WIP: Decouple threads and contexts in PythonPool, so a single context…

… may still handle multiple requests in parallel
graalvm · Jan 28, 2025 · 78402d1 · 78402d1
1 parent ef15ee4
commit 78402d1
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Showing 2 changed files with 20 additions and 11 deletions.
diff --git a/graalpy/graalpy-micronaut-multithreaded/pom.xml b/graalpy/graalpy-micronaut-multithreaded/pom.xml
@@ -36,7 +36,7 @@
     <!--TODO: Selecting a Python version different from the Micronaut BOM -->
     <dependency>
       <groupId>org.graalvm.python</groupId>
-      <artifactId>python-community</artifactId>
+      <artifactId>python</artifactId>
       <version>${python.version}</version>
       <type>pom</type>
     </dependency>
@@ -118,7 +118,7 @@
           <version>${python.version}</version>
           <configuration>
               <packages>
-                  <package>pandas==2.2.0</package>
+                  <package>pandas==2.2.2</package>
               </packages>
           </configuration>
           <executions>

diff --git a/...lpy-micronaut-multithreaded/src/main/java/graalpy/micronaut/multithreaded/PythonPool.java b/...lpy-micronaut-multithreaded/src/main/java/graalpy/micronaut/multithreaded/PythonPool.java
@@ -4,24 +4,24 @@
 import java.nio.file.Path;
 import java.util.List;
 import java.util.concurrent.AbstractExecutorService;
-import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.BlockingDeque;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
-import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.LinkedBlockingDeque;
 import java.util.concurrent.ThreadFactory;
 import java.util.concurrent.TimeUnit;
 
 import org.graalvm.polyglot.Context;
 import org.graalvm.polyglot.Engine;
 import org.graalvm.polyglot.Value;
-import org.graalvm.python.embedding.utils.GraalPyResources;
-import org.graalvm.python.embedding.utils.VirtualFileSystem;
+import org.graalvm.python.embedding.GraalPyResources;
+import org.graalvm.python.embedding.VirtualFileSystem;
 
 @io.micronaut.context.annotation.Context
 public class PythonPool extends AbstractExecutorService {
     private final Engine engine;
     private final ThreadLocal<Context> thisContext;
-    private final BlockingQueue<Context> contexts;
+    private final BlockingDeque<Context> contexts;
     private final ExecutorService threadPool;
     private final int size;
 
@@ -70,15 +70,24 @@ public int getPoolSize() {
     private PythonPool(int nContexts) {
         size = nContexts;
         engine = Engine.create();
-        contexts = new LinkedBlockingQueue<>();
+        contexts = new LinkedBlockingDeque<>();
         thisContext = new ThreadLocal<>();
-        threadPool = Executors.newFixedThreadPool(nContexts, new ThreadFactory() {
+        for (int i = 0; i < nContexts; i++) {
+            contexts.addLast(createContext(engine));
+        }
+        threadPool = Executors.newCachedThreadPool(new ThreadFactory() {
             @Override
             public Thread newThread(Runnable r) {
+                // associate contexts with threads round-robin
                 return new Thread(() -> {
-                    var c = createContext(engine);
-                    contexts.add(c);
+                    Context c;
+                    try {
+                        c = contexts.takeFirst();
+                    } catch (InterruptedException e) {
+                        throw new RuntimeException(e);
+                    }
                     thisContext.set(c);
+                    contexts.addLast(c);
                     r.run();
                 });
             }