APM - 零侵入监控Http服务

本是古典何须时尚 2022-12-12 15:21 143阅读 0赞

### 文章目录 ###

*  Pre
 *  HTTP采集入口
 *  Code

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# Pre #

[APM - 零侵入监控Service服务][APM - _Service]

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# HTTP采集入口 #

1.  DispacherServlet .doServer() ？
2.  @Control ？
3.  javax.servlet.http.HttpServlet ？

很显然第三种更具有通用性，不管是DispacherServlet 还是@Control 都会是基于`HttpServlet#service`

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbmdzaGFuZ3dlaQ_size_16_color_FFFFFF_t_70_pic_center 1]

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# Code #

package com.artisan.collects;
    
    import com.artisan.ApmContext;
    import com.artisan.intf.ICollect;
    import com.artisan.model.HttpStatistics;
    import javassist.*;
    
    import java.lang.instrument.Instrumentation;
    import java.lang.reflect.Method;
    import java.util.Map;
    
    /** * Http采集器 */
    public class HttpCollect extends AbstractByteTransformCollect implements ICollect { 
        // 采集目标
        // 1.DispatchServlet
        // 2.@control 下的方法
        // 3.采集 javax.servlet.service() ---- 采用这种通用的方式
        private static final String TARGET_CLASS = "javax.servlet.http.HttpServlet";
        private static final String TARGET_METHOD = "service";
        private static ApmContext context;
    
        public HttpCollect(ApmContext context, Instrumentation instrumentation) { 
            super(instrumentation);
            this.context = context;
        }
    
    
        public byte[] buildClass(ClassLoader loader) throws Exception { 
            ClassPool pool = new ClassPool();
            pool.insertClassPath(new LoaderClassPath(loader));
            CtClass ctClass = pool.get(TARGET_CLASS);
            CtMethod oldMethod = ctClass.getDeclaredMethod(TARGET_METHOD);
            CtMethod newMethod = CtNewMethod.copy(oldMethod, ctClass, null);
            oldMethod.setName(oldMethod.getName() + "$agent");
            //HttpServlet.service()'
    
            String beginSrc = "Object stat=com.artisan.collects.HttpCollect.begin($args);";
            String errorSrc = "com.artisan.collects.HttpCollect.error(e,stat);";
            String endSrc = "com.artisan.collects.HttpCollect.end(stat);";
            newMethod.setBody(String.format(voidSource, beginSrc, TARGET_METHOD, errorSrc, endSrc));
            ctClass.addMethod(newMethod);
            return ctClass.toBytecode();
        }
    
        // url,client IP
        public static HttpStatistics begin(Object args[]) { 
            HttpStatistics httpStatistics = new HttpStatistics();
            httpStatistics.setBeginTime(System.currentTimeMillis());
            // 采用适配器的方式 ，避免在tomcat下 agent【appLauncher装载】无法获取到HttpServletRequest【common加载】（classLoader机制）
            HttpServletRequestAdapter adapter = new HttpServletRequestAdapter(args[0]);
            httpStatistics.setUrl(adapter.getRequestURI());
            httpStatistics.setClientIp(adapter.getClientIp());
            return httpStatistics;
        }
    
        public static void end(Object obj) { 
            HttpStatistics stat = (HttpStatistics) obj;
            ((HttpStatistics) obj).setUseTime(System.currentTimeMillis() - stat.getBeginTime());
            context.submitCollectResult(stat);
        }
    
        public static void error(Throwable error, Object obj) { 
            HttpStatistics stat = (HttpStatistics) obj;
            stat.setError(error.getMessage());
            System.out.println(stat);
        }
    
        final static String voidSource = "{\n"
                + "%s"
                + " try {\n"
                + " %s$agent($$);\n"
                + " } catch (Throwable e) {\n"
                + "%s"
                + " throw e;\n"
                + " }finally{\n"
                + "%s"
                + " }\n"
                + "}\n";
    
        @Override
        public byte[] transform(ClassLoader loader, String className) throws Exception { 
            if (!TARGET_CLASS.equals(className)) { 
                return null;
            }
            try { 
                return buildClass(loader);
            } catch (Exception e) { 
                e.printStackTrace();
            }
            return null;
        }
    
        private static class HttpServletRequestAdapter { 
            private final Object target;
            private final Method _getRequestURI;
            private final Method _getRequestURL;
            private final Method _getParameterMap;
            private final Method _getMethod;
            private final Method _getHeader;
            private final Method _getRemoteAddr;
            private final static String targetClassName = "javax.servlet.http.HttpServletRequest";
    
            public HttpServletRequestAdapter(Object target) { 
                this.target = target;
                try { 
                    Class<?> targetClass = target.getClass().getClassLoader().loadClass(targetClassName);
                    _getRequestURI = targetClass.getMethod("getRequestURI");
                    _getParameterMap = targetClass.getMethod("getParameterMap");
                    _getMethod = targetClass.getMethod("getMethod");
                    _getHeader = targetClass.getMethod("getHeader", String.class);
                    _getRemoteAddr = targetClass.getMethod("getRemoteAddr");
                    _getRequestURL = targetClass.getMethod("getRequestURL");
                } catch (NoSuchMethodException e) { 
                    throw new IllegalArgumentException("error :" + e.getMessage() + ". probable cause the target is not belong javax.servlet.http.HttpServletRequest ");
                } catch (ClassNotFoundException e) { 
                    throw new IllegalArgumentException("error :" + e.getMessage() + ". probable cause the target is not belong javax.servlet.http.HttpServletRequest ");
                }
            }
    
    
            public String getRequestURI() { 
                try { 
                    return (String) _getRequestURI.invoke(target);
                } catch (Exception e) { 
                    throw new RuntimeException(e);
                }
            }
    
            public String getRequestURL() { 
                try { 
                    return _getRequestURL.invoke(target).toString();
                } catch (Exception e) { 
                    throw new RuntimeException(e);
                }
            }
    
            public Map<String, String[]> getParameterMap() { 
                try { 
                    return (Map<String, String[]>) _getParameterMap.invoke(target);
                } catch (Exception e) { 
                    throw new RuntimeException(e);
                }
            }
    
            public String getMethod() { 
                try { 
                    return (String) _getMethod.invoke(target);
                } catch (Exception e) { 
                    throw new RuntimeException(e);
                }
            }
    
            public String getHeader(String name) { 
                try { 
                    return (String) _getHeader.invoke(target, name);
                } catch (Exception e) { 
                    throw new RuntimeException(e);
                }
            }
    
            public String getRemoteAddr() { 
                try { 
                    return (String) _getRemoteAddr.invoke(target);
                } catch (Exception e) { 
                    throw new RuntimeException(e);
                }
            }
    
            public String getClientIp() { 
                String ip = getHeader("x-forwarded-for");
                if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) { 
                    ip = getHeader("Proxy-Client-IP");
                }
                if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) { 
                    ip = getHeader("WL-Proxy-Client-IP");
                }
                if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) { 
                    ip = getRemoteAddr();
                }
                return ip;
            }
    
        }
    }

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbmdzaGFuZ3dlaQ_size_16_color_FFFFFF_t_70_pic_center]: /images/20221123/6da051d2c0474556af7fc10d351e1134.png
[APM - _Service]: https://blog.csdn.net/yangshangwei/article/details/108959730
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbmdzaGFuZ3dlaQ_size_16_color_FFFFFF_t_70_pic_center 1]: /images/20221123/ac1cae3aa93c4805bb142016d7b254f9.png