Init project (#1)

* Init project

* Init project

.github/dependabot.yml

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+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"

.github/workflows/publish.yml

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+name: Publish package to GitHub Packages
+on:
+  release:
+    types: [created]
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: coursier/cache-action@v6
+      - uses: actions/[email protected]
+        with:
+          distribution: temurin
+          java-version: 11
+          check-latest: true
+      - name: Set output
+        id: vars
+        run: echo ::set-output name=tag::${GITHUB_REF#refs/*/}
+      - name: Publish package
+        run: sbt clean test publish
+        env:
+          CREATED_TAG: ${{ steps.vars.outputs.tag }}
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/scala-steward.yml

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+# This workflow will launch everyday at 00:00
+on:
+  schedule:
+    - cron: '0 0 * * *'
+
+name: Launch Scala Steward
+
+jobs:
+  scala-steward:
+    runs-on: ubuntu-latest
+    name: Launch Scala Steward
+    steps:
+      - name: Launch Scala Steward
+        uses: scala-steward-org/scala-steward-action@v2
+        with:
+          github-token: ${{ secrets.SCALA_STEWARD }}

.github/workflows/test.yml

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+name: Tests
+on:
+  push:
+    branches: [main, master]
+  pull_request:
+    branches: ["*"]
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: coursier/cache-action@v6
+      - uses: actions/[email protected]
+        with:
+          distribution: temurin
+          java-version: 11
+          check-latest: true
+      - name: Tests
+        run: sbt clean test

.gitignore

@@ -1,2 +1,111 @@
+### VisualStudioCode template
+.vscode/*
+!.vscode/settings.json
+!.vscode/tasks.json
+!.vscode/launch.json
+!.vscode/extensions.json
+*.code-workspace
+
+# Local History for Visual Studio Code
+.history/
+
+### JetBrains template
+# Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio, WebStorm and Rider
+# Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
+
+# User-specific stuff
+.idea/**/workspace.xml
+.idea/**/tasks.xml
+.idea/**/usage.statistics.xml
+.idea/**/dictionaries
+.idea/**/shelf
+
+# Generated files
+.idea/**/contentModel.xml
+
+# Sensitive or high-churn files
+.idea/**/dataSources/
+.idea/**/dataSources.ids
+.idea/**/dataSources.local.xml
+.idea/**/sqlDataSources.xml
+.idea/**/dynamic.xml
+.idea/**/uiDesigner.xml
+.idea/**/dbnavigator.xml
+
+# Gradle
+.idea/**/gradle.xml
+.idea/**/libraries
+
+.idea/
+
+# Gradle and Maven with auto-import
+# When using Gradle or Maven with auto-import, you should exclude module files,
+# since they will be recreated, and may cause churn.  Uncomment if using
+# auto-import.
+# .idea/artifacts
+# .idea/compiler.xml
+# .idea/jarRepositories.xml
+# .idea/modules.xml
+# .idea/*.iml
+# .idea/modules
+# *.iml
+# *.ipr
+
+# CMake
+cmake-build-*/
+
+# Mongo Explorer plugin
+.idea/**/mongoSettings.xml
+
+# File-based project format
+*.iws
+
+# IntelliJ
+out/
+
+# mpeltonen/sbt-idea plugin
+.idea_modules/
+
+# JIRA plugin
+atlassian-ide-plugin.xml
+
+# Cursive Clojure plugin
+.idea/replstate.xml
+
+# Crashlytics plugin (for Android Studio and IntelliJ)
+com_crashlytics_export_strings.xml
+crashlytics.properties
+crashlytics-build.properties
+fabric.properties
+
+# Editor-based Rest Client
+.idea/httpRequests
+
+# Android studio 3.1+ serialized cache file
+.idea/caches/build_file_checksums.ser
+
+### Scala template
 *.class
 *.log
+
+### SBT template
+# Simple Build Tool
+# http://www.scala-sbt.org/release/docs/Getting-Started/Directories.html#configuring-version-control
+
+dist/*
+target/
+lib_managed/
+src_managed/
+project/boot/
+project/plugins/project/
+.history
+.cache
+.lib/
+
+### Metals template
+ # Generated Metals (Scala Language Server) files
+ # Reference: https://scalameta.org/metals/
+.metals/
+.bloop/
+project/metals.sbt
+.bsp/

.scalafmt.conf

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+version = "3.0.8"
+runner.dialect = scala213
+maxColumn = 140
+align.preset = most
+continuationIndent.defnSite = 2
+assumeStandardLibraryStripMargin = true
+docstrings.style = Asterisk
+lineEndings = preserve
+includeCurlyBraceInSelectChains = false
+danglingParentheses.preset = true
+optIn.annotationNewlines = true
+newlines.alwaysBeforeMultilineDef = false
+trailingCommas = preserve
+
+rewrite.rules = [RedundantBraces, SortModifiers]
+
+rewrite.sortModifiers.order = [
+  "implicit", "override", "private", "protected", "final", "sealed", "abstract", "lazy"
+]
+rewrite.redundantBraces.generalExpressions = false
+rewriteTokens = {
+  "⇒": "=>"
+  "→": "->"
+  "←": "<-"
+}

README.md

@@ -1,2 +1,87 @@
 # my_custom_deserializers
-Kafka deserializer examples
+
+Kafka deserializers examples to use to demo/test the Conduktor "custom deserializers" feature.
+
+You can download the latest jar containing these deserializers here: TODO Jules
+
+To learn how to use the "custom deserializer" feature provided in Condukot, you can read the documentation of the feature: https://docs.conduktor.io/features/consuming-data/custom-deserializers
+
+## Deserializers implementation details
+
+Here's the list of the deserializers available in this jar and a quick explanation of each deserializer behaviour.    
+These deserializers are for demo/test purpose only.
+
+### io.example.conduktor.custom.deserializers.constant.ConstantString
+
+This deserializer completely ignores the messages it receives from Kafka.     
+For each message it receives from Kafka, it returns `this is a message`.
+
+### io.example.conduktor.custom.deserializers.constant.ConstantChar
+
+This deserializer completely ignores the messages it receives from Kafka.     
+For each message it receives from Kafka, it returns the letter `c`.
+
+### io.example.conduktor.custom.deserializers.constant.ConstantInt
+
+This deserializer completely ignores the messages it receives from Kafka.     
+For each message it receives from Kafka, it returns the value `1`.
+
+### io.example.conduktor.custom.deserializers.constant.ConstantDouble
+
+This deserializer completely ignores the messages it receives from Kafka.     
+For each message it receives from Kafka, it returns the value `1.234`.
+
+### io.example.conduktor.custom.deserializers.constant.ConstantFloat
+
+This deserializer completely ignores the messages it receives from Kafka.     
+For each message it receives from Kafka, it returns the value `1.456`.
+
+### io.example.conduktor.custom.deserializers.constant.ConstantShort
+
+This deserializer completely ignores the messages it receives from Kafka.     
+For each message it receives from Kafka, it returns the value `2`.
+
+### io.example.conduktor.custom.deserializers.constant.ConstantBoolean
+
+This deserializer completely ignores the messages it receives from Kafka.     
+For each message it receives from Kafka, it returns the value `true`.
+
+### io.example.conduktor.custom.deserializers.constant.ConstantByte
+
+This deserializer completely ignores the messages it receives from Kafka.     
+For each message it receives from Kafka, it returns the value `6`.
+
+### io.example.conduktor.custom.deserializers.constant.ConstantNull
+
+This deserializer completely ignores the messages it receives from Kafka.     
+For each message it receives from Kafka, it returns `null`.
+
+### io.example.conduktor.custom.deserializers.MyCustomDeserializer
+
+This deserializer transforms the data (bytes) it receives from Kafka into a `String` (text),     
+then sees if it matches then following format:
+```
+-- this is the serialized data
+```
+- If the message received from Kakfa effectively starts with a `--<space>` characters sequence then followed by some text, 
+it creates a new instance of a data structure named `MyMessage`, that contains only one field named `value` and is of type `String`, as following:     
+    ```scala
+    MyMessage(value = "this is the serialized data")
+    ```
+
+    In Conduktor, this data structure will be interpreted and displayed as JSON:     
+    ```json
+    { "value": "this is the serialized data" }
+    ```
+
+- If the message received from Kafka doesn't match the expected format, then the deserializer fails with an error message:
+  ```
+  Invalid format received for message: <the received message>
+  ```
+
+This simple example is here to demonstrate 2 things:
+  - What's happening when a custom deserializer fails to deserialize a message.
+  - Give a simple example of "deserialization" (the message has to respect of certain format so that the deserializer can extract the data)
+
+
+

build.sbt

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+name                                     := "my_custom_deserializers"
+version                                  := sys.env.getOrElse("CREATED_TAG", "0.1")
+scalaVersion                             := "2.13.7"
+libraryDependencies += "org.apache.kafka" % "kafka-clients" % "2.8.1"
+
+// ## Github Packages publish configs
+// More info, see: https://gist.github.com/guizmaii/2ca47b74ad8e26c772d7df6ada8ddb00
+val GITHUB_OWNER   = "conduktor"
+val GITHUB_PROJECT = "my_custom_deserializers"
+
+ThisBuild / publishTo         := Some(
+  s"GitHub $GITHUB_OWNER Apache Maven Packages" at s"https://maven.pkg.github.com/$GITHUB_OWNER/$GITHUB_PROJECT"
+)
+ThisBuild / publishMavenStyle := true
+ThisBuild / credentials += Credentials(
+  "GitHub Package Registry",
+  "maven.pkg.github.com",
+  GITHUB_OWNER,
+  System.getenv("GITHUB_TOKEN")
+)

project/build.properties

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+sbt.version = 1.5.5

project/plugins.sbt

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+addSbtPlugin("io.github.davidgregory084" % "sbt-tpolecat" % "0.1.20")

src/main/scala/io/example/conduktor/custom/deserializers/MyCustomDeserializer.scala

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+package io.example.conduktor.custom.deserializers
+
+import org.apache.kafka.common.serialization.{Deserializer, Serializer}
+
+import java.nio.charset.StandardCharsets
+
+final case class MyMessage(value: String)
+
+final class MyCustomSerializer extends Serializer[MyMessage] {
+  override def serialize(topic: String, data: MyMessage): Array[Byte] = s"-- ${data.value}".getBytes(StandardCharsets.UTF_8)
+}
+
+final class MyCustomDeserializer extends Deserializer[MyMessage] {
+  override def deserialize(topic: String, data: Array[Byte]): MyMessage =
+    new String(data, StandardCharsets.UTF_8) match {
+      case s"-- $data" => MyMessage(value = data)
+      case m           => throw new RuntimeException(s"Invalid format received for message: $m")
+    }
+}

src/main/scala/io/example/conduktor/custom/deserializers/constant/Deserializers.scala

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+package io.example.conduktor.custom.deserializers.constant
+
+import org.apache.kafka.common.serialization.Deserializer
+
+class ConstantString  extends Deserializer[String]  {
+  override def deserialize(topic: String, data: Array[Byte]): String = "this is a message"
+}
+class ConstantChar    extends Deserializer[Char]    {
+  override def deserialize(topic: String, data: Array[Byte]): Char = 'c'
+}
+class ConstantInt     extends Deserializer[Int]     {
+  override def deserialize(topic: String, data: Array[Byte]): Int = 1
+}
+class ConstantDouble  extends Deserializer[Double]  {
+  override def deserialize(topic: String, data: Array[Byte]): Double = 1.234
+}
+class ConstantFloat   extends Deserializer[Float]   {
+  override def deserialize(topic: String, data: Array[Byte]): Float = 1.456f
+}
+class ConstantShort   extends Deserializer[Short]   {
+  override def deserialize(topic: String, data: Array[Byte]): Short = 2
+}
+class ConstantBoolean extends Deserializer[Boolean] {
+  override def deserialize(topic: String, data: Array[Byte]): Boolean = true
+}
+class ConstantByte    extends Deserializer[Byte]    {
+  override def deserialize(topic: String, data: Array[Byte]): Byte = 6.toByte
+}
+class ConstantNull    extends Deserializer[Any]     {
+  override def deserialize(topic: String, data: Array[Byte]): Any = null
+}