, 2024 · 3a9ef43 · 3a9ef43
2 parents d397128 + 7bd918f
commit 3a9ef43
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Showing 4 changed files with 25 additions and 5 deletions.
diff --git a/src/braft/node.cpp b/src/braft/node.cpp
@@ -894,15 +894,23 @@ void NodeImpl::unsafe_register_conf_change(const Configuration& old_conf,
     return _conf_ctx.start(old_conf, new_conf, done);
 }
 
-butil::Status NodeImpl::list_peers(std::vector<PeerId>* peers) {
+butil::Status NodeImpl::list_members(std::vector<PeerId>* peers, const ConfigurationEntry& conf) {
     BAIDU_SCOPED_LOCK(_mutex);
     if (_state != STATE_LEADER) {
         return butil::Status(EPERM, "Not leader");
     }
-    _conf.conf.list_peers(peers);
+    conf.conf.list_peers(peers);
     return butil::Status::OK();
 }
 
+butil::Status NodeImpl::list_peers(std::vector<PeerId>* peers) {
+   return list_members(peers, _conf); 
+}
+
+butil::Status NodeImpl::list_learners(std::vector<PeerId>* learners) {
+    return list_members(learners, _learner_conf);
+}
+
 void NodeImpl::add_peer(const PeerId& peer, Closure* done) {
     BAIDU_SCOPED_LOCK(_mutex);
     Configuration new_conf = _conf.conf;

diff --git a/src/braft/node.h b/src/braft/node.h
@@ -133,8 +133,10 @@ friend class VoteBallotCtx;
     //              Otherwise we will specifit the error and call it.
     //
     void apply(const Task& task);
-
+
+    butil::Status list_members(std::vector<PeerId>* peers, const ConfigurationEntry& conf);
     butil::Status list_peers(std::vector<PeerId>* peers);
+    butil::Status list_learners(std::vector<PeerId>* learners);
 
     // @Node configuration change
     void add_peer(const PeerId& peer, Closure* done);

diff --git a/src/braft/raft.cpp b/src/braft/raft.cpp
@@ -19,6 +19,7 @@
 #include <unistd.h>
 #include <butil/string_printf.h>
 #include <butil/class_name.h>
+#include <vector>
 #include "braft/raft.h"
 #include "braft/node.h"
 #include "braft/storage.h"
@@ -186,6 +187,10 @@ butil::Status Node::list_peers(std::vector<PeerId>* peers) {
     return _impl->list_peers(peers);
 }
 
+butil::Status Node::list_learners(std::vector<PeerId>* learners) {
+    return _impl->list_learners(learners);
+}
+
 void Node::add_peer(const PeerId& peer, Closure* done) {
     _impl->add_peer(peer, done);
 }

diff --git a/src/braft/raft.h b/src/braft/raft.h
@@ -282,10 +282,10 @@ enum State {
 };
 
 inline const char* state2str(State state) {
-    const char* str[] = {"LEADER", "TRANSFERRING", "CANDIDATE", "FOLLOWER", 
+    const char* str[] = {"LEARNER", "LEADER", "TRANSFERRING", "CANDIDATE", "FOLLOWER", 
                          "ERROR", "UNINITIALIZED", "SHUTTING", "SHUTDOWN", };
     if (state < STATE_END) {
-        return str[(int)state - 1];
+        return str[(int)state];
     } else {
         return "UNKNOWN";
     }
@@ -689,6 +689,11 @@ class Node {
     // because add_peer/remove_peer immediately modify configuration in memory
     butil::Status list_peers(std::vector<PeerId>* peers);
 
+    // list learner peers of this raft group, only leader retruns ok
+    // [NOTE] when list_learner_peers concurrency with add_learner/remove_learner, maybe return learner_peers is staled.
+    // because add_learner/remove_learner immediately modify configuration in memory
+    butil::Status list_learners(std::vector<PeerId>* learners);
+
     // Add a new peer to the raft group. done->Run() would be invoked after this
     // operation finishes, describing the detailed result.
     void add_peer(const PeerId& peer, Closure* done);