adding quarkdb-health redis command, currently displays free space left

src/Commands.cc

@@ -97,6 +97,7 @@ struct cmdMapInit {
     redis_cmd_map["activate_stale_reads"] = {RedisCommand::ACTIVATE_STALE_READS, CommandType::RAFT};
 
     redis_cmd_map["quarkdb_info"] = {RedisCommand::QUARKDB_INFO, CommandType::QUARKDB};
+    redis_cmd_map["quarkdb_health"] = {RedisCommand::QUARKDB_HEALTH, CommandType::QUARKDB};
     redis_cmd_map["quarkdb_detach"] = {RedisCommand::QUARKDB_DETACH, CommandType::QUARKDB};
     redis_cmd_map["quarkdb_attach"] = {RedisCommand::QUARKDB_ATTACH, CommandType::QUARKDB};
     redis_cmd_map["quarkdb_start_resilvering"] = {RedisCommand::QUARKDB_START_RESILVERING, CommandType::QUARKDB};

src/Commands.hh

@@ -101,6 +101,7 @@ enum class RedisCommand {
   ACTIVATE_STALE_READS,
 
   QUARKDB_INFO,
+  QUARKDB_HEALTH,
   QUARKDB_DETACH,
   QUARKDB_ATTACH,
   QUARKDB_START_RESILVERING,

src/QuarkDBNode.cc

@@ -31,6 +31,7 @@
 #include "utils/TimeFormatting.hh"
 
 #include <sys/stat.h>
+#include <sys/statvfs.h>
 
 using namespace quarkdb;
 
@@ -98,6 +99,9 @@ LinkStatus QuarkDBNode::dispatch(Connection *conn, RedisRequest &req) {
     case RedisCommand::QUARKDB_INFO: {
       return conn->statusVector(this->info().toVector());
     }
+    case RedisCommand::QUARKDB_HEALTH: {
+      return conn->statusVector(this->health().toVector());
+    }
     default: {
       return shard->dispatch(conn, req);
     }
@@ -119,3 +123,22 @@ std::vector<std::string> QuarkDBInfo::toVector() const {
   ret.emplace_back(SSTR("UPTIME " << uptime << " (" << formatTime(std::chrono::seconds(uptime)) << ")"));
   return ret;
 }
+
+QuarkDBHealth QuarkDBNode::health() {
+  struct statvfs buf;
+
+  // add some error checking pls
+  statvfs(configuration.getDatabase().c_str(), &buf);
+  double freeSpace = ((buf.f_bfree * 1.) / buf.f_blocks) * 100.;
+
+  return {freeSpace
+  };
+}
+
+std::vector<std::string> QuarkDBHealth::toVector() const {
+  std::vector<std::string> ret;
+  ret.emplace_back(SSTR("FREE-SPACE " << freeSpace << "%"));
+  ret.emplace_back(SSTR("RAFT-STABILITY placeholder"));
+  ret.emplace_back(SSTR("NODE-STATUS placeholder"));
+  return ret;
+}

src/QuarkDBNode.hh

@@ -44,6 +44,12 @@ struct QuarkDBInfo {
   std::vector<std::string> toVector() const;
 };
 
+struct QuarkDBHealth {
+  double freeSpace;
+
+  std::vector<std::string> toVector() const;
+};
+
 class Shard; class ShardDirectory; class MultiOp;
 
 class QuarkDBNode : public Dispatcher {
@@ -70,6 +76,8 @@ private:
 
   QuarkDBInfo info();
 
+  QuarkDBHealth health();
+
   std::atomic<bool> shutdown {false};
   const RaftTimeouts timeouts;
 

tools/quarkdb-create.cc

@@ -74,7 +74,7 @@ bool verify_options_sane(option::Parser &parse, std::vector<option::Option> &opt
 std::vector<option::Option> parse_args(int argc, char** argv) {
   const option::Descriptor usage[] = {
     {Opt::UNKNOWN, 0, "", "", option::Arg::None, "Tool to initialize new quarkdb nodes.\n"
-                                                 "USAGE: quarkdb-journal [options]\n\n" "Options:" },
+                                                 "USAGE: quarkdb-create [options]\n\n" "Options:" },
     {Opt::HELP, 0, "", "help", option::Arg::None, " --help \tPrint usage and exit." },
     {Opt::PATH, 0, "", "path", Opt::nonempty, " --path \tthe directory where the journal lives in."},
     {Opt::CLUSTERID, 0, "", "clusterID", Opt::nonempty, " --clusterID \tspecify the identifier for the new cluster - should be globally unique."},