Logging improvements for WebFlux

Issue: SPR-16898

Author: rstoyanchev

spring-core/src/main/java/org/springframework/core/codec/AbstractDecoder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,6 +20,8 @@
 import java.util.List;
 import java.util.Map;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 import org.reactivestreams.Publisher;
 import reactor.core.publisher.Mono;
 
@@ -37,6 +39,8 @@
  */
 public abstract class AbstractDecoder<T> implements Decoder<T> {
 
+	protected final Log logger = LogFactory.getLog(getClass());
+
 	private final List<MimeType> decodableMimeTypes;
 
 

spring-core/src/main/java/org/springframework/core/codec/AbstractEncoder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,6 +18,10 @@
 
 import java.util.Arrays;
 import java.util.List;
+import java.util.Map;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 
 import org.springframework.core.ResolvableType;
 import org.springframework.lang.Nullable;
@@ -32,6 +36,8 @@
  */
 public abstract class AbstractEncoder<T> implements Encoder<T> {
 
+	protected final Log logger = LogFactory.getLog(getClass());
+
 	private final List<MimeType> encodableMimeTypes;
 
 
@@ -53,4 +59,17 @@ public boolean canEncode(ResolvableType elementType, @Nullable MimeType mimeType
 		return this.encodableMimeTypes.stream().anyMatch(candidate -> candidate.isCompatibleWith(mimeType));
 	}
 
+	/**
+	 * Helper method to obtain the logger to use from the Map of hints, or fall
+	 * back on the default logger. This may be used for example to override
+	 * logging, e.g. for a multipart request where the full map of part values
+	 * has already been logged.
+	 * @param hints the hints passed to the encode method
+	 * @return the logger to use
+	 * @since 5.1
+	 */
+	protected Log getLogger(@Nullable Map<String, Object> hints) {
+		return hints != null ? ((Log) hints.getOrDefault(Log.class.getName(), logger)) : logger;
+	}
+
 }

spring-core/src/main/java/org/springframework/core/codec/ByteArrayDecoder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -53,6 +53,9 @@ protected byte[] decodeDataBuffer(DataBuffer dataBuffer, ResolvableType elementT
 		byte[] result = new byte[dataBuffer.readableByteCount()];
 		dataBuffer.read(result);
 		DataBufferUtils.release(dataBuffer);
+		if (logger.isDebugEnabled()) {
+			logger.debug("Read " + result.length + " bytes");
+		}
 		return result;
 	}
 

spring-core/src/main/java/org/springframework/core/codec/ByteArrayEncoder.java

@@ -18,6 +18,7 @@
 
 import java.util.Map;
 
+import org.apache.commons.logging.Log;
 import org.reactivestreams.Publisher;
 import reactor.core.publisher.Flux;
 
@@ -52,7 +53,14 @@ public Flux<DataBuffer> encode(Publisher<? extends byte[]> inputStream,
 			DataBufferFactory bufferFactory, ResolvableType elementType, @Nullable MimeType mimeType,
 			@Nullable Map<String, Object> hints) {
 
-		return Flux.from(inputStream).map(bufferFactory::wrap);
+		return Flux.from(inputStream).map(bytes -> {
+			DataBuffer dataBuffer = bufferFactory.wrap(bytes);
+			Log logger = getLogger(hints);
+			if (logger.isDebugEnabled()) {
+				logger.debug("Writing " + dataBuffer.readableByteCount() + " bytes");
+			}
+			return dataBuffer;
+		});
 	}
 
 }

spring-core/src/main/java/org/springframework/core/codec/ByteBufferDecoder.java

@@ -52,10 +52,14 @@ public boolean canDecode(ResolvableType elementType, @Nullable MimeType mimeType
 	protected ByteBuffer decodeDataBuffer(DataBuffer dataBuffer, ResolvableType elementType,
 			@Nullable MimeType mimeType, @Nullable Map<String, Object> hints) {
 
-		ByteBuffer copy = ByteBuffer.allocate(dataBuffer.readableByteCount());
+		int byteCount = dataBuffer.readableByteCount();
+		ByteBuffer copy = ByteBuffer.allocate(byteCount);
 		copy.put(dataBuffer.asByteBuffer());
 		copy.flip();
 		DataBufferUtils.release(dataBuffer);
+		if (logger.isDebugEnabled()) {
+			logger.debug("Read " + byteCount + " bytes");
+		}
 		return copy;
 	}
 

spring-core/src/main/java/org/springframework/core/codec/ByteBufferEncoder.java

@@ -19,6 +19,7 @@
 import java.nio.ByteBuffer;
 import java.util.Map;
 
+import org.apache.commons.logging.Log;
 import org.reactivestreams.Publisher;
 import reactor.core.publisher.Flux;
 
@@ -53,7 +54,14 @@ public Flux<DataBuffer> encode(Publisher<? extends ByteBuffer> inputStream,
 			DataBufferFactory bufferFactory, ResolvableType elementType, @Nullable MimeType mimeType,
 			@Nullable Map<String, Object> hints) {
 
-		return Flux.from(inputStream).map(bufferFactory::wrap);
+		return Flux.from(inputStream).map(byteBuffer -> {
+			DataBuffer dataBuffer = bufferFactory.wrap(byteBuffer);
+			Log logger = getLogger(hints);
+			if (logger.isDebugEnabled()) {
+				logger.debug("Writing " + dataBuffer.readableByteCount() + " bytes");
+			}
+			return dataBuffer;
+		});
 	}
 
 }

spring-core/src/main/java/org/springframework/core/codec/CharSequenceEncoder.java

@@ -22,6 +22,7 @@
 import java.nio.charset.StandardCharsets;
 import java.util.Map;
 
+import org.apache.commons.logging.Log;
 import org.reactivestreams.Publisher;
 import reactor.core.publisher.Flux;
 
@@ -65,6 +66,10 @@ public Flux<DataBuffer> encode(Publisher<? extends CharSequence> inputStream,
 		Charset charset = getCharset(mimeType);
 
 		return Flux.from(inputStream).map(charSequence -> {
+			Log logger = getLogger(hints);
+			if (logger.isDebugEnabled()) {
+				logger.debug("Writing '" + charSequence + "'");
+			}
 			CharBuffer charBuffer = CharBuffer.wrap(charSequence);
 			ByteBuffer byteBuffer = charset.encode(charBuffer);
 			return bufferFactory.wrap(byteBuffer);

spring-core/src/main/java/org/springframework/core/codec/DataBufferDecoder.java

@@ -62,6 +62,9 @@ public Flux<DataBuffer> decode(Publisher<DataBuffer> inputStream, ResolvableType
 	protected DataBuffer decodeDataBuffer(DataBuffer buffer, ResolvableType elementType,
 			@Nullable MimeType mimeType, @Nullable Map<String, Object> hints) {
 
+		if (logger.isDebugEnabled()) {
+			logger.debug("Read " + buffer.readableByteCount() + " bytes");
+		}
 		return buffer;
 	}
 

spring-core/src/main/java/org/springframework/core/codec/DataBufferEncoder.java

@@ -18,6 +18,7 @@
 
 import java.util.Map;
 
+import org.apache.commons.logging.Log;
 import org.reactivestreams.Publisher;
 import reactor.core.publisher.Flux;
 
@@ -52,7 +53,14 @@ public Flux<DataBuffer> encode(Publisher<? extends DataBuffer> inputStream,
 			DataBufferFactory bufferFactory, ResolvableType elementType, @Nullable MimeType mimeType,
 			@Nullable Map<String, Object> hints) {
 
-		return Flux.from(inputStream);
+		Flux<DataBuffer> flux = Flux.from(inputStream);
+
+		Log logger = getLogger(hints);
+		if (logger.isDebugEnabled()) {
+			flux = flux.doOnNext(buffer -> logger.debug("Writing " + buffer.readableByteCount() + " bytes"));
+		}
+
+		return flux;
 	}
 
 }

spring-core/src/main/java/org/springframework/core/codec/ResourceDecoder.java

@@ -72,6 +72,10 @@ protected Resource decodeDataBuffer(DataBuffer dataBuffer, ResolvableType elemen
 		Class<?> clazz = elementType.getRawClass();
 		Assert.state(clazz != null, "No resource class");
 
+		if (logger.isDebugEnabled()) {
+			logger.debug("Read " + bytes.length + " bytes");
+		}
+
 		if (InputStreamResource.class == clazz) {
 			return new InputStreamResource(new ByteArrayInputStream(bytes));
 		}