Added JSON serialize SMT (#1)

.gitattributes

@@ -0,0 +1,5 @@
+#
+# https://help.github.com/articles/dealing-with-line-endings/
+#
+# These are explicitly windows files and should use crlf
+*.bat           text eol=crlf

.github/workflows/release.yml

@@ -0,0 +1,36 @@
+name: Release
+
+on:
+  push:
+    tags:
+      - 'v*'
+
+jobs:
+  build-project:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout project sources
+        uses: actions/checkout@v2
+      - name: Setup Gradle
+        uses: gradle/gradle-build-action@v2
+      - name: Build project
+        run: ./gradlew build
+      - name: Create release
+        id: create_release
+        uses: actions/create-release@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }} # This token is provided by Actions, you do not need to create your own token
+        with:
+          tag_name: ${{ github.ref }}
+          release_name: ${{ github.ref }}
+          draft: true
+          prerelease: false
+      - name: Upload artifact
+        uses: actions/[email protected]
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          upload_url: ${{ steps.create_release.outputs.upload_url }}
+          asset_path: ./build/libs/onliner-kafka-smt-1.0.0.jar
+          asset_name: onliner-kafka-smt.jar
+          asset_content_type: application/java-archive

.github/workflows/test.yml

@@ -0,0 +1,17 @@
+name: Tests
+
+on:
+  push:
+    branches:
+      - '*'
+
+jobs:
+  run-tests:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout project sources
+        uses: actions/checkout@v2
+      - name: Setup Gradle
+        uses: gradle/gradle-build-action@v2
+      - name: Run tests
+        run: ./gradlew test

.gitignore

@@ -0,0 +1,6 @@
+# Ignore Gradle project-specific cache directory
+.gradle
+# Ignore Gradle build output directory
+build
+lib/build
+.idea

LICENSE

@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) Onliner
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

README.md

@@ -1 +1,38 @@
-# kafka-smt
+# Onliner Transformations for Apache Kafka® Connect
+
+A collection of [Single Message Transformations (SMTs)](https://kafka.apache.org/documentation/#connect_transforms) for Apache Kafka Connect.
+
+## Transformations
+
+See [the Kafka documentation](https://kafka.apache.org/documentation/#connect_transforms) for more details about configuring transformations.
+
+### `JsonSerialize`
+
+This transformation serialize part of the original record's data to JSON strings.
+
+The transformation:
+- expects the record value/key to be either a `STRUCT` or a `MAP`;
+- expects it to have a specified field;
+
+Exists in two variants:
+- `org.onliner.kafka.transforms.JsonSerialize$Key` - works on keys;
+- `org.onliner.kafka.transforms.JsonSerialize$Value` - works on values.
+
+The transformation defines the following configurations:
+- `fields` - List of fields to serialize. Cannot be `null` or empty.
+
+- Here's an example of this transformation configuration:
+
+```properties
+transforms=encode
+transforms.encode.type=org.onliner.kafka.transforms.JsonSerialize$Value
+transforms.encode.fields=comma,separated,list,of,fields
+```
+
+## License
+
+This project is licensed under the [MIT license](LICENSE).
+
+## Trademarks
+
+Apache Kafka and Apache Kafka Connect are either registered trademarks or trademarks of the Apache Software Foundation in the United States and/or other countries.

build.gradle.kts

@@ -0,0 +1,102 @@
+/*
+ * User Manual available at https://docs.gradle.org/7.4/userguide/building_java_projects.html
+ */
+
+group = "org.onliner.kafka.smt"
+version = System.getenv("VERSION") ?: "1.0.0"
+
+val javaVersion = 11
+
+val artifactoryContext =
+    project.properties.getOrDefault("artifactory_context", System.getenv("ARTIFACTORY_CONTEXT")).toString()
+val artifactoryUsern =
+    project.properties.getOrDefault("artifactory_user", System.getenv("ARTIFACTORY_USER")).toString()
+val artifactoryPassword =
+    project.properties.getOrDefault("artifactory_password", System.getenv("ARTIFACTORY_PWD")).toString()
+
+plugins {
+    kotlin("jvm") version "1.6.21"
+    idea // Generates files that are used by IntelliJ IDEA, thus making it possible to open the project from IDEA
+    `java-library` // Apply the java-library plugin for API and implementation separation.
+    `maven-publish`
+    id("io.gitlab.arturbosch.detekt") version "1.20.0"
+}
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    val kafkaConnectVersion = "3.2.+"
+    val junitVersion = "5.8.2"
+
+    compileOnly(platform("org.jetbrains.kotlin:kotlin-bom")) // Align versions of all Kotlin components
+    compileOnly("org.jetbrains.kotlin:kotlin-stdlib-jdk8") // Use the Kotlin JDK 8 standard library.
+
+    implementation("org.apache.kafka:connect-api:$kafkaConnectVersion")
+    implementation("org.apache.kafka:connect-json:$kafkaConnectVersion")
+    implementation("org.apache.kafka:connect-transforms:$kafkaConnectVersion")
+
+    testImplementation("org.jetbrains.kotlin:kotlin-test-junit")
+    testImplementation("org.junit.jupiter:junit-jupiter-api:$junitVersion")
+}
+
+kotlin {
+    jvmToolchain {
+        (this as JavaToolchainSpec).languageVersion.set(JavaLanguageVersion.of(javaVersion))
+    }
+}
+
+publishing {
+    publications {
+        create<MavenPublication>("maven") {
+            groupId = project.group.toString()
+            artifactId = project.name
+            version = project.version.toString()
+
+            pom {
+                name.set("onliner-kafka-smt")
+                description.set( project.description)
+                url.set("https://github.com/onliner/kafka-smt")
+                organization {
+                    name.set("Onliner")
+                    url.set("https://github.com/onliner")
+                }
+                issueManagement {
+                    system.set("GitHub")
+                    url.set("https://github.com/onliner/kafka-smt/issues")
+                }
+                licenses {
+                    license {
+                        name.set( "Apache License 2.0")
+                        url.set("https://github.com/onliner/kafka-smt/blob/master/LICENSE")
+                        distribution.set("repo")
+                    }
+                }
+                developers {
+                    developer {
+                        name.set("onliner")
+                    }
+                }
+                scm {
+                    url.set("https://github.com/onliner/kafka-smt")
+                    connection.set("scm:git:git://github.com/onliner/kafka-smt.git")
+                    developerConnection.set("scm:git:ssh://[email protected]:onliner/kafka-smt.git")
+                }
+            }
+
+            from(components["java"])
+        }
+    }
+    repositories {
+        maven {
+            name = "ArtifactoryLocal"
+            url = uri(artifactoryContext + "/libs-release-local")
+            credentials {
+                username = artifactoryUsern
+                password = artifactoryPassword
+            }
+        }
+    }
+}
+