add more boilerplates for serverless triggers (#748)

#431

community/boilerplates/event-triggers/aws-lambda/java/echo/README.md

@@ -0,0 +1,30 @@
+# Setup tables
+1. Create table:
+
+```
+notes:
+  id: int
+  note: text
+```
+
+# Setup AWS Lambda
+Create a lambda function in AWS. This will be our webhook.
+
+1. Create a function.
+2. Select Java 8 as the runtime.
+3. Select "start from scratch".
+4. Add API gateway as a trigger.
+5. Add an API to API gateway.
+6. Edit the code in the `handleRequest` method in `/src/main/java/example/Hello.java`.
+
+# Deploy AWS Lambda
+
+1. In terminal go into project: `cd community/boilerplates/serverless-triggers/aws-lambda/java/echo`
+2. Build deployment package: `mvn package`
+2. Upload `target/java-lambda-1.0-SNAPSHOT.jar` using AWS console.
+
+
+# Add the trigger in Hasura GraphQL
+1. In events tab, add a trigger
+2. Select all insert, update, delete operations for the trigger.
+3. Paste the API endpoint of your AWS lambda as the webhook.

community/boilerplates/event-triggers/aws-lambda/java/echo/pom.xml

@@ -0,0 +1,65 @@
+<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/maven-v4_0_0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>io.hasura.serverless</groupId>
+    <artifactId>java-lambda</artifactId>
+    <packaging>jar</packaging>
+    <version>1.0-SNAPSHOT</version>
+    <name>Java Lambda</name>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.amazonaws</groupId>
+            <artifactId>aws-lambda-java-core</artifactId>
+            <version>1.2.0</version>
+        </dependency>
+        <dependency>
+            <groupId>com.jayway.jsonpath</groupId>
+            <artifactId>json-path</artifactId>
+            <version>2.4.0</version>
+        </dependency>
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-nop</artifactId>
+            <version>1.7.25</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-api</artifactId>
+            <version>5.1.0</version>
+            <scope>test</scope>
+        </dependency>
+
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-shade-plugin</artifactId>
+                <version>3.2.0</version>
+                <configuration>
+                    <createDependencyReducedPom>false</createDependencyReducedPom>
+                </configuration>
+                <executions>
+                    <execution>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>shade</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>1.8</source>
+                    <target>1.8</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+</project>

community/boilerplates/event-triggers/aws-lambda/java/echo/src/main/java/example/Hello.java

@@ -0,0 +1,48 @@
+package example;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import com.amazonaws.services.lambda.runtime.Context;
+import com.amazonaws.services.lambda.runtime.RequestHandler;
+import com.jayway.jsonpath.DocumentContext;
+import com.jayway.jsonpath.JsonPath;
+
+public class Hello implements RequestHandler<Map<String, Object>, Map<String, Object>> {
+
+    private static final int INTERNAL_SERVER_ERROR = 500;
+    private final Notebook notebook;
+
+    public Hello() {
+        this.notebook = new Notebook();
+    }
+
+    @Override
+    public Map<String, Object> handleRequest(Map<String, Object> request, Context context) {
+        context.getLogger().log(request.toString());
+        Map<String, Object> response = new HashMap<>();
+        response.put("isBase64Encoded", false);
+        try {
+            String requestBody = (String) request.get("body");
+            response.put("body", handleRequestBody(requestBody));
+            response.put("statusCode", 200);
+        } catch (Exception e) {
+            response.put("body", e.toString());
+            response.put("statusCode", INTERNAL_SERVER_ERROR);
+        }
+        return response;
+    }
+
+    private String handleRequestBody(String requestBody) {
+        DocumentContext body = JsonPath.parse(requestBody);
+        String table = body.read("$.table.name");
+        if (table != null && table.equals("notes")) {
+            Notebook.Operation operation = Notebook.Operation.valueOf(body.read("$.event.op"));
+            Note newNote = body.read("$.event.data.new", Note.class);
+            Note oldNote = body.read("$.event.data.old", Note.class);
+            return notebook.handleOperation(operation, newNote, oldNote);
+        } else {
+            throw new UnsupportedOperationException("table: " + table);
+        }
+    }
+}

community/boilerplates/event-triggers/aws-lambda/java/echo/src/main/java/example/Note.java

@@ -0,0 +1,23 @@
+package example;
+
+class Note {
+
+    private Integer id;
+    private String note;
+
+    Integer getId() {
+        return id;
+    }
+
+    void setId(Integer id) {
+        this.id = id;
+    }
+
+    String getNote() {
+        return note;
+    }
+
+    void setNote(String note) {
+        this.note = note;
+    }
+}

community/boilerplates/event-triggers/aws-lambda/java/echo/src/main/java/example/Notebook.java

@@ -0,0 +1,22 @@
+package example;
+
+class Notebook {
+
+    enum Operation {
+        INSERT, UPDATE, DELETE;
+    }
+
+    String handleOperation(Operation operation, Note newNote, Note oldNote) {
+        switch (operation) {
+            case INSERT:
+                return "New note " + newNote.getId() + " inserted, with data: " + newNote.getNote();
+            case UPDATE:
+                return "Note " + newNote.getId() + " updated, with data: " + newNote.getNote();
+            case DELETE:
+                return "Note " + oldNote.getId() + " deleted, with data: " + oldNote.getNote();
+            default:
+                throw new UnsupportedOperationException("operation: " + operation);
+        }
+    }
+
+}

community/boilerplates/event-triggers/aws-lambda/java/echo/src/test/java/example/ContextStub.java

@@ -0,0 +1,74 @@
+package example;
+
+import com.amazonaws.services.lambda.runtime.ClientContext;
+import com.amazonaws.services.lambda.runtime.CognitoIdentity;
+import com.amazonaws.services.lambda.runtime.Context;
+import com.amazonaws.services.lambda.runtime.LambdaLogger;
+
+public class ContextStub implements Context {
+
+    @Override
+    public LambdaLogger getLogger() {
+        return new LambdaLogger() {
+            @Override
+            public void log(String s) {
+                System.out.println(s);
+            }
+
+            @Override
+            public void log(byte[] bytes) {
+                log(new String(bytes));
+            }
+        };
+    }
+
+    @Override
+    public String getAwsRequestId() {
+        return null;
+    }
+
+    @Override
+    public String getLogGroupName() {
+        return null;
+    }
+
+    @Override
+    public String getLogStreamName() {
+        return null;
+    }
+
+    @Override
+    public String getFunctionName() {
+        return null;
+    }
+
+    @Override
+    public String getFunctionVersion() {
+        return null;
+    }
+
+    @Override
+    public String getInvokedFunctionArn() {
+        return null;
+    }
+
+    @Override
+    public CognitoIdentity getIdentity() {
+        return null;
+    }
+
+    @Override
+    public ClientContext getClientContext() {
+        return null;
+    }
+
+    @Override
+    public int getRemainingTimeInMillis() {
+        return -1;
+    }
+
+    @Override
+    public int getMemoryLimitInMB() {
+        return -1;
+    }
+}

community/boilerplates/event-triggers/aws-lambda/java/echo/src/test/java/example/HelloTest.java

@@ -0,0 +1,35 @@
+package example;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class HelloTest {
+
+    @Test
+    void handleRequestDelete() throws IOException {
+        Map<String, Object> request = new HashMap<>();
+        request.put("body", loadResource("delete.json"));
+
+        Map<String, Object> response = new Hello().handleRequest(request, new ContextStub());
+
+        assertEquals(200, response.get("statusCode"));
+        assertEquals("Note 1 deleted, with data: a", response.get("body"));
+    }
+
+    private String loadResource(String name) {
+        return new BufferedReader(new InputStreamReader(
+                ClassLoader.getSystemResourceAsStream(name)
+        ))
+                .lines()
+                .collect(Collectors.joining("\n"));
+    }
+
+}

community/boilerplates/event-triggers/aws-lambda/java/echo/src/test/resources/delete.json

@@ -0,0 +1,18 @@
+{
+  "table": {
+    "name": "notes"
+  },
+  "event": {
+    "op": "DELETE",
+    "data": {
+      "new": {
+        "id": 2,
+        "note": "b"
+      },
+      "old": {
+        "id": 1,
+        "note": "a"
+      }
+    }
+  }
+}