Added additional sample implementations of service handlers and metri…

…cs exposure (#10)

Added additional sample implementations of service handlers and metrics exposure

README.md

@@ -1,3 +1,3 @@
 To view the readme for a specific example, please go to the specific example's readme file.
 
-See [Gateway framework user's guide](https://download.diffusiondata.com/gateway-framework/latest/user-guide/contents/index.html) to get started with writing a Gateway application using the framework.
+See [Gateway framework user's guide](https://download.diffusiondata.com/gateway-framework/latest/user-guide/contents/index.html) to get started with understanding Framework concepts, running a Gateway application and writing a Gateway application using the framework.

csv-file-adapter/csv-file-sink/src/main/java/com/diffusiondata/gateway/adapter/csv/sink/CsvFileSinkApplication.java

@@ -17,7 +17,7 @@
 /**
  * Main Gateway Application implementation for Csv sink application.
  *
- * @author Push Technology Limited
+ * @author DiffusionData Ltd
  */
 final class CsvFileSinkApplication implements GatewayApplication {
 

csv-file-adapter/csv-file-sink/src/main/java/com/diffusiondata/gateway/adapter/csv/sink/CsvFileSinkHandler.java

@@ -20,7 +20,7 @@
 /**
  * CSV file sink handler to write received string update into a CSV file.
  *
- * @author Push Technology Limited
+ * @author DiffusionData Ltd
  */
 @Immutable
 final class CsvFileSinkHandler implements SinkHandler<String> {
@@ -34,7 +34,6 @@ final class CsvFileSinkHandler implements SinkHandler<String> {
     @Override
     public SinkServiceProperties getSinkServiceProperties() throws InvalidConfigurationException {
         return newSinkServicePropertiesBuilder()
-            .topicType(TopicType.JSON)
             .payloadConvertorName("$JSON_to_CSV_STRING")
             .build();
     }

csv-file-adapter/csv-file-sink/src/main/java/com/diffusiondata/gateway/adapter/csv/sink/Runner.java

@@ -5,7 +5,7 @@
 /**
  * Main Runner class.
  *
- * @author Push Technology Limited
+ * @author DiffusionData Ltd
  */
 public class Runner {
     public static void main(String[] args) {

csv-file-adapter/csv-file-sink/src/main/java/com/diffusiondata/gateway/adapter/csv/sink/SimpleJSONToCsvStringConvertor.java

@@ -28,7 +28,7 @@
  * all the items of array will be looped to extract the headers. Hence, this
  * convertor is suggested to be used only for simple and small JSON payload.
  *
- * @author Push Technology Limited
+ * @author DiffusionData Ltd
  */
 public final class SimpleJSONToCsvStringConvertor
     implements OutboundPayloadConvertor<String, JSON> {

csv-file-adapter/csv-file-sink/src/test/java/com/diffusiondata/gateway/adapter/csv/sink/CsvFileSinkApplicationTest.java

@@ -18,7 +18,7 @@
 /**
  * Tests for {@link CsvFileSinkApplication}.
  *
- * @author Push Technology Limited
+ * @author DiffusionData Ltd
  */
 class CsvFileSinkApplicationTest {
 

csv-file-adapter/csv-file-sink/src/test/java/com/diffusiondata/gateway/adapter/csv/sink/CsvFileSinkHandlerTest.java

@@ -17,7 +17,7 @@
 /**
  * Tests for {@link CsvFileSinkHandler}.
  *
- * @author Push Technology Limited
+ * @author DiffusionData Ltd
  */
 class CsvFileSinkHandlerTest {
 

csv-file-adapter/csv-file-source/src/main/java/com/diffusiondata/gateway/adapter/csv/source/CsvFileSourceApplication.java

@@ -17,7 +17,7 @@
 /**
  * Main Gateway Application implementation for Csv source application.
  *
- * @author Push Technology Limited
+ * @author DiffusionData Ltd
  */
 final class CsvFileSourceApplication implements GatewayApplication {
 

csv-file-adapter/csv-file-source/src/main/java/com/diffusiondata/gateway/adapter/csv/source/CsvPollingSourceHandler.java

@@ -21,7 +21,7 @@
 /**
  * Polling source handler implementation for CSV source.
  *
- * @author Push Technology Limited
+ * @author DiffusionData Ltd
  */
 final class CsvPollingSourceHandler implements PollingSourceHandler {
     private static final Logger LOG =

csv-file-adapter/csv-file-source/src/main/java/com/diffusiondata/gateway/adapter/csv/source/CsvStreamingSourceHandler.java

@@ -32,7 +32,7 @@
  * Implementation of {@link StreamingSourceHandler} which listens to csv file
  * changes and publishes contents to Diffusion server.
  *
- * @author Push Technology Limited
+ * @author DiffusionData Ltd
  */
 final class CsvStreamingSourceHandler implements StreamingSourceHandler {
     private static final Logger LOG =

csv-file-adapter/csv-file-source/src/main/java/com/diffusiondata/gateway/adapter/csv/source/Runner.java

@@ -7,7 +7,7 @@
 /**
  * Main Runner class.
  *
- * @author Push Technology Limited
+ * @author DiffusionData Ltd
  */
 public class Runner {
     public static void main(String[] args) {

csv-file-adapter/csv-file-source/src/main/java/com/diffusiondata/gateway/adapter/csv/source/SourceConfig.java

@@ -3,7 +3,7 @@
 /**
  * Sample configuration required for source application.
  *
- * @author Push Technology Limited
+ * @author DiffusionData Ltd
  */
 public final class SourceConfig {
     private String fileName;

csv-file-adapter/csv-file-source/src/main/java/com/diffusiondata/gateway/adapter/csv/source/SourceConfigValidator.java

@@ -8,7 +8,7 @@
 /**
  * Validator for {@link SourceConfig} instance.
  *
- * @author Push Technology Limited
+ * @author DiffusionData Ltd
  */
 public final class SourceConfigValidator {
 

csv-file-adapter/csv-file-source/src/test/java/com/diffusiondata/gateway/adapter/csv/source/CsvFileSourceApplicationTest.java

@@ -38,7 +38,7 @@
 /**
  * Tests for {@link CsvFileSourceApplication}.
  *
- * @author Push Technology Limited
+ * @author DiffusionData Ltd
  */
 @ExtendWith(MockitoExtension.class)
 class CsvFileSourceApplicationTest {

csv-file-adapter/csv-file-source/src/test/java/com/diffusiondata/gateway/adapter/csv/source/CsvPollingSourceHandlerTest.java

@@ -31,7 +31,7 @@
 /**
  * Tests for {@link CsvPollingSourceHandler}.
  *
- * @author Push Technology Limited
+ * @author DiffusionData Ltd
  */
 @ExtendWith({MockitoExtension.class})
 class CsvPollingSourceHandlerTest {

csv-file-adapter/csv-file-source/src/test/java/com/diffusiondata/gateway/adapter/csv/source/CsvStreamingSourceHandlerTest.java

@@ -35,7 +35,7 @@
 /**
  * Tests for {@link CsvStreamingSourceHandler}.
  *
- * @author Push Technology Limited
+ * @author DiffusionData Ltd
  */
 @ExtendWith(MockitoExtension.class)
 class CsvStreamingSourceHandlerTest {

csv-file-adapter/csv-file-source/src/test/java/com/diffusiondata/gateway/adapter/csv/source/SourceConfigValidatorTest.java

@@ -23,7 +23,7 @@
 /**
  * Tests for {@link SourceConfigValidator}.
  *
- * @author Push Technology Limited
+ * @author DiffusionData Ltd
  */
 @ExtendWith(MockitoExtension.class)
 class SourceConfigValidatorTest {

misc/README.md

@@ -0,0 +1,119 @@
+# Example Gateway Application
+
+## Introduction
+
+This example Gateway application is created to demonstrate creating Hybrid
+service type (handlers) and Streaming source service types which handles missing
+topic notifications. It is also implemented to expose JMX and Prometheus metrics.
+
+This application supports two service types:
+
+1. DATE_APPENDER
+2. MISSING_TOPIC_HANDLER
+
+### DATE_APPENDER
+
+This hybrid service supports getting Diffusion JSON topic updates and appends
+a timestamp to the JSON data, if the data is of type JSON object. Any other types of JSON data will be ignored. The updated data will then be
+published to another Diffusion JSON topic. This target Diffusion topic path will
+be created by appending value of `targetTopicPrefix` from service configuration
+to the actual path, from where the update is received. Setting `targetTopicPrefix` in configuration is optional. If this configuration parameter is not set then its default value is used which is `enhanced/`.
+
+The schema of configuration for this service type is:
+
+```json
+ {
+  "$schema": "http://json-schema.org/draft-04/schema#",
+  "type": "object",
+  "properties": {
+    "targetTopicPrefix": {
+      "type": "string",
+      "default": "enhanced/",
+      "description": "The target Diffusion topic prefix to publish updates to. This prefix is appended to the topic path from which the update is received, creating a new topic path. The updated data is then published to the newly created topic path"
+    }
+  }
+}
+```
+
+Below is an example of an overall configuration of a service of
+type `DATE_APPENDER`:
+
+```json
+    {
+  "serviceName": "dateAppender1",
+  "serviceType": "DATE_APPENDER",
+  "config": {
+    "framework": {
+      "sink": {
+        "diffusionTopicSelector": "fx/EUR"
+      }
+    },
+    "application": {
+      "targetTopicPrefix": "updated/"
+    }
+  }
+}
+```
+
+With this configuration, the service will subscribe to the `fx/EUR` topic path.
+Upon receiving an update for this topic, if the update is in the form of a JSON
+object, the service will add a timestamp to the update and publish it to a new
+JSON topic named `updated/fx/EUR`
+
+### MISSING_TOPIC_HANDLER
+
+This streaming source service registers a Missing topic notification handler for
+the `missingTopicSelector` that is passed in the configuration. If there is any
+subscription to the configured missing topic branch, the service would create
+the missing topic of type JSON and publish a dummy JSON data.
+
+The schema of configuration for this service type is:
+
+```json
+{
+  "$schema": "http://json-schema.org/draft-04/schema#",
+  "type": "object",
+  "properties": {
+    "missingTopicSelector": {
+      "type": "string",
+      "description": "Missing topic selector to get missing topic notifications"
+    }
+  },
+  "required": [
+    "missingTopicSelector"
+  ]
+}
+```
+
+Below is an example of an overall configuration of a service of
+type `MISSING_TOPIC_HANDLER`:
+
+```json
+    {
+  "serviceName": "missingTopicHandler1",
+  "serviceType": "MISSING_TOPIC_HANDLER",
+  "config": {
+    "application": {
+      "missingTopicSelector": "fx/EUR"
+    }
+  }
+}
+```
+
+With this configuration, the service will register for missing topic
+notifications for the `fx/EUR` topic path. If any other session subscribes to
+this path and the topic does not exist in the server, this service will create a
+JSON-type topic and publish dummy data to it.
+
+NOTE:
+> For the demonstration purposes, the supplied configuration file: `src/main/resources/configuration.json` is created such that, a service of type `MISSING_TOPIC_HANDLER` will be created which will register for missing topic notification for topic path `fx/EUR`. Services of type `DATE_APPENDER` are created such that they subscribe to topic `fx/EUR`. Hence, when these services are added into the application, services `dateAppender1` and `dateAppender2` will subscribe to `fx/EUR` topic and service `missingTopicHandler` will create and update `fx/EUR` topic. As soon as the topic is created, `dateAppender1` and `dateAppender2` will send updates with date appended in them to topics `updated/fx/EUR` and `enhanced/fx/EUR` respectively. 
+
+## Metrics
+Out of the box metrics provided by Framework are exposed with JMX and Prometheus. 
+
+Exposed Prometheus metrics can be accessed using `http://localhost:8085/metrics`.
+
+## Running the application in IDE
+To run the application via IDE, run `misc/src/main/java/com/diffusiondata/gateway/example/Runner.java` file. Configuration file can be set as VM arguments in Run configuration as follows:
+
+> -Dgateway.config.file=misc/src/main/resources/configuration.json -Dgateway.config.use-local-services=true

misc/pom.xml

@@ -0,0 +1,32 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>gateway-examples</artifactId>
+        <groupId>com.diffusiondata.gateway.adapter</groupId>
+        <version>1.0.0</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>misc</artifactId>
+
+    <properties>
+        <maven.compiler.source>11</maven.compiler.source>
+        <maven.compiler.target>11</maven.compiler.target>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>io.micrometer</groupId>
+            <artifactId>micrometer-registry-jmx</artifactId>
+            <version>1.8.1</version>
+        </dependency>
+        <dependency>
+            <groupId>io.micrometer</groupId>
+            <artifactId>micrometer-registry-prometheus</artifactId>
+            <version>1.8.1</version>
+        </dependency>
+    </dependencies>
+
+</project>