issue #221: HomeStore to report capacity stats (#222)

* issue #221: HomeStore to report capacity stats
1. total used capacity
2. total capacity

conanfile.py

@@ -5,7 +5,7 @@
 
 class HomestoreConan(ConanFile):
     name = "homestore"
-    version = "4.5.10"
+    version = "4.6.1"
 
     homepage = "https://github.com/eBay/Homestore"
     description = "HomeStore Storage Engine"

src/include/homestore/blkdata_service.hpp

@@ -187,6 +187,10 @@ class BlkDataService {
      */
     void start();
 
+    uint64_t get_total_capacity() const;
+
+    uint64_t get_used_capacity() const;
+
 private:
     /**
      * @brief Initializes the block data service.

src/include/homestore/homestore.hpp

@@ -67,6 +67,11 @@ struct hs_vdev_context {
 
 using hs_before_services_starting_cb_t = std::function< void(void) >;
 
+struct hs_stats {
+    uint64_t total_capacity{0ul};
+    uint64_t used_capacity{0ul};
+};
+
 struct HS_SERVICE {
     static constexpr uint32_t META = 1 << 0;
     static constexpr uint32_t LOG_REPLICATED = 1 << 1;

src/include/homestore/replication_service.hpp

@@ -31,6 +31,7 @@ VENUM(ReplServiceError, int32_t,
 
 class ReplDev;
 class ReplDevListener;
+struct hs_stats;
 
 template < typename V, typename E >
 using Result = folly::Expected< V, E >;
@@ -84,5 +85,9 @@ class ReplicationService {
     /// @brief Iterate over all repl devs and then call the callback provided
     /// @param cb Callback with repl dev
     virtual void iterate_repl_devs(std::function< void(cshared< ReplDev >&) > const& cb) = 0;
+
+    /// @brief get the capacity stats form underlying backend;
+    /// @return the capacity stats;
+    virtual hs_stats get_cap_stats() const = 0;
 };
 } // namespace homestore

src/lib/blkdata_svc/blkdata_service.cpp

@@ -224,4 +224,8 @@ void BlkDataService::start() {
                                      std::move(std::make_unique< DataSvcCPCallbacks >(m_vdev)));
 }
 
+uint64_t BlkDataService::get_total_capacity() const { return m_vdev->size(); }
+
+uint64_t BlkDataService::get_used_capacity() const { return m_vdev->used_size(); }
+
 } // namespace homestore

src/lib/replication/service/repl_service_impl.cpp

@@ -17,6 +17,8 @@
 #include "common/homestore_assert.hpp"
 #include "replication/service/repl_service_impl.h"
 #include "replication/repl_dev/solo_repl_dev.h"
+#include "homestore/blkdata_service.hpp"
+#include "homestore/homestore.hpp"
 
 namespace homestore {
 ReplicationService& repl_service() { return hs()->repl_service(); }
@@ -46,6 +48,14 @@ void ReplicationServiceImpl::stop() {
     m_rd_map.clear();
 }
 
+hs_stats ReplicationServiceImpl::get_cap_stats() const {
+    hs_stats stats;
+
+    stats.total_capacity = data_service().get_total_capacity();
+    stats.used_capacity = data_service().get_used_capacity();
+    return stats;
+}
+
 AsyncReplResult< shared< ReplDev > >
 ReplicationServiceImpl::create_repl_dev(uuid_t group_id, std::set< std::string, std::less<> >&& members,
                                         std::unique_ptr< ReplDevListener > listener) {

src/lib/replication/service/repl_service_impl.h

@@ -69,6 +69,8 @@ class ReplicationServiceImpl : public ReplicationService {
 
     folly::Future< ReplServiceError > replace_member(uuid_t group_id, std::string const& member_out,
                                                      std::string const& member_in) const override;
+    hs_stats get_cap_stats() const override;
+
 
 private:
     shared< ReplDev > create_repl_dev_instance(superblk< repl_dev_superblk > const& rd_sb, bool load_existing);

src/tests/test_solo_repl_dev.cpp

@@ -249,6 +249,10 @@ class SoloReplDevTest : public testing::Test {
         }
 
         auto& rdev = (rand() % 2) ? m_repl_dev1 : m_repl_dev2;
+
+        auto const cap = hs()->repl_service().get_cap_stats();
+        LOGDEBUG("Before write, cap stats: used={} total={}", cap.used_capacity, cap.total_capacity);
+
         rdev->async_alloc_write(*req->header, req->key ? *req->key : sisl::blob{}, req->write_sgs, req);
     }
 
@@ -285,6 +289,9 @@ class SoloReplDevTest : public testing::Test {
         if (req->write_sgs.size != 0) {
             req->read_sgs = HSTestHelper::create_sgs(req->write_sgs.size, g_block_size, req->write_sgs.size);
 
+            auto const cap = hs()->repl_service().get_cap_stats();
+            LOGDEBUG("Write complete with cap stats: used={} total={}", cap.used_capacity, cap.total_capacity);
+
             rdev.async_read(req->written_blkids, req->read_sgs, req->read_sgs.size)
                 .thenValue([this, &rdev, req](auto&& err) {
                     RELEASE_ASSERT(!err, "Error during async_read");