Add Span amount control mechanism, also memory limit mechanism

apm-network/src/main/proto/TraceSegmentService.proto

@@ -26,6 +26,7 @@ message TraceSegmentObject {
     repeated SpanObject spans = 3;
     int32 applicationId = 4;
     int32 applicationInstanceId = 5;
+    bool isSizeLimited = 6;
 }
 
 message TraceSegmentReference {

apm-sniffer/apm-agent-core/src/main/java/org/skywalking/apm/agent/core/conf/Config.java

@@ -31,22 +31,27 @@ public class Config {
 
     public static class Agent {
         /**
-         * Application code is showed in sky-walking-ui.
-         * Suggestion: set an unique name for each application, one application's nodes share the same code.
+         * Application code is showed in sky-walking-ui. Suggestion: set an unique name for each application, one
+         * application's nodes share the same code.
          */
         public static String APPLICATION_CODE = "";
 
         /**
-         * Negative or zero means off, by default.
-         * {@link #SAMPLE_N_PER_3_SECS} means sampling N {@link TraceSegment} in 10 seconds tops.
+         * Negative or zero means off, by default. {@link #SAMPLE_N_PER_3_SECS} means sampling N {@link TraceSegment} in
+         * 10 seconds tops.
          */
         public static int SAMPLE_N_PER_3_SECS = -1;
 
         /**
-         * If the operation name of the first span is included in this set,
-         * this segment should be ignored.
+         * If the operation name of the first span is included in this set, this segment should be ignored.
          */
         public static String IGNORE_SUFFIX = ".jpg,.jpeg,.js,.css,.png,.bmp,.gif,.ico,.mp3,.mp4,.html,.svg";
+
+        /**
+         * The max number of spans in a single segment. Through this config item, skywalking keep your application
+         * memory cost estimated.
+         */
+        public static int SPAN_LIMIT_PER_SEGMENT = 300;
     }
 
     public static class Collector {
@@ -63,9 +68,7 @@ public static class Collector {
          */
         public static long DISCOVERY_CHECK_INTERVAL = 60;
         /**
-         * Collector REST-Service address.
-         * e.g.
-         * SERVERS="127.0.0.1:8080"  for single collector node.
+         * Collector REST-Service address. e.g. SERVERS="127.0.0.1:8080"  for single collector node.
          * SERVERS="10.2.45.126:8080,10.2.45.127:7600"  for multi collector nodes.
          */
         public static String SERVERS = "";
@@ -105,16 +108,15 @@ public static class Logging {
         public static String FILE_NAME = "skywalking-api.log";
 
         /**
-         * Log files directory.
-         * Default is blank string, means, use "system.out" to output logs.
+         * Log files directory. Default is blank string, means, use "system.out" to output logs.
          *
          * @see {@link WriterFactory#getLogWriter()}
          */
         public static String DIR = "";
 
         /**
-         * The max size of log file.
-         * If the size is bigger than this, archive the current file, and write into a new file.
+         * The max size of log file. If the size is bigger than this, archive the current file, and write into a new
+         * file.
          */
         public static int MAX_FILE_SIZE = 300 * 1024 * 1024;
 
@@ -129,8 +131,7 @@ public static class Logging {
     public static class Plugin {
         public static class MongoDB {
             /**
-             * If true, trace all the parameters, default is false.
-             * Only trace the operation, not include parameters.
+             * If true, trace all the parameters, default is false. Only trace the operation, not include parameters.
              */
             public static boolean TRACE_PARAM = false;
         }

apm-sniffer/apm-agent-core/src/main/java/org/skywalking/apm/agent/core/context/TracingContext.java

@@ -21,30 +21,32 @@
 import java.util.LinkedList;
 import java.util.List;
 import org.skywalking.apm.agent.core.boot.ServiceManager;
+import org.skywalking.apm.agent.core.conf.Config;
 import org.skywalking.apm.agent.core.context.trace.AbstractSpan;
 import org.skywalking.apm.agent.core.context.trace.AbstractTracingSpan;
 import org.skywalking.apm.agent.core.context.trace.EntrySpan;
 import org.skywalking.apm.agent.core.context.trace.ExitSpan;
 import org.skywalking.apm.agent.core.context.trace.LocalSpan;
+import org.skywalking.apm.agent.core.context.trace.NoopExitSpan;
+import org.skywalking.apm.agent.core.context.trace.NoopSpan;
 import org.skywalking.apm.agent.core.context.trace.TraceSegment;
 import org.skywalking.apm.agent.core.context.trace.TraceSegmentRef;
+import org.skywalking.apm.agent.core.context.trace.WithPeerInfo;
 import org.skywalking.apm.agent.core.dictionary.DictionaryManager;
 import org.skywalking.apm.agent.core.dictionary.DictionaryUtil;
 import org.skywalking.apm.agent.core.dictionary.PossibleFound;
 import org.skywalking.apm.agent.core.sampling.SamplingService;
 
 /**
- * The <code>TracingContext</code> represents a core tracing logic controller.
- * It build the final {@link TracingContext}, by the stack mechanism,
- * which is similar with the codes work.
+ * The <code>TracingContext</code> represents a core tracing logic controller. It build the final {@link
+ * TracingContext}, by the stack mechanism, which is similar with the codes work.
  *
- * In opentracing concept, it means, all spans in a segment tracing context(thread)
- * are CHILD_OF relationship, but no FOLLOW_OF.
+ * In opentracing concept, it means, all spans in a segment tracing context(thread) are CHILD_OF relationship, but no
+ * FOLLOW_OF.
  *
- * In skywalking core concept, FOLLOW_OF is an abstract concept
- * when cross-process MQ or cross-thread async/batch tasks happen,
- * we used {@link TraceSegmentRef} for these scenarios.
- * Check {@link TraceSegmentRef} which is from {@link ContextCarrier} or {@link ContextSnapshot}.
+ * In skywalking core concept, FOLLOW_OF is an abstract concept when cross-process MQ or cross-thread async/batch tasks
+ * happen, we used {@link TraceSegmentRef} for these scenarios. Check {@link TraceSegmentRef} which is from {@link
+ * ContextCarrier} or {@link ContextSnapshot}.
  *
  * @author wusheng
  */
@@ -60,13 +62,11 @@ public class TracingContext implements AbstractTracerContext {
     private TraceSegment segment;
 
     /**
-     * Active spans stored in a Stack, usually called 'ActiveSpanStack'.
-     * This {@link LinkedList} is the in-memory storage-structure.
-     * <p>
-     * I use {@link LinkedList#removeLast()}, {@link LinkedList#addLast(Object)} and {@link LinkedList#last} instead of
-     * {@link #pop()}, {@link #push(AbstractTracingSpan)}, {@link #peek()}
+     * Active spans stored in a Stack, usually called 'ActiveSpanStack'. This {@link LinkedList} is the in-memory
+     * storage-structure. <p> I use {@link LinkedList#removeLast()}, {@link LinkedList#addLast(Object)} and {@link
+     * LinkedList#last} instead of {@link #pop()}, {@link #push(AbstractSpan)}, {@link #peek()}
      */
-    private LinkedList<AbstractTracingSpan> activeSpanStack = new LinkedList<AbstractTracingSpan>();
+    private LinkedList<AbstractSpan> activeSpanStack = new LinkedList<AbstractSpan>();
 
     /**
      * A counter for the next span.
@@ -93,21 +93,24 @@ public class TracingContext implements AbstractTracerContext {
      */
     @Override
     public void inject(ContextCarrier carrier) {
-        AbstractTracingSpan span = this.activeSpan();
+        AbstractSpan span = this.activeSpan();
         if (!span.isExit()) {
             throw new IllegalStateException("Inject can be done only in Exit Span");
         }
-        ExitSpan exitSpan = (ExitSpan)span;
+
+        WithPeerInfo spanWithPeer = (WithPeerInfo)span;
+        String peer = spanWithPeer.getPeer();
+        int peerId = spanWithPeer.getPeerId();
 
         carrier.setTraceSegmentId(this.segment.getTraceSegmentId());
         carrier.setSpanId(span.getSpanId());
 
         carrier.setParentApplicationInstanceId(segment.getApplicationInstanceId());
 
-        if (DictionaryUtil.isNull(exitSpan.getPeerId())) {
-            carrier.setPeerHost(exitSpan.getPeer());
+        if (DictionaryUtil.isNull(peerId)) {
+            carrier.setPeerHost(peer);
         } else {
-            carrier.setPeerId(exitSpan.getPeerId());
+            carrier.setPeerId(peerId);
         }
         List<TraceSegmentRef> refs = this.segment.getRefs();
         int operationId;
@@ -119,7 +122,7 @@ public void inject(ContextCarrier carrier) {
             operationName = ref.getEntryOperationName();
             entryApplicationInstanceId = ref.getEntryApplicationInstanceId();
         } else {
-            AbstractTracingSpan firstSpan = first();
+            AbstractSpan firstSpan = first();
             operationId = firstSpan.getOperationId();
             operationName = firstSpan.getOperationName();
             entryApplicationInstanceId = this.segment.getApplicationInstanceId();
@@ -169,7 +172,7 @@ public ContextSnapshot capture() {
         int entryOperationId;
         String entryOperationName;
         int entryApplicationInstanceId;
-        AbstractTracingSpan firstSpan = first();
+        AbstractSpan firstSpan = first();
         if (refs != null && refs.size() > 0) {
             TraceSegmentRef ref = refs.get(0);
             entryOperationId = ref.getEntryOperationId();
@@ -225,8 +228,12 @@ public String getReadableGlobalTraceId() {
      */
     @Override
     public AbstractSpan createEntrySpan(final String operationName) {
-        AbstractTracingSpan entrySpan;
-        final AbstractTracingSpan parentSpan = peek();
+        if (isLimitMechanismWorking()) {
+            NoopSpan span = new NoopSpan();
+            return push(span);
+        }
+        AbstractSpan entrySpan;
+        final AbstractSpan parentSpan = peek();
         final int parentSpanId = parentSpan == null ? -1 : parentSpan.getSpanId();
         if (parentSpan == null) {
             entrySpan = (AbstractTracingSpan)DictionaryManager.findOperationNameCodeSection()
@@ -269,7 +276,11 @@ public AbstractSpan createEntrySpan(final String operationName) {
      */
     @Override
     public AbstractSpan createLocalSpan(final String operationName) {
-        AbstractTracingSpan parentSpan = peek();
+        if (isLimitMechanismWorking()) {
+            NoopSpan span = new NoopSpan();
+            return push(span);
+        }
+        AbstractSpan parentSpan = peek();
         final int parentSpanId = parentSpan == null ? -1 : parentSpan.getSpanId();
         AbstractTracingSpan span = (AbstractTracingSpan)DictionaryManager.findOperationNameCodeSection()
             .findOrPrepare4Register(segment.getApplicationId(), operationName)
@@ -298,17 +309,21 @@ public Object doProcess() {
      */
     @Override
     public AbstractSpan createExitSpan(final String operationName, final String remotePeer) {
-        AbstractTracingSpan exitSpan;
-        AbstractTracingSpan parentSpan = peek();
+        AbstractSpan exitSpan;
+        AbstractSpan parentSpan = peek();
         if (parentSpan != null && parentSpan.isExit()) {
             exitSpan = parentSpan;
         } else {
             final int parentSpanId = parentSpan == null ? -1 : parentSpan.getSpanId();
-            exitSpan = (AbstractTracingSpan)DictionaryManager.findApplicationCodeSection()
+            exitSpan = (AbstractSpan)DictionaryManager.findApplicationCodeSection()
                 .find(remotePeer).doInCondition(
                     new PossibleFound.FoundAndObtain() {
                         @Override
                         public Object doProcess(final int peerId) {
+                            if (isLimitMechanismWorking()) {
+                                return new NoopExitSpan(peerId);
+                            }
+
                             return DictionaryManager.findOperationNameCodeSection()
                                 .findOnly(segment.getApplicationId(), operationName)
                                 .doInCondition(
@@ -328,6 +343,10 @@ public Object doProcess() {
                     new PossibleFound.NotFoundAndObtain() {
                         @Override
                         public Object doProcess() {
+                            if (isLimitMechanismWorking()) {
+                                return new NoopExitSpan(remotePeer);
+                            }
+
                             return DictionaryManager.findOperationNameCodeSection()
                                 .findOnly(segment.getApplicationId(), operationName)
                                 .doInCondition(
@@ -354,25 +373,30 @@ public Object doProcess() {
      * @return the active span of current context, the top element of {@link #activeSpanStack}
      */
     @Override
-    public AbstractTracingSpan activeSpan() {
-        AbstractTracingSpan span = peek();
+    public AbstractSpan activeSpan() {
+        AbstractSpan span = peek();
         if (span == null) {
             throw new IllegalStateException("No active span.");
         }
         return span;
     }
 
     /**
-     * Stop the given span, if and only if this one is the top element of {@link #activeSpanStack}.
-     * Because the tracing core must make sure the span must match in a stack module, like any program did.
+     * Stop the given span, if and only if this one is the top element of {@link #activeSpanStack}. Because the tracing
+     * core must make sure the span must match in a stack module, like any program did.
      *
      * @param span to finish
      */
     @Override
     public void stopSpan(AbstractSpan span) {
-        AbstractTracingSpan lastSpan = peek();
+        AbstractSpan lastSpan = peek();
         if (lastSpan == span) {
-            if (lastSpan.finish(segment)) {
+            if (lastSpan instanceof AbstractTracingSpan) {
+                AbstractTracingSpan toFinishSpan = (AbstractTracingSpan)lastSpan;
+                if (toFinishSpan.finish(segment)) {
+                    pop();
+                }
+            } else {
                 pop();
             }
         } else {
@@ -389,7 +413,7 @@ public void stopSpan(AbstractSpan span) {
      * TracingContext.ListenerManager}
      */
     private void finish() {
-        TraceSegment finishedSegment = segment.finish();
+        TraceSegment finishedSegment = segment.finish(isLimitMechanismWorking());
         /**
          * Recheck the segment if the segment contains only one span.
          * Because in the runtime, can't sure this segment is part of distributed trace.
@@ -421,9 +445,9 @@ public static synchronized void add(TracingContextListener listener) {
         }
 
         /**
-         * Notify the {@link TracingContext.ListenerManager} about the given {@link TraceSegment} have finished.
-         * And trigger {@link TracingContext.ListenerManager} to notify all {@link #LISTENERS} 's
-         * {@link TracingContextListener#afterFinished(TraceSegment)}
+         * Notify the {@link TracingContext.ListenerManager} about the given {@link TraceSegment} have finished. And
+         * trigger {@link TracingContext.ListenerManager} to notify all {@link #LISTENERS} 's {@link
+         * TracingContextListener#afterFinished(TraceSegment)}
          *
          * @param finishedSegment
          */
@@ -445,7 +469,7 @@ public static synchronized void remove(TracingContextListener listener) {
     /**
      * @return the top element of 'ActiveSpanStack', and remove it.
      */
-    private AbstractTracingSpan pop() {
+    private AbstractSpan pop() {
         return activeSpanStack.removeLast();
     }
 
@@ -454,22 +478,26 @@ private AbstractTracingSpan pop() {
      *
      * @param span
      */
-    private AbstractTracingSpan push(AbstractTracingSpan span) {
+    private AbstractSpan push(AbstractSpan span) {
         activeSpanStack.addLast(span);
         return span;
     }
 
     /**
      * @return the top element of 'ActiveSpanStack' only.
      */
-    private AbstractTracingSpan peek() {
+    private AbstractSpan peek() {
         if (activeSpanStack.isEmpty()) {
             return null;
         }
         return activeSpanStack.getLast();
     }
 
-    private AbstractTracingSpan first() {
+    private AbstractSpan first() {
         return activeSpanStack.getFirst();
     }
+
+    private boolean isLimitMechanismWorking() {
+        return spanIdGenerator >= Config.Agent.SPAN_LIMIT_PER_SEGMENT;
+    }
 }

apm-sniffer/apm-agent-core/src/main/java/org/skywalking/apm/agent/core/context/trace/AbstractSpan.java

@@ -22,8 +22,7 @@
 import org.skywalking.apm.network.trace.component.Component;
 
 /**
- * The <code>AbstractSpan</code> represents the span's skeleton,
- * which contains all open methods.
+ * The <code>AbstractSpan</code> represents the span's skeleton, which contains all open methods.
  *
  * @author wusheng
  */
@@ -37,8 +36,8 @@ public interface AbstractSpan {
     AbstractSpan setComponent(Component component);
 
     /**
-     * Only use this method in explicit instrumentation, like opentracing-skywalking-bridge.
-     * It it higher recommend don't use this for performance consideration.
+     * Only use this method in explicit instrumentation, like opentracing-skywalking-bridge. It it higher recommend
+     * don't use this for performance consideration.
      *
      * @param componentName
      * @return the span for chaining.
@@ -89,4 +88,24 @@ public interface AbstractSpan {
      * @return this Span instance, for chaining
      */
     AbstractSpan setOperationName(String operationName);
+
+    /**
+     * Start a span.
+     *
+     * @return this Span instance, for chaining
+     */
+    AbstractSpan start();
+
+    /**
+     * Get the id of span
+     *
+     * @return id value.
+     */
+    int getSpanId();
+
+    int getOperationId();
+
+    String getOperationName();
+
+    AbstractSpan setOperationId(int operationId);
 }