Skywalking-08：OAL原理——如何动态生成Class类

我不是女神ヾ 2022-09-02 13:44 77阅读 0赞

# `OAL` 如何动态生成 `Class` 类 #

## 代码入口 ##

在 `org.apache.skywalking.oal.rt.OALRuntime#start` 方法

public void start(ClassLoader currentClassLoader) throws ModuleStartException, OALCompileException { 
            if (!IS_RT_TEMP_FOLDER_INIT_COMPLETED) { 
                prepareRTTempFolder();
                IS_RT_TEMP_FOLDER_INIT_COMPLETED = true;
            }
    
            this.currentClassLoader = currentClassLoader;
            Reader read;
    
            try { 
                read = ResourceUtils.read(oalDefine.getConfigFile());
            } catch (FileNotFoundException e) { 
                throw new ModuleStartException("Can't locate " + oalDefine.getConfigFile(), e);
            }
    
            OALScripts oalScripts;
            try { 
                ScriptParser scriptParser = ScriptParser.createFromFile(read, oalDefine.getSourcePackage());
                // 解析oal脚本，生成OALScripts对象
                oalScripts = scriptParser.parse();
            } catch (IOException e) { 
                throw new ModuleStartException("OAL script parse analysis failure.", e);
            }
    		// OALScripts对象动态生成需要的类
            this.generateClassAtRuntime(oalScripts);
        }

## 时序图 ##

[OALRuntime-generate-class-at-runtime.sdt][] 该文件可以在 `IDEA` 的 `Sequence Diagram` 插件中打开

![请添加图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3E1NDc1NTA4MzE_size_16_color_FFFFFF_t_70]

## 案例 ##

启动 `OAP` 配置中，配置下环境变量 `SW_OAL_ENGINE_DEBUG=Y`，这样能在工作目录下的 `oal-rt` 目录下找到生成的 `Class` 文件。

通过如下目录结构，可以看出有三种 `Class` ：

*  `dispatcher` ：调度器，将指标对象发送 `MetricsStreamProcessor` (指标处理器)
 *  `metrics` ：指标类，存储指标数据
 *  `StorageBuilder` ：存储构造器，实现类 `StorageBuilder` 接口，提供 `map` 与 `StorageData` 之间互转的方法

oal-rt
    ├── dispatcher
    │   ├── ServiceInstanceJVMClassDispatcher.class
    │   └── ServiceInstanceJVMThreadDispatcher.class
    └── metrics
        ├── InstanceJvmClassLoadedClassCountMetrics.class
        ├── InstanceJvmClassTotalLoadedClassCountMetrics.class
        ├── InstanceJvmClassUnloadedClassCountMetrics.class
        ├── InstanceJvmThreadDaemonCountMetrics.class
        ├── InstanceJvmThreadDeadlockedMetrics.class
        ├── InstanceJvmThreadLiveCountMetrics.class
        └── builder
            ├── InstanceJvmClassLoadedClassCountMetricsBuilder.class
            ├── InstanceJvmClassTotalLoadedClassCountMetricsBuilder.class
            ├── InstanceJvmClassUnloadedClassCountMetricsBuilder.class
            ├── InstanceJvmThreadDaemonCountMetricsBuilder.class
            ├── InstanceJvmThreadDeadlockedMetricsBuilder.class
            └── InstanceJvmThreadLiveCountMetricsBuilder.class

### 指标类 ###

package org.apache.skywalking.oap.server.core.source.oal.rt.metrics;
    
    import org.apache.skywalking.oap.server.core.analysis.Stream;
    import org.apache.skywalking.oap.server.core.analysis.metrics.LongAvgMetrics;
    import org.apache.skywalking.oap.server.core.analysis.metrics.Metrics;
    import org.apache.skywalking.oap.server.core.analysis.metrics.MetricsMetaInfo;
    import org.apache.skywalking.oap.server.core.analysis.metrics.WithMetadata;
    import org.apache.skywalking.oap.server.core.analysis.worker.MetricsStreamProcessor;
    import org.apache.skywalking.oap.server.core.remote.grpc.proto.RemoteData;
    import org.apache.skywalking.oap.server.core.remote.grpc.proto.RemoteData.Builder;
    import org.apache.skywalking.oap.server.core.source.oal.rt.metrics.builder.InstanceJvmClassLoadedClassCountMetricsBuilder;
    import org.apache.skywalking.oap.server.core.storage.annotation.Column;
    
    @Stream(
        name = "instance_jvm_class_loaded_class_count",
        scopeId = 11000,
        builder = InstanceJvmClassLoadedClassCountMetricsBuilder.class,
        processor = MetricsStreamProcessor.class
    )
    public class InstanceJvmClassLoadedClassCountMetrics extends LongAvgMetrics implements WithMetadata { 
        @Column(
            columnName = "entity_id",
            length = 512
        )
        private String entityId;
        @Column(
            columnName = "service_id",
            length = 256
        )
        private String serviceId;
    
        public InstanceJvmClassLoadedClassCountMetrics() { 
        }
    
        public String getEntityId() { 
            return this.entityId;
        }
    
        public void setEntityId(String var1) { 
            this.entityId = var1;
        }
    
        public String getServiceId() { 
            return this.serviceId;
        }
    
        public void setServiceId(String var1) { 
            this.serviceId = var1;
        }
    
        public String id() { 
            String var1 = String.valueOf(this.getTimeBucket());
            var1 = String.valueOf(var1).concat(String.valueOf("_" + this.entityId));
            return var1;
        }
    
        public int hashCode() { 
            byte var1 = 17;
            int var2 = 31 * var1 + this.entityId.hashCode();
            var2 = 31 * var2 + (int)this.getTimeBucket();
            return var2;
        }
    
        public int remoteHashCode() { 
            byte var1 = 17;
            int var2 = 31 * var1 + this.entityId.hashCode();
            return var2;
        }
    
        public boolean equals(Object var1) { 
            if (this == var1) { 
                return true;
            } else if (var1 == null) { 
                return false;
            } else if (this.getClass() != var1.getClass()) { 
                return false;
            } else { 
                InstanceJvmClassLoadedClassCountMetrics var2 = (InstanceJvmClassLoadedClassCountMetrics)var1;
                if (!this.entityId.equals(var2.entityId)) { 
                    return false;
                } else { 
                    return this.getTimeBucket() == var2.getTimeBucket();
                }
            }
        }
    
        public Builder serialize() { 
            Builder var1 = RemoteData.newBuilder();
            var1.addDataStrings(this.getEntityId());
            var1.addDataStrings(this.getServiceId());
            var1.addDataLongs(this.getSummation());
            var1.addDataLongs(this.getCount());
            var1.addDataLongs(this.getValue());
            var1.addDataLongs(this.getTimeBucket());
            return var1;
        }
    
        public void deserialize(RemoteData var1) { 
            this.setEntityId(var1.getDataStrings(0));
            this.setServiceId(var1.getDataStrings(1));
            this.setSummation(var1.getDataLongs(0));
            this.setCount(var1.getDataLongs(1));
            this.setValue(var1.getDataLongs(2));
            this.setTimeBucket(var1.getDataLongs(3));
        }
    
        public MetricsMetaInfo getMeta() { 
            return new MetricsMetaInfo("instance_jvm_class_loaded_class_count", 11000, this.entityId);
        }
    
        public Metrics toHour() { 
            InstanceJvmClassLoadedClassCountMetrics var1 = new InstanceJvmClassLoadedClassCountMetrics();
            var1.setEntityId(this.getEntityId());
            var1.setServiceId(this.getServiceId());
            var1.setSummation(this.getSummation());
            var1.setCount(this.getCount());
            var1.setValue(this.getValue());
            var1.setTimeBucket(this.toTimeBucketInHour());
            return var1;
        }
    
        public Metrics toDay() { 
            InstanceJvmClassLoadedClassCountMetrics var1 = new InstanceJvmClassLoadedClassCountMetrics();
            var1.setEntityId(this.getEntityId());
            var1.setServiceId(this.getServiceId());
            var1.setSummation(this.getSummation());
            var1.setCount(this.getCount());
            var1.setValue(this.getValue());
            var1.setTimeBucket(this.toTimeBucketInDay());
            return var1;
        }
    }

### 存储构造器 ###

package org.apache.skywalking.oap.server.core.source.oal.rt.metrics.builder;
    
    import java.util.HashMap;
    import java.util.Map;
    import org.apache.skywalking.oap.server.core.source.oal.rt.metrics.InstanceJvmClassLoadedClassCountMetrics;
    import org.apache.skywalking.oap.server.core.storage.StorageBuilder;
    import org.apache.skywalking.oap.server.core.storage.StorageData;
    
    public class InstanceJvmClassLoadedClassCountMetricsBuilder implements StorageBuilder { 
        public InstanceJvmClassLoadedClassCountMetricsBuilder() { 
        }
    
        public Map data2Map(StorageData var1) { 
            InstanceJvmClassLoadedClassCountMetrics var2 = (InstanceJvmClassLoadedClassCountMetrics)var1;
            HashMap var3 = new HashMap();
            var3.put((Object)"entity_id", var2.getEntityId());
            var3.put((Object)"service_id", var2.getServiceId());
            var3.put((Object)"summation", new Long(var2.getSummation()));
            var3.put((Object)"count", new Long(var2.getCount()));
            var3.put((Object)"value", new Long(var2.getValue()));
            var3.put((Object)"time_bucket", new Long(var2.getTimeBucket()));
            return var3;
        }
    
        public StorageData map2Data(Map var1) { 
            InstanceJvmClassLoadedClassCountMetrics var2 = new InstanceJvmClassLoadedClassCountMetrics();
            var2.setEntityId((String)var1.get("entity_id"));
            var2.setServiceId((String)var1.get("service_id"));
            var2.setSummation(((Number)var1.get("summation")).longValue());
            var2.setCount(((Number)var1.get("count")).longValue());
            var2.setValue(((Number)var1.get("value")).longValue());
            var2.setTimeBucket(((Number)var1.get("time_bucket")).longValue());
            return var2;
        }
    }

### 调度器 ###

package org.apache.skywalking.oap.server.core.source.oal.rt.dispatcher;
    
    import org.apache.skywalking.oap.server.core.analysis.SourceDispatcher;
    import org.apache.skywalking.oap.server.core.analysis.worker.MetricsStreamProcessor;
    import org.apache.skywalking.oap.server.core.source.ServiceInstanceJVMClass;
    import org.apache.skywalking.oap.server.core.source.Source;
    import org.apache.skywalking.oap.server.core.source.oal.rt.metrics.InstanceJvmClassLoadedClassCountMetrics;
    import org.apache.skywalking.oap.server.core.source.oal.rt.metrics.InstanceJvmClassTotalLoadedClassCountMetrics;
    import org.apache.skywalking.oap.server.core.source.oal.rt.metrics.InstanceJvmClassUnloadedClassCountMetrics;
    
    public class ServiceInstanceJVMClassDispatcher implements SourceDispatcher<ServiceInstanceJVMClass> { 
        private void doInstanceJvmClassLoadedClassCount(ServiceInstanceJVMClass var1) { 
            InstanceJvmClassLoadedClassCountMetrics var2 = new InstanceJvmClassLoadedClassCountMetrics();
            var2.setTimeBucket(var1.getTimeBucket());
            var2.setEntityId(var1.getEntityId());
            var2.setServiceId(var1.getServiceId());
            var2.combine(var1.getLoadedClassCount(), (long)1);
            MetricsStreamProcessor.getInstance().in(var2);
        }
    
        private void doInstanceJvmClassUnloadedClassCount(ServiceInstanceJVMClass var1) { 
            InstanceJvmClassUnloadedClassCountMetrics var2 = new InstanceJvmClassUnloadedClassCountMetrics();
            var2.setTimeBucket(var1.getTimeBucket());
            var2.setEntityId(var1.getEntityId());
            var2.setServiceId(var1.getServiceId());
            var2.combine(var1.getUnloadedClassCount(), (long)1);
            MetricsStreamProcessor.getInstance().in(var2);
        }
    
        private void doInstanceJvmClassTotalLoadedClassCount(ServiceInstanceJVMClass var1) { 
            InstanceJvmClassTotalLoadedClassCountMetrics var2 = new InstanceJvmClassTotalLoadedClassCountMetrics();
            var2.setTimeBucket(var1.getTimeBucket());
            var2.setEntityId(var1.getEntityId());
            var2.setServiceId(var1.getServiceId());
            var2.combine(var1.getTotalLoadedClassCount(), (long)1);
            MetricsStreamProcessor.getInstance().in(var2);
        }
    
        public void dispatch(Source var1) { 
            ServiceInstanceJVMClass var2 = (ServiceInstanceJVMClass)var1;
            this.doInstanceJvmClassLoadedClassCount(var2);
            this.doInstanceJvmClassUnloadedClassCount(var2);
            this.doInstanceJvmClassTotalLoadedClassCount(var2);
        }
    
        public ServiceInstanceJVMClassDispatcher() { 
        }
    }

[OALRuntime-generate-class-at-runtime.sdt]: https://raw.githubusercontent.com/Switch-vov/skywalking-learning/main/metrics/OALRuntime-generate-class-at-runtime.sdt
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3E1NDc1NTA4MzE_size_16_color_FFFFFF_t_70]: /images/20220829/997b4d4a8d7d408389466031bc98265e.png