【NIFI】开发自定义Nifi Processor - H__D

H__D

【NIFI】开发自定义Nifi Processor

　　本例需要基础知识：【NIFI】 Apache NiFI 安装及简单的使用

　　Nifi不光可以使用自带的Processor，还可以自定义Processor。本例简单介绍开发一个Processor

开发

　　1、新建一个Maven工程，这里采用的是eclipse的模板原型来创建。

　　　　a、创建

　　　　b、添加模板，内容：

- - Archetype Group Id：org.apache.nifi
  - Archetype Artifact Id：nifi-processor-bundle-archetype
  - Archetype Version：1.2.0

　　　　c、根据模板创建，maven项目

　　2、创建后，项目目录如下：

　　　　其中3个pom文件如下

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <!--
 3   Licensed to the Apache Software Foundation (ASF) under one or more
 4   contributor license agreements. See the NOTICE file distributed with
 5   this work for additional information regarding copyright ownership.
 6   The ASF licenses this file to You under the Apache License, Version 2.0
 7   (the "License"); you may not use this file except in compliance with
 8   the License. You may obtain a copy of the License at
 9   http://www.apache.org/licenses/LICENSE-2.0
10   Unless required by applicable law or agreed to in writing, software
11   distributed under the License is distributed on an "AS IS" BASIS,
12   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   See the License for the specific language governing permissions and
14   limitations under the License.
15 -->
16 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
17     <modelVersion>4.0.0</modelVersion>
18 
19     <parent>
20         <groupId>org.apache.nifi</groupId>
21         <artifactId>nifi-nar-bundles</artifactId>
22         <version>1.2.0</version>
23     </parent>
24 
25     <groupId>com.test</groupId>
26     <artifactId>my-processor</artifactId>
27     <version>1.0-SNAPSHOT</version>
28     <packaging>pom</packaging>
29 
30     <modules>
31         <module>nifi-my-processor-processors</module>
32         <module>nifi-my-processor-nar</module>
33     </modules>
34     
35 </project>

my-processor pom.xml　

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <!--
 3   Licensed to the Apache Software Foundation (ASF) under one or more
 4   contributor license agreements. See the NOTICE file distributed with
 5   this work for additional information regarding copyright ownership.
 6   The ASF licenses this file to You under the Apache License, Version 2.0
 7   (the "License"); you may not use this file except in compliance with
 8   the License. You may obtain a copy of the License at
 9   http://www.apache.org/licenses/LICENSE-2.0
10   Unless required by applicable law or agreed to in writing, software
11   distributed under the License is distributed on an "AS IS" BASIS,
12   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   See the License for the specific language governing permissions and
14   limitations under the License.
15 -->
16 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
17     <modelVersion>4.0.0</modelVersion>
18 
19     <parent>
20         <groupId>com.test</groupId>
21         <artifactId>my-processor</artifactId>
22         <version>1.0-SNAPSHOT</version>
23     </parent>
24 
25     <artifactId>nifi-my-processor-nar</artifactId>
26     <packaging>nar</packaging>
27     <properties>
28         <maven.javadoc.skip>true</maven.javadoc.skip>
29         <source.skip>true</source.skip>
30     </properties>
31 
32     <dependencies>
33         <dependency>
34             <groupId>com.test</groupId>
35             <artifactId>nifi-my-processor-processors</artifactId>
36             <version>1.0-SNAPSHOT</version>
37         </dependency>
38     </dependencies>
39 
40 </project>

nifi-my-processor-nar pom.xml

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <!--
 3   Licensed to the Apache Software Foundation (ASF) under one or more
 4   contributor license agreements. See the NOTICE file distributed with
 5   this work for additional information regarding copyright ownership.
 6   The ASF licenses this file to You under the Apache License, Version 2.0
 7   (the "License"); you may not use this file except in compliance with
 8   the License. You may obtain a copy of the License at
 9   http://www.apache.org/licenses/LICENSE-2.0
10   Unless required by applicable law or agreed to in writing, software
11   distributed under the License is distributed on an "AS IS" BASIS,
12   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   See the License for the specific language governing permissions and
14   limitations under the License.
15 -->
16 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
17     <modelVersion>4.0.0</modelVersion>
18 
19     <parent>
20         <groupId>com.test</groupId>
21         <artifactId>my-processor</artifactId>
22         <version>1.0-SNAPSHOT</version>
23     </parent>
24 
25     <artifactId>nifi-my-processor-processors</artifactId>
26     <packaging>jar</packaging>
27 
28     <dependencies>
29         <dependency>
30             <groupId>org.apache.nifi</groupId>
31             <artifactId>nifi-api</artifactId>
32         </dependency>
33         <dependency>
34             <groupId>org.apache.nifi</groupId>
35             <artifactId>nifi-utils</artifactId>
36         </dependency>
37         <dependency>
38             <groupId>org.apache.nifi</groupId>
39             <artifactId>nifi-mock</artifactId>
40             <scope>test</scope>
41         </dependency>
42         <dependency>
43             <groupId>org.slf4j</groupId>
44             <artifactId>slf4j-simple</artifactId>
45             <scope>test</scope>
46         </dependency>
47         <dependency>
48             <groupId>junit</groupId>
49             <artifactId>junit</artifactId>
50             <scope>test</scope>
51         </dependency>
52     </dependencies>
53 </project>

nifi-my-processor-processors pom.xml

　　3、修改项目，因环境引起的错误

　　　　a、删除nifi-my-processor-processors子项目中，src/test中的测试文件（打包可能出现错误）

　　　　b、在org.apache.nifi.processor.Processor文件中配置自己的Porcessor

　　4、代码编写，编辑MyProcessor.java文件，文件在项目创建的时候已经生成，做适当修改即可。其中有设置状态，属性，及处理方法（onTrigger）等

　　　　内容：

  1 /*
  2  * Licensed to the Apache Software Foundation (ASF) under one or more
  3  * contributor license agreements.  See the NOTICE file distributed with
  4  * this work for additional information regarding copyright ownership.
  5  * The ASF licenses this file to You under the Apache License, Version 2.0
  6  * (the "License"); you may not use this file except in compliance with
  7  * the License.  You may obtain a copy of the License at
  8  *
  9  *     http://www.apache.org/licenses/LICENSE-2.0
 10  *
 11  * Unless required by applicable law or agreed to in writing, software
 12  * distributed under the License is distributed on an "AS IS" BASIS,
 13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 14  * See the License for the specific language governing permissions and
 15  * limitations under the License.
 16  */
 17 package com.test.processors;
 18 
 19 import org.apache.nifi.components.PropertyDescriptor;
 20 import org.apache.nifi.flowfile.FlowFile;
 21 import org.apache.nifi.annotation.behavior.ReadsAttribute;
 22 import org.apache.nifi.annotation.behavior.ReadsAttributes;
 23 import org.apache.nifi.annotation.behavior.WritesAttribute;
 24 import org.apache.nifi.annotation.behavior.WritesAttributes;
 25 import org.apache.nifi.annotation.lifecycle.OnScheduled;
 26 import org.apache.nifi.annotation.documentation.CapabilityDescription;
 27 import org.apache.nifi.annotation.documentation.SeeAlso;
 28 import org.apache.nifi.annotation.documentation.Tags;
 29 import org.apache.nifi.processor.exception.ProcessException;
 30 import org.apache.nifi.processor.AbstractProcessor;
 31 import org.apache.nifi.processor.ProcessContext;
 32 import org.apache.nifi.processor.ProcessSession;
 33 import org.apache.nifi.processor.ProcessorInitializationContext;
 34 import org.apache.nifi.processor.Relationship;
 35 import org.apache.nifi.processor.util.StandardValidators;
 36 
 37 import java.io.InputStreamReader;
 38 import java.io.StringWriter;
 39 import java.util.ArrayList;
 40 import java.util.Collections;
 41 import java.util.HashSet;
 42 import java.util.List;
 43 import java.util.Set;
 44 import java.util.concurrent.atomic.AtomicReference;
 45 
 46 @Tags({"example"})
 47 @CapabilityDescription("Provide a description")
 48 @SeeAlso({})
 49 @ReadsAttributes({@ReadsAttribute(attribute="", description="")})
 50 @WritesAttributes({@WritesAttribute(attribute="", description="")})
 51 public class MyProcessor extends AbstractProcessor {
 52 
 53     public static final PropertyDescriptor MY_PROPERTY = new PropertyDescriptor
 54             .Builder().name("MY_PROPERTY")
 55             .displayName("My property")
 56             .description("Example Property")
 57             .required(true)
 58             .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
 59             .build();
 60 
 61     public static final Relationship MY_RELATIONSHIP_SUCCESS = new Relationship.Builder()
 62             .name("sucess")
 63             .description("Example relationship Success")
 64             .build();
 65     
 66     public static final Relationship MY_RELATIONSHIP_FAILURE = new Relationship.Builder()
 67             .name("failure")
 68             .description("Example relationship Failure")
 69             .build();
 70 
 71     private List<PropertyDescriptor> descriptors;
 72 
 73     private Set<Relationship> relationships;
 74 
 75     @Override
 76     protected void init(final ProcessorInitializationContext context) {
 77         final List<PropertyDescriptor> descriptors = new ArrayList<PropertyDescriptor>();
 78         descriptors.add(MY_PROPERTY);
 79         this.descriptors = Collections.unmodifiableList(descriptors);
 80 
 81         final Set<Relationship> relationships = new HashSet<Relationship>();
 82         relationships.add(MY_RELATIONSHIP_SUCCESS);
 83         relationships.add(MY_RELATIONSHIP_FAILURE);
 84         this.relationships = Collections.unmodifiableSet(relationships);
 85     }
 86 
 87     @Override
 88     public Set<Relationship> getRelationships() {
 89         return this.relationships;
 90     }
 91 
 92     @Override
 93     public final List<PropertyDescriptor> getSupportedPropertyDescriptors() {
 94         return descriptors;
 95     }
 96 
 97     @OnScheduled
 98     public void onScheduled(final ProcessContext context) {
 99 
100     }
101 
102     @Override
103     public void onTrigger(final ProcessContext context, final ProcessSession session) throws ProcessException {
104         FlowFile flowFile = session.get();
105         if ( flowFile == null ) {
106             return;
107         }
108         // TODO implement
109         final AtomicReference<String> value = new AtomicReference<>();
110         session.read(flowFile, in -> {
111             try{
112                 StringWriter sw = new StringWriter();
113                 InputStreamReader inr = new InputStreamReader(in);
114                 char[] buffer = new char[1024];
115                 int n = 0;
116                 while (-1 != (n = inr.read(buffer))) {
117                     sw.write(buffer, 0, n);
118                 }
119                 String str = sw.toString();
120                 
121                 String result = "处理了：" + str + context.getProperty("MY_PROPERTY").getValue();
122                 value.set(result);
123             }catch(Exception ex){
124                 ex.printStackTrace();
125                 getLogger().error("Failed to read json string.");
126             }
127         });
128 
129         String results = value.get();
130         if(results != null && !results.isEmpty()){
131             flowFile = session.putAttribute(flowFile, "match", results);
132         }
133 
134         flowFile = session.write(flowFile, out -> out.write(value.get().getBytes()));
135 
136         session.transfer(flowFile, MY_RELATIONSHIP_SUCCESS);
137         
138     }
139 }