[checkmk-commits] 4695 FIX Make communication with event console more robust

Module: check_mk Branch: master Commit: 68ee4716145e871785e5aba177ce25fa49e8e30c URL: http://git.mathias-kettner.de/git/?p=check_mk.git;a=commit;h=68ee4716145e87… Author: Sven Panne &lt;sp(a)mathias-kettner.de&gt; Date: Fri Jun 23 13:42:57 2017 +0200 4695 FIX Make communication with event console more robust When the monitoring core connects to the event console very rapidly, a "No buffer space available" error could happen intermittently. This can be seen in the log, and the corresponding command fails, too, e.g. archiving an event. This has been fixed, the connection is simply retried when this rare but harmless error happens. Change-Id: Id382dfe9f4267bb7d660ac306a963a3e622a8041 --- .werks/4695 | 14 ++++++++++++++ livestatus/src/EventConsoleConnection.cc | 23 ++++++++++++++++++++++- 2 files changed, 36 insertions(+), 1 deletion(-) diff --git a/.werks/4695 b/.werks/4695 new file mode 100644 index 0000000..793fecd --- /dev/null +++ b/.werks/4695 @@ -0,0 +1,14 @@ +Title: Make communication with event console more robust +Level: 1 +Component: livestatus +Compatible: compat +Edition: cre +Version: 1.5.0i1 +Date: 1498217686 +Class: fix + +When the monitoring core connects to the event console very rapidly, a "No +buffer space available" error could happen intermittently. This can be seen +in the log, and the corresponding command fails, too, e.g. archiving an +event. This has been fixed, the connection is simply retried when this +rare but harmless error happens. diff --git a/livestatus/src/EventConsoleConnection.cc b/livestatus/src/EventConsoleConnection.cc index 61fbb61..474d31f 100644 --- a/livestatus/src/EventConsoleConnection.cc +++ b/livestatus/src/EventConsoleConnection.cc @@ -26,8 +26,12 @@ // IWYU pragma: no_include <boost/asio/basic_socket_streambuf.hpp> #include "EventConsoleConnection.h" #include <boost/asio/socket_base.hpp> +#include <boost/system/error_code.hpp> #include <boost/system/system_error.hpp> +#include <chrono> #include <ostream> +#include <ratio> +#include <thread> #include <utility> #include "Logger.h" @@ -43,7 +47,24 @@ EventConsoleConnection::~EventConsoleConnection() { void EventConsoleConnection::run() { boost::asio::local::stream_protocol::endpoint ep(_path); - boost::asio::local::stream_protocol::iostream stream(ep); + // Attention, tricky timing-dependent stuff ahead: When we connect very + // rapidly, a no_buffer_space (= ENOBUFS) error can happen. This is probably + // caused by some internal Boost Kung Fu, remapping EGAIN to ENOBUFS, and + // looks like a bug in Boost, but that's a bit unclear. So instead of + // relying on Boost to retry under these circumstances, we do it ourselves. + boost::asio::local::stream_protocol::iostream stream; + while (true) { + stream.connect(ep); + if (stream.error() != + boost::system::error_code(boost::system::errc::no_buffer_space, + boost::system::system_category())) { + break; + } + Debug(_logger) << "retrying to connect"; + stream.clear(); + std::this_thread::sleep_for(std::chrono::milliseconds(1)); + } + check(stream, "connect"); Debug(_logger) << prefix("successfully connected");