Using Avro Schemas that refer other Avro Schema to generate specific record class in Java

Question

I have 2 schemas i.e. LogLine and User schemas

{
  "namespace": "com.sample.log",
  "type": "record",
  "name": "User",
  "fields": [
    {"name": "username", "type": "string"},
    {"name": "user_type", "type": "string"},
  ]
}

  
{
  "namespace": "com.sample.log",
  "type": "record",
  "name": "LogLine",
  "fields": [
    {"name": "ip", "type": "string"},
    {"name": "timestamp",  "type": "long"},
    {"name": "url",  "type": "string"},
    {"name": "referrer",  "type": "string"},
    {"name": "useragent",  "type": "string"},
    {"name": "sessionid",  "type": ["null","int"], "default": null}
    {"name": "user",  "type": ["null","user"], "default": null}
  ]
}

I have defined the Logline schema such that I need to refer to another schema "user" schema. I need to generate the specific record class by using the Avro Maven plugin.

When I try to do the same getting error

Failed to execute goal org.apache.avro:avro-maven-plugin:1.8.2:schema (default) on project Logging: Execution default of goal org.apache.avro:avro-maven-plugin:1.8.2:schema failed Undefined Name "User"

Answer 1

Since I was using Avro Maven plugin I need to import the User schema first which is a dependency for Logline schema. Below I have added the import unser the imports section and it worked for me.

         <plugin>
            <groupId>org.apache.avro</groupId>
            <artifactId>avro-maven-plugin</artifactId>
            <version>${avro.version}</version>
            <executions>
                <execution>
                    <phase>generate-sources</phase>
                    <goals>
                        <goal>schema</goal>
                    </goals>
                    <configuration>
                        <sourceDirectory>${project.basedir}/src/main/resources/typedmessages/</sourceDirectory>
                        <imports>
                            <import>${project.basedir}/src/main/resources/typedmessages/user.avsc</import>
                        </imports>
                        <includes>
                            <include>*.avsc</include>
                        </includes>
                        <outputDirectory>${project.build.directory}/generated-sources</outputDirectory>
                    </configuration>
                </execution>
            </executions>
        </plugin>

More details can be found in the blog: https://feitam.es/use-of-avro-maven-plugin-with-complex-schemas-defined-in-several-files-to-be-reused-in-different-typed-messages/