Spring Sleuth实现主动添加日志的方式

最新推荐文章于 2025-06-08 08:44:48 发布

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最新推荐文章于 2025-06-08 08:44:48 发布

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文章标签： java

原文链接：https://my.oschina.net/seal90/blog/3086404

本文详细介绍了Spring Sleuth如何通过修改logging.pattern.level变量实现在日志中注入跟踪信息，包括Span ID和Trace ID等关键数据。在Spring Boot应用中，当启用Sleuth时，它会自动调整日志模式，以便在不额外配置的情况下，可以在日志输出中看到跟踪信息。

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Spring Sleuth 是通过 logging.pattern.level 变量来实现主动日志添加的。

添加在 TraceEnvironmentPostProcessor 中

	@Override
	public void postProcessEnvironment(ConfigurableEnvironment environment,
			SpringApplication application) {
		Map<String, Object> map = new HashMap<String, Object>();
		// This doesn't work with all logging systems but it's a useful default so you see
		// traces in logs without having to configure it.
		// 在这里判断开启 sleuth 则修改 logging.pattern.level 的值
		if (Boolean.parseBoolean(environment.getProperty("spring.sleuth.enabled", "true"))) {
			map.put("logging.pattern.level",
					"%5p [${spring.zipkin.service.name:${spring.application.name:-}},%X{X-B3-TraceId:-},%X{X-B3-SpanId:-},%X{X-Span-Export:-}]");
		}
		// TODO: Remove this in 2.0.x. For compatibility we always set to true
		if (!environment.containsProperty(SPRING_AOP_PROXY_TARGET_CLASS)) {
			map.put(SPRING_AOP_PROXY_TARGET_CLASS, "true");
		}
		addOrReplace(environment.getPropertySources(), map);
	}

在 LoggingSystemProperties 将 LOG_LEVEL_PATTERN 的值设置为 logging.pattern.level 的值

	public void apply(LogFile logFile) {
		RelaxedPropertyResolver propertyResolver = RelaxedPropertyResolver
				.ignoringUnresolvableNestedPlaceholders(this.environment, "logging.");
		setSystemProperty(propertyResolver, EXCEPTION_CONVERSION_WORD,
				"exception-conversion-word");
		setSystemProperty(PID_KEY, new ApplicationPid().toString());
		setSystemProperty(propertyResolver, CONSOLE_LOG_PATTERN, "pattern.console");
		setSystemProperty(propertyResolver, FILE_LOG_PATTERN, "pattern.file");
		// LOG_LEVEL_PATTERN = "LOG_LEVEL_PATTERN" 设置到环境变量
		setSystemProperty(propertyResolver, LOG_LEVEL_PATTERN, "pattern.level");
		if (logFile != null) {
			logFile.applyToSystemProperties();
		}
	}

设置

在 PropertyAction#begin 解析配置在 InterpretationContext 解析当前的字符串

    public String subst(String value) {
        if (value == null) {
            return null;
        }
        return OptionHelper.substVars(value, this, context);
    }

    public static String substVars(String input, PropertyContainer pc0, PropertyContainer pc1) {
        try {
            return NodeToStringTransformer.substituteVariable(input, pc0, pc1);
        } catch (ScanException e) {
            throw new IllegalArgumentException("Failed to parse input [" + input + "]", e);
        }
    }

    public static String substituteVariable(String input, PropertyContainer pc0, PropertyContainer pc1) throws ScanException {
        Node node = tokenizeAndParseString(input);
        NodeToStringTransformer nodeToStringTransformer = new NodeToStringTransformer(node, pc0, pc1);
        return nodeToStringTransformer.transform();
    }

    public String transform() throws ScanException {
        StringBuilder stringBuilder = new StringBuilder();
        compileNode(node, stringBuilder, new Stack<Node>());
        return stringBuilder.toString();
    }
    private void compileNode(Node inputNode, StringBuilder stringBuilder, Stack<Node> cycleCheckStack) throws ScanException {
        Node n = inputNode;
        while (n != null) {
            switch (n.type) {
            case LITERAL:
                handleLiteral(n, stringBuilder);
                break;
            case VARIABLE:
                handleVariable(n, stringBuilder, cycleCheckStack);
                break;
            }
            n = n.next;
        }
    }

	private void handleVariable(Node n, StringBuilder stringBuilder, Stack<Node> cycleCheckStack) throws ScanException {
		// ...
		String key = keyBuffer.toString();
        String value = lookupKey(key);
		// ...
	}
	private String lookupKey(String key) {
        String value = propertyContainer0.getProperty(key);
        if (value != null)
            return value;

        if (propertyContainer1 != null) {
            value = propertyContainer1.getProperty(key);
            if (value != null)
                return value;
        }
		// 在这里找到值
        value = OptionHelper.getSystemProperty(key, null);
        if (value != null)
            return value;

        value = OptionHelper.getEnv(key);
        if (value != null) {
            return value;
        }

        return null;
    }

    public static String getSystemProperty(String key, String def) {
        try {
            return System.getProperty(key, def);
        } catch (SecurityException e) {
            return def;
        }
    }

转载于:https://my.oschina.net/seal90/blog/3086404