Move span operation to Scope from Tracer (opensearch-project#8411)

* Move span operation to Scope from Tracer

Signed-off-by: suranjay <surajkumar.tu@gmail.com>

* Add changelog entry

Signed-off-by: suranjay <surajkumar.tu@gmail.com>

* Change method to setError

Signed-off-by: suranjay <surajkumar.tu@gmail.com>

* Removed unused classes

Signed-off-by: suranjay <surajkumar.tu@gmail.com>

* Fix merge issue

Signed-off-by: suranjay <surajkumar.tu@gmail.com>

---------

Signed-off-by: suranjay <surajkumar.tu@gmail.com>
Signed-off-by: Shivansh Arora <hishiv@amazon.com>

Author: suranjay

CHANGELOG.md

@@ -51,6 +51,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Improve summary error message for invalid setting updates ([#4792](https://github.com/opensearch-project/OpenSearch/pull/4792))
 - Pass localNode info to all plugins on node start ([#7919](https://github.com/opensearch-project/OpenSearch/pull/7919))
 - Improved performance of parsing floating point numbers ([#7909](https://github.com/opensearch-project/OpenSearch/pull/7909))
+- Move span actions to Scope ([#8411](https://github.com/opensearch-project/OpenSearch/pull/8411))
 
 ### Deprecated
 

libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/DefaultSpanScope.java

@@ -0,0 +1,70 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import java.util.function.Consumer;
+
+/**
+ * Default implementation of Scope
+ */
+public class DefaultSpanScope implements SpanScope {
+
+    private final Span span;
+
+    private final Consumer<Span> onCloseConsumer;
+
+    /**
+     * Creates Scope instance for the given span
+     *
+     * @param span underlying span
+     * @param onCloseConsumer consumer to execute on scope close
+     */
+    public DefaultSpanScope(Span span, Consumer<Span> onCloseConsumer) {
+        this.span = span;
+        this.onCloseConsumer = onCloseConsumer;
+    }
+
+    @Override
+    public void addSpanAttribute(String key, String value) {
+        span.addAttribute(key, value);
+    }
+
+    @Override
+    public void addSpanAttribute(String key, long value) {
+        span.addAttribute(key, value);
+    }
+
+    @Override
+    public void addSpanAttribute(String key, double value) {
+        span.addAttribute(key, value);
+    }
+
+    @Override
+    public void addSpanAttribute(String key, boolean value) {
+        span.addAttribute(key, value);
+    }
+
+    @Override
+    public void addSpanEvent(String event) {
+        span.addEvent(event);
+    }
+
+    @Override
+    public void setError(Exception exception) {
+        span.setError(exception);
+    }
+
+    /**
+     * Executes the runnable to end the scope
+     */
+    @Override
+    public void close() {
+        onCloseConsumer.accept(span);
+    }
+}

libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/DefaultTracer.java

@@ -13,8 +13,8 @@
 
 /**
  *
- * The default tracer implementation. This class implements the basic logic for span lifecycle and its state management.
- * It also handles tracing context propagation between spans.
+ * The default tracer implementation. It handles tracing context propagation between spans by maintaining
+ * current active span in its storage
  *
  *
  */
@@ -36,41 +36,11 @@ public DefaultTracer(TracingTelemetry tracingTelemetry, TracerContextStorage<Str
     }
 
     @Override
-    public Scope startSpan(String spanName) {
+    public SpanScope startSpan(String spanName) {
         Span span = createSpan(spanName, getCurrentSpan());
         setCurrentSpanInContext(span);
         addDefaultAttributes(span);
-        return new ScopeImpl(() -> endSpan(span));
-    }
-
-    @Override
-    public void addSpanAttribute(String key, String value) {
-        Span currentSpan = getCurrentSpan();
-        currentSpan.addAttribute(key, value);
-    }
-
-    @Override
-    public void addSpanAttribute(String key, long value) {
-        Span currentSpan = getCurrentSpan();
-        currentSpan.addAttribute(key, value);
-    }
-
-    @Override
-    public void addSpanAttribute(String key, double value) {
-        Span currentSpan = getCurrentSpan();
-        currentSpan.addAttribute(key, value);
-    }
-
-    @Override
-    public void addSpanAttribute(String key, boolean value) {
-        Span currentSpan = getCurrentSpan();
-        currentSpan.addAttribute(key, value);
-    }
-
-    @Override
-    public void addSpanEvent(String event) {
-        Span currentSpan = getCurrentSpan();
-        currentSpan.addEvent(event);
+        return new DefaultSpanScope(span, (scopeSpan) -> endSpan(scopeSpan));
     }
 
     @Override

libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/Scope.java

@@ -62,6 +62,13 @@ public interface Span {
      */
     void addAttribute(String key, Boolean value);
 
+    /**
+     * Records error in the span
+     *
+     * @param exception exception to be recorded
+     */
+    void setError(Exception exception);
+
     /**
      * Adds an event in the span
      *

libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/ScopeImpl.java

@@ -0,0 +1,74 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing;
+
+import org.opensearch.telemetry.tracing.noop.NoopSpanScope;
+
+/**
+ * An auto-closeable that represents scope of the span.
+ * It provides interface for all the span operations.
+ */
+public interface SpanScope extends AutoCloseable {
+    /**
+     * No-op Scope implementation
+     */
+    SpanScope NO_OP = new NoopSpanScope();
+
+    /**
+     * Adds string attribute to the {@link Span}.
+     *
+     * @param key   attribute key
+     * @param value attribute value
+     */
+    void addSpanAttribute(String key, String value);
+
+    /**
+     * Adds long attribute to the {@link Span}.
+     *
+     * @param key   attribute key
+     * @param value attribute value
+     */
+    void addSpanAttribute(String key, long value);
+
+    /**
+     * Adds double attribute to the {@link Span}.
+     *
+     * @param key   attribute key
+     * @param value attribute value
+     */
+    void addSpanAttribute(String key, double value);
+
+    /**
+     * Adds boolean attribute to the {@link Span}.
+     *
+     * @param key   attribute key
+     * @param value attribute value
+     */
+    void addSpanAttribute(String key, boolean value);
+
+    /**
+     * Adds an event to the {@link Span}.
+     *
+     * @param event event name
+     */
+    void addSpanEvent(String event);
+
+    /**
+     * Records error in the span
+     *
+     * @param exception exception to be recorded
+     */
+    void setError(Exception exception);
+
+    /**
+     * closes the scope
+     */
+    @Override
+    void close();
+}

libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/Span.java

@@ -11,7 +11,7 @@
 import java.io.Closeable;
 
 /**
- * Tracer is the interface used to create a {@link Span} and interact with current active {@link Span}.
+ * Tracer is the interface used to create a {@link Span}
  * It automatically handles the context propagation between threads, tasks, nodes etc.
  *
  * All methods on the Tracer object are multi-thread safe.
@@ -24,44 +24,6 @@ public interface Tracer extends Closeable {
      * @param spanName span name
      * @return scope of the span, must be closed with explicit close or with try-with-resource
      */
-    Scope startSpan(String spanName);
+    SpanScope startSpan(String spanName);
 
-    /**
-     * Adds string attribute to the current active {@link Span}.
-     *
-     * @param key   attribute key
-     * @param value attribute value
-     */
-    void addSpanAttribute(String key, String value);
-
-    /**
-     * Adds long attribute to the current active {@link Span}.
-     *
-     * @param key   attribute key
-     * @param value attribute value
-     */
-    void addSpanAttribute(String key, long value);
-
-    /**
-     * Adds double attribute to the current active {@link Span}.
-     *
-     * @param key   attribute key
-     * @param value attribute value
-     */
-    void addSpanAttribute(String key, double value);
-
-    /**
-     * Adds boolean attribute to the current active {@link Span}.
-     *
-     * @param key   attribute key
-     * @param value attribute value
-     */
-    void addSpanAttribute(String key, boolean value);
-
-    /**
-     * Adds an event to the current active {@link Span}.
-     *
-     * @param event event name
-     */
-    void addSpanEvent(String event);
 }

libs/telemetry/src/main/java/org/opensearch/telemetry/tracing/SpanScope.java

@@ -0,0 +1,57 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.telemetry.tracing.noop;
+
+import org.opensearch.telemetry.tracing.SpanScope;
+
+/**
+ * No-op implementation of SpanScope
+ */
+public final class NoopSpanScope implements SpanScope {
+
+    /**
+     * No-args constructor
+     */
+    public NoopSpanScope() {}
+
+    @Override
+    public void addSpanAttribute(String key, String value) {
+
+    }
+
+    @Override
+    public void addSpanAttribute(String key, long value) {
+
+    }
+
+    @Override
+    public void addSpanAttribute(String key, double value) {
+
+    }
+
+    @Override
+    public void addSpanAttribute(String key, boolean value) {
+
+    }
+
+    @Override
+    public void addSpanEvent(String event) {
+
+    }
+
+    @Override
+    public void setError(Exception exception) {
+
+    }
+
+    @Override
+    public void close() {
+
+    }
+}