Initial commit

.gitignore

@@ -0,0 +1,11 @@
+# Compiled classes
+*.class
+# Gradle files
+.gralde
+# IntelliJ IDEA files
+.idea
+# Build files
+build
+# Log files
+*.log
+logs

README.md

@@ -1,2 +1,39 @@
-# spring-telemetry-receiver
+# Spring Kafka based Telemetry Data Receiver
-A RESTful microservice using spring boot, to receive telemetry data and publish to kafka using the spring-kafka library
+The project is built on spring boot using spring kafka, to receive telemetry data on a REST endpoint and publish the same to a Kafka topic. The related blog post can be found at [https://www.barrelsofdata.com/spring-boot-based-telemetry-data-receiver-api-spring-kafka-producer/](https://www.barrelsofdata.com/spring-boot-based-telemetry-data-receiver-api-spring-kafka-producer/)
+
+## Build instructions
+From the root of the project execute the below commands
+- To clear all compiled classes, build and log directories
+```shell script
+./gradlew clean
+```
+- To run tests
+```shell script
+./gradlew test
+```
+- To build jar
+```shell script
+./gradlew bootJar
+```
+- Build OCI compliant image
+```shell script
+./gradlew bootBuildImage
+```
+- All combined
+```shell script
+./gradlew clean test bootBuildImage
+```
+- Run from IDE
+```shell script
+./gradlew bootRun -PjvmArgs="-D--spring.config.location=config/dev.properties"
+```
+
+## Run native
+```shell script
+java -jar build/libs/spring-telemetry-receiver-1.0.jar --spring.config.location=config/dev.properties
+```
+
+## Run as docker container
+```shell script
+docker run -itd --rm --network host --mount type=bind,source=$(pwd)/config/dev.properties,target=/application.properties,readonly -e JAVA_OPTS=-D--spring.config.location=/application.properties --name spring-telemetry-server spring-telemetry-receiver:1.0
+```

build.gradle

@@ -0,0 +1,47 @@
+plugins {
+    id "java"
+    id "org.springframework.boot" version "${springBootVersion}"
+}
+
+group "${projectGroup}"
+version "${projectVersion}"
+sourceCompatibility = JavaVersion.VERSION_1_8
+targetCompatibility = JavaVersion.VERSION_1_8
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation group: "org.springframework.boot", name:"spring-boot-starter-web", version:"${springBootVersion}"
+    implementation group: "org.springframework.boot", name:"spring-boot-starter-validation", version:"${springBootVersion}"
+    implementation group: "org.springframework.kafka", name: "spring-kafka", version: "${springKafkaVersion}"
+
+    implementation group: "org.projectlombok", name: "lombok", version: "${lombokVersion}"
+    annotationProcessor group: "org.projectlombok", name: "lombok", version: "${lombokVersion}"
+
+    testImplementation group: "org.springframework.boot", name: "spring-boot-starter-test", version:"${springBootVersion}"
+    testImplementation group: "org.springframework.kafka", name: "spring-kafka-test", version:"${springKafkaVersion}"
+}
+
+springBoot {
+    mainClass.set("${applicationClass}")
+}
+
+compileJava {
+    options.encoding = "UTF-8"
+}
+
+test {
+    useJUnitPlatform()
+}
+
+bootBuildImage {
+    imageName = "${rootProject.name}:${projectVersion}"
+}
+
+bootRun {
+    if ( project.hasProperty('jvmArgs') ) {
+        jvmArgs project.jvmArgs.split('\\s+')
+    }
+}

config/dev.properties

@@ -0,0 +1,13 @@
+server.port=9080
+spring.main.banner-mode=off
+debug=false
+
+spring.kafka.bootstrap-servers=localhost:9092
+spring.kafka.producer.topic=telemetry
+spring.kafka.properties.retries=1
+spring.kafka.properties.max.block.ms=500
+
+logging.level.org.springframework=WARN
+logging.level.org.apache.catalina=WARN
+logging.level.org.apache.kafka=INFO
+logging.level.com.barrelsofdata=DEBUG

config/prod.properties

@@ -0,0 +1,12 @@
+server.port=9080
+spring.main.banner-mode=off
+debug=false
+
+spring.kafka.bootstrap-servers=localhost:9092
+spring.kafka.producer.topic=telemetry
+spring.kafka.properties.retries=1
+spring.kafka.properties.max.block.ms=500
+
+logging.level.org.springframework=WARN
+logging.level.org.apache.catalina=WARN
+logging.level.org.apache.kafka=WARN

config/qa.properties

@@ -0,0 +1,12 @@
+server.port=9080
+spring.main.banner-mode=off
+debug=false
+
+spring.kafka.bootstrap-servers=localhost:9092
+spring.kafka.producer.topic=telemetry
+spring.kafka.properties.retries=1
+spring.kafka.properties.max.block.ms=500
+
+logging.level.org.springframework=WARN
+logging.level.org.apache.catalina=WARN
+logging.level.org.apache.kafka=WARN

gradle.properties

@@ -0,0 +1,9 @@
+springBootVersion=2.4.0
+springKafkaVersion=2.6.3
+lombokVersion=1.18.16
+
+applicationClass=com.barrelsofdata.springexamples.Application
+projectGroup=com.barrelsofdata.springexamples
+projectVersion=1.0
+
+org.gradle.daemon=false

gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.7.1-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

gradlew

@@ -0,0 +1,185 @@
+#!/usr/bin/env sh
+
+#
+# Copyright 2015 the original author or authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=`expr $i + 1`
+    done
+    case $i in
+        0) set -- ;;
+        1) set -- "$args0" ;;
+        2) set -- "$args0" "$args1" ;;
+        3) set -- "$args0" "$args1" "$args2" ;;
+        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=`save "$@"`
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+exec "$JAVACMD" "$@"

gradlew.bat

@@ -0,0 +1,89 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

settings.gradle

@@ -0,0 +1 @@
+rootProject.name = 'spring-telemetry-receiver'

src/main/java/com/barrelsofdata/springexamples/Application.java

@@ -0,0 +1,13 @@
+package com.barrelsofdata.springexamples;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.ComponentScan;
+
+@SpringBootApplication
+@ComponentScan(basePackages = "com.barrelsofdata.springexamples")
+public class Application {
+    public static void main(String[] args) {
+        SpringApplication.run(Application.class, args);
+    }
+}

src/main/java/com/barrelsofdata/springexamples/constants/EventType.java

@@ -0,0 +1,6 @@
+package com.barrelsofdata.springexamples.constants;
+
+public enum EventType {
+    LEFT_MOUSE_BUTTON_CLICK,
+    RIGHT_MOUSE_BUTTON_CLICK
+}

src/main/java/com/barrelsofdata/springexamples/controller/ApplicationErrorController.java

@@ -0,0 +1,45 @@
+package com.barrelsofdata.springexamples.controller;
+
+import com.barrelsofdata.springexamples.dto.ExceptionDto;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.web.error.ErrorAttributeOptions;
+import org.springframework.boot.web.servlet.error.ErrorAttributes;
+import org.springframework.boot.web.servlet.error.ErrorController;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.context.request.RequestAttributes;
+import org.springframework.web.context.request.WebRequest;
+
+import javax.servlet.RequestDispatcher;
+import java.util.Date;
+import java.util.Map;
+
+@Controller
+public class ApplicationErrorController implements ErrorController {
+
+    @Autowired
+    private ErrorAttributes errorAttributes;
+
+    @RequestMapping("/error")
+    public ResponseEntity<ExceptionDto> handleError(WebRequest request) {
+        Map<String, Object> requestErrors = errorAttributes.getErrorAttributes(request, ErrorAttributeOptions.defaults());
+        Object statusObject = request.getAttribute(RequestDispatcher.ERROR_STATUS_CODE, RequestAttributes.SCOPE_REQUEST);
+        StringBuilder errorMessage = new StringBuilder();
+        ExceptionDto.ExceptionDtoBuilder exceptionBuilder = ExceptionDto.builder();
+        if(requestErrors.containsKey("timestamp")) exceptionBuilder.timestamp((Date) requestErrors.get("timestamp"));
+        if(requestErrors.containsKey("error")) errorMessage.append(requestErrors.get("error"));
+        if(requestErrors.containsKey("message")) errorMessage.append((String) requestErrors.get("message"));
+        exceptionBuilder.error(errorMessage.toString());
+        HttpStatus status = statusObject != null ? HttpStatus.resolve(Integer.parseInt(statusObject.toString())) : HttpStatus.INTERNAL_SERVER_ERROR;
+        ExceptionDto exception = exceptionBuilder.build();
+        return new ResponseEntity<>(exception, status);
+    }
+
+    @Override
+    @SuppressWarnings( "deprecation" )
+    public String getErrorPath() {
+        return "/error";
+    }
+}

src/main/java/com/barrelsofdata/springexamples/controller/TelemetryController.java

@@ -0,0 +1,30 @@
+package com.barrelsofdata.springexamples.controller;
+
+import com.barrelsofdata.springexamples.dto.EventRequestDto;
+import com.barrelsofdata.springexamples.service.TelemetryService;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.PutMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RestController;
+
+import javax.validation.Valid;
+
+@RestController
+public class TelemetryController {
+
+    @Autowired private TelemetryService telemetryService;
+
+    @PutMapping(
+            value = "/telemetry",
+            consumes = MediaType.APPLICATION_JSON_VALUE,
+            produces = MediaType.APPLICATION_JSON_VALUE
+    )
+    public ResponseEntity<String> receiveTelemetry(@RequestBody @Valid EventRequestDto eventRequest) {
+        telemetryService.receiveTelemetry(eventRequest);
+        return new ResponseEntity<>(HttpStatus.CREATED.getReasonPhrase(), HttpStatus.CREATED);
+    }
+
+}

src/main/java/com/barrelsofdata/springexamples/dto/EventDetailsDto.java

@@ -0,0 +1,21 @@
+package com.barrelsofdata.springexamples.dto;
+
+import com.fasterxml.jackson.annotation.JsonAlias;
+
+import lombok.Getter;
+import lombok.Setter;
+import lombok.ToString;
+
+@ToString
+@Setter
+@Getter
+public class EventDetailsDto {
+    @JsonAlias("w")
+    private Integer width;
+    @JsonAlias("h")
+    private Integer height;
+    @JsonAlias("x")
+    private Float x;
+    @JsonAlias("y")
+    private Float y;
+}

src/main/java/com/barrelsofdata/springexamples/dto/EventRequestDto.java

@@ -0,0 +1,28 @@
+package com.barrelsofdata.springexamples.dto;
+
+import com.barrelsofdata.springexamples.constants.EventType;
+import com.fasterxml.jackson.annotation.JsonAlias;
+
+import lombok.Getter;
+import lombok.Setter;
+import lombok.ToString;
+
+import javax.validation.constraints.NotNull;
+import java.sql.Timestamp;
+
+@ToString
+@Setter
+@Getter
+public class EventRequestDto {
+    @NotNull
+    @JsonAlias("ts")
+    private Timestamp timestamp;
+    @NotNull
+    @JsonAlias("id")
+    private Integer id;
+    @NotNull
+    @JsonAlias("ty")
+    private EventType type;
+    @JsonAlias("pl")
+    private EventDetailsDto payload;
+}

src/main/java/com/barrelsofdata/springexamples/dto/ExceptionDto.java

@@ -0,0 +1,14 @@
+package com.barrelsofdata.springexamples.dto;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+import lombok.Builder;
+
+import java.util.Date;
+
+@Builder
+public class ExceptionDto {
+    @JsonProperty("timestamp")
+    private Date timestamp;
+    @JsonProperty("error")
+    private String error;
+}

src/main/java/com/barrelsofdata/springexamples/exception/JsonConversionException.java

@@ -0,0 +1,17 @@
+package com.barrelsofdata.springexamples.exception;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.web.bind.annotation.ResponseStatus;
+
+@ResponseStatus(code = HttpStatus.BAD_REQUEST)
+public class JsonConversionException extends RuntimeException {
+    public JsonConversionException() {
+        super();
+    }
+    public JsonConversionException(String message) {
+        super(message);
+    }
+    public JsonConversionException(String message, Exception e) {
+        super(message, e);
+    }
+}

src/main/java/com/barrelsofdata/springexamples/producer/Kafka.java

@@ -0,0 +1,7 @@
+package com.barrelsofdata.springexamples.producer;
+
+import org.springframework.kafka.KafkaException;
+
+public interface Kafka {
+    void publish(String eventRequest) throws KafkaException;
+}

src/main/java/com/barrelsofdata/springexamples/producer/KafkaImpl.java

@@ -0,0 +1,36 @@
+package com.barrelsofdata.springexamples.producer;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.kafka.KafkaException;
+import org.springframework.kafka.core.KafkaTemplate;
+import org.springframework.kafka.support.SendResult;
+import org.springframework.stereotype.Component;
+import org.springframework.util.concurrent.ListenableFuture;
+import org.springframework.util.concurrent.ListenableFutureCallback;
+
+@Component
+public class KafkaImpl implements Kafka {
+    private static final Logger logger = LoggerFactory.getLogger(Kafka.class);
+
+    @Autowired private KafkaTemplate<String, String> kafkaTemplate;
+
+    @Value("${spring.kafka.producer.topic}")
+    private String topic;
+
+    public void publish(String payload) throws KafkaException {
+        ListenableFuture<SendResult<String, String>> future = kafkaTemplate.send(topic, payload); // Blocks call if kafka broker isn't available/responding
+        future.addCallback(new ListenableFutureCallback<SendResult<String, String>>() {
+            @Override
+            public void onSuccess(SendResult<String, String> result) {
+                logger.info("Message published to Kafka partition {} with offset {}", result.getRecordMetadata().partition(), result.getRecordMetadata().offset());
+            }
+            @Override
+            public void onFailure(Throwable ex) {
+                logger.error("Unable to publish message {}", payload, ex);
+            }
+        });
+    }
+}

src/main/java/com/barrelsofdata/springexamples/service/TelemetryService.java

@@ -0,0 +1,7 @@
+package com.barrelsofdata.springexamples.service;
+
+import com.barrelsofdata.springexamples.dto.EventRequestDto;
+
+public interface TelemetryService {
+    void receiveTelemetry(EventRequestDto eventRequest);
+}

src/main/java/com/barrelsofdata/springexamples/service/TelemetryServiceImpl.java

@@ -0,0 +1,35 @@
+package com.barrelsofdata.springexamples.service;
+
+import com.barrelsofdata.springexamples.dto.EventRequestDto;
+import com.barrelsofdata.springexamples.exception.JsonConversionException;
+import com.barrelsofdata.springexamples.producer.Kafka;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.kafka.KafkaException;
+import org.springframework.stereotype.Service;
+
+@Service
+public class TelemetryServiceImpl implements TelemetryService {
+    private static final Logger logger = LoggerFactory.getLogger(TelemetryService.class);
+
+    @Autowired private Kafka producer;
+
+    @Autowired private ObjectMapper jsonMapper;
+
+    @Override
+    public void receiveTelemetry(EventRequestDto eventRequest) {
+        try {
+            String payload = jsonMapper.writeValueAsString(eventRequest);
+            producer.publish(payload);
+        } catch (JsonProcessingException e) {
+            logger.error("Unable to convert message to json {}", eventRequest);
+            throw new JsonConversionException("Failed json conversion");
+        } catch (KafkaException e) {
+            logger.error("Kafka exception for request {}", eventRequest);
+            // TODO: Handle what you want to do with the data here
+        }
+    }
+}

src/test/java/com/barrelsofdata/springexamples/ApplicationIntegrationTest.java

@@ -0,0 +1,138 @@
+package com.barrelsofdata.springexamples;
+
+import com.barrelsofdata.springexamples.service.TelemetryService;
+import org.apache.kafka.clients.consumer.ConsumerRecord;
+import org.apache.kafka.common.serialization.StringDeserializer;
+import org.assertj.core.api.Assertions;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.kafka.core.DefaultKafkaConsumerFactory;
+import org.springframework.kafka.listener.ContainerProperties;
+import org.springframework.kafka.listener.KafkaMessageListenerContainer;
+import org.springframework.kafka.listener.MessageListener;
+import org.springframework.kafka.test.EmbeddedKafkaBroker;
+import org.springframework.kafka.test.context.EmbeddedKafka;
+import org.springframework.kafka.test.utils.ContainerTestUtils;
+import org.springframework.kafka.test.utils.KafkaTestUtils;
+import org.springframework.test.context.junit.jupiter.SpringExtension;
+import org.springframework.test.web.servlet.MockMvc;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.TimeUnit;
+
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.put;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+
+@SpringBootTest
+@ExtendWith(SpringExtension.class)
+@EmbeddedKafka
+@AutoConfigureMockMvc
+public class ApplicationIntegrationTest {
+    private int NUMBER_OF_BROKERS = 2;
+    private boolean CONTROLLER_SHUTDOWN = false;
+    private int NUMBER_OF_PARTITIONS = 2;
+    @Value("${spring.kafka.producer.topic}")
+    private String TOPIC;
+
+    @Autowired private TelemetryService telemetryService;
+
+    @Autowired private MockMvc mockMvc;
+
+    @Autowired
+    private EmbeddedKafkaBroker embeddedKafkaBroker = new EmbeddedKafkaBroker(NUMBER_OF_BROKERS, CONTROLLER_SHUTDOWN, NUMBER_OF_PARTITIONS, TOPIC);
+
+    private BlockingQueue<ConsumerRecord<String, String>> records;
+    private KafkaMessageListenerContainer<String, String> container;
+
+    @BeforeEach
+    void setUp() {
+        Map<String, Object> consumerConfigs = new HashMap<>(KafkaTestUtils.consumerProps("consumer", "false", embeddedKafkaBroker));
+        DefaultKafkaConsumerFactory<String, String> consumerFactory = new DefaultKafkaConsumerFactory<>(consumerConfigs, new StringDeserializer(), new StringDeserializer());
+        ContainerProperties containerProperties = new ContainerProperties(TOPIC);
+        container = new KafkaMessageListenerContainer<>(consumerFactory, containerProperties);
+        records = new LinkedBlockingQueue<>();
+        container.setupMessageListener((MessageListener<String, String>) records::add);
+        container.start();
+        ContainerTestUtils.waitForAssignment(container, embeddedKafkaBroker.getPartitionsPerTopic());
+    }
+
+    @AfterEach
+    void tearDown() {
+        container.stop();
+    }
+
+    @ParameterizedTest(name = "Integration: API request success")
+    @CsvSource(value = {
+            "{\"ts\":\"1606297994000\",\"id\":\"123\",\"ty\":\"LEFT_MOUSE_BUTTON_CLICK\",\"pl\":{\"x\":1000,\"y\":5000,\"w\":213,\"h\":124}};{\"timestamp\":\"2020-11-25T09:53:14.000+00:00\",\"id\":123,\"type\":\"LEFT_MOUSE_BUTTON_CLICK\",\"payload\":{\"width\":213,\"height\":124,\"x\":1000.0,\"y\":5000.0}}",
+            "{\"ts\":\"1606297994000\",\"id\":\"123\",\"ty\":\"RIGHT_MOUSE_BUTTON_CLICK\"};{\"timestamp\":\"2020-11-25T09:53:14.000+00:00\",\"id\":123,\"type\":\"RIGHT_MOUSE_BUTTON_CLICK\",\"payload\":null}"}
+            , delimiter = ';')
+    public void success(String inputJson, String kafkaJson) throws Exception {
+        HttpHeaders headers = new HttpHeaders();
+
+        mockMvc.perform(
+                put("/telemetry")
+                        .contentType(MediaType.APPLICATION_JSON)
+                        .content(inputJson)
+                        .headers(headers))
+                .andExpect(
+                        status().isCreated()
+                )
+                .andExpect(
+                        content().contentType(MediaType.APPLICATION_JSON)
+                )
+                .andExpect(
+                        content().string(HttpStatus.CREATED.getReasonPhrase())
+                );
+
+        Thread.sleep(1000);
+        ConsumerRecord<String, String> singleRecord = records.poll(100, TimeUnit.MILLISECONDS);
+        Assertions.assertThat(singleRecord).isNotNull();
+        Assertions.assertThat(singleRecord.key()).isNull();
+        Assertions.assertThat(singleRecord.value()).isEqualTo(kafkaJson);
+    }
+
+    @ParameterizedTest(name = "Integration: API request success")
+    @CsvSource(value = {
+            "{\"ts\":\"1606297994000\",\"id\":\"123\",\"ty\":\"LEFT_MOUSE_BUTTON_CLICK\",\"pl\":{\"x\":1000,\"y\":5000,\"w\":213,\"h\":124}};{\"timestamp\":\"2020-11-25T09:53:14.000+00:00\",\"id\":123,\"type\":\"LEFT_MOUSE_BUTTON_CLICK\",\"payload\":{\"width\":213,\"height\":124,\"x\":1000.0,\"y\":5000.0}}",
+            "{\"ts\":\"1606297994000\",\"id\":\"123\",\"ty\":\"RIGHT_MOUSE_BUTTON_CLICK\"};{\"timestamp\":\"2020-11-25T09:53:14.000+00:00\",\"id\":123,\"type\":\"RIGHT_MOUSE_BUTTON_CLICK\",\"payload\":null}"}
+            , delimiter = ';')
+    public void unsupportedMedia(String inputJson, String kafkaJson) throws Exception {
+        HttpHeaders headers = new HttpHeaders();
+
+        mockMvc.perform(
+                put("/telemetry")
+                        .contentType(MediaType.APPLICATION_JSON)
+                        .content(inputJson)
+                        .headers(headers))
+                .andExpect(
+                        status().isCreated()
+                )
+                .andExpect(
+                        content().contentType(MediaType.APPLICATION_JSON)
+                )
+                .andExpect(
+                        content().string(HttpStatus.CREATED.getReasonPhrase())
+                );
+
+        Thread.sleep(1000);
+        ConsumerRecord<String, String> singleRecord = records.poll(100, TimeUnit.MILLISECONDS);
+        Assertions.assertThat(singleRecord).isNotNull();
+        Assertions.assertThat(singleRecord.key()).isNull();
+        Assertions.assertThat(singleRecord.value()).isEqualTo(kafkaJson);
+    }
+
+}

src/test/java/com/barrelsofdata/springexamples/controller/TelemetryControllerTest.java

@@ -0,0 +1,121 @@
+package com.barrelsofdata.springexamples.controller;
+
+import com.barrelsofdata.springexamples.dto.EventRequestDto;
+import com.barrelsofdata.springexamples.exception.JsonConversionException;
+import com.barrelsofdata.springexamples.producer.Kafka;
+import com.barrelsofdata.springexamples.service.TelemetryService;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+import org.mockito.Mockito;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.mock.mockito.MockBean;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.test.context.junit.jupiter.SpringExtension;
+import org.springframework.test.web.servlet.MockMvc;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.put;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+
+@SpringBootTest
+@ExtendWith(SpringExtension.class)
+@AutoConfigureMockMvc
+public class TelemetryControllerTest {
+    @MockBean private TelemetryService telemetryService;
+    @MockBean private Kafka kafka;
+    @Autowired private MockMvc mockMvc;
+
+    @ParameterizedTest(name = "Success API request")
+    @ValueSource(strings = {"{\"ts\":\"1606297994000\",\"id\":\"123\",\"ty\":\"LEFT_MOUSE_BUTTON_CLICK\",\"pl\":{\"x\":1000,\"y\":5000,\"w\":213,\"h\":124}}","{\"ts\":\"1606297994000\",\"id\":\"123\",\"ty\":\"RIGHT_MOUSE_BUTTON_CLICK\"}"})
+    public void success(String json) throws Exception {
+        HttpHeaders headers = new HttpHeaders();
+        Mockito.doNothing().when(telemetryService).receiveTelemetry(any(EventRequestDto.class));
+
+        mockMvc.perform(
+                put("/telemetry")
+                        .contentType(MediaType.APPLICATION_JSON)
+                        .content(json)
+                        .headers(headers))
+                .andExpect(
+                        status().isCreated()
+                )
+                .andExpect(
+                        content().contentType(MediaType.APPLICATION_JSON)
+                )
+                .andExpect(
+                        content().string(HttpStatus.CREATED.getReasonPhrase())
+                );
+    }
+
+    @ParameterizedTest(name = "Json conversion fail API response")
+    @ValueSource(strings = {"{\"ts\":\"1606297994000\",\"id\":\"123\",\"ty\":\"LEFT_MOUSE_BUTTON_CLICK\",\"pl\":{\"x\":1000,\"y\":5000,\"w\":213,\"h\":124}}","{\"ts\":\"1606297994000\",\"id\":\"123\",\"ty\":\"RIGHT_MOUSE_BUTTON_CLICK\"}"})
+    public void failBadJson(String json) throws Exception {
+        String expectedErrorMessage = "Failed json conversion";
+        HttpHeaders headers = new HttpHeaders();
+        Mockito.doThrow(new JsonConversionException(expectedErrorMessage)).when(telemetryService).receiveTelemetry(any(EventRequestDto.class));
+
+        mockMvc.perform(
+                put("/telemetry")
+                        .contentType(MediaType.APPLICATION_JSON)
+                        .content(json)
+                        .headers(headers))
+                .andExpect(
+                        status().isBadRequest()
+                );
+    }
+
+    @ParameterizedTest(name = "Unsupported media type")
+    @ValueSource(strings = {"{\"ts\":\"1606297994000\",\"id\":\"123\",\"ty\":\"LEFT_MOUSE_BUTTON_CLICK\",\"pl\":{\"x\":1000,\"y\":5000,\"w\":213,\"h\":124}}}","{\"ts\":\"1606297994000\",\"id\":\"123\",\"ty\":\"RIGHT_MOUSE_BUTTON_CLICK\"}}"})
+    public void unsupportedMediaType(String json) throws Exception {
+        HttpHeaders headers = new HttpHeaders();
+        Mockito.doNothing().when(telemetryService).receiveTelemetry(any(EventRequestDto.class));
+
+        mockMvc.perform(
+                put("/telemetry")
+                        .contentType(MediaType.TEXT_PLAIN)
+                        .content(json)
+                        .headers(headers))
+                .andExpect(
+                        status().isUnsupportedMediaType()
+                );
+    }
+
+    @ParameterizedTest(name = "Missing required field or wrong value for type, bad request")
+    @ValueSource(strings = {"{\"ts\":\"1606297994000\",\"ty\":\"LEFT_MOUSE_BUTTON_CLICK\",\"pl\":{\"x\":1000,\"y\":5000,\"w\":213,\"h\":124}}","{\"ts\":\"1606297994000\",\"id\":\"123\",\"ty\":\"MOUSE_BUTTON_CLICK\"}"})
+    public void missingRequiredField(String json) throws Exception {
+        HttpHeaders headers = new HttpHeaders();
+        Mockito.doNothing().when(telemetryService).receiveTelemetry(any(EventRequestDto.class));
+
+        mockMvc.perform(
+                put("/telemetry")
+                        .contentType(MediaType.APPLICATION_JSON)
+                        .content(json)
+                        .headers(headers))
+                .andExpect(
+                        status().isBadRequest()
+                );
+    }
+
+    @ParameterizedTest(name = "Method not allowed for non-PUT requests")
+    @ValueSource(strings = {"{\"ts\":\"1606297994000\",\"id\":\"123\",\"ty\":\"LEFT_MOUSE_BUTTON_CLICK\",\"pl\":{\"x\":1000,\"y\":5000,\"w\":213,\"h\":124}}","{\"ts\":\"1606297994000\",\"id\":\"123\",\"ty\":\"RIGHT_MOUSE_BUTTON_CLICK\"}"})
+    public void methodNotAllowed(String json) throws Exception {
+        HttpHeaders headers = new HttpHeaders();
+        Mockito.doNothing().when(telemetryService).receiveTelemetry(any(EventRequestDto.class));
+
+        mockMvc.perform(
+                post("/telemetry")
+                        .contentType(MediaType.APPLICATION_JSON)
+                        .content(json)
+                        .headers(headers))
+                .andExpect(
+                        status().isMethodNotAllowed()
+                );
+    }
+}

src/test/java/com/barrelsofdata/springexamples/producer/KafkaTest.java

@@ -0,0 +1,52 @@
+package com.barrelsofdata.springexamples.producer;
+
+import com.barrelsofdata.springexamples.dto.EventRequestDto;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.apache.kafka.common.KafkaException;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+import org.mockito.InjectMocks;
+import org.mockito.Mockito;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.mock.mockito.MockBean;
+import org.springframework.kafka.core.KafkaTemplate;
+import org.springframework.kafka.support.SendResult;
+import org.springframework.test.context.junit.jupiter.SpringExtension;
+import org.springframework.util.concurrent.ListenableFuture;
+import org.springframework.util.concurrent.SettableListenableFuture;
+
+import static org.mockito.ArgumentMatchers.any;
+
+@SpringBootTest
+@ExtendWith(SpringExtension.class)
+public class KafkaTest {
+    @MockBean private KafkaTemplate<String, String> kafkaTemplate;
+
+    @Autowired @InjectMocks private KafkaImpl producer;
+
+    @Autowired private ObjectMapper mapper;
+
+
+    @ParameterizedTest(name = "Check successful send")
+    @ValueSource(strings = {"{\"ts\":\"1606297994000\",\"id\":\"123\",\"ty\":\"LEFT_MOUSE_BUTTON_CLICK\",\"pl\":{\"x\":1000,\"y\":5000,\"w\":213,\"h\":124}}","{\"ts\":\"1606297994000\",\"id\":\"123\",\"ty\":\"RIGHT_MOUSE_BUTTON_CLICK\"}"})
+    public void successSend(String json) throws JsonProcessingException {
+        EventRequestDto eventRequestDto = mapper.readValue(json, EventRequestDto.class);
+        String kafkaPayload = mapper.writeValueAsString(eventRequestDto);
+        Mockito.doReturn(new SettableListenableFuture<>()).when(kafkaTemplate).send(any(String.class), any(String.class));
+        Assertions.assertDoesNotThrow(() -> producer.publish(kafkaPayload));
+    }
+
+    @ParameterizedTest(name = "Check failed send")
+    @ValueSource(strings = {"{\"ts\":\"1606297994000\",\"id\":\"123\",\"ty\":\"LEFT_MOUSE_BUTTON_CLICK\",\"pl\":{\"x\":1000,\"y\":5000,\"w\":213,\"h\":124}}","{\"ts\":\"1606297994000\",\"id\":\"123\",\"ty\":\"RIGHT_MOUSE_BUTTON_CLICK\"}"})
+    public void failedSend(String json) throws JsonProcessingException, InterruptedException {
+        EventRequestDto eventRequestDto = mapper.readValue(json, EventRequestDto.class);
+        String kafkaPayload = mapper.writeValueAsString(eventRequestDto);
+        Mockito.doThrow(KafkaException.class).when(kafkaTemplate).send(any(String.class), any(String.class));
+        Assertions.assertThrows(KafkaException.class, () -> producer.publish(kafkaPayload));
+    }
+
+}

src/test/java/com/barrelsofdata/springexamples/service/TelemetryServiceTest.java

@@ -0,0 +1,44 @@
+package com.barrelsofdata.springexamples.service;
+
+import com.barrelsofdata.springexamples.dto.EventRequestDto;
+import com.barrelsofdata.springexamples.exception.JsonConversionException;
+import com.barrelsofdata.springexamples.producer.Kafka;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+import org.mockito.InjectMocks;
+import org.mockito.Mockito;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.mock.mockito.MockBean;
+import org.springframework.test.context.junit.jupiter.SpringExtension;
+
+import static org.mockito.ArgumentMatchers.any;
+
+@SpringBootTest
+@ExtendWith(SpringExtension.class)
+public class TelemetryServiceTest {
+    @MockBean private Kafka kafka;
+    @MockBean private ObjectMapper mapper;
+    @Autowired @InjectMocks private TelemetryServiceImpl telemetryService;
+
+    @ParameterizedTest(name = "Successful publish")
+    @ValueSource(strings = {"{\"ts\":\"1606297994000\",\"id\":\"123\",\"ty\":\"LEFT_MOUSE_BUTTON_CLICK\",\"pl\":{\"x\":1000,\"y\":5000,\"w\":213,\"h\":124}}","{\"ts\":\"1606297994000\",\"id\":\"123\",\"ty\":\"RIGHT_MOUSE_BUTTON_CLICK\"}"})
+    public void successPublish(String json) throws JsonProcessingException {
+        EventRequestDto eventRequestDto = new ObjectMapper().readValue(json, EventRequestDto.class);
+        telemetryService.receiveTelemetry(eventRequestDto);
+    }
+
+    @ParameterizedTest(name = "Json conversion failure")
+    @ValueSource(strings = {"{\"ts\":\"1606297994000\",\"id\":\"123\",\"ty\":\"LEFT_MOUSE_BUTTON_CLICK\",\"pl\":{\"x\":1000,\"y\":5000,\"w\":213,\"h\":124}}"})
+    public void failPublish(String json) throws JsonProcessingException {
+        EventRequestDto eventRequestDto = new ObjectMapper().readValue(json, EventRequestDto.class);
+        Mockito.doThrow(JsonProcessingException.class).when(mapper).writeValueAsString(any(EventRequestDto.class));
+        JsonConversionException exception = Assertions.assertThrows(JsonConversionException.class, () -> telemetryService.receiveTelemetry(eventRequestDto));
+        Assertions.assertEquals("Failed json conversion", exception.getMessage());
+    }
+
+}

src/test/resources/application.properties

@@ -0,0 +1,13 @@
+server.port=9080
+spring.main.banner-mode=off
+debug=false
+
+spring.kafka.bootstrap-servers=${spring.embedded.kafka.brokers}
+spring.kafka.producer.topic=telemetryTest
+spring.kafka.properties.retries=1
+spring.kafka.properties.max.block.ms=500
+
+logging.level.org.springframework=WARN
+logging.level.org.apache.catalina=WARN
+logging.level.org.apache.kafka=INFO
+logging.level.com.barrelsofdata=DEBUG