Add support for memcached stats command

server/main_service.cc

@@ -494,7 +494,11 @@ void Service::DispatchMC(const MemcacheParser::Command& cmd, std::string_view va
     case MemcacheParser::GET:
       strcpy(cmd_name, "MGET");
       break;
+    case MemcacheParser::STATS:
+      server_family_.StatsMC(cmd.key, cntx);
+      return;
     default:
+
       mc_builder->SendClientError("bad command line format");
       return;
   }

server/memcache_parser.cc

@@ -92,7 +92,7 @@ auto MemcacheParser::Parse(string_view str, uint32_t* consumed, Command* cmd) ->
     return str.size() > 300 ? PARSE_ERROR : INPUT_PENDING;
   }
 
-  if (pos == 0 || str[pos - 1] != '\r') {
+  if (pos == 0) {
     return PARSE_ERROR;
   }
   *consumed = pos + 1;
@@ -107,8 +107,8 @@ auto MemcacheParser::Parse(string_view str, uint32_t* consumed, Command* cmd) ->
     ++cur;
 
   uint32_t s = cur;
-  for (; cur < pos; ++cur) {
-    if (str[cur] == ' ' || str[cur] == '\r') {
+  for (; cur <= pos; ++cur) {
+    if (absl::ascii_isspace(str[cur])) {
       if (cur != s) {
         tokens[num_tokens++] = str.substr(s, cur - s);
         if (num_tokens == ABSL_ARRAYSIZE(tokens)) {

server/reply_builder.h

@@ -27,7 +27,7 @@ class ReplyBuilderInterface {
   struct ResponseValue {
     std::string_view key;
     std::string value;
-    uint64_t mc_ver  = 0;  // 0 means we do not output it (i.e has not been requested).
+    uint64_t mc_ver = 0;  // 0 means we do not output it (i.e has not been requested).
     uint32_t mc_flag = 0;
   };
 
@@ -72,10 +72,10 @@ class SinkReplyBuilder : public ReplyBuilderInterface {
     io_write_bytes_ = 0;
   }
 
- protected:
   //! Sends a string as is without any formatting. raw should be encoded according to the protocol.
   void SendDirect(std::string_view str);
 
+ protected:
   void Send(const iovec* v, uint32_t len);
 
   std::string batch_;

server/server_family.cc

@@ -8,6 +8,7 @@
 #include <absl/random/random.h>  // for master_id_ generation.
 #include <absl/strings/match.h>
 #include <malloc.h>
+#include <sys/resource.h>
 
 #include <filesystem>
 
@@ -96,6 +97,46 @@ void ServerFamily::Shutdown() {
   });
 }
 
+void ServerFamily::StatsMC(std::string_view section, ConnectionContext* cntx) {
+  if (!section.empty()) {
+    return cntx->reply_builder()->SendError("");
+  }
+  string info;
+
+#define ADD_LINE(name, val) absl::StrAppend(&info, "STAT " #name " ", val, "\r\n")
+
+  time_t now = time(NULL);
+  size_t uptime = now - start_time_;
+  struct rusage ru;
+  getrusage(RUSAGE_SELF, &ru);
+
+  auto dbl_time = [](const timeval& tv) -> double {
+    return tv.tv_sec + double(tv.tv_usec) / 1000000.0;
+  };
+
+  double utime = dbl_time(ru.ru_utime);
+  double systime = dbl_time(ru.ru_stime);
+
+  Metrics m = GetMetrics();
+
+  ADD_LINE(pid, getpid());
+  ADD_LINE(uptime, uptime);
+  ADD_LINE(time, now);
+  ADD_LINE(version, "1.6.12");
+  ADD_LINE(libevent, "iouring");
+  ADD_LINE(pointer_size, sizeof(void*));
+  ADD_LINE(rusage_user, utime);
+  ADD_LINE(rusage_system, systime);
+  ADD_LINE(max_connections, -1);
+  ADD_LINE(curr_connections, m.conn_stats.num_conns);
+  ADD_LINE(total_connections, -1);
+  ADD_LINE(rejected_connections, -1);
+  absl::StrAppend(&info, "END\r\n");
+
+  MCReplyBuilder* builder = static_cast<MCReplyBuilder*>(cntx->reply_builder());
+  builder->SendDirect(info);
+}
+
 void ServerFamily::DbSize(CmdArgList args, ConnectionContext* cntx) {
   atomic_ulong num_keys{0};
 

server/server_family.h

@@ -48,6 +48,8 @@ class ServerFamily {
     return script_mgr_.get();
   }
 
+  void StatsMC(std::string_view section, ConnectionContext* cntx);
+
  private:
   uint32_t shard_count() const {
     return ess_.size();