java support with prometheus and dependency management with maven (#738)

* basic java support with prometheus and dependency management with maven

* pass the event and context details to called function

* fix NPE when all expected event details are not there

* buid container support to run java functions with deps

* addressing review comments

* review fixes

* docs for java runtime

* update the runtimeImage and initImage for Java

docker/runtime/java/Dockerfile

@@ -0,0 +1,5 @@
+FROM openjdk:8-jdk-alpine
+
+USER 1000
+
+CMD ["java", "-cp", "/kubeless/lib/*:/kubeless/handler/target/handler-1.0-SNAPSHOT.jar:/kubeless/function/target/function-1.0-SNAPSHOT.jar", "io.kubeless.Handler"]

docker/runtime/java/Dockerfile.init

@@ -0,0 +1,5 @@
+FROM openjdk:8-jdk-alpine
+
+RUN apk add --no-cache maven
+
+COPY . /usr/src/myapp

docker/runtime/java/Makefile

@@ -0,0 +1,14 @@
+init-image:
+	docker build -f Dockerfile.init -t kubeless/java-init:1.8 .
+
+runtime-image:
+	docker build -f Dockerfile -t kubeless/java:1.8 .
+
+push-init:
+	docker push kubeless/java-init:1.8
+
+push-runtime:
+	docker push kubeless/java:1.8
+
+build-all: init-image runtime-image
+push-all: push-init push-runtime

docker/runtime/java/function/pom.xml

@@ -0,0 +1,18 @@
+<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">
+  <modelVersion>4.0.0</modelVersion>
+  <artifactId>function</artifactId>
+  <name>function</name>
+  <version>1.0-SNAPSHOT</version>
+  <dependencies>
+      <dependency>
+          <groupId>io.kubeless</groupId>
+          <artifactId>params</artifactId>
+          <version>1.0-SNAPSHOT</version>
+      </dependency>
+  </dependencies>
+  <parent>
+    <groupId>io.kubeless</groupId>
+    <artifactId>kubeless</artifactId>
+    <version>1.0-SNAPSHOT</version>
+  </parent>
+</project>

docker/runtime/java/function/src/main/java/io/kubeless/Example.java

@@ -0,0 +1,7 @@
+package io.kubeless;
+
+public class Example {
+    public String sayHello(io.kubeless.Event event, io.kubeless.Context context) {
+        return "Hello world!";
+    }
+}

docker/runtime/java/handler/pom.xml

@@ -0,0 +1,51 @@
+<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">
+  <modelVersion>4.0.0</modelVersion>
+  <artifactId>handler</artifactId>
+  <name>handler</name>
+  <version>1.0-SNAPSHOT</version>
+  <parent>
+    <groupId>io.kubeless</groupId>
+    <artifactId>kubeless</artifactId>
+    <version>1.0-SNAPSHOT</version>
+  </parent>
+  <dependencies>
+      <dependency>
+          <groupId>io.kubeless</groupId>
+          <artifactId>function</artifactId>
+          <version>1.0-SNAPSHOT</version>
+      </dependency>
+      <dependency>
+          <groupId>io.kubeless</groupId>
+          <artifactId>params</artifactId>
+          <version>1.0-SNAPSHOT</version>
+      </dependency>
+      <dependency>
+        <groupId>io.prometheus</groupId>
+        <artifactId>simpleclient</artifactId>
+        <version>0.3.0</version>
+      </dependency>
+      <!-- Hotspot JVM metrics-->
+      <dependency>
+        <groupId>io.prometheus</groupId>
+        <artifactId>simpleclient_hotspot</artifactId>
+        <version>0.3.0</version>
+      </dependency>
+      <!-- Exposition HTTPServer-->
+      <dependency>
+        <groupId>io.prometheus</groupId>
+        <artifactId>simpleclient_httpserver</artifactId>
+        <version>0.3.0</version>
+      </dependency>
+      <!-- Pushgateway exposition-->
+      <dependency>
+        <groupId>io.prometheus</groupId>
+        <artifactId>simpleclient_pushgateway</artifactId>
+        <version>0.3.0</version>
+      </dependency>
+      <dependency>
+        <groupId>log4j</groupId>
+        <artifactId>log4j</artifactId>
+        <version>1.2.17</version>
+      </dependency>
+  </dependencies>
+</project>

docker/runtime/java/handler/src/main/java/io/kubeless/Handler.java

@@ -0,0 +1,189 @@
+/*
+Copyright (c) 2016-2017 Bitnami
+
+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
+
+    http://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.
+*/
+package io.kubeless;
+
+import com.sun.net.httpserver.HttpExchange;
+import com.sun.net.httpserver.HttpHandler;
+import com.sun.net.httpserver.HttpServer;
+import com.sun.net.httpserver.Headers;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.InputStreamReader;
+import java.io.BufferedReader;
+import java.lang.reflect.Method;
+import java.lang.reflect.InvocationTargetException;
+import java.net.InetSocketAddress;
+import java.nio.charset.StandardCharsets;
+import java.util.List;
+import java.util.stream.Collectors;
+import io.prometheus.client.Counter;
+import io.prometheus.client.Histogram;
+import io.kubeless.Event;
+import io.kubeless.Context;
+import org.apache.log4j.Logger;
+import org.apache.log4j.BasicConfigurator;
+
+public class Handler {
+
+    static String className   = System.getenv("MOD_NAME");
+    static String methodName  = System.getenv("FUNC_HANDLER");
+    static String timeout     = System.getenv("FUNC_TIMEOUT");
+    static String runtime     = System.getenv("FUNC_RUNTIME");
+    static String memoryLimit = System.getenv("FUNC_MEMORY_LIMIT");
+    static Method method;
+    static Object obj;
+    static Logger logger = Logger.getLogger(Handler.class.getName());
+
+    static final Counter requests = Counter.build().name("function_calls_total").help("Total function calls.").register();
+    static final Counter failures = Counter.build().name("function_failures_total").help("Total function call failuress.").register();
+    static final Histogram requestLatency = Histogram.build().name("function_duration_seconds").help("Duration of time user function ran in seconds.").register();
+
+    public static void main(String[] args) {
+
+        BasicConfigurator.configure();
+
+        String funcPort = System.getenv("FUNC_PORT");
+        if(funcPort == null || funcPort.isEmpty()) {
+            funcPort = "8080";
+        }
+        int port = Integer.parseInt(funcPort);
+        try {
+            HttpServer server = HttpServer.create(new InetSocketAddress(port), 0);
+            server.createContext("/", new FunctionHandler());
+            server.createContext("/healthz", new HealthHandler());
+            server.setExecutor(java.util.concurrent.Executors.newFixedThreadPool(50));
+            server.start();
+
+            Class<?> c = Class.forName("io.kubeless."+className);
+            obj = c.newInstance();
+            method = c.getMethod(methodName, io.kubeless.Event.class, io.kubeless.Context.class);
+        } catch (Exception e) {
+            failures.inc();
+            if (e instanceof ClassNotFoundException) {
+                logger.error("Class: " + className + " not found");
+            } else if (e instanceof NoSuchMethodException) {
+                logger.error("Method: " + methodName + " not found");
+            } else if (e instanceof java.io.IOException) {
+                logger.error("Failed to starting listener.");
+            } else {
+                logger.error("An exception occured running Class: " + className + " method: " + methodName);
+                e.printStackTrace();
+            }
+        }
+    }
+
+    static class FunctionHandler implements HttpHandler {
+
+        @Override
+        public void handle(HttpExchange he) throws IOException {
+            Histogram.Timer requestTimer = requestLatency.startTimer();
+            try {
+                requests.inc();
+
+                InputStreamReader reader = new InputStreamReader(he.getRequestBody(), StandardCharsets.UTF_8.name());
+                BufferedReader br = new BufferedReader(reader);
+                String requestBody = br.lines().collect(Collectors.joining());
+                br.close();
+                reader.close();
+
+                Headers headers = he.getRequestHeaders();
+                String eventId  = getEventId(headers);
+                String eventType = getEventType(headers);
+                String eventTime = getEventTime(headers);
+                String eventNamespace = getEventNamespace(headers);
+
+                Event event = new Event(requestBody, eventId, eventType, eventTime, eventNamespace);
+                Context context = new Context(methodName, timeout, runtime, memoryLimit);
+
+                Object returnValue = Handler.method.invoke(Handler.obj, event, context);
+                String response = (String)returnValue;
+                logger.info("Response: " + response);
+                he.sendResponseHeaders(200, response.length());
+                OutputStream os = he.getResponseBody();
+                os.write(response.getBytes());
+                os.close();
+            } catch (Exception e) {
+                failures.inc();
+                if (e instanceof ClassNotFoundException) {
+                    logger.error("Class: " + className + " not found");
+                } else if (e instanceof NoSuchMethodException) {
+                    logger.error("Method: " + methodName + " not found");
+                } else if (e instanceof InvocationTargetException) {
+                    logger.error("Failed to Invoke Method: " + methodName);
+                } else if (e instanceof InstantiationException) {
+                    logger.error("Failed to instantiate method: " + methodName);
+                } else {
+                    logger.error("An exception occured running Class: " + className + " method: " + methodName);
+                    e.printStackTrace();
+                }
+            } finally {
+                requestTimer.observeDuration();
+            }
+        }
+
+        private String getEventType(Headers headers) {
+            if (headers.containsKey("event-type")) {
+                List<String> values = headers.get("event-type");
+                if (values != null) {
+                    return values.get(0);
+                }
+            }
+            return "";
+        }
+
+        private String getEventTime(Headers headers) {
+            if (headers.containsKey("event-time")) {
+                List<String> values = headers.get("event-time");
+                if (values != null) {
+                    return values.get(0);
+                }
+            }
+            return "";
+        }
+
+        private String getEventNamespace(Headers headers) {
+            if (headers.containsKey("event-namespace")) {
+                List<String> values = headers.get("event-namespace");
+                if (values != null) {
+                    return values.get(0);
+                }
+            }
+            return "";
+        }
+
+        private String getEventId(Headers headers) {
+            if (headers.containsKey("event-id")) {
+                List<String> values = headers.get("event-id");
+                if (values != null) {
+                    return values.get(0);
+                }
+            }
+            return "";
+        }
+    }
+
+    static class HealthHandler implements HttpHandler {
+        @Override
+        public void handle(HttpExchange t) throws IOException {
+            String response = "OK";
+            t.sendResponseHeaders(200, response.length());
+            OutputStream os = t.getResponseBody();
+            os.write(response.getBytes());
+            os.close();
+        }
+    }
+}

docker/runtime/java/handler/src/resources/log4j.properties

@@ -0,0 +1,8 @@
+# Root logger option
+log4j.rootLogger=INFO, stdout
+
+# Redirect log messages to console
+log4j.appender.stdout=org.apache.log4j.ConsoleAppender
+log4j.appender.stdout.Target=System.out
+log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
+log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n

docker/runtime/java/params/pom.xml

@@ -0,0 +1,11 @@
+<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">
+  <modelVersion>4.0.0</modelVersion>
+  <artifactId>params</artifactId>
+  <name>params</name>
+  <version>1.0-SNAPSHOT</version>
+  <parent>
+    <groupId>io.kubeless</groupId>
+    <artifactId>kubeless</artifactId>
+    <version>1.0-SNAPSHOT</version>
+  </parent>
+</project>

docker/runtime/java/params/src/main/java/io/kubeless/Context.java

@@ -0,0 +1,34 @@
+/*
+Copyright (c) 2016-2017 Bitnami
+
+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
+
+    http://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.
+*/
+
+package io.kubeless;
+
+/**
+ * Context includes information about the function environment
+ */
+public class Context {
+	String functionName;
+	String timeout;
+	String runtime;
+	String memoryLimit;
+
+    public Context(String functionName, String timeout, String runtime, String memoryLimit) {
+        this.functionName = functionName;
+        this.timeout = timeout;
+        this.runtime = runtime;
+        this.memoryLimit = memoryLimit;
+    }
+}

docker/runtime/java/params/src/main/java/io/kubeless/Event.java

@@ -0,0 +1,36 @@
+/*
+Copyright (c) 2016-2017 Bitnami
+
+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
+
+    http://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.
+*/
+
+package io.kubeless;
+
+/**
+ * Event includes information about the event source
+ */
+public class Event {
+	String Data;
+	String EventID;
+	String EventType;
+	String EventTime;
+	String EventNamespace;
+
+    public Event(String data, String eventId, String eventType, String eventTime, String eventNamespace) {
+        this.Data = data;
+        this.EventID = eventId;
+        this.EventType = eventType;
+        this.EventTime = eventTime;
+        this.EventNamespace = eventNamespace;
+    }
+}