Implements "KeepAlive" feature, and enhance "lock" with a lease.

Signed-off-by: Tao He <sighingnow@gmail.com>

README.md

@@ -294,6 +294,25 @@ prefix will be deleted. All deleted keys will be placed in ```response.values()`
 However, if recursive parameter is false, functionality will be the same as just deleting a key.
 The key supplied will NOT be treated as a prefix and will be treated as a normal key name.
 
+### Lock
+
+Etcd lock has been supported as follows:
+
+```c++
+  etcd::Client etcd("http://127.0.0.1:4001");
+  etcd.lock("/test/lock");
+```
+
+It will create a lease and a keep-alive job behind the screen, the lease will be revoked until
+the lock is unlocked.
+
+Users can also feed their own lease directory for lock:
+
+```c++
+  etcd::Client etcd("http://127.0.0.1:4001");
+  etcd.lock("/test/lock", lease_id);
+```
+
 ### Watching for changes
 
 Watching for a change is possible with the ```watch()``` operation of the client. The watch method
@@ -343,22 +362,7 @@ fact it just sends the asynchron request, sets up a callback for the response an
 callback is executed by some thread from the pplx library's thread pool and the callback (in this
 case a small lambda function actually) will call ```watch_for_changes``` again from there.
 
-
+#### Watcher Class
-### Requesting for lease
-
-Users can request for lease which is governed by a time-to-live(TTL) value given by the user.
-Moreover, user can attached the lease to a key(s) by indicating the lease id in ```add()```,
-```set()```, ```modify()``` and ```modify_if()```. Also the ttl will that was granted by etcd
-server will be indicated in ```ttl()```.
-
-```c++
-  etcd::Client etcd("http://127.0.0.1:4001");
-  etcd::Response resp = etcd.leasegrant(60).get();
-  etcd.set("/test/key2", "bar", resp.value().lease());
-  std::cout <<"ttl" << resp.value().ttl();
-```
-
-### Watcher Class
 
 Users can watch a key indefinitely or until user cancels the watch. This can be done by
 instantiating a Watcher class. The supplied callback function in Watcher class will be
@@ -375,11 +379,46 @@ either by user implicitly calling ```Cancel()``` or when watcher class is destro
 }
 ```
 
+### Requesting for lease
+
+Users can request for lease which is governed by a time-to-live(TTL) value given by the user.
+Moreover, user can attached the lease to a key(s) by indicating the lease id in ```add()```,
+```set()```, ```modify()``` and ```modify_if()```. Also the ttl will that was granted by etcd
+server will be indicated in ```ttl()```.
+
+```c++
+  etcd::Client etcd("http://127.0.0.1:4001");
+  etcd::Response resp = etcd.leasegrant(60).get();
+  etcd.set("/test/key2", "bar", resp.value().lease());
+  std::cout << "ttl" << resp.value().ttl();
+```
+
+The lease can be revoked by
+
+```c++
+  etcd.leaserevoke(resp.value().lease());
+```
+
+The remaining time-to-live of a lease can be inspected by
+
+```c++
+  etcd::Response resp2 = etcd.leasetimetolive(resp.value().lease()).get();
+  std::cout << "ttl" << resp.value().ttl();
+```
+
+#### Keep alive
+
+Keep alive for leases is implemented using a seperate class `KeepAlive`, which can be used as:
+
+```c++
+  etcd::KeepAlive keepalive(etcd, lease_id, ttl);
+```
+
+It will perform a periodly keep-alive action before it is cancelled explicitly, or destructed implicitly.
+
 ### TODO
 
 1. Cancellation of asynchronous calls(except for watch)
-2. LeaseKeepAlive
-3. Authentication
 
 ## License
 

etcd/Client.hpp

@@ -3,6 +3,7 @@
 
 #include "etcd/Response.hpp"
 
+#include <map>
 #include <string>
 
 #include <grpc++/grpc++.h>
@@ -21,6 +22,7 @@ namespace etcdv3 {
 
 namespace etcd
 {
+  class KeepAlive;
   class Watcher;
 
   /**
@@ -215,16 +217,36 @@ namespace etcd
     pplx::task<Response> leasegrant(int ttl);
 
     /**
-     * Gains a lock at a key.
+     * Revoke a lease.
+     * @param lease_id is the id the lease
+     */
+    pplx::task<Response> leaserevoke(int64_t lease_id);
+
+    /**
+     * Get time-to-live of a lease.
+     * @param lease_id is the id the lease
+     */
+    pplx::task<Response> leasetimetolive(int64_t lease_id);
+
+    /**
+     * Gains a lock at a key, using a default created lease, using the default lease (60 seconds), with
+     * keeping alive has already been taken care of by the library.
      * @param key is the key to be used to request the lock.
      */
     pplx::task<Response> lock(std::string const &key);
 
+    /**
+     * Gains a lock at a key, using a user-provided lease, the lifetime of the lease won't be taken care
+     * of by the library.
+     * @param key is the key to be used to request the lock.
+     */
+    pplx::task<Response> lock(std::string const &key, int64_t lease_id);
+
     /**
      * Releases a lock at a key.
      * @param key is the lock key to release.
      */
-    pplx::task<Response> unlock(std::string const &key);
+    pplx::task<Response> unlock(std::string const &lock_key);
 
      /**
       * Execute a etcd transaction.
@@ -240,6 +262,10 @@ namespace etcd
     std::unique_ptr<Lease::Stub> leaseServiceStub;
     std::unique_ptr<Lock::Stub> lockServiceStub;
 
+    std::map<std::string, int64_t> leases_for_locks;
+    std::map<int64_t, std::shared_ptr<KeepAlive>> keep_alive_for_locks;
+
+    friend class KeepAlive;
     friend class Watcher;
 };
 

etcd/KeepAlive.hpp

@@ -0,0 +1,63 @@
+#ifndef __ETCD_KEEPALIVE_HPP__
+#define __ETCD_KEEPALIVE_HPP__
+
+#include <string>
+
+#include "etcd/Client.hpp"
+#include "etcd/Response.hpp"
+
+#include <boost/asio/io_context.hpp>
+#include <boost/asio/steady_timer.hpp>
+
+#include <grpc++/grpc++.h>
+#include "proto/rpc.grpc.pb.h"
+
+namespace etcdv3 {
+  class AsyncLeaseKeepAliveAction;
+}
+
+using etcdserverpb::KV;
+using etcdserverpb::Lease;
+using grpc::Channel;
+
+namespace etcd
+{
+  /**
+   * If ID is set to 0, etcd will choose an ID.
+   */
+  class KeepAlive
+  {
+  public:
+    KeepAlive(Client const &client, int ttl, int64_t lease_id=0);
+    KeepAlive(std::string const & address, int ttl, int64_t lease_id=0);
+    KeepAlive(std::string const & address,
+              std::string const & username, std::string const & password,
+              int ttl, int64_t lease_id=0);
+
+    KeepAlive(KeepAlive const &) = delete;
+    KeepAlive(KeepAlive &&) = delete;
+
+    /**
+     * Stop the keep alive action.
+     */
+    void Cancel();
+
+    ~KeepAlive();
+
+  protected:
+    void refresh();
+
+    pplx::task<void> currentTask;
+    std::unique_ptr<Lease::Stub> leaseServiceStub;
+    std::unique_ptr<etcdv3::AsyncLeaseKeepAliveAction> call;
+
+  private:
+    int ttl;
+    int64_t lease_id;
+    bool continue_next;
+    boost::asio::io_context context;
+    std::unique_ptr<boost::asio::steady_timer> keepalive_timer_;
+  };
+}
+
+#endif

etcd/SyncClient.hpp

@@ -58,6 +58,8 @@ namespace etcd
     Response mkdir(std::string const & key, int ttl = 0);
     Response rmdir(std::string const & key, bool recursive = false);
     Response leasegrant(int ttl);
+    Response leaserevoke(int64_t lease_id);
+    Response leasetimetolive(int64_t lease_id);
 
     /**
      * Watches for changes of a key or a subtree. Please note that if you watch e.g. "/testdir" and

etcd/Watcher.hpp

@@ -39,6 +39,9 @@ namespace etcd
             std::string const & key, int fromIndex,
             std::function<void(Response)> callback, bool recursive=false);
 
+    Watcher(Watcher const &) = delete;
+    Watcher(Watcher &&) = delete;
+
     /**
      * Wait util the task has been stopped, actively or passively, e.g., the watcher
      * get cancelled or the server closes the connection.

etcd/v3/AsyncLeaseAction.hpp

@@ -0,0 +1,80 @@
+#ifndef __ASYNC_LEASEACTION_HPP__
+#define __ASYNC_LEASEACTION_HPP__
+
+#include <mutex>
+
+#include <grpc++/grpc++.h>
+#include "proto/rpc.grpc.pb.h"
+#include "etcd/v3/Action.hpp"
+#include "etcd/v3/AsyncLeaseResponse.hpp"
+
+using grpc::ClientAsyncResponseReader;
+using grpc::ClientAsyncReaderWriter;
+using etcdserverpb::LeaseGrantResponse;
+using etcdserverpb::LeaseRevokeResponse;
+using etcdserverpb::LeaseCheckpoint;
+using etcdserverpb::LeaseCheckpointResponse;
+using etcdserverpb::LeaseKeepAliveRequest;
+using etcdserverpb::LeaseKeepAliveResponse;
+using etcdserverpb::LeaseTimeToLiveResponse;
+using etcdserverpb::LeaseStatus;
+using etcdserverpb::LeaseLeasesResponse;
+
+namespace etcdv3
+{
+  class AsyncLeaseGrantAction : public etcdv3::Action {
+    public:
+      AsyncLeaseGrantAction(etcdv3::ActionParameters param);
+      AsyncLeaseGrantResponse ParseResponse();
+    private:
+      LeaseGrantResponse reply;
+      std::unique_ptr<ClientAsyncResponseReader<LeaseGrantResponse>> response_reader;
+  };
+
+  class AsyncLeaseRevokeAction: public etcdv3::Action {
+    public:
+      AsyncLeaseRevokeAction(etcdv3::ActionParameters param);
+      AsyncLeaseRevokeResponse ParseResponse();
+    private:
+      LeaseRevokeResponse reply;
+      std::unique_ptr<ClientAsyncResponseReader<LeaseRevokeResponse>> response_reader;
+  };
+
+  class AsyncLeaseKeepAliveAction: public etcdv3::Action {
+    public:
+      AsyncLeaseKeepAliveAction(etcdv3::ActionParameters param);
+      AsyncLeaseKeepAliveResponse ParseResponse();
+
+      AsyncLeaseKeepAliveResponse Refresh();
+      void CancelKeepAlive();
+      bool Cancelled() const;
+
+    private:
+      LeaseKeepAliveResponse reply;
+      std::unique_ptr<ClientAsyncReaderWriter<LeaseKeepAliveRequest, LeaseKeepAliveResponse>> stream;
+
+      LeaseKeepAliveRequest req;
+      bool isCancelled;
+      std::mutex protect_is_cancelled;
+  };
+
+  class AsyncLeaseTimeToLiveAction: public etcdv3::Action {
+    public:
+      AsyncLeaseTimeToLiveAction(etcdv3::ActionParameters param);
+      AsyncLeaseTimeToLiveResponse ParseResponse();
+    private:
+      LeaseTimeToLiveResponse reply;
+      std::unique_ptr<ClientAsyncResponseReader<LeaseTimeToLiveResponse>> response_reader;
+  };
+
+  class AsyncLeaseLeasesAction: public etcdv3::Action {
+    public:
+      AsyncLeaseLeasesAction(etcdv3::ActionParameters param);
+      AsyncLeaseLeasesResponse ParseResponse();
+    private:
+      LeaseLeasesResponse reply;
+      std::unique_ptr<ClientAsyncResponseReader<LeaseLeasesResponse>> response_reader;
+  };
+}
+
+#endif

etcd/v3/AsyncLeaseGrantAction.hpp

@@ -1,25 +0,0 @@
-#ifndef __ASYNC_LEASEGRANTACTION_HPP__
-#define __ASYNC_LEASEGRANTACTION_HPP__
-
-#include <grpc++/grpc++.h>
-#include "proto/rpc.grpc.pb.h"
-#include "etcd/v3/Action.hpp"
-#include "etcd/v3/AsyncLeaseGrantResponse.hpp"
-
-using grpc::ClientAsyncResponseReader;
-using etcdserverpb::LeaseGrantResponse;
-
-namespace etcdv3
-{
-  class AsyncLeaseGrantAction : public etcdv3::Action
-  {
-    public:
-      AsyncLeaseGrantAction(etcdv3::ActionParameters param);
-      AsyncLeaseGrantResponse ParseResponse();
-    private:
-      LeaseGrantResponse reply;
-      std::unique_ptr<ClientAsyncResponseReader<LeaseGrantResponse>> response_reader;
-  };
-}
-
-#endif

etcd/v3/AsyncLeaseGrantResponse.hpp

@@ -1,21 +0,0 @@
-#ifndef __ASYNC_LEASEGRANTRESPONSE_HPP__
-#define __ASYNC_LEASEGRANTRESPONSE_HPP__
-
-#include <grpc++/grpc++.h>
-#include "proto/rpc.grpc.pb.h"
-#include "etcd/v3/V3Response.hpp"
-
-
-using etcdserverpb::LeaseGrantResponse;
-
-namespace etcdv3
-{
-  class AsyncLeaseGrantResponse : public etcdv3::V3Response
-  {
-    public:
-      AsyncLeaseGrantResponse(){};
-      void ParseResponse(LeaseGrantResponse& resp);
-  };
-}
-
-#endif

etcd/v3/AsyncLeaseResponse.hpp

@@ -0,0 +1,55 @@
+#ifndef __ASYNC_LEASERESPONSE_HPP__
+#define __ASYNC_LEASERESPONSE_HPP__
+
+#include <grpc++/grpc++.h>
+#include "proto/rpc.grpc.pb.h"
+#include "etcd/v3/V3Response.hpp"
+
+using etcdserverpb::LeaseGrantResponse;
+using etcdserverpb::LeaseRevokeResponse;
+using etcdserverpb::LeaseCheckpoint;
+using etcdserverpb::LeaseCheckpointResponse;
+using etcdserverpb::LeaseKeepAliveResponse;
+using etcdserverpb::LeaseTimeToLiveResponse;
+using etcdserverpb::LeaseStatus;
+using etcdserverpb::LeaseLeasesResponse;
+
+namespace etcdv3
+{
+  class AsyncLeaseGrantResponse : public etcdv3::V3Response
+  {
+    public:
+      AsyncLeaseGrantResponse(){};
+      void ParseResponse(LeaseGrantResponse& resp);
+  };
+
+  class AsyncLeaseRevokeResponse : public etcdv3::V3Response
+  {
+    public:
+      AsyncLeaseRevokeResponse(){};
+      void ParseResponse(LeaseRevokeResponse& resp);
+  };
+
+  class AsyncLeaseKeepAliveResponse : public etcdv3::V3Response
+  {
+    public:
+      AsyncLeaseKeepAliveResponse(){};
+      void ParseResponse(LeaseKeepAliveResponse& resp);
+  };
+
+  class AsyncLeaseTimeToLiveResponse : public etcdv3::V3Response
+  {
+    public:
+      AsyncLeaseTimeToLiveResponse(){};
+      void ParseResponse(LeaseTimeToLiveResponse& resp);
+  };
+
+  class AsyncLeaseLeasesResponse : public etcdv3::V3Response
+  {
+    public:
+      AsyncLeaseLeasesResponse(){};
+      void ParseResponse(LeaseLeasesResponse& resp);
+  };
+}
+
+#endif

etcd/v3/Transaction.hpp

@@ -24,15 +24,12 @@ public:
 	void setup_delete_sequence(std::string const &key, std::string const &range_end, bool recursive);
 	void setup_delete_failure_operation(std::string const &key, std::string const &range_end, bool recursive);
 	void setup_compare_and_delete_operation(std::string const& key);
-	void setup_lease_grant_operation(int ttl);
 
 	// update without `get` and no `prev_kv` returned
 	void setup_put(std::string const &key, std::string const &value);
 	void setup_delete(std::string const &key);
 
 	etcdserverpb::TxnRequest txn_request;
-	etcdserverpb::LeaseGrantRequest leasegrant_request;
-
 private:
 	std::string key;
 };

src/Client.cpp

@@ -13,6 +13,7 @@
 #include <limits>
 #include <memory>
 #include "etcd/Client.hpp"
+#include "etcd/KeepAlive.hpp"
 #include "etcd/v3/action_constants.hpp"
 #include "etcd/v3/Action.hpp"
 #include "etcd/v3/AsyncTxnResponse.hpp"
@@ -30,7 +31,7 @@
 #include "etcd/v3/AsyncGetAction.hpp"
 #include "etcd/v3/AsyncDeleteAction.hpp"
 #include "etcd/v3/AsyncWatchAction.hpp"
-#include "etcd/v3/AsyncLeaseGrantAction.hpp"
+#include "etcd/v3/AsyncLeaseAction.hpp"
 #include "etcd/v3/AsyncLockAction.hpp"
 #include "etcd/v3/AsyncTxnAction.hpp"
 
@@ -354,7 +355,7 @@ pplx::task<etcd::Response> etcd::Client::modify_if(std::string const & key, std:
   params.key.assign(key);
   params.value.assign(value);
   params.old_revision = old_index;
-  params.kv_stub = kvServiceStub .get();
+  params.kv_stub = kvServiceStub.get();
   if(ttl > 0)
   {
     auto res = leasegrant(ttl).get();
@@ -491,19 +492,85 @@ pplx::task<etcd::Response> etcd::Client::leasegrant(int ttl)
   return Response::create(call);
 }
 
+pplx::task<etcd::Response> etcd::Client::leaserevoke(int64_t lease_id)
+{
+  etcdv3::ActionParameters params;
+  params.auth_token.assign(this->auth_token);
+  params.lease_id = lease_id;
+  params.lease_stub = leaseServiceStub.get();
+  std::shared_ptr<etcdv3::AsyncLeaseRevokeAction> call(new etcdv3::AsyncLeaseRevokeAction(params));
+  return Response::create(call);
+}
+
+pplx::task<etcd::Response> etcd::Client::leasetimetolive(int64_t lease_id)
+{
+  etcdv3::ActionParameters params;
+  params.auth_token.assign(this->auth_token);
+  params.lease_id = lease_id;
+  params.lease_stub = leaseServiceStub.get();
+  std::shared_ptr<etcdv3::AsyncLeaseTimeToLiveAction> call(new etcdv3::AsyncLeaseTimeToLiveAction(params));
+  return Response::create(call);
+}
+
 pplx::task<etcd::Response> etcd::Client::lock(std::string const &key) {
   etcdv3::ActionParameters params;
   params.auth_token.assign(this->auth_token);
+
+  static const int DEFAULT_LEASE_TTL_FOR_LOCK = 10;
+
+  // routines in lock usually will be fast, less than 10 seconds.
+  //
+  // (base on our experiences in vineyard and GraphScope).
+  auto resp = this->leasegrant(DEFAULT_LEASE_TTL_FOR_LOCK).get();
+  int64_t lease_id = resp.value().lease();
+  this->keep_alive_for_locks[lease_id].reset(new KeepAlive(*this, DEFAULT_LEASE_TTL_FOR_LOCK, lease_id));
   params.key = key;
+  params.lease_id = lease_id;
+  params.lock_stub = lockServiceStub.get();
+  std::shared_ptr<etcdv3::AsyncLockAction> call(new etcdv3::AsyncLockAction(params));
+  return Response::create(call).then(
+    [this, lease_id](pplx::task<etcd::Response> const &resp_task) -> etcd::Response {
+      auto const& resp = resp_task.get();
+      if (resp.is_ok()) {
+        this->leases_for_locks[resp.lock_key()] = lease_id;
+      } else {
+        this->keep_alive_for_locks.erase(lease_id);
+      }
+      return resp;
+    }
+  );
+}
+
+pplx::task<etcd::Response> etcd::Client::lock(std::string const &key,
+                                              int64_t lease_id) {
+  etcdv3::ActionParameters params;
+  params.auth_token.assign(this->auth_token);
+  params.key = key;
+  params.lease_id = lease_id;
   params.lock_stub = lockServiceStub.get();
   std::shared_ptr<etcdv3::AsyncLockAction> call(new etcdv3::AsyncLockAction(params));
   return Response::create(call);
 }
 
-pplx::task<etcd::Response> etcd::Client::unlock(std::string const &key) {
+pplx::task<etcd::Response> etcd::Client::unlock(std::string const &lock_key) {
+  std::cout << "begin unlock" << std::endl;
+  // cancel the KeepAlive first, it exists
+  auto p_leases = this->leases_for_locks.find(lock_key);
+  if (p_leases != this->leases_for_locks.end()) {
+    std::cout << "Unlock for " << lock_key << " and revoke lease " << std::hex << p_leases->second << std::dec << std::endl;
+    auto p_keeps_alive = this->keep_alive_for_locks.find(p_leases->second);
+    if (p_keeps_alive != this->keep_alive_for_locks.end()) {
+      this->keep_alive_for_locks.erase(p_keeps_alive);
+    }
+    this->leases_for_locks.erase(p_leases);
+  } else {
+    std::cout << "Unable to find lease_id for " << lock_key;
+  }
+
+  // issue a "unlock" request
   etcdv3::ActionParameters params;
   params.auth_token.assign(this->auth_token);
-  params.key = key;
+  params.key = lock_key;
   params.lock_stub = lockServiceStub.get();
   std::shared_ptr<etcdv3::AsyncUnlockAction> call(new etcdv3::AsyncUnlockAction(params));
   return Response::create(call);

src/KeepAlive.cpp

@@ -0,0 +1,78 @@
+#include "etcd/KeepAlive.hpp"
+#include "etcd/v3/AsyncLeaseAction.hpp"
+
+etcd::KeepAlive::KeepAlive(Client const &client, int ttl, int64_t lease_id):
+    ttl(ttl), lease_id(lease_id), continue_next(true) {
+  leaseServiceStub= Lease::NewStub(client.channel);
+
+  etcdv3::ActionParameters params;
+  params.auth_token.assign(client.auth_token);
+  params.lease_id = lease_id;
+  params.lease_stub = leaseServiceStub.get();
+
+  call.reset(new etcdv3::AsyncLeaseKeepAliveAction(params));
+  currentTask = pplx::task<void>([this]() {
+    // start refresh
+    this->refresh();
+    context.run();
+    context.stop();  // clean up
+  });
+}
+
+etcd::KeepAlive::KeepAlive(std::string const & address, int ttl, int64_t lease_id):
+    KeepAlive(Client(address), ttl, lease_id) {
+}
+
+etcd::KeepAlive::KeepAlive(std::string const & address,
+                           std::string const & username, std::string const & password,
+                           int ttl, int64_t lease_id):
+    KeepAlive(Client(address, username, password), ttl, lease_id) {
+}
+
+etcd::KeepAlive::~KeepAlive()
+{
+  this->Cancel();
+}
+
+void etcd::KeepAlive::Cancel()
+{
+#ifndef NDEBUG
+  {
+    std::ios::fmtflags os_flags (std::cout.flags());
+    std::cout << "Cancel keepalive for " << std::hex << lease_id << std::endl;
+    std::cout.flags(os_flags);
+  }
+#endif
+  call->CancelKeepAlive();
+  if (keepalive_timer_) {
+    keepalive_timer_->cancel();
+  }
+  currentTask.wait();
+}
+
+void etcd::KeepAlive::refresh()
+{
+  // minimal resolution: 1 second
+  int keepalive_ttl = std::max(ttl - 1, 1);
+#ifndef NDEBUG
+  {
+    std::ios::fmtflags os_flags (std::cout.flags());
+    std::cout << "Trigger the next keepalive round with ttl " << keepalive_ttl
+              << " for " << std::hex << lease_id << std::endl;
+    std::cout.flags(os_flags);
+  }
+#endif
+  keepalive_timer_.reset(new boost::asio::steady_timer(
+      context, boost::asio::chrono::seconds(keepalive_ttl)));
+  keepalive_timer_->async_wait([this](const boost::system::error_code& error) {
+    if (error) {
+#ifndef NDEBUG
+      std::cerr << "keepalive timer error: " << error << ", " << error.message() << std::endl;
+#endif
+    } else {
+      this->call->Refresh();
+      // trigger the next round;
+      this->refresh();
+    }
+  });
+}

src/SyncClient.cpp

@@ -109,6 +109,16 @@ etcd::Response etcd::SyncClient::leasegrant(int ttl)
   CHECK_EXCEPTIONS(client.leasegrant(ttl).get());
 }
 
+etcd::Response etcd::SyncClient::leaserevoke(int64_t lease_id)
+{
+  CHECK_EXCEPTIONS(client.leaserevoke(lease_id).get());
+}
+
+etcd::Response etcd::SyncClient::leasetimetolive(int64_t lease_id)
+{
+  CHECK_EXCEPTIONS(client.leasetimetolive(lease_id).get());
+}
+
 etcd::Response etcd::SyncClient::watch(std::string const & key, bool recursive)
 {
   CHECK_EXCEPTIONS(client.watch(key, recursive).get());

src/v3/AsyncLeaseAction.cpp

@@ -0,0 +1,172 @@
+#include "etcd/v3/AsyncLeaseAction.hpp"
+#include "etcd/v3/action_constants.hpp"
+#include "etcd/v3/Transaction.hpp"
+
+using etcdserverpb::LeaseGrantRequest;
+using etcdserverpb::LeaseRevokeRequest;
+using etcdserverpb::LeaseCheckpointRequest;
+using etcdserverpb::LeaseKeepAliveRequest;
+using etcdserverpb::LeaseTimeToLiveRequest;
+using etcdserverpb::LeaseLeasesRequest;
+
+etcdv3::AsyncLeaseGrantAction::AsyncLeaseGrantAction(etcdv3::ActionParameters param)
+  : etcdv3::Action(param)
+{
+	LeaseGrantRequest leasegrant_request;
+  leasegrant_request.set_ttl(parameters.ttl);
+  // If ID is set to 0, etcd will choose an ID.
+  leasegrant_request.set_id(parameters.lease_id);
+
+  response_reader = parameters.lease_stub->AsyncLeaseGrant(&context, leasegrant_request, &cq_);
+  response_reader->Finish(&reply, &status, (void*)this);
+}
+
+etcdv3::AsyncLeaseGrantResponse etcdv3::AsyncLeaseGrantAction::ParseResponse()
+{
+  AsyncLeaseGrantResponse lease_resp;
+  if (!status.ok()) {
+    lease_resp.set_error_code(status.error_code());
+    lease_resp.set_error_message(status.error_message());
+  } else { 
+    lease_resp.ParseResponse(reply);
+  }
+  return lease_resp;
+}
+
+etcdv3::AsyncLeaseRevokeAction::AsyncLeaseRevokeAction(etcdv3::ActionParameters param)
+  : etcdv3::Action(param)
+{
+	LeaseRevokeRequest leaserevoke_request;
+  leaserevoke_request.set_id(parameters.lease_id);
+
+  response_reader = parameters.lease_stub->AsyncLeaseRevoke(&context, leaserevoke_request, &cq_);
+  response_reader->Finish(&reply, &status, (void*)this);
+}
+
+etcdv3::AsyncLeaseRevokeResponse etcdv3::AsyncLeaseRevokeAction::ParseResponse()
+{
+  AsyncLeaseRevokeResponse lease_resp;
+  if (!status.ok()) {
+    lease_resp.set_error_code(status.error_code());
+    lease_resp.set_error_message(status.error_message());
+  } else { 
+    lease_resp.ParseResponse(reply);
+  }
+  return lease_resp;
+}
+
+etcdv3::AsyncLeaseKeepAliveAction::AsyncLeaseKeepAliveAction(etcdv3::ActionParameters param)
+  : etcdv3::Action(param)
+{
+  isCancelled = false;
+  stream = parameters.lease_stub->AsyncLeaseKeepAlive(&context, &cq_, (void*)"keepalive create");
+
+  void *got_tag = nullptr;
+  bool ok = false;
+  if (cq_.Next(&got_tag, &ok) && ok && got_tag == (void *)"keepalive create") {
+    // ok
+  } else {
+    throw std::runtime_error("Failed to create a lease keep-alive connection");
+  }
+}
+
+etcdv3::AsyncLeaseKeepAliveResponse etcdv3::AsyncLeaseKeepAliveAction::ParseResponse()
+{
+  AsyncLeaseKeepAliveResponse lease_resp;
+  if (!status.ok()) {
+    lease_resp.set_error_code(status.error_code());
+    lease_resp.set_error_message(status.error_message());
+  } else { 
+    lease_resp.ParseResponse(reply);
+  }
+  return lease_resp;
+}
+
+etcdv3::AsyncLeaseKeepAliveResponse etcdv3::AsyncLeaseKeepAliveAction::Refresh()
+{
+  std::lock_guard<std::mutex> scope_lock(this->protect_is_cancelled);
+
+  if (isCancelled) {
+    return ParseResponse();
+  }
+
+  LeaseKeepAliveRequest leasekeepalive_request;
+  leasekeepalive_request.set_id(parameters.lease_id);
+
+  void *got_tag = nullptr;
+  bool ok = false;
+
+  stream->Write(leasekeepalive_request, (void *)"keepalive write");
+  // wait write finish
+  if (cq_.Next(&got_tag, &ok) && ok && got_tag == (void *)"keepalive write") {
+    stream->Read(&reply, (void*)"keepalive read");
+    // wait read finish
+    if (cq_.Next(&got_tag, &ok) && ok && got_tag == (void *)"keepalive read") {
+      return ParseResponse();
+    }
+  }
+  throw std::runtime_error("Failed to create a lease keep-alive connection");
+}
+
+void etcdv3::AsyncLeaseKeepAliveAction::CancelKeepAlive()
+{
+  std::lock_guard<std::mutex> scope_lock(this->protect_is_cancelled);
+  if(isCancelled == false)
+  {
+    isCancelled = true;
+    stream->WritesDone((void*)"keepalive done");
+    grpc::Status status;
+    stream->Finish(&status, (void *)this);
+    cq_.Shutdown();
+  }
+}
+
+bool etcdv3::AsyncLeaseKeepAliveAction::Cancelled() const
+{
+  return isCancelled;
+}
+
+etcdv3::AsyncLeaseTimeToLiveAction::AsyncLeaseTimeToLiveAction(etcdv3::ActionParameters param)
+  : etcdv3::Action(param)
+{
+	LeaseTimeToLiveRequest leasetimetolive_request;
+  leasetimetolive_request.set_id(parameters.lease_id);
+  // FIXME: unsupported parameters: "keys"
+  // leasetimetolive_request.set_keys(parameters.keys);
+
+  response_reader = parameters.lease_stub->AsyncLeaseTimeToLive(&context, leasetimetolive_request, &cq_);
+  response_reader->Finish(&reply, &status, (void*)this);
+}
+
+etcdv3::AsyncLeaseTimeToLiveResponse etcdv3::AsyncLeaseTimeToLiveAction::ParseResponse()
+{
+  AsyncLeaseTimeToLiveResponse lease_resp;
+  if (!status.ok()) {
+    lease_resp.set_error_code(status.error_code());
+    lease_resp.set_error_message(status.error_message());
+  } else { 
+    lease_resp.ParseResponse(reply);
+  }
+  return lease_resp;
+}
+
+etcdv3::AsyncLeaseLeasesAction::AsyncLeaseLeasesAction(etcdv3::ActionParameters param)
+  : etcdv3::Action(param)
+{
+	LeaseLeasesRequest leaseleases_request;
+
+  response_reader = parameters.lease_stub->AsyncLeaseLeases(&context, leaseleases_request, &cq_);
+  response_reader->Finish(&reply, &status, (void*)this);
+}
+
+etcdv3::AsyncLeaseLeasesResponse etcdv3::AsyncLeaseLeasesAction::ParseResponse()
+{
+  AsyncLeaseLeasesResponse lease_resp;
+  if (!status.ok()) {
+    lease_resp.set_error_code(status.error_code());
+    lease_resp.set_error_message(status.error_message());
+  } else { 
+    lease_resp.ParseResponse(reply);
+  }
+  return lease_resp;
+}

src/v3/AsyncLeaseGrantAction.cpp

@@ -1,32 +0,0 @@
-#include "etcd/v3/AsyncLeaseGrantAction.hpp"
-#include "etcd/v3/action_constants.hpp"
-#include "etcd/v3/Transaction.hpp"
-
-using etcdserverpb::LeaseGrantRequest;
-
-etcdv3::AsyncLeaseGrantAction::AsyncLeaseGrantAction(etcdv3::ActionParameters param)
-  : etcdv3::Action(param)
-{
-  etcdv3::Transaction transaction;
-  transaction.setup_lease_grant_operation(parameters.ttl);
-
-  response_reader = parameters.lease_stub->AsyncLeaseGrant(&context, transaction.leasegrant_request, &cq_);
-  response_reader->Finish(&reply, &status, (void*)this);
-  
-}
-
-
-etcdv3::AsyncLeaseGrantResponse etcdv3::AsyncLeaseGrantAction::ParseResponse()
-{
-  AsyncLeaseGrantResponse lease_resp;
-  if(!status.ok())
-  {
-    lease_resp.set_error_code(status.error_code());
-    lease_resp.set_error_message(status.error_message());
-  }
-  else
-  { 
-    lease_resp.ParseResponse(reply);
-  }
-  return lease_resp;
-}

src/v3/AsyncLeaseGrantResponse.cpp

@@ -1,11 +0,0 @@
-#include "etcd/v3/AsyncLeaseGrantResponse.hpp"
-#include "etcd/v3/action_constants.hpp"
-
-
-void etcdv3::AsyncLeaseGrantResponse::ParseResponse(LeaseGrantResponse& resp)
-{
-  index = resp.header().revision();
-  value.kvs.set_lease(resp.id());
-  value.set_ttl(resp.ttl());
-  error_message = resp.error();
-}

src/v3/AsyncLeaseResponse.cpp

@@ -0,0 +1,35 @@
+#include "etcd/v3/AsyncLeaseResponse.hpp"
+#include "etcd/v3/action_constants.hpp"
+
+
+void etcdv3::AsyncLeaseGrantResponse::ParseResponse(LeaseGrantResponse& resp) {
+  index = resp.header().revision();
+  value.kvs.set_lease(resp.id());
+  value.set_ttl(resp.ttl());
+  error_message = resp.error();
+}
+
+void etcdv3::AsyncLeaseRevokeResponse::ParseResponse(LeaseRevokeResponse& resp) {
+  index = resp.header().revision();
+}
+
+void etcdv3::AsyncLeaseKeepAliveResponse::ParseResponse(LeaseKeepAliveResponse& resp) {
+  index = resp.header().revision();
+  value.kvs.set_lease(resp.id());
+  value.set_ttl(resp.ttl());
+}
+
+void etcdv3::AsyncLeaseTimeToLiveResponse::ParseResponse(LeaseTimeToLiveResponse& resp) {
+  index = resp.header().revision();
+  value.kvs.set_lease(resp.id());
+  value.set_ttl(resp.ttl());
+  // FIXME: unsupported: fields "grantedTTL" and "keys"
+}
+
+void etcdv3::AsyncLeaseLeasesResponse::ParseResponse(LeaseLeasesResponse& resp) {
+  index = resp.header().revision();
+  // FIXME: only the first leases is recorded.
+  if (resp.leases_size() > 0) {
+    value.kvs.set_lease(resp.leases(0).id());
+  }
+}

src/v3/AsyncLockAction.cpp

@@ -9,6 +9,7 @@ etcdv3::AsyncLockAction::AsyncLockAction(ActionParameters param)
 {
   LockRequest lock_request;
   lock_request.set_name(parameters.key);
+  lock_request.set_lease(parameters.lease_id);
 
   response_reader = parameters.lock_stub->AsyncLock(&context, lock_request, &cq_);
   response_reader->Finish(&reply, &status, (void*)this);

src/v3/AsyncWatchAction.cpp

@@ -69,7 +69,11 @@ void etcdv3::AsyncWatchAction::waitForResponse()
         //
         // 1. watch for a future revision, return immediately with empty events set
         // 2. receive any effective events.
+        isCancelled = true;
         stream->WritesDone((void*)"writes done");
+        grpc::Status status;
+        stream->Finish(&status, (void *)this);
+        cq_.Shutdown();
 
         // leave a warning if the response is too large and been fragmented
         if (reply.fragment()) {
@@ -90,9 +94,12 @@ void etcdv3::AsyncWatchAction::CancelWatch()
   std::lock_guard<std::mutex> scope_lock(this->protect_is_cancalled);
   if(isCancelled == false)
   {
-    stream->WritesDone((void*)"writes done");
-  }
     isCancelled = true;
+    stream->WritesDone((void*)"writes done");
+    grpc::Status status;
+    stream->Finish(&status, (void *)this);
+    cq_.Shutdown();
+  }
 }
 
 bool etcdv3::AsyncWatchAction::Cancelled() const {

src/v3/Transaction.cpp

@@ -155,11 +155,6 @@ void etcdv3::Transaction::setup_compare_and_delete_operation(std::string const&
 	req_success->set_allocated_request_delete_range(del_request.release());
 }
 
-void etcdv3::Transaction::setup_lease_grant_operation(int ttl)
-{
-  leasegrant_request.set_ttl(ttl);
-}
-
 void etcdv3::Transaction::setup_put(std::string const &key, std::string const &value) {
 	std::unique_ptr<PutRequest> put_request(new PutRequest());
 	put_request->set_key(key);

tst/LockTest.cpp

@@ -60,7 +60,8 @@ TEST_CASE("double lock will fail")
 
     // create a duration
     first_lock_release = true;
-    std::this_thread::sleep_for(std::chrono::seconds(1));
+    // using a duration longer than default lease TTL for lock (see: DEFAULT_LEASE_TTL_FOR_LOCK)
+    std::this_thread::sleep_for(std::chrono::seconds(15));
 
     // unlock the first lock
     etcd::Response resp4 = etcd.unlock(lock_key).get();