debug statistics (recording iteration lag)

common/pom.xml

@@ -88,6 +88,16 @@
             <groupId>ch.qos.logback</groupId>
             <artifactId>logback-classic</artifactId>
             <scope>test</scope>
+        </dependency>        
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-databind</artifactId>
+            <version>2.10.0.pr1</version>
+        </dependency>    
+        <dependency>
+            <groupId>commons-collections</groupId>
+            <artifactId>commons-collections</artifactId>
+            <version>3.2.2</version>
         </dependency>
     </dependencies>
 

common/src/main/java/ctbrec/recorder/SimplifiedLocalRecorder.java

@@ -39,6 +39,7 @@ import static java.util.concurrent.TimeUnit.SECONDS;
 
 @Slf4j
 public class SimplifiedLocalRecorder implements Recorder {
+    public static final Statistics STATS = new Statistics();
 
     public static final boolean IGNORE_CACHE = true;
     private final List<Model> models = Collections.synchronizedList(new ArrayList<>());

common/src/main/java/ctbrec/recorder/Statistics.java

@@ -0,0 +1,21 @@
+package ctbrec.recorder;
+
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+
+import org.apache.commons.collections.buffer.CircularFifoBuffer;
+ 
+
+public class Statistics {
+    public ReadWriteLock statsLock = new ReentrantReadWriteLock();
+    public CircularFifoBuffer stats = new CircularFifoBuffer(100);
+    
+    public void add(Object val) {
+        statsLock.writeLock().lock();
+        try {
+            stats.add(val);
+        } finally {
+            statsLock.writeLock().unlock();
+        }
+    }
+}

common/src/main/java/ctbrec/recorder/download/hls/AbstractHlsDownload.java

@@ -14,6 +14,7 @@ import ctbrec.io.HttpClient;
 import ctbrec.io.HttpConstants;
 import ctbrec.io.HttpException;
 import ctbrec.recorder.InvalidPlaylistException;
+import ctbrec.recorder.SimplifiedLocalRecorder;
 import ctbrec.recorder.download.AbstractDownload;
 import ctbrec.recorder.download.HttpHeaderFactory;
 import ctbrec.recorder.download.StreamSource;
@@ -108,6 +109,7 @@ public abstract class AbstractHlsDownload extends AbstractDownload {
 
     @Override
     public AbstractHlsDownload call() throws Exception {
+        SimplifiedLocalRecorder.STATS.add(Duration.between(rescheduleTime, Instant.now()).toMillis());
 
         try {
             if (segmentPlaylistUrl == null) {

server/src/main/java/ctbrec/recorder/server/DebugServlet.java

@@ -2,6 +2,7 @@ package ctbrec.recorder.server;
 
 import ctbrec.Config;
 import ctbrec.io.HttpClient;
+import ctbrec.recorder.SimplifiedLocalRecorder;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.json.JSONObject;
@@ -68,6 +69,14 @@ public class DebugServlet extends AbstractCtbrecServlet {
                                         HttpClient.getGLOBAL_HTTP_CONN_POOL().connectionCount(),
                                         HttpClient.getGLOBAL_HTTP_CONN_POOL().idleConnectionCount());
                 
+                var rlock = SimplifiedLocalRecorder.STATS.statsLock.readLock();
+                rlock.lock();
+                try {
+                    text += String.format("Time between download iterations = %s\n", SimplifiedLocalRecorder.STATS.stats.toString());
+                } finally {
+                    rlock.unlock();
+                }
+                
                 log.debug("Stats Request");
                 resp.setContentType("text/plain");
                 sendResponse(resp, SC_OK, text);