AF-2637: Implement SVG backend Service for Kie Server (apache#1067)

* AF-2637: Implement SVG backend Service for Kie Server

* Improvements

* Checking optional before getting value

* fixing method

* Improvements

* fixing typo

dashbuilder/dashbuilder-backend/dashbuilder-external-backend/src/main/java/org/dashbuilder/external/impl/BackendComponentFunction.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2020 Red Hat, Inc. and/or its affiliates.
+ *
+ * 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 org.dashbuilder.external.impl;
+
+import java.util.Map;
+
+/**
+ * Server side component functions contract.
+ *
+ * @param <T>
+ * The function return type.
+ */
+public interface BackendComponentFunction<T> {
+
+    default String getName() {
+        return this.getClass().getSimpleName();
+    }
+
+    /**
+     * 
+     * The function execution. Must return an object that can be used in browser windows communication. 
+     * @param params
+     * Params set by user when configuring the component.
+     * @return
+     * The result
+     * 
+     */
+    T exec(Map<String, Object> params);
+
+}

dashbuilder/dashbuilder-backend/dashbuilder-external-backend/src/main/java/org/dashbuilder/external/impl/BackendComponentFunctionServiceImpl.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright 2020 Red Hat, Inc. and/or its affiliates.
+ *
+ * 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 org.dashbuilder.external.impl;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import javax.annotation.PostConstruct;
+import javax.enterprise.context.ApplicationScoped;
+import javax.enterprise.inject.Instance;
+import javax.inject.Inject;
+
+import org.dashbuilder.external.service.BackendComponentFunctionService;
+import org.jboss.errai.bus.server.annotations.Service;
+
+@Service
+@ApplicationScoped
+public class BackendComponentFunctionServiceImpl implements BackendComponentFunctionService {
+
+    Map<String, BackendComponentFunction<?>> functions;
+
+    @Inject
+    Instance<BackendComponentFunction<?>> functionsInstances;
+
+    @PostConstruct
+    void loadFunctions() {
+        functions = new HashMap<>();
+        functionsInstances.forEach(instance -> functions.put(instance.getName(), instance));
+    }
+
+    @Override
+    public List<String> listFunctions() {
+        return new ArrayList<>(functions.keySet());
+    }
+
+    @Override
+    public Object callFunction(String name, Map<String, Object> params) {
+        BackendComponentFunction<?> function = functions.get(name);
+        return function.exec(params);
+    }
+
+}

dashbuilder/dashbuilder-backend/dashbuilder-external-backend/src/main/java/org/dashbuilder/external/impl/BackendDateFunction.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2020 Red Hat, Inc. and/or its affiliates.
+ *
+ * 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 org.dashbuilder.external.impl;
+
+import java.text.SimpleDateFormat;
+import java.util.Date;
+import java.util.Map;
+
+import javax.enterprise.context.Dependent;
+
+/**
+ * Component backend function that returns the date.
+ *
+ */
+@Dependent
+public class BackendDateFunction implements BackendComponentFunction<String> {
+
+    private static final String FORMAT_PARAM = "format";
+
+    @Override
+    public String exec(Map<String, Object> params) {
+        Object pattern = params.get(FORMAT_PARAM);
+        if (pattern != null) {
+            return new SimpleDateFormat(pattern.toString()).format(new Date());
+        }
+        return new Date().toString();
+    }
+
+}

dashbuilder/dashbuilder-backend/dashbuilder-kie-server-backend/pom.xml

@@ -1,46 +1,52 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!-- ~ Copyright 2014 Red Hat, Inc. and/or its affiliates. ~ ~ 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. -->
+  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. -->
 
 <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>
-	<parent>
-		<groupId>org.dashbuilder</groupId>
-		<artifactId>dashbuilder-backend</artifactId>
-		<version>7.46.0-SNAPSHOT</version>
-	</parent>
+  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>
+  <parent>
+    <groupId>org.dashbuilder</groupId>
+    <artifactId>dashbuilder-backend</artifactId>
+    <version>7.46.0-SNAPSHOT</version>
+  </parent>
 
-	<artifactId>dashbuilder-kie-server-backend</artifactId>
-	<packaging>jar</packaging>
-	<name>Dashbuilder Kie Server Backend</name>
+  <artifactId>dashbuilder-kie-server-backend</artifactId>
+  <packaging>jar</packaging>
+  <name>Dashbuilder Kie Server Backend</name>
 
-	<dependencies>
-		<dependency>
-			<groupId>org.dashbuilder</groupId>
-			<artifactId>dashbuilder-kie-server-api</artifactId>
-		</dependency>
-		<dependency>
-			<groupId>javax.enterprise</groupId>
-			<artifactId>cdi-api</artifactId>
-			<scope>provided</scope>
-		</dependency>
-		<dependency>
-			<groupId>org.jboss.errai</groupId>
-			<artifactId>errai-config</artifactId>
-		</dependency>
-		<dependency>
-			<groupId>org.jboss.resteasy</groupId>
-			<artifactId>resteasy-client</artifactId>
-			<scope>provided</scope>
-		</dependency>
-	</dependencies>
+  <dependencies>
+    <dependency>
+      <groupId>org.dashbuilder</groupId>
+      <artifactId>dashbuilder-kie-server-api</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>javax.enterprise</groupId>
+      <artifactId>cdi-api</artifactId>
+      <scope>provided</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.jboss.errai</groupId>
+      <artifactId>errai-config</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>org.jboss.resteasy</groupId>
+      <artifactId>resteasy-client</artifactId>
+      <scope>provided</scope>
+    </dependency>
+
+    <dependency>
+      <groupId>org.dashbuilder</groupId>
+      <artifactId>dashbuilder-external-backend</artifactId>
+      <scope>provided</scope>
+    </dependency>
+  </dependencies>
 
 </project>

dashbuilder/dashbuilder-backend/dashbuilder-kie-server-backend/src/main/java/org/dashbuilder/kieserver/backend/KieServerConnectionInfoProviderImpl.java

@@ -19,6 +19,7 @@
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
+import java.util.Objects;
 import java.util.Optional;
 import java.util.function.BiFunction;
 import java.util.stream.Collectors;
@@ -45,6 +46,7 @@ public class KieServerConnectionInfoProviderImpl implements KieServerConnectionI
                                                "You should provide user/password or token authentication";
 
     private static final String SERVER_TEMPLATE_SEPARATOR = ",";
+    static final String DEFAULT_SERVER_TEMPLATE_PROPERTY = "dashbuilder.kieserver.defaultServerTemplate";
     static final String SERVER_TEMPLATE_LIST_PROPERTY = "dashbuilder.kieserver.serverTemplates";
     static final String SERVER_TEMPLATE_PROP_PREFFIX = "dashbuilder.kieserver.serverTemplate";
     static final String DATASET_PROP_PREFFIX = "dashbuilder.kieserver.dataset";
@@ -130,6 +132,15 @@ public Optional<String> remoteDatasetProperty(String datasetUUID,
         return filteredProperty(property);
     }
 
+    @Override
+    public Optional<KieServerConnectionInfo> getDefault() {
+        String defaultTemplate = System.getProperty(DEFAULT_SERVER_TEMPLATE_PROPERTY);
+        if (defaultTemplate != null) {
+            return this.get(null, defaultTemplate);
+        }
+        return findFirstServerTemplateConf().flatMap(template -> get(null, template));
+    }
+
     private Optional<String> filteredProperty(String property) {
         return Optional.ofNullable(System.getProperty(property)).filter(v -> !v.trim().isEmpty());
     }
@@ -155,4 +166,23 @@ private Optional<KieServerConnectionInfo> get(String confType,
         return Optional.of(new KieServerConnectionInfo(url, user, password, token, replaceQuery));
     }
 
+    Optional<String> findFirstServerTemplateConf() {
+        return Collections.list(System.getProperties().keys())
+                          .stream()
+                          .map(Object::toString)
+                          .filter(key -> key.startsWith(SERVER_TEMPLATE_PROP_PREFFIX))
+                          .map(this::retrieveTemplateId)
+                          .filter(Objects::nonNull)
+                          .findFirst();
+
+    }
+
+    String retrieveTemplateId(String property) {
+        String[] parts = property.replaceAll(SERVER_TEMPLATE_PROP_PREFFIX, "")
+                                 .split("\\.");
+        if (parts.length > 1) {
+            return parts[1];
+        }
+        return null;
+    }
 }

dashbuilder/dashbuilder-backend/dashbuilder-kie-server-backend/src/main/java/org/dashbuilder/kieserver/backend/function/ProcessSVGFunction.java

@@ -0,0 +1,98 @@
+/*
+ * Copyright 2020 Red Hat, Inc. and/or its affiliates.
+ *
+ * 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 org.dashbuilder.kieserver.backend.function;
+
+import java.util.Map;
+
+import javax.enterprise.context.Dependent;
+import javax.inject.Inject;
+import javax.ws.rs.WebApplicationException;
+
+import org.dashbuilder.external.impl.BackendComponentFunction;
+import org.dashbuilder.kieserver.KieServerConnectionInfo;
+import org.dashbuilder.kieserver.KieServerConnectionInfoProvider;
+import org.dashbuilder.kieserver.backend.rest.KieServerQueryClient;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+@Dependent
+public class ProcessSVGFunction implements BackendComponentFunction<String> {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(ProcessSVGFunction.class);
+
+    private static final String ERROR_REQUESTING_SVG = "Error requesting SVG from Kie Server: %s";
+
+    private static final String NOT_FOUND_MSG = "Process SVG not found for container %s and process %s";
+
+    private static final String CONTAINERID_PARAM = "containerId";
+    private static final String PROCESSID_PARAM = "processId";
+    private static final String SERVER_TEMPLATE_PARAM = "serverTemplate";
+
+    @Inject
+    KieServerQueryClient queryClient;
+
+    @Inject
+    KieServerConnectionInfoProvider connectionInfoProvider;
+
+    @Override
+    public String exec(Map<String, Object> params) {
+        String containerId = getRequiredParam(CONTAINERID_PARAM, params);
+        String processId = getRequiredParam(PROCESSID_PARAM, params);
+        Object serverTemplate = params.get(SERVER_TEMPLATE_PARAM);
+        KieServerConnectionInfo connectionInfo;
+        if (serverTemplate != null && !serverTemplate.toString().trim().isEmpty()) {
+            connectionInfo = connectionInfoProvider.get(null, serverTemplate.toString())
+                                                   .orElseThrow(() -> new RuntimeException("Configuration for server template not found " + serverTemplate));
+        } else {
+            connectionInfo = connectionInfoProvider.getDefault()
+                                                   .orElseThrow(() -> new RuntimeException("Not able to find credentials to retrieve processes SVG"));
+        }
+        try {
+            return queryClient.processSVG(connectionInfo, containerId, processId);
+        } catch (WebApplicationException e) {
+            if (e.getResponse().getStatus() == 404) {
+                notFoundSVGError(containerId, processId);
+            }
+            errorRetrievingSVG(e);
+        } catch (Exception e) {
+            errorRetrievingSVG(e);
+        }
+        return null;
+    }
+
+    private void errorRetrievingSVG(Exception e) {
+        String message = String.format(ERROR_REQUESTING_SVG, e.getMessage());
+        LOGGER.warn(message);
+        LOGGER.debug(message, e);
+        throw new RuntimeException(message, e);
+    }
+
+    private void notFoundSVGError(String containerId, String processId) {
+        String notFoundMessage = String.format(NOT_FOUND_MSG, containerId, processId);
+        LOGGER.warn(notFoundMessage);
+        throw new RuntimeException(notFoundMessage);
+    }
+
+    private String getRequiredParam(String param, Map<String, Object> params) {
+        Object value = params.get(param);
+        if (value == null || value.toString().trim().isEmpty()) {
+            throw new RuntimeException("Param '" + param + "' is required.");
+        }
+        return value.toString();
+    }
+
+}