avro-kotlin-maven-plugin

Maven Plugin to generate Kotlin Source code of Avro SpecificRecord classes based on Avro Schema definitions.

The plugin is tested against Avro data created by the org.apache.avro:avro-maven-plugin:1.9.0 plugin (and vice versa, tested that classes created by this plugin can read data serialized by the equivalent Kotlin classes).

Related resources:

• avro-kotlin-maven-plugin Git Repository
• avro-kotlin-maven-plugin Issue Tracker
• Avro Schema Spec
• original Apache Avro Maven Plugin Git Repo (creates Java sources)

How to use

<plugin>
    <groupId>net.stefanfuchs</groupId>
    <artifactId>avro-kotlin-maven-plugin</artifactId>
    <version>1.0</version>
    <executions>
        <execution>
            <phase>generate-sources</phase>
            <goals>
                <goal>schema</goal>
            </goals>
            <configuration>
                <sourcePath>${project.basedir}/src/main/resources/avro/</sourcePath>
                <destinationPath>${project.basedir}/src/main/generated-sources/kotlin/</destinationPath>
            </configuration>
        </execution>
    </executions>
</plugin>

Plugin Configuration

The following settings can be used to control the plugin

setting	type	default	description
sourcePath	Path		This path will be searched recursively for files ending with [extensionFilter] extensions
includeFileList	List<File>		List of files to be included and considered as Avro Schema (no matter if the extension matches or if they are located in another directory than [sourcePath]
extensionFilter	List<String>	'.avro', '.avsc'	Only consider files with this extensions in [sourcePath] as Avro Schema files
generateLogicalType	Boolean	true	When true, the plugin will generate getter/setter of Kotlin data types that are closest to the logicalType (e.g. ZonedDateTime instead of Long for logicalType 'epoch-millis')
destinationPath	Path	'./generated-sources'	Output path, where the Kotlin class source code is written to

The plugin will fail:

• if one of the Schema definitions is invalid
• class (schema namespace + name) has been defined twice but with different schema structure
• a class already exists as a path name

The plugin will not cleanup the destination folder before the code generation (use maven-clean-plugin to achive this).

Datatype mapping

Data is internally stored by the Kotlin equivalent of the Avro type, but when a logical type is specified, a more specific data type is used for getter/setter to work with the DTO.

Avro type	logical type	Kotlin type
null		Any? (Unions are the specific type but optional (?)
bytes		ByteArray
bytes	decimal	BigDecimal
string		String
string	uuid	UUID
int		Int
int	date	LocalDate
int	time-millis	LocalTime
long		Long
long	time-micros	LocalTime
long	timestamp-millis	ZonedDateTime (UTC)
long	timestamp-micros	ZonedDateTime (UTC)
boolean		Boolean
float		Float
double		Double
record		org.apache.avro.specific.SpecificRecord
enum		org.apache.avro.generic.GenericEnumSymbol
array		Array<>
map		MutableMap<>
fixed		org.apache.avro.specific.SpecificFixed