[VOL-4709] Expose dhcpl2relay-allocations via REST API

Change-Id: I2c912b85d3bbdbfd5de4f9e49dc1631ca8bca514
Signed-off-by: Gustavo Silva <gsilva@furukawalatam.com>
diff --git a/README.md b/README.md
index 259705d..7add9b3 100644
--- a/README.md
+++ b/README.md
@@ -51,3 +51,34 @@
     }
  ```
 
+# REST API
+
+Information about the DHCP allocations are available through REST API.
+
+You can query all DHCP allocations using the endpoint "/onos/dhcpl2relay/app/allocations", e.g:
+```sh
+$ curl -u karaf:karaf 'http://localhost:8181/onos/dhcpl2relay/app/allocations'
+```
+
+You can also filter by device-id "/onos/dhcpl2relay/app/allocations/{device-id}", e.g:
+```sh
+curl -u karaf:karaf 'http://localhost:8181/onos/dhcpl2relay/app/allocations/of%3A00000a0a0a0a0a0a'
+```
+
+These commands will output a JSON representation of the allocations, e.g:
+```sh
+{
+  "entries": [
+    {
+      "subscriberId": "BBSM000a0001-1",
+      "connectPoint": "of:00000a0a0a0a0a0a/256",
+      "state": "DHCPACK",
+      "macAddress": "2E:0A:00:01:00:00",
+      "vlanId": 900,
+      "circuitId": "BBSM000a0001-1",
+      "ipAllocated": "10.1.0.0",
+      "allocationTimestamp": "2022-05-25T20:09:28.672454Z"
+    }
+  ]
+}
+```
diff --git a/app/pom.xml b/app/pom.xml
index 3c57714..8f009c8 100644
--- a/app/pom.xml
+++ b/app/pom.xml
@@ -38,6 +38,13 @@
         <onos.app.requires>
             org.opencord.sadis
         </onos.app.requires>
+
+        <web.context>/onos/dhcpl2relay</web.context>
+        <api.version>1.0.0</api.version>
+        <api.title>DhcpL2Relay REST API</api.title>
+        <api.description>REST API to query DhcpL2Relay allocation entries.</api.description>
+        <api.package>org.opencord.dhcpl2relay.rest</api.package>
+
     </properties>
 
     <dependencies>
@@ -132,6 +139,19 @@
             <scope>provided</scope>
         </dependency>
 
+        <dependency>
+            <groupId>org.onosproject</groupId>
+            <artifactId>onlab-rest</artifactId>
+            <version>${onos.version}</version>
+            <scope>provided</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>javax.ws.rs</groupId>
+            <artifactId>javax.ws.rs-api</artifactId>
+            <scope>provided</scope>
+        </dependency>
+
     </dependencies>
 
     <build>
@@ -146,6 +166,15 @@
                 <artifactId>maven-bundle-plugin</artifactId>
                 <configuration>
                     <instructions>
+                        <_wab>src/main/webapp/</_wab>
+                        <Include-Resource>
+                            WEB-INF/classes/apidoc/swagger.json=target/swagger.json,
+                            {maven-resources}
+                        </Include-Resource>
+                        <Import-Package>
+                            *,org.glassfish.jersey.servlet
+                        </Import-Package>
+                        <Web-ContextPath>${web.context}</Web-ContextPath>
                         <Karaf-Commands>org.opencord.dhcpl2relay.cli</Karaf-Commands>
                     </instructions>
                 </configuration>
diff --git a/app/src/main/java/org/opencord/dhcpl2relay/rest/DhcpL2RelayWebResource.java b/app/src/main/java/org/opencord/dhcpl2relay/rest/DhcpL2RelayWebResource.java
new file mode 100644
index 0000000..25e607c
--- /dev/null
+++ b/app/src/main/java/org/opencord/dhcpl2relay/rest/DhcpL2RelayWebResource.java
@@ -0,0 +1,126 @@
+/*
+ * Copyright 2022-present Open Networking Foundation
+ *
+ * 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.opencord.dhcpl2relay.rest;
+
+import com.fasterxml.jackson.databind.node.ArrayNode;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+
+import java.util.Objects;
+import java.util.stream.Collectors;
+import java.util.Map;
+import java.util.Map.Entry;
+
+import javax.ws.rs.core.MediaType;
+import javax.ws.rs.core.Response;
+import javax.ws.rs.GET;
+import javax.ws.rs.Path;
+import javax.ws.rs.PathParam;
+import javax.ws.rs.Produces;
+
+import org.onosproject.net.DeviceId;
+import org.onosproject.rest.AbstractWebResource;
+
+import org.opencord.dhcpl2relay.DhcpAllocationInfo;
+import org.opencord.dhcpl2relay.DhcpL2RelayService;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import static javax.ws.rs.core.Response.Status.INTERNAL_SERVER_ERROR;
+
+/**
+ * DhcpL2Relay web resource.
+ */
+@Path("app")
+public class DhcpL2RelayWebResource extends AbstractWebResource {
+    private final ObjectNode root = mapper().createObjectNode();
+    private final ArrayNode node = root.putArray("entries");
+    private final Logger log = LoggerFactory.getLogger(getClass());
+
+    private static final String SUBSCRIBER_ID = "subscriberId";
+    private static final String CONNECT_POINT = "connectPoint";
+    private static final String MAC_ADDRESS = "macAddress";
+    private static final String STATE = "state";
+    private static final String VLAN_ID = "vlanId";
+    private static final String CIRCUIT_ID = "circuitId";
+    private static final String IP_ALLOCATED = "ipAllocated";
+    private static final String ALLOCATION_TIMESTAMP = "allocationTimestamp";
+
+    /**
+     *
+     * Shows all the successful DHCP allocations relayed by the dhcpl2relay.
+     *
+     * @return 200 OK
+     */
+    @GET
+    @Path("/allocations")
+    @Produces(MediaType.APPLICATION_JSON)
+    public Response getAllocations() {
+       return getAllocations(null);
+    }
+
+    /**
+     * Shows the successful DHCP allocations relayed by the dhcpl2relay for a specific access device.
+     *
+     * @param deviceId Access device ID.
+     *
+     * @return 200 OK
+     */
+    @GET
+    @Path("/allocations/{deviceId}")
+    @Produces(MediaType.APPLICATION_JSON)
+    public Response getAllocation(@PathParam("deviceId") String deviceId) {
+        return getAllocations(deviceId);
+    }
+
+    private Response getAllocations(String deviceId) {
+        DhcpL2RelayService service = get(DhcpL2RelayService.class);
+        Map<String, DhcpAllocationInfo> allocations = service.getAllocationInfo();
+
+        try {
+            buildAllocationsNodeObject(allocations, deviceId);
+            return ok(mapper().writeValueAsString(root)).build();
+        } catch (Exception e) {
+            log.error("Error while fetching DhcpL2Relay allocations information through REST API: {}", e.getMessage());
+            return Response.status(INTERNAL_SERVER_ERROR).build();
+        }
+    }
+
+    private void buildAllocationsNodeObject(Map<String, DhcpAllocationInfo> allocationMap, String strDeviceId) {
+        if (Objects.nonNull(strDeviceId)) {
+            DeviceId deviceId = DeviceId.deviceId(strDeviceId);
+            allocationMap = allocationMap.entrySet().stream()
+                    .filter(a -> a.getValue().location().deviceId().equals(deviceId))
+                    .collect(Collectors.toMap(Entry::getKey, Entry::getValue));
+        }
+
+        allocationMap.forEach((key, value) -> {
+            node.add(encodeDhcpAllocationInfo(value));
+        });
+    }
+
+    private ObjectNode encodeDhcpAllocationInfo(DhcpAllocationInfo entry) {
+        return mapper().createObjectNode()
+                .put(SUBSCRIBER_ID, entry.subscriberId())
+                .put(CONNECT_POINT, entry.location().toString())
+                .put(STATE, entry.type().toString())
+                .put(MAC_ADDRESS, entry.macAddress().toString())
+                .put(VLAN_ID, entry.vlanId().toShort())
+                .put(CIRCUIT_ID, entry.circuitId())
+                .put(IP_ALLOCATED, entry.ipAddress().getIp4Address().toString())
+                .put(ALLOCATION_TIMESTAMP, entry.allocationTime().toString());
+    }
+}
diff --git a/app/src/main/java/org/opencord/dhcpl2relay/rest/package-info.java b/app/src/main/java/org/opencord/dhcpl2relay/rest/package-info.java
new file mode 100755
index 0000000..37de45e
--- /dev/null
+++ b/app/src/main/java/org/opencord/dhcpl2relay/rest/package-info.java
@@ -0,0 +1,20 @@
+/*
+ * Copyright 2022-present Open Networking Foundation
+ *
+ * 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.
+ */
+
+/**
+ *  DHCP-L2RELAY rest interface.
+ */
+package org.opencord.dhcpl2relay.rest;
diff --git a/app/src/main/webapp/WEB-INF/web.xml b/app/src/main/webapp/WEB-INF/web.xml
new file mode 100644
index 0000000..f91b795
--- /dev/null
+++ b/app/src/main/webapp/WEB-INF/web.xml
@@ -0,0 +1,54 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  ~ Copyright 2022-present Open Networking Foundation
+  ~
+  ~ 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.
+  -->
+<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee"
+         xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
+         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
+         id="ONOS" version="2.5">
+    <display-name>DhcpL2Relay REST API v1.0</display-name>
+    <security-constraint>
+        <web-resource-collection>
+            <web-resource-name>Secured</web-resource-name>
+            <url-pattern>/*</url-pattern>
+        </web-resource-collection>
+        <auth-constraint>
+            <role-name>admin</role-name>
+        </auth-constraint>
+    </security-constraint>
+    <security-role>
+        <role-name>admin</role-name>
+    </security-role>
+    <login-config>
+        <auth-method>BASIC</auth-method>
+        <realm-name>karaf</realm-name>
+    </login-config>
+    <servlet>
+        <servlet-name>JAX-RS Service</servlet-name>
+        <servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
+        <init-param>
+            <param-name>jersey.config.server.provider.classnames</param-name>
+            <param-value>
+                org.opencord.dhcpl2relay.rest.DhcpL2RelayWebResource
+            </param-value>
+        </init-param>
+        <load-on-startup>1</load-on-startup>
+    </servlet>
+
+    <servlet-mapping>
+        <servlet-name>JAX-RS Service</servlet-name>
+        <url-pattern>/*</url-pattern>
+    </servlet-mapping>
+</web-app>