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Skywalking-07：OAL原理——解释器实现

发布2021-09-01浏览566次

详情内容

OAL 解释器实现

OAL 解释器是基于 Antlr4 实现的，我们先来了解下 Antlr4

Antlr4 基本介绍

Antlr4 使用案例

参考Antlr4的使用简介这篇文章，我们实现了一个简单的案例：antlr案例：简单的计算器，下面来讲讲这个案例。

首先，装好ANTLR v4(IDEA插件)插件，这个之后验证语法树的时候会用到。

在 pom.xml 中配置 antlr4 的依赖和插件

  1. <dependency>
  2.   <groupId>org.antlr</groupId>
  3.   <artifactId>antlr4-runtime</artifactId>
  4.   <version>4.7.1</version>
  5. </dependency>
  1. <plugin>
  2.   <groupId>org.antlr</groupId>
  3.   <artifactId>antlr4-maven-plugin</artifactId>
  4.   <version>${antlr.version}</version>
  5.   <executions>
  6.     <execution>
  7.       <id>antlr</id>
  8.       <goals>
  9.         <goal>antlr4</goal>
  10.       </goals>
  11.     </execution>
  12.   </executions>
  13. </plugin>

在 src/main/antlr4/com/switchvov/antlr/demo/calc 目录下添加一个 Calc.g4 文件

  1. grammar Calc;   //名称需要和文件名一致
  2.  
  3. root : expr EOF;   //解决问题: no viable alternative at input '<EOF>'
  4.  
  5. expr
  6.     : expr '+' expr     #add   //标签会生成对应访问方法方便我们实现调用逻辑编写
  7.     | expr '-' expr     #sub
  8.     | INT               #int
  9.     ;
  10.  
  11. INT : [0-9]+                   //定义整数
  12.     ;
  13.  
  14. WS : [ \r\n\t]+ -> skip      //跳过空白类字符
  15.    ;

执行一下： mvn compile -Dmaven.test.skip=true ，在 target/generated-sources/antlr4 会生成相应的 Java 代码。

使用方式默认是监听器模式，也可以配置成访问者模式。

监听器模式：主要借助了 ParseTreeWalker 这样一个类,相当于是一个 hook ，每经过一个树的节点,便会触发对应节点的方法。好处就算是比较方python教程便,但是灵活性不够,不能够自主性的调用任意节点进行使用。

访问者模式：将每个数据的节点类型高度抽象出来够,根据你传入的上下文类型来判断你想要访问的是哪个节点,触发对应的方法

PS：结论，简单语法监听器模式就可以了，如果语法比较灵活可以考虑使用访问者模式。

  1. antlr4
  2. ├── Calc.tokens
  3. ├── CalcLexer.tokens
  4. └── com
  5.     └── switchvov
  6.         └── antlr
  7.             └── demo
  8.                 └── calc
  9.                     ├── Calc.interp
  10.                     ├── CalcBaseListener.java # 监听模式下生成的监听器基类，实现类监听器接口，通过继承该类可以实现相应的功能
  11.                     ├── CalcLexer.interp
  12.                     ├── CalcLexer.java  # 词法解析器
  13.                     ├── CalcListener.java # 监听模式下生成的监听器接口
  14.                     └── CalcParser.java # 语法解析器

继承 com.switchvov.antlr.demo.calc.CalcBaseListener ，实现计算器相应功能

  1. package com.switchvov.antlr.demo.calc;
  2.  
  3. import java.util.ArrayDeque;
  4. import java.util.Deque;
  5.  
  6. /**
  7.  * @author switch
  8.  * @since 2021/6/30
  9.  */
  10. public class CalcExecuteListener extends CalcBaseListener {
  11. 	
  12.     Deque<Integer> queue = new ArrayDeque<>(16);
  13.  
  14.     @Override
  15.     public void exitInt(CalcParser.IntContext ctx) {
  16.         queue.add(Integer.parseInt(ctx.INT().getText()));
  17.     }
  18.  
  19.     @Override
  20.     public void exitAdd(CalcParser.AddContext ctx) {
  21.         int r = queue.pop();
  22.         int l = queue.pop();
  23.         queue.add(l + r);
  24.     }
  25.  
  26.     @Override
  27.     public void exitSub(CalcParser.SubContext ctx) {
  28.         int r = queue.pop();
  29.         int l = queue.pop();
  30.         queue.add(l - r);
  31.     }
  32.  
  33.     public int result() {
  34.         return queue.pop();
  35.     }
  36. }

测试一下

  1. package com.switchvov.antlr.demo.calc;
  2.  
  3. import org.antlr.v4.runtime.CharStreams;
  4. import org.antlr.v4.runtime.CodePointCharStream;
  5. import org.antlr.v4.runtime.CommonTokenStream;
  6. import org.antlr.v4.runtime.tree.ParseTree;
  7. import org.antlr.v4.runtime.tree.ParseTreeWalker;
  8. import org.junit.Test;
  9.  
  10.  
  11. /**
  12.  * @author switch
  13.  * @since 2021/6/30
  14.  */
  15. public class CalcTest {
  16.  
  17.     public static int exec(String input) {
  18.         // 读入字符串
  19.         CodePointCharStream cs = CharStreams.fromString(input);
  20.         // 词法解析
  21.         CalcLexer lexer = new CalcLexer(cs);
  22.         CommonTokenStream tokens = new CommonTokenStream(lexer);
  23.         // 语法解析
  24.         CalcParser parser = new CalcParser(tokens);
  25.  
  26.         // 监听器触发获取执行结果
  27.         ParseTree tree = parser.expr();
  28.         ParseTreeWalker walker = new ParseTreeWalker();
  29.         CalcExecuteListener listener = new CalcExecuteListener();
  30.         walker.walk(listener, tree);
  31.         return listener.result();
  32.     }
  33.  
  34.     @Test
  35.     public void testCalc() {
  36.         String input = "1+2";
  37.         // 输出结果：3
  38.         System.out.println(exec(input));
  39.     }
  40.  
  41. }

Antlr4 IDEA 插件使用

在 Calc.g4 语法定义文件中，鼠标右击可以选择 Test Rule root ，然后在 ANTLR Preview 的输入框中填入 1 + 2 就可以校验语法文件是否 OK ，并且也可以看到相应的语法树

file

file

Antlr4 在 Skywalking 的应用

通过“ Antlr4 基本介绍”一节，基本上对 Antlr4 使用有了个大概的认识。下面来看看 Skywalking 中 Antlr4 是如何使用的。

词法定义

在 oap-server/oal-grammar/src/main/antlr4/org/apache/skywalking/oal/rt/grammar/OALLexer.g4 文件中，我们能看到 OAL 的词法定义

  1. // Observability Analysis Language lexer
  2. lexer grammar OALLexer;
  3.  
  4. @Header {package org.apache.skywalking.oal.rt.grammar;}
  5.  
  6. // Keywords
  7.  
  8. FROM: 'from';
  9. FILTER: 'filter';
  10. DISABLE: 'disable';
  11. SRC_ALL: 'All';
  12. SRC_SERVICE: 'Service';
  13. SRC_SERVICE_INSTANCE: 'ServiceInstance';
  14. SRC_ENDPOINT: 'Endpoint';
  15. SRC_SERVICE_RELATION: 'ServiceRelation';
  16. SRC_SERVICE_INSTANCE_RELATION: 'ServiceInstanceRelation';
  17. SRC_ENDPOINT_RELATION: 'EndpointRelation';
  18. SRC_SERVICE_INSTANCE_JVM_CPU: 'ServiceInstanceJVMCPU';
  19. SRC_SERVICE_INSTANCE_JVM_MEMORY: 'ServiceInstanceJVMMemory';
  20. SRC_SERVICE_INSTANCE_JVM_MEMORY_POOL: 'ServiceInstanceJVMMemoryPool';
  21. SRC_SERVICE_INSTANCE_JVM_GC: 'ServiceInstanceJVMGC';
  22. SRC_SERVICE_INSTANCE_JVM_THREAD: 'ServiceInstanceJVMThread';
  23. SRC_SERVICE_INSTANCE_JVM_CLASS:'ServiceInstanceJVMClass';
  24. SRC_DATABASE_ACCESS: 'DatabaseAccess';
  25. SRC_SERVICE_INSTANCE_CLR_CPU: 'ServiceInstanceCLRCPU';
  26. SRC_SERVICE_INSTANCE_CLR_GC: 'ServiceInstanceCLRGC';
  27. SRC_SERVICE_INSTANCE_CLR_THREAD: 'ServiceInstanceCLRThread';
  28. SRC_ENVOY_INSTANCE_METRIC: 'EnvoyInstanceMetric';
  29.  
  30. // Browser keywords
  31. SRC_BROWSER_APP_PERF: 'BrowserAppPerf';
  32. SRC_BROWSER_APP_PAGE_PERF: 'BrowserAppPagePerf';
  33. SRC_BROWSER_APP_SINGLE_VERSION_PERF: 'BrowserAppSingleVersionPerf';
  34. SRC_BROWSER_APP_TRAFFIC: 'BrowserAppTraffic';
  35. SRC_BROWSER_APP_PAGE_TRAFFIC: 'BrowserAppPageTraffic';
  36. SRC_BROWSER_APP_SINGLE_VERSION_TRAFFIC: 'BrowserAppSingleVersionTraffic';
  37.  
  38. // Constructors symbols
  39.  
  40. DOT:                                 '.';
  41. LR_BRACKET:                          '(';
  42. RR_BRACKET:                          ')';
  43. LS_BRACKET:                          '[';
  44. RS_BRACKET:                          ']';
  45. COMMA:                               ',';
  46. SEMI:                                ';';
  47. EQUAL:                               '=';
  48. DUALEQUALS:                          '==';
  49. ALL:                                 '*';
  50. GREATER:                             '>';
  51. LESS:                                '<';
  52. GREATER_EQUAL:                       '>=';
  53. LESS_EQUAL:                          '<=';
  54. NOT_EQUAL:                           '!=';
  55. LIKE:                                'like';
  56. IN:                                  'in';
  57. CONTAIN:                            'contain';
  58. NOT_CONTAIN:                        'not contain';
  59.  
  60. // Literals
  61.  
  62. BOOL_LITERAL:       'true'
  63.             |       'false'
  64.             ;
  65.  
  66. NUMBER_LITERAL :   Digits+;
  67.  
  68. CHAR_LITERAL:       '\'' (~['\\\r\n] | EscapeSequence) '\'';
  69.  
  70. STRING_LITERAL:     '"' (~["\\\r\n] | EscapeSequence)* '"';
  72. DelimitedComment
  73.     : '/*' ( DelimitedComment | . )*? '*/'
  74.       -> channel(HIDDEN)
  75.     ;
  77. LineComment
  78.     : '//' ~[\u000A\u000D]*
  79.       -> channel(HIDDEN)
  80.     ;
  81.  
  82. SPACE:                               [ \t\r\n]+    -> channel(HIDDEN);
  83.  
  84. // Identifiers
  85.  
  86. IDENTIFIER:         Letter LetterOrDigit*;
  87.  
  88. // Fragment rules
  89.  
  90. fragment EscapeSequence
  91.     : '\\' [btnfr"'\\]
  92.     | '\\' ([0-3]? [0-7])? [0-7]
  93.     | '\\' 'u'+ HexDigit HexDigit HexDigit HexDigit
  94.     ;
  96. fragment HexDigits
  97.     : HexDigit ((HexDigit | '_')* HexDigit)?
  98.     ;
  100. fragment HexDigit
  101.     : [0-9a-fA-F]
  102.     ;
  104. fragment Digits
  105.     : [0-9] ([0-9_]* [0-9])?
  106.     ;
  108. fragment LetterOrDigit
  109.     : Letter
  110.     | [0-9]
  111.     ;
  113. fragment Letter
  114.     : [a-zA-Z$_] // these are the "java letters" below 0x7F
  115.     | ~[\u0000-\u007F\uD800-\uDBFF] // covers all characters above 0x7F which are not a surrogate
  116.     | [\uD800-\uDBFF] [\uDC00-\uDFFF] // covers UTF-16 surrogate pairs encodings for U+10000 to U+10FFFF
  117.     ;

语法定义

在 oap-server/oal-grammar/src/main/antlr4/org/apache/skywalking/oal/rt/grammar/OALParser.g4 文件中，我们能看到 OAL 的语法定义

  1. parser grammar OALParser;
  2.  
  3. @Header {package org.apache.skywalking.oal.rt.grammar;}
  4.  
  5. options { tokenVocab=OALLexer; }
  6.  
  7.  
  8. // Top Level Description
  9.  
  10. root
  11.     : (aggregationStatement | disableStatement)*
  12.     ;
  13.  
  14. aggregationStatement
  15.     : variable (SPACE)? EQUAL (SPACE)? metricStatement DelimitedComment? LineComment? (SEMI|EOF)
  16.     ;
  17.  
  18. disableStatement
  19.     : DISABLE LR_BRACKET disableSource RR_BRACKET DelimitedComment? LineComment? (SEMI|EOF)
  20.     ;
  21.  
  22. metricStatement
  23.     : FROM LR_BRACKET source (sourceAttributeStmt+) RR_BRACKET (filterStatement+)? DOT aggregateFunction
  24.     ;
  25.  
  26. filterStatement
  27.     : DOT FILTER LR_BRACKET filterExpression RR_BRACKET
  28.     ;
  29.  
  30. filterExpression
  31.     : expression
  32.     ;
  33.  
  34. source
  35.     : SRC_ALL | SRC_SERVICE | SRC_DATABASE_ACCESS | SRC_SERVICE_INSTANCE | SRC_ENDPOINT |
  36.       SRC_SERVICE_RELATION | SRC_SERVICE_INSTANCE_RELATION | SRC_ENDPOINT_RELATION |
  37.       SRC_SERVICE_INSTANCE_JVM_CPU | SRC_SERVICE_INSTANCE_JVM_MEMORY | SRC_SERVICE_INSTANCE_JVM_MEMORY_POOL | SRC_SERVICE_INSTANCE_JVM_GC | SRC_SERVICE_INSTANCE_JVM_THREAD | SRC_SERVICE_INSTANCE_JVM_CLASS |// JVM source of service instance
  38.       SRC_SERVICE_INSTANCE_CLR_CPU | SRC_SERVICE_INSTANCE_CLR_GC | SRC_SERVICE_INSTANCE_CLR_THREAD |
  39.       SRC_ENVOY_INSTANCE_METRIC |
  40.       SRC_BROWSER_APP_PERF | SRC_BROWSER_APP_PAGE_PERF | SRC_BROWSER_APP_SINGLE_VERSION_PERF |
  41.       SRC_BROWSER_APP_TRAFFIC | SRC_BROWSER_APP_PAGE_TRAFFIC | SRC_BROWSER_APP_SINGLE_VERSION_TRAFFIC
  42.     ;
  43.  
  44. disableSource
  45.     : IDENTIFIER
  46.     ;
  47.  
  48. sourceAttributeStmt
  49.     : DOT sourceAttribute
  50.     ;
  51.  
  52. sourceAttribute
  53.     : IDENTIFIER | ALL
  54.     ;
  55.  
  56. variable
  57.     : IDENTIFIER
  58.     ;
  59.  
  60. aggregateFunction
  61.     : functionName LR_BRACKET ((funcParamExpression (COMMA funcParamExpression)?) | (literalExpression (COMMA literalExpression)?))? RR_BRACKET
  62.     ;
  63.  
  64. functionName
  65.     : IDENTIFIER
  66.     ;
  67.  
  68. funcParamExpression
  69.     : expression
  70.     ;
  71.  
  72. literalExpression
  73.     : BOOL_LITERAL | NUMBER_LITERAL | IDENTIFIER
  74.     ;
  75.  
  76. expression
  77.     : booleanMatch | stringMatch | greaterMatch | lessMatch | greaterEqualMatch | lessEqualMatch | notEqualMatch | booleanNotEqualMatch | likeMatch | inMatch | containMatch | notContainMatch
  78.     ;
  79.  
  80. containMatch
  81.     : conditionAttributeStmt CONTAIN stringConditionValue
  82.     ;
  83.  
  84. notContainMatch
  85.     : conditionAttributeStmt NOT_CONTAIN stringConditionValue
  86.     ;
  87.  
  88. booleanMatch
  89.     : conditionAttributeStmt DUALEQUALS booleanConditionValue
  90.     ;
  91.  
  92. stringMatch
  93.     :  conditionAttributeStmt DUALEQUALS (stringConditionValue | enumConditionValue)
  94.     ;
  95.  
  96. greaterMatch
  97.     :  conditionAttributeStmt GREATER numberConditionValue
  98.     ;
  99.  
  100. lessMatch
  101.     :  conditionAttributeStmt LESS numberConditionValue
  102.     ;
  103.  
  104. greaterEqualMatch
  105.     :  conditionAttributeStmt GREATER_EQUAL numberConditionValue
  106.     ;
  107.  
  108. lessEqualMatch
  109.     :  conditionAttributeStmt LESS_EQUAL numberConditionValue
  110.     ;
  111.  
  112. booleanNotEqualMatch
  113.     :  conditionAttributeStmt NOT_EQUAL booleanConditionValue
  114.     ;
  115.  
  116. notEqualMatch
  117.     :  conditionAttributeStmt NOT_EQUAL (numberConditionValue | stringConditionValue | enumConditionValue)
  118.     ;
  119.  
  120. likeMatch
  121.     :  conditionAttributeStmt LIKE stringConditionValue
  122.     ;
  123.  
  124. inMatch
  125.     :  conditionAttributeStmt IN multiConditionValue
  126.     ;
  127.  
  128. multiConditionValue
  129.     : LS_BRACKET (numberConditionValue ((COMMA numberConditionValue)*) | stringConditionValue ((COMMA stringConditionValue)*) | enumConditionValue ((COMMA enumConditionValue)*)) RS_BRACKET
  130.     ;
  131.  
  132. conditionAttributeStmt
  133.     : conditionAttribute ((DOT conditionAttribute)*)
  134.     ;
  135.  
  136. conditionAttribute
  137.     : IDENTIFIER
  138.     ;
  139.  
  140. booleanConditionValue
  141.     : BOOL_LITERAL
  142.     ;
  143.  
  144. stringConditionValue
  145.     : STRING_LITERAL
  146.     ;
  147.  
  148. enumConditionValue
  149.     : IDENTIFIER DOT IDENTIFIER
  150.     ;
  151.  
  152. numberConditionValue
  153.     : NUMBER_LITERAL
  154.     ;

Antlr4 生成 Java 代码

在 oap-server/oal-grammar 下执行 mvn compile -Dmaven.test.skip=true 会在 oap-server/oal-grammar/target/generated-sources/antlr4 目录下生成相应的 Java 代码

  1. .
  2. ├── OALLexer.tokens
  3. ├── OALParser.tokens
  4. └── org
  5.     └── apache
  6.         └── skywalking
  7.             └── oal
  8.                 └── rt
  9.                     └── grammar
  10.                         ├── OALLexer.interp
  11.                         ├── OALLexer.java # 词法解析器
  12.                         ├── OALParser.interp
  13.                         ├── OALParser.java # 语法解析器
  14.                         ├── OALParserBaseListener.java # 监听器
  15.                         └── OALParserListener.java

在 Skywalking 的使用

通过“ Antlr4 使用案例”一节，可以知道 Antlr4 有两种功能实现方式：监听器或者访问器。

通过“ Antlr4 生成 Java 代码”一节，知道 Skywalking 使用的是监听器模式。

Skywalking 关于 OAL 的相应的代码都在 oap-server/oal-rt 模块中。

org.apache.skywalking.oal.rt.grammar.OALParserBaseListener 的继承类坐标是 org.apache.skywalking.oal.rt.parser.OALListener

  1. package org.apache.skywalking.oal.rt.parser;
  2.  
  3. import java.util.Arrays;
  4. import java.util.List;
  5. import org.antlr.v4.runtime.misc.NotNull;
  6. import org.apache.skywalking.oal.rt.grammar.OALParser;
  7. import org.apache.skywalking.oal.rt.grammar.OALParserBaseListener;
  8. import org.apache.skywalking.oap.server.core.source.DefaultScopeDefine;
  9.  
  10. public class OALListener extends OALParserBaseListener {
  11.     private List<AnalysisResult> results;
  12.     private AnalysisResult current;
  13.     private DisableCollection collection;
  14.  
  15.     private ConditionExpression conditionExpression;
  16.  
  17.     private final String sourcePackage;
  18.  
  19.     public OALListener(OALScripts scripts, String sourcePackage) {
  20.         this.results = scripts.getMetricsStmts();
  21.         this.collection = scripts.getDisableCollection();
  22.         this.sourcePackage = sourcePackage;
  23.     }
  24.  
  25.     @Override
  26.     public void enterAggregationStatement(@NotNull OALParser.AggregationStatementContext ctx) {
  27.         current = new AnalysisResult();
  28.     }
  29.  
  30.     @Override
  31.     public void exitAggregationStatement(@NotNull OALParser.AggregationStatementContext ctx) {
  32.         DeepAnalysis deepAnalysis = new DeepAnalysis();
  33.         results.add(deepAnalysis.analysis(current));
  34.         current = null;
  35.     }
  36.  
  37.     @Override
  38.     public void enterSource(OALParser.SourceContext ctx) {
  39.         current.setSourceName(ctx.getText());
  40.         current.setSourceScopeId(DefaultScopeDefine.valueOf(metricsNameFormat(ctx.getText())));
  41.     }
  42.  
  43.     @Override
  44.     public void enterSourceAttribute(OALParser.SourceAttributeContext ctx) {
  45.         current.getSourceAttribute().add(ctx.getText());
  46.     }
  47.  
  48.     @Override
  49.     public void enterVariable(OALParser.VariableContext ctx) {
  50.     }
  51.  
  52.     @Override
  53.     public void exitVariable(OALParser.VariableContext ctx) {
  54.         current.setVarName(ctx.getText());
  55.         current.setMetricsName(metricsNameFormat(ctx.getText()));
  56.         current.setTableName(ctx.getText().toLowerCase());
  57.     }
  58.  
  59.     @Override
  60.     public void enterFunctionName(OALParser.FunctionNameContext ctx) {
  61.         current.setAggregationFunctionName(ctx.getText());
  62.     }
  63.  
  64.     @Override
  65.     public void enterFilterStatement(OALParser.FilterStatementContext ctx) {
  66.         conditionExpression = new ConditionExpression();
  67.     }
  68.  
  69.     @Override
  70.     public void exitFilterStatement(OALParser.FilterStatementContext ctx) {
  71.         current.addFilterExpressionsParserResult(conditionExpression);
  72.         conditionExpression = null;
  73.     }
  74.  
  75.     @Override
  76.     public void enterFuncParamExpression(OALParser.FuncParamExpressionContext ctx) {
  77.         conditionExpression = new ConditionExpression();
  78.     }
  79.  
  80.     @Override
  81.     public void exitFuncParamExpression(OALParser.FuncParamExpressionContext ctx) {
  82.         current.addFuncConditionExpression(conditionExpression);
  83.         conditionExpression = null;
  84.     }
  85.  
  86.     /
  87.     // Expression
  88.     
  89.     @Override
  90.     public void enterConditionAttribute(OALParser.ConditionAttributeContext ctx) {
  91.         conditionExpression.getAttributes().add(ctx.getText());
  92.     }
  93.  
  94.     @Override
  95.     public void enterBooleanMatch(OALParser.BooleanMatchContext ctx) {
  96.         conditionExpression.setExpressionType("booleanMatch");
  97.     }
  98.  
  99.     @Override
  100.     public void enterStringMatch(OALParser.StringMatchContext ctx) {
  101.         conditionExpression.setExpressionType("stringMatch");
  102.     }
  103.  
  104.     @Override
  105.     public void enterGreaterMatch(OALParser.GreaterMatchContext ctx) {
  106.         conditionExpression.setExpressionType("greaterMatch");
  107.     }
  108.  
  109.     @Override
  110.     public void enterGreaterEqualMatch(OALParser.GreaterEqualMatchContext ctx) {
  111.         conditionExpression.setExpressionType("greaterEqualMatch");
  112.     }
  113.  
  114.     @Override
  115.     public void enterLessMatch(OALParser.LessMatchContext ctx) {
  116.         conditionExpression.setExpressionType("lessMatch");
  117.     }
  118.  
  119.     @Override
  120.     public void enterLessEqualMatch(OALParser.LessEqualMatchContext ctx) {
  121.         conditionExpression.setExpressionType("lessEqualMatch");
  122.     }
  123.  
  124.     @Override
  125.     public void enterNotEqualMatch(final OALParser.NotEqualMatchContext ctx) {
  126.         conditionExpression.setExpressionType("notEqualMatch");
  127.     }
  128.  
  129.     @Override
  130.     public void enterBooleanNotEqualMatch(final OALParser.BooleanNotEqualMatchContext ctx) {
  131.         conditionExpression.setExpressionType("booleanNotEqualMatch");
  132.     }
  133.  
  134.     @Override
  135.     public void enterLikeMatch(final OALParser.LikeMatchContext ctx) {
  136.         conditionExpression.setExpressionType("likeMatch");
  137.     }
  138.  
  139.     @Override
  140.     public void enterContainMatch(final OALParser.ContainMatchContext ctx) {
  141.         conditionExpression.setExpressionType("containMatch");
  142.     }
  143.  
  144.     @Override
  145.     public void enterNotContainMatch(final OALParser.NotContainMatchContext ctx) {
  146.         conditionExpression.setExpressionType("notContainMatch");
  147.     }
  148.  
  149.     @Override
  150.     public void enterInMatch(final OALParser.InMatchContext ctx) {
  151.         conditionExpression.setExpressionType("inMatch");
  152.     }
  153.  
  154.     @Override
  155.     public void enterMultiConditionValue(final OALParser.MultiConditionValueContext ctx) {
  156.         conditionExpression.enterMultiConditionValue();
  157.     }
  158.  
  159.     @Override
  160.     public void exitMultiConditionValue(final OALParser.MultiConditionValueContext ctx) {
  161.         conditionExpression.exitMultiConditionValue();
  162.     }
  163.  
  164.     @Override
  165.     public void enterBooleanConditionValue(OALParser.BooleanConditionValueContext ctx) {
  166.         enterConditionValue(ctx.getText());
  167.     }
  168.  
  169.     @Override
  170.     public void enterStringConditionValue(OALParser.StringConditionValueContext ctx) {
  171.         enterConditionValue(ctx.getText());
  172.     }
  173.  
  174.     @Override
  175.     public void enterEnumConditionValue(OALParser.EnumConditionValueContext ctx) {
  176.         enterConditionValue(ctx.getText());
  177.     }
  178.  
  179.     @Override
  180.     public void enterNumberConditionValue(OALParser.NumberConditionValueContext ctx) {
  181.         conditionExpression.isNumber();
  182.         enterConditionValue(ctx.getText());
  183.     }
  184.  
  185.     private void enterConditionValue(String value) {
  186.         if (value.split("\\.").length == 2 && !value.startsWith("\"")) {
  187.             // Value is an enum.
  188.             value = sourcePackage + value;
  189.         }
  190.         conditionExpression.addValue(value);
  191.     }
  192.  
  193.     /
  194.     // Expression end.
  195.     
  196.  
  197.     @Override
  198.     public void enterLiteralExpression(OALParser.LiteralExpressionContext ctx) {
  199.         if (ctx.IDENTIFIER() == null) {
  200.             current.addFuncArg(new Argument(EntryMethod.LITERAL_TYPE, Arrays.asList(ctx.getText())));
  201.             return;
  202.         }
  203.         current.addFuncArg(new Argument(EntryMethod.IDENTIFIER_TYPE, Arrays.asList(ctx.getText().split("\\."))));
  204.     }
  205.  
  206.     private String metricsNameFormat(String source) {
  207.         source = firstLetterUpper(source);
  208.         int idx;
  209.         while ((idx = source.indexOf("_")) > -1) {
  210.             source = source.substring(0, idx) + firstLetterUpper(source.substring(idx + 1));
  211.         }
  212.         return source;
  213.     }
  214.  
  215.     /**
  216.      * Disable source
  217.      */
  218.     @Override
  219.     public void enterDisableSource(OALParser.DisableSourceContext ctx) {
  220.         collection.add(ctx.getText());
  221.     }
  222.  
  223.     private String firstLetterUpper(String source) {
  224.         return source.substring(0, 1).toUpperCase() + source.substring(1);
  225.     }
  226. }

简单来说，就是通过监python教程听器封装了个 org.apache.skywalking.oal.rt.parser.OALScripts 对象

  1. package org.apache.skywalking.oal.rt.parser;
  2.  
  3. import java.util.LinkedList;
  4. import java.util.List;
  5. import lombok.Getter;
  6.  
  7. @Getter
  8. public class OALScripts {
  9.     // 解析出来的分析结果集合
  10.     private List<AnalysisResult> metricsStmts;
  11.     // 禁用表达式集合
  12.     private DisableCollection disableCollection;
  13.  
  14.     public OALScripts() {
  15.         metricsStmts = new LinkedList<>();
  16.         disableCollection = new DisableCollection();
  17.     }
  18. }
  19.

org.apache.skywalking.oal.rt.parser.ScriptParser 类读取 oal 文件，使用 Antlr 生成的 Java 类进行解析

  1. package org.apache.skywalking.oal.rt.parser;
  2.  
  3. import java.io.IOException;
  4. import java.io.Reader;
  5. import org.antlr.v4.runtime.CharStreams;
  6. import org.antlr.v4.runtime.CommonTokenStream;
  7. import org.antlr.v4.runtime.tree.ParseTree;
  8. import org.antlr.v4.runtime.tree.ParseTreeWalker;
  9. import org.apache.skywalking.oal.rt.grammar.OALLexer;
  10. import org.apache.skywalking.oal.rt.grammar.OALParser;
  11.  
  12. /**
  13.  * Script reader and parser.
  14.  */
  15. public class ScriptParser {
  16.     private OALLexer lexer;
  17.  
  18.     private String sourcePackage;
  19.  
  20.     private ScriptParser() {
  21.  
  22.     }
  23.  
  24.     public static ScriptParser createFromFile(Reader scriptReader, String sourcePackage) throws IOException {
  25.         ScriptParser parser = new ScriptParser();
  26.         parser.lexer = new OALLexer(CharStreams.fromReader(scriptReader));
  27.         parser.sourcePackage = sourcePackage;
  28.         return parser;
  29.     }
  30.  
  31.     public static ScriptParser createFromScriptText(String script, String sourcePackage) throws IOException {
  32.         ScriptParser parser = new ScriptParser();
  33.         parser.lexer = new OALLexer(CharStreams.fromString(script));
  34.         parser.sourcePackage = sourcePackage;
  35.         return parser;
  36.     }
  37.  
  38.     public OALScripts parse() throws IOException {
  39.         OALScripts scripts = new OALScripts();
  40.  
  41.         CommonTokenStream tokens = new CommonTokenStream(lexer);
  42.  
  43.         OALParser parser = new OALParser(tokens);
  44.  
  45.         ParseTree tree = parser.root();
  46.         ParseTreeWalker walker = new ParseTreeWalker();
  47.  
  48.         walker.walk(new OALListener(scripts, sourcePackage), tree);
  49.  
  50.         return scripts;
  51.     }
  52.  
  53.     public void close() {
  54.     }
  55. }

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