场景

在使用spring cloud gateway时想要输出请求日志，考虑到两种实现方案

方案一

官网中使用Reactor Netty Access Logs方案，配置“-Dreactor.netty.http.server.accessLogEnabled=true”开启日志记录。

输出如下：

reactor.netty.http.server.AccessLog      :
10.2.20.177 - - [02/Dec/2020:16:41:57 +0800] "GET /fapi/gw/hi/login HTTP/1.1" 200 319 8080 626 ms

• 优点:简单方便
• 缺点:格式固定，信息量少

方案二

创建一个logfilter，在logfilter中解析request，并输出请求信息

• 优点:可以自定义日志格式和内容,可以获取body信息
• 缺点:返回信息需要再写一个filter,没有匹配到路由时无法进入到logfilter中

思路

对方案一进行改造，使其满足需求。对reactor-netty源码分析，主要涉及

• AccessLog：日志工具，日志结构体
• AccessLogHandler：http1.1协议日志控制，我们主要使用这个。
• AccessLogHandler2：http2协议日志控制

代码如下：

package reactor.netty.http.server;

import reactor.util.Logger;
import reactor.util.Loggers;

import java.time.ZonedDateTime;
import java.time.format.DateTimeFormatter;
import java.util.Locale;
import java.util.Objects;

final class AccessLog {
	static final Logger log = Loggers.getLogger("reactor.netty.http.server.AccessLog");
	static final DateTimeFormatter DATE_TIME_FORMATTER =
			DateTimeFormatter.ofPattern("dd/MMM/yyyy:HH:mm:ss Z", Locale.US);
	static final String COMMON_LOG_FORMAT =
			"{} - {} [{}] \"{} {} {}\" {} {} {} {} ms";
	static final String MISSING = "-";

	final String zonedDateTime;

	String address;
	CharSequence method;
	CharSequence uri;
	String protocol;
	String user = MISSING;
	CharSequence status;
	long contentLength;
	boolean chunked;
	long startTime = System.currentTimeMillis();
	int port;

	AccessLog() {
		this.zonedDateTime = ZonedDateTime.now().format(DATE_TIME_FORMATTER);
	}

	AccessLog address(String address) {
		this.address = Objects.requireNonNull(address, "address");
		return this;
	}

	AccessLog port(int port) {
		this.port = port;
		return this;
	}

	AccessLog method(CharSequence method) {
		this.method = Objects.requireNonNull(method, "method");
		return this;
	}

	AccessLog uri(CharSequence uri) {
		this.uri = Objects.requireNonNull(uri, "uri");
		return this;
	}

	AccessLog protocol(String protocol) {
		this.protocol = Objects.requireNonNull(protocol, "protocol");
		return this;
	}

	AccessLog status(CharSequence status) {
		this.status = Objects.requireNonNull(status, "status");
		return this;
	}

	AccessLog contentLength(long contentLength) {
		this.contentLength = contentLength;
		return this;
	}

	AccessLog increaseContentLength(long contentLength) {
		if (chunked) {
			this.contentLength += contentLength;
		}
		return this;
	}

	AccessLog chunked(boolean chunked) {
		this.chunked = chunked;
		return this;
	}

	long duration() {
		return System.currentTimeMillis() - startTime;
	}

	void log() {
		if (log.isInfoEnabled()) {
			log.info(COMMON_LOG_FORMAT, address, user, zonedDateTime,
					method, uri, protocol, status, (contentLength > -1 ? contentLength : MISSING), port, duration());
		}
	}
}

• AccessLogHandler：日志控制

package reactor.netty.http.server;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufHolder;
import io.netty.channel.ChannelDuplexHandler;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPromise;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.http.HttpRequest;
import io.netty.handler.codec.http.HttpResponse;
import io.netty.handler.codec.http.HttpResponseStatus;
import io.netty.handler.codec.http.HttpUtil;
import io.netty.handler.codec.http.LastHttpContent;

/**
 * @author Violeta Georgieva
 */
final class AccessLogHandler extends ChannelDuplexHandler {

	AccessLog accessLog = new AccessLog();

	@Override
	public void channelRead(ChannelHandlerContext ctx, Object msg) {
		if (msg instanceof HttpRequest) {
			final HttpRequest request = (HttpRequest) msg;
			final SocketChannel channel = (SocketChannel) ctx.channel();

			accessLog = new AccessLog()
			        .address(channel.remoteAddress().getHostString())
			        .port(channel.localAddress().getPort())
			        .method(request.method().name())
			        .uri(request.uri())
			        .protocol(request.protocolVersion().text());
		}
		ctx.fireChannelRead(msg);
	}

	@Override
	@SuppressWarnings("FutureReturnValueIgnored")
	public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) {
		if (msg instanceof HttpResponse) {
			final HttpResponse response = (HttpResponse) msg;
			final HttpResponseStatus status = response.status();

			if (status.equals(HttpResponseStatus.CONTINUE)) {
				//"FutureReturnValueIgnored" this is deliberate
				ctx.write(msg, promise);
				return;
			}

			final boolean chunked = HttpUtil.isTransferEncodingChunked(response);
			accessLog.status(status.codeAsText())
			         .chunked(chunked);
			if (!chunked) {
				accessLog.contentLength(HttpUtil.getContentLength(response, -1));
			}
		}
		if (msg instanceof LastHttpContent) {
			accessLog.increaseContentLength(((LastHttpContent) msg).content().readableBytes());
			ctx.write(msg, promise.unvoid())
			   .addListener(future -> {
			       if (future.isSuccess()) {
			           accessLog.log();
			       }
			   });
			return;
		}
		if (msg instanceof ByteBuf) {
			accessLog.increaseContentLength(((ByteBuf) msg).readableBytes());
		}
		if (msg instanceof ByteBufHolder) {
			accessLog.increaseContentLength(((ByteBufHolder) msg).content().readableBytes());
		}
		//"FutureReturnValueIgnored" this is deliberate
		ctx.write(msg, promise);
	}
}

• 执行顺序

AccessLogHandler.channelRead > GlobalFilter.filter > AbstractLoadBalance.choose >response.writeWith >AccessLogHandler.write

 

解决方案

对AccessLog和AccessLogHandler进行重写，输出自己想要的内容和样式。

AccessLogHandler中重写了ChannelDuplexHandler中的channelRead和write方法，还可以对ChannelInboundHandler和ChannelOutboundHandler中的方法进行重写，覆盖请求的整个生命周期。