[GitHub] [beam] scwhittle commented on a change in pull request #11096: [BEAM-9399] Change the redirection of System.err to be a custom PrintStream

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scwhittle commented on a change in pull request #11096: [BEAM-9399] Change the redirection of System.err to be a custom PrintStream
URL: https://github.com/apache/beam/pull/11096#discussion_r391210501
 
 

 ##########
 File path: runners/google-cloud-dataflow-java/worker/src/main/java/org/apache/beam/runners/dataflow/worker/logging/JulHandlerPrintStreamAdapterFactory.java
 ##########
 @@ -37,114 +37,272 @@
 class JulHandlerPrintStreamAdapterFactory {
   private static final AtomicBoolean outputWarning = new AtomicBoolean(false);
 
-  /**
-   * Creates a {@link PrintStream} which redirects all output to the JUL {@link Handler} with the
-   * specified {@code loggerName} and {@code level}.
-   */
-  static PrintStream create(Handler handler, String loggerName, Level messageLevel) {
-    try {
-      return new PrintStream(
-          new JulHandlerAdapterOutputStream(handler, loggerName, messageLevel),
-          false,
-          StandardCharsets.UTF_8.name());
-    } catch (UnsupportedEncodingException e) {
-      throw new RuntimeException(e);
-    }
-  }
-
-  /**
-   * An output stream adapter which is able to take a stream of UTF-8 data and output to a named JUL
-   * log handler. The log messages will be buffered until the system dependent new line separator is
-   * seen, at which point the buffered string will be output.
-   */
-  private static class JulHandlerAdapterOutputStream extends OutputStream {
+  private static class JulHandlerPrintStream extends PrintStream {
     private static final String LOGGING_DISCLAIMER =
         String.format(
             "Please use a logger instead of System.out or System.err.%n"
                 + "Please switch to using org.slf4j.Logger.%n"
                 + "See: https://cloud.google.com/dataflow/pipelines/logging");
-    // This limits the number of bytes which we buffer in case we don't see a newline character.
-    private static final int BUFFER_LIMIT = 1 << 14; // 16384 bytes
-    private static final byte[] NEW_LINE = System.lineSeparator().getBytes(StandardCharsets.UTF_8);
+    // This limits the number of bytes which we buffer in case we don't have a flush.
+    private static final int BUFFER_LIMIT = 1 << 10; // 1024 chars
 
     /** Hold reference of named logger to check configured {@link Level}. */
     private Logger logger;
 
     private Handler handler;
     private String loggerName;
-    private ByteArrayOutputStream baos;
+    private StringBuilder buffer;
     private Level messageLevel;
-    private int matched = 0;
 
-    private JulHandlerAdapterOutputStream(Handler handler, String loggerName, Level logLevel) {
+    private JulHandlerPrintStream(Handler handler, String loggerName, Level logLevel) {
+      super(
+          new OutputStream() {
+            @Override
+            public void write(int i) throws IOException {
+              throw new RuntimeException("All methods should be overwritten so this is unused");
+            }
+          });
       this.handler = handler;
       this.loggerName = loggerName;
       this.messageLevel = logLevel;
       this.logger = Logger.getLogger(loggerName);
-      this.baos = new ByteArrayOutputStream(BUFFER_LIMIT);
+      this.buffer = new StringBuilder(BUFFER_LIMIT);
     }
 
     @Override
-    public void write(int b) {
-      if (outputWarning.compareAndSet(false, true)) {
-        publish(Level.WARNING, LOGGING_DISCLAIMER);
+    public void flush() {
+      publish(flushToString());
+    }
+
+    private synchronized String flushToString() {
+      if (buffer.length() > 0 && buffer.charAt(buffer.length() - 1) == '\n') {
+        buffer.setLength(buffer.length() - 1);
       }
+      String result = buffer.toString();
+      buffer.setLength(0);
+      return result;
+    }
 
-      baos.write(b);
-      // Check to see if the next byte matches further into new line string.
-      if (NEW_LINE[matched] == b) {
-        matched += 1;
-        // If we have matched the entire new line, output the contents of the buffer.
-        if (matched == NEW_LINE.length) {
-          output();
-        }
-      } else {
-        // Reset the match
-        matched = 0;
+    @Override
+    public void close() {
+      flush();
+    }
+
+    @Override
+    public boolean checkError() {
+      return false;
+    }
+
+    @Override
+    public synchronized void write(int i) {
+      buffer.append(i);
+    }
+
+    @Override
+    public void write(byte[] a, int start, int limit) {
+      // XXX this enforces decoding on boundaries where before it didn't, does that matter?
+      print(new String(a, start, limit, Charset.defaultCharset()));
+    }
+
+    @Override
+    public synchronized void print(boolean b) {
+      buffer.append(b ? "true" : "false");
+    }
+
+    @Override
+    public synchronized void print(char c) {
+      buffer.append(c);
+    }
+
+    @Override
+    public synchronized void print(int i) {
+      buffer.append(i);
+    }
+
+    @Override
+    public synchronized void print(long l) {
+      buffer.append(l);
+    }
+
+    @Override
+    public synchronized void print(float f) {
+      buffer.append(f);
+    }
+
+    @Override
+    public synchronized void print(double d) {
+      buffer.append(d);
+    }
+
+    @Override
+    public synchronized void print(char[] a) {
+      buffer.append(a);
+    }
+
+    @Override
+    public synchronized void print(String s) {
+      buffer.append(s);
+    }
+
+    @Override
+    public synchronized void print(Object o) {
+      buffer.append(o);
+    }
+
+    @Override
+    public void println() {
+      flush();
+    }
+
+    @Override
+    public void println(boolean b) {
+      String msg;
+      synchronized (this) {
+        buffer.append(b);
+        msg = flushToString();
       }
-      if (baos.size() == BUFFER_LIMIT) {
-        output();
+      publish(msg);
+    }
+
+    @Override
+    public void println(char c) {
+      String msg;
+      synchronized (this) {
+        buffer.append(c);
+        msg = flushToString();
       }
+      publish(msg);
     }
 
     @Override
-    public void flush() throws IOException {
-      output();
+    public void println(int i) {
+      String msg;
+      synchronized (this) {
+        buffer.append(i);
+        msg = flushToString();
+      }
+      publish(msg);
     }
 
     @Override
-    public void close() throws IOException {
-      output();
+    public void println(long l) {
+      String msg;
+      synchronized (this) {
+        buffer.append(l);
+        msg = flushToString();
+      }
+      publish(msg);
     }
 
-    private void output() {
-      // If nothing was output, do not log anything
-      if (baos.size() == 0) {
-        return;
+    @Override
+    public void println(float f) {
+      String msg;
+      synchronized (this) {
+        buffer.append(f);
+        msg = flushToString();
       }
-      try {
-        String message = baos.toString(StandardCharsets.UTF_8.name());
-        // Strip the new line if it exists
-        if (message.endsWith(System.lineSeparator())) {
-          message = message.substring(0, message.length() - System.lineSeparator().length());
-        }
+      publish(msg);
+    }
+
+    @Override
+    public void println(double d) {
+      String msg;
+      synchronized (this) {
+        buffer.append(d);
+        msg = flushToString();
+      }
+      publish(msg);
+    }
+
+    @Override
+    public void println(char[] a) {
+      String msg;
+      synchronized (this) {
+        buffer.append(a);
+        msg = flushToString();
+      }
+      publish(msg);
+    }
+
+    @Override
+    public void println(String s) {
+      String msg;
+      synchronized (this) {
+        buffer.append(s);
+        msg = flushToString();
+      }
+      publish(msg);
+    }
 
-        publish(messageLevel, message);
-      } catch (UnsupportedEncodingException e) {
-        publish(
-            Level.SEVERE, String.format("Unable to decode string output to stdout/stderr %s", e));
+    @Override
+    public void println(Object o) {
+      String msg;
+      synchronized (this) {
+        buffer.append(o);
+        msg = flushToString();
       }
-      matched = 0;
-      baos.reset();
+      publish(msg);
     }
 
-    private void publish(Level level, String message) {
-      if (logger.isLoggable(level)) {
-        LogRecord log = new LogRecord(level, message);
+    @Override
+    public PrintStream format(String format, Object... args) {
+      return format(Locale.getDefault(), format, args);
+    }
+
+    @Override
+    public PrintStream format(Locale locale, String format, Object... args) {
+      String flushed;
+      int newlineIndex;
+      synchronized (this) {
+        int startLength = buffer.length();
+        Formatter formatter = new Formatter(buffer, locale);
+        formatter.format(format, args);
+        newlineIndex = buffer.indexOf("\n", startLength);
+        if (newlineIndex < 0) {
+          return this;
+        }
+        flushed = flushToString();
+      }
+      while (newlineIndex > 0) {
+        publish(flushed.substring(0, newlineIndex));
+        flushed = flushed.substring(newlineIndex + 1);
+        newlineIndex = flushed.indexOf('\n');
+      }
+      publish(flushed);
+      return this;
+    }
+
+    @Override
+    public synchronized PrintStream append(CharSequence cs, int start, int limit) {
+      buffer.append(cs.subSequence(start, limit));
+      return this;
+    }
+
+    // Note to avoid a deadlock, publish may never be called synchronized. See BEAM-9399.
+    private void publish(Level messageLevel, String message) {
+      if (logger.isLoggable(messageLevel)) {
 
 Review comment:
   Done

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