聊聊tomcat的connection-timeout

序

本文主要研究一下tomcat的connection-timeout

ServerProperties.Tomcat

org/springframework/boot/autoconfigure/web/ServerProperties.java

    public static class Tomcat {

        /**
         * Access log configuration.
         */
        private final Accesslog accesslog = new Accesslog();

        /**
         * Thread related configuration.
         */
        private final Threads threads = new Threads();

        /**
         * Tomcat base directory. If not specified, a temporary directory is used.
         */
        private File basedir;

        /**
         * Delay between the invocation of backgroundProcess methods. If a duration suffix
         * is not specified, seconds will be used.
         */
        @DurationUnit(ChronoUnit.SECONDS)
        private Duration backgroundProcessorDelay = Duration.ofSeconds(10);

        /**
         * Maximum size of the form content in any HTTP post request.
         */
        private DataSize maxHttpFormPostSize = DataSize.ofMegabytes(2);

        /**
         * Maximum amount of request body to swallow.
         */
        private DataSize maxSwallowSize = DataSize.ofMegabytes(2);

        /**
         * Whether requests to the context root should be redirected by appending a / to
         * the path. When using SSL terminated at a proxy, this property should be set to
         * false.
         */
        private Boolean redirectContextRoot = true;

        /**
         * Whether HTTP 1.1 and later location headers generated by a call to sendRedirect
         * will use relative or absolute redirects.
         */
        private boolean useRelativeRedirects;

        /**
         * Character encoding to use to decode the URI.
         */
        private Charset uriEncoding = StandardCharsets.UTF_8;

        /**
         * Maximum number of connections that the server accepts and processes at any
         * given time. Once the limit has been reached, the operating system may still
         * accept connections based on the "acceptCount" property.
         */
        private int maxConnections = 8192;

        /**
         * Maximum queue length for incoming connection requests when all possible request
         * processing threads are in use.
         */
        private int acceptCount = 100;

        /**
         * Maximum number of idle processors that will be retained in the cache and reused
         * with a subsequent request. When set to -1 the cache will be unlimited with a
         * theoretical maximum size equal to the maximum number of connections.
         */
        private int processorCache = 200;

        /**
         * Comma-separated list of additional patterns that match jars to ignore for TLD
         * scanning. The special '?' and '*' characters can be used in the pattern to
         * match one and only one character and zero or more characters respectively.
         */
        private List<String> additionalTldSkipPatterns = new ArrayList<>();

        /**
         * Comma-separated list of additional unencoded characters that should be allowed
         * in URI paths. Only "< > [ \ ] ^ ` { | }" are allowed.
         */
        private List<Character> relaxedPathChars = new ArrayList<>();

        /**
         * Comma-separated list of additional unencoded characters that should be allowed
         * in URI query strings. Only "< > [ \ ] ^ ` { | }" are allowed.
         */
        private List<Character> relaxedQueryChars = new ArrayList<>();

        /**
         * Amount of time the connector will wait, after accepting a connection, for the
         * request URI line to be presented.
         */
        private Duration connectionTimeout;

        /**
         * Static resource configuration.
         */
        private final Resource resource = new Resource();

        /**
         * Modeler MBean Registry configuration.
         */
        private final Mbeanregistry mbeanregistry = new Mbeanregistry();

        /**
         * Remote Ip Valve configuration.
         */
        private final Remoteip remoteip = new Remoteip();

        //......
    }    

springboot的ServerProperties.Tomcat定义了connectionTimeout属性，用于指定接受连接之后等待uri的时间

customizeConnectionTimeout

org/springframework/boot/autoconfigure/web/embedded/TomcatWebServerFactoryCustomizer.java

    private void customizeConnectionTimeout(ConfigurableTomcatWebServerFactory factory, Duration connectionTimeout) {
        factory.addConnectorCustomizers((connector) -> {
            ProtocolHandler handler = connector.getProtocolHandler();
            if (handler instanceof AbstractProtocol) {
                AbstractProtocol<?> protocol = (AbstractProtocol<?>) handler;
                protocol.setConnectionTimeout((int) connectionTimeout.toMillis());
            }
        });
    }

customizeConnectionTimeout将connectionTimeout写入到AbstractProtocol

AbstractProtocol

org/apache/coyote/AbstractProtocol.java

    public void setConnectionTimeout(int timeout) {
        endpoint.setConnectionTimeout(timeout);
    }

AbstractProtocol将timeout设置到endpoint

AbstractEndpoint

org/apache/tomcat/util/net/AbstractEndpoint.java

    public void setConnectionTimeout(int soTimeout) { 
        socketProperties.setSoTimeout(soTimeout); 
    }

    /**
     * Keepalive timeout, if not set the soTimeout is used.
     */
    private Integer keepAliveTimeout = null;
    public int getKeepAliveTimeout() {
        if (keepAliveTimeout == null) {
            return getConnectionTimeout();
        } else {
            return keepAliveTimeout.intValue();
        }
    }

AbstractEndpoint将timeout设置到socketProperties的soTimeout，另外它的getKeepAliveTimeout方法在keepAliveTimeout为null的时候，使用的是getConnectionTimeout

Http11Processor

org/apache/coyote/http11/Http11Processor.java

    public SocketState service(SocketWrapperBase<?> socketWrapper)
        throws IOException {
        RequestInfo rp = request.getRequestProcessor();
        rp.setStage(org.apache.coyote.Constants.STAGE_PARSE);

        // Setting up the I/O
        setSocketWrapper(socketWrapper);

        // Flags
        keepAlive = true;
        openSocket = false;
        readComplete = true;
        boolean keptAlive = false;
        SendfileState sendfileState = SendfileState.DONE;

        while (!getErrorState().isError() && keepAlive && !isAsync() && upgradeToken == null &&
                sendfileState == SendfileState.DONE && !protocol.isPaused()) {

            // Parsing the request header
            try {
                if (!inputBuffer.parseRequestLine(keptAlive, protocol.getConnectionTimeout(),
                        protocol.getKeepAliveTimeout())) {
                    if (inputBuffer.getParsingRequestLinePhase() == -1) {
                        return SocketState.UPGRADING;
                    } else if (handleIncompleteRequestLineRead()) {
                        break;
                    }
                }

                //......
            }
            
            //......
        }
        
        //......
    }          

Http11Processor的service方法在执行inputBuffer.parseRequestLine时传入了keptAlive、protocol.getConnectionTimeout()、protocol.getKeepAliveTimeout()参数

小结

springboot提供了tomcat的connection-timeout参数配置，其配置的是socket timeout，不过springboot没有提供对keepAliveTimeout的配置，它默认是null，读取的是connection timeout的配置。