[5477] dhcpsrv/postgres and kea-dhcp4 now support db reconnect

kea-dhcp4
    added support for max-reconnect-tries and reconnect-wait-time
    to lease and host db parsers

    Added a callback for when DB backends detect loss of connectivity

    Added a self-rescheduling method to attempt to reconnect to the
    backends if retries are enabled

dhcpsrv
    Added a callback that DatabaseConnection derivations should invoke
    when they lose connectivity.

    Added an optional callback parameter from CfgDbAccess::createManagers()
    all the way down to DatabaseConnection ctor.

    pgsql_connection.cc
        PgSqlConnection::~PgSqlConnection() - Added logic to close the
        connection only when the connect state is still OK.
        Otherwise it likes to core dump.

        PgSqlConnection::checkStatementError() - Modified to invoke the
        connectivity lost callback on "fatal" errors

    pgsql_lease_mgr_unittest.cc
    pgsql_host_data_source_unittest.cc
        Added tests to verify that the lost callback is NOT invoked on an
        open failure

1 files changed, 5 insertions, 1 deletions

diff --git a/src/lib/dhcpsrv/lease_mgr_factory.h b/src/lib/dhcpsrv/lease_mgr_factory.h
index 4c6baf1270..e598951668 100644
--- a/src/lib/dhcpsrv/lease_mgr_factory.h
+++ b/src/lib/dhcpsrv/lease_mgr_factory.h
@@ -63,11 +63,15 @@ public:
     ///        -end specific, although must include the "type" keyword which
     ///        gives the backend in use.
     ///
+    /// @param db_lost_callback function to invoke if connectivity to lease
+    /// database is lost.
+    ///
     /// @throw isc::InvalidParameter dbaccess string does not contain the "type"
     ///        keyword.
     /// @throw isc::dhcp::InvalidType The "type" keyword in dbaccess does not
     ///        identify a supported backend.
-    static void create(const std::string& dbaccess);
+    static void create(const std::string& dbaccess, 
+                       DatabaseConnection::Callback db_lost_callback = NULL);
 
     /// @brief Destroy lease manager
     ///