Make the max send retries configurable

Reverts default to infinite as before

Author: jacomago

src/core/com/cosylab/epics/caj/CAJContext.java

@@ -176,6 +176,12 @@ public class CAJContext extends Context implements CAContext, CAJConstants, Conf
 	 */
 	protected int maxArrayBytes = 16384;
 
+	/**
+	 * Maximum number of times to retry a partial TCP send before giving up.
+	 * A value of -1 means retry indefinitely (the default).
+	 */
+	protected int maxSendRetries = -1;
+
 	/**
 	 * Minimum interval in seconds between CA search broadcasts. Default is 0.1 seconds
 	 */
@@ -465,6 +471,11 @@ protected void loadConfiguration()
 				catch (Exception ex)
 				{   logger.log(Level.WARNING, "Cannot parse EPICS_CA_MAX_ARRAY_BYTES='" + tmp + "'", ex); }
 
+			tmp = System.getenv("EPICS_CA_MAX_SEND_RETRIES");
+			if (tmp != null)
+				try { maxSendRetries = Integer.parseInt(tmp); }
+				catch (Exception ex)
+				{   logger.log(Level.WARNING, "Cannot parse EPICS_CA_MAX_SEND_RETRIES='" + tmp + "'", ex); }
 
 			tmp = System.getenv("EPICS_CA_MAX_SEARCH_PERIOD");
 			if (tmp != null)
@@ -485,9 +496,10 @@ protected void loadConfiguration()
 			repeaterPort = jcaLibrary.getPropertyAsInt(contextClassName + ".repeater_port", repeaterPort);
 			serverPort = jcaLibrary.getPropertyAsInt(contextClassName + ".server_port", serverPort);
 			maxArrayBytes = jcaLibrary.getPropertyAsInt(contextClassName + ".max_array_bytes", maxArrayBytes);
+			maxSendRetries = jcaLibrary.getPropertyAsInt(contextClassName + ".max_send_retries", maxSendRetries);
 			maxSearchInterval = jcaLibrary.getPropertyAsFloat(contextClassName + ".max_search_interval", maxSearchInterval);
 			eventDispatcherClassName = jcaLibrary.getProperty(contextClassName + ".event_dispatcher");
-	
+
 			// load CAJ specific configuration (overrides default)
 			addressList = jcaLibrary.getProperty(thisClassName + ".addr_list", addressList);
 			autoAddressList = jcaLibrary.getPropertyAsBoolean(thisClassName + ".auto_addr_list",  autoAddressList);
@@ -500,6 +512,7 @@ protected void loadConfiguration()
 			repeaterPort = jcaLibrary.getPropertyAsInt(thisClassName + ".repeater_port", repeaterPort);
 			serverPort = jcaLibrary.getPropertyAsInt(thisClassName + ".server_port", serverPort);
 			maxArrayBytes = jcaLibrary.getPropertyAsInt(thisClassName + ".max_array_bytes", maxArrayBytes);
+			maxSendRetries = jcaLibrary.getPropertyAsInt(thisClassName + ".max_send_retries", maxSendRetries);
 			minSearchInterval = jcaLibrary.getPropertyAsFloat(thisClassName + ".min_search_interval", minSearchInterval);
 			maxSearchInterval = jcaLibrary.getPropertyAsFloat(thisClassName + ".max_search_interval", maxSearchInterval);
 	    }
@@ -580,6 +593,13 @@ public void configure(Configuration configuration)
 				maxArrayBytes = configuration.getAttributeAsInteger("max_array_bytes", maxArrayBytes);
 			}
 
+			// max. send retries (-1 = infinite)
+			try {
+				maxSendRetries = configuration.getChild("max_send_retries", false).getValueAsInteger();
+			} catch(Exception ex) {
+				maxSendRetries = configuration.getAttributeAsInteger("max_send_retries", maxSendRetries);
+			}
+
 			// max. search interval
 			try {
 				maxSearchInterval = configuration.getChild("max_search_interval", false).getValueAsFloat();
@@ -1322,6 +1342,7 @@ public void printInfo(PrintStream out) throws IllegalStateException {
 		out.println("REPEATER_PORT : " + repeaterPort);
 		out.println("SERVER_PORT : " + serverPort);
 		out.println("MAX_ARRAY_BYTES : " + maxArrayBytes);
+		out.println("MAX_SEND_RETRIES : " + (maxSendRetries < 0 ? "infinite" : maxSendRetries));
 		out.println("MIN_SEARCH_INTERVAL : " + minSearchInterval);
 		out.println("MAX_SEARCH_INTERVAL : " + maxSearchInterval);
 		out.println("EVENT_DISPATCHER: " + eventDispatcher);
@@ -1438,6 +1459,14 @@ public int getMaxArrayBytes() {
 		return maxArrayBytes;
 	}
 
+	/**
+	 * Get maximum number of TCP send retries (-1 means infinite).
+	 * @return max send retries, or -1 for unlimited.
+	 */
+	public int getMaxSendRetries() {
+		return maxSendRetries;
+	}
+
 	/**
 	 * Get repeater port.
 	 * @return repeater port.

src/core/com/cosylab/epics/caj/impl/CATransport.java

@@ -628,9 +628,6 @@ protected void enableFlowControl()
 		}
 	}
 
-	/** Maximum number of times to retry a partial write before giving up. */
-	private static final int MAX_SEND_RETRIES = 10;
-
 	/**
 	 * Send a buffer through the transport.
 	 * NOTE: TCP sent buffer/sending has to be synchronized.
@@ -657,8 +654,9 @@ public void send(ByteBuffer buffer) throws IOException
 	 * <p>Flips the buffer, then loops until all bytes are written.  If the
 	 * kernel TCP send buffer is full, waits briefly and retries.  Throws
 	 * {@link IOException} (and closes the transport) if the send buffer
-	 * remains full after {@value #MAX_SEND_RETRIES} retries, the channel is
-	 * already closed, or the calling thread is interrupted.
+	 * remains full after the configured max send retries (see
+	 * {@link CAJContext#getMaxSendRetries()}; -1 means retry indefinitely),
+	 * the channel is already closed, or the calling thread is interrupted.
 	 *
 	 * @param buffer	fully-written buffer to send (will be flipped)
 	 * @throws IOException on write error, persistent backpressure, or interrupt
@@ -672,6 +670,7 @@ private void noSyncSend(ByteBuffer buffer) throws IOException
 			context.getLogger().finest("Sending " + buffer.limit() + " bytes to " + socketAddress + ".");
 
 			int tries = 0;
+			final int maxRetries = context.getMaxSendRetries();
 			while (buffer.hasRemaining())
 			{
 				int bytesSent = channel.write(buffer);
@@ -683,11 +682,13 @@ private void noSyncSend(ByteBuffer buffer) throws IOException
 					if (closed)
 						throw new IOException("transport closed on the client side");
 
-					if (++tries > MAX_SEND_RETRIES)
+					tries++;
+					if (maxRetries >= 0 && tries > maxRetries)
 						throw new IOException("TCP send buffer persistently full, disconnecting " + socketAddress);
 
 					context.getLogger().finest("Send buffer full for " + socketAddress
-							+ ", waiting (attempt " + tries + "/" + MAX_SEND_RETRIES + ")...");
+							+ ", waiting (attempt " + tries
+							+ (maxRetries < 0 ? "" : "/" + maxRetries) + ")...");
 					try {
 						Thread.sleep(Math.min(15000, 10 + tries * 100));
 					} catch (InterruptedException e) {