Implement frequency limiting class to be used for controlled messages-per-second ratio during send to syslog

CMakeLists.txt

@@ -8,4 +8,5 @@ enable_testing()
 add_test(NAME SyslogBulkUploaderTests COMMAND SyslogBulkUploaderTests)
 add_test(NAME SyslogMessageTests COMMAND SyslogMessageTests)
 add_test(NAME RFC3164FormattedSyslogMessageTests COMMAND RFC3164FormattedSyslogMessageTests)
+add_test(NAME FrequencyLimitTests COMMAND FrequencyLimitTests)
 

src/FrequencyLimit.cpp

@@ -0,0 +1,35 @@
+/*
+ The MIT License (MIT)
+
+Copyright (c) 2015 Marko Živanović
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+ */
+
+#include "FrequencyLimit.h"
+
+FrequencyLimit::FrequencyLimit() {
+}
+
+FrequencyLimit::FrequencyLimit(const FrequencyLimit& orig) {
+}
+
+FrequencyLimit::~FrequencyLimit() {
+}
+

src/FrequencyLimit.h

@@ -0,0 +1,63 @@
+/*
+ The MIT License (MIT)
+
+Copyright (c) 2015 Marko Živanović
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+ */
+
+#ifndef FREQUENCYLIMIT_H
+#define	FREQUENCYLIMIT_H
+
+#include <boost/noncopyable.hpp>
+#include <boost/date_time/posix_time/posix_time.hpp>
+#include <boost/thread/thread.hpp>
+
+class FrequencyLimit {
+public:
+
+    FrequencyLimit(const size_t& limit) : _target(boost::posix_time::microseconds(1000000 / limit)), _delay(boost::posix_time::milliseconds(0)) {
+    };
+
+    void tick() {
+        auto now(boost::posix_time::microsec_clock::local_time());
+        if (_prev == boost::posix_time::not_a_date_time) {
+            _prev = now;
+        } else {
+            auto dur = now - _prev;
+            auto diff = _target - dur;
+//            _delay = (_delay + diff) / 2;
+            _delay = _delay + diff;
+//            std::cout << "dur: " << dur << " diff: " << diff << " _delay: " << _delay << std::endl;
+            if (diff > boost::posix_time::microseconds(0)) {
+                boost::this_thread::sleep(_delay);
+            }
+//            _prev = boost::posix_time::microsec_clock::local_time();
+            _prev = now;
+        }
+    };
+
+private:
+    const boost::posix_time::time_duration _target;
+    boost::posix_time::time_duration _delay;
+    boost::posix_time::ptime _prev;
+};
+
+#endif	/* FREQUENCYLIMIT_H */
+

test/CMakeLists.txt

@@ -1,4 +1,4 @@
-find_package(Boost COMPONENTS unit_test_framework date_time filesystem system REQUIRED)
+find_package(Boost COMPONENTS unit_test_framework date_time filesystem system thread REQUIRED)
 find_package(Threads)
 include_directories(
     ${TEST_SOURCE_DIR/src}
@@ -30,3 +30,11 @@ target_link_libraries(RFC3164FormattedSyslogMessageTests
         ${Boost_DATE_TIME_LIBRARY}
 )
 
+add_executable(FrequencyLimitTests FrequencyLimitTests.cpp)
+target_link_libraries(FrequencyLimitTests
+	slbu-lib
+	${Boost_UNIT_TEST_FRAMEWORK_LIBRARY}
+        ${Boost_DATE_TIME_LIBRARY}
+        ${Boost_THREAD_LIBRARY}
+)
+

test/FrequencyLimitTests.cpp

@@ -0,0 +1,51 @@
+/*
+ The MIT License (MIT)
+
+Copyright (c) 2015 Marko Živanović
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+ */
+
+#define BOOST_TEST_MODULE FrequencyLimitTests
+#include <boost/test/unit_test.hpp>
+#include <boost/date_time/posix_time/posix_time.hpp>
+#include "../src/FrequencyLimit.h"
+
+using namespace boost::posix_time;
+
+size_t countInLoop(size_t freq, time_duration duration) {
+    FrequencyLimit f(freq);
+    ptime start(second_clock::local_time());
+    int c = 0;
+    while (second_clock::local_time() - start < duration) {
+        f.tick();
+        c++;
+    }
+    return c;
+}
+
+BOOST_AUTO_TEST_CASE(test_slow) {
+    size_t c = countInLoop(5, seconds(5));
+    BOOST_WARN_CLOSE((float) c, 25, 10);
+}
+
+BOOST_AUTO_TEST_CASE(test_fast) {
+    size_t c = countInLoop(100, seconds(5));
+    BOOST_WARN_CLOSE((float) c, 500, 10);
+}