Improve network config validation errors to show which fields are invalid.

Previously, uploading invalid config results in a generic error message
which makes it difficult to figure out what is wrong with the config

Change-Id: I307d2fc0669679b067389c722556eef3aae098b9

+/*
+ * Copyright 2016 Open Networking Laboratory
+ *
+ * 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.onosproject.net.config;
+
+/**
+ * Indicates an invalid configuration was supplied by the user.
+ */
+public class InvalidConfigException extends RuntimeException {
+
+    private final String subjectKey;
+    private final String subject;
+    private final String configKey;
+
+    /**
+     * Creates a new invalid config exception about a specific config.
+     *
+     * @param subjectKey config's subject key
+     * @param subject config's subject
+     * @param configKey config's config key
+     */
+    public InvalidConfigException(String subjectKey, String subject, String configKey) {
+        this(subjectKey, subject, configKey, null);
+    }
+
+    /**
+     * Creates a new invalid config exception about a specific config with an
+     * exception regarding the cause of the invalidity.
+     *
+     * @param subjectKey config's subject key
+     * @param subject config's subject
+     * @param configKey config's config key
+     * @param cause cause of the invalidity
+     */
+    public InvalidConfigException(String subjectKey, String subject, String configKey, Throwable cause) {
+        super(message(subjectKey, subject, configKey, cause), cause);
+        this.subjectKey = subjectKey;
+        this.subject = subject;
+        this.configKey = configKey;
+    }
+
+    /**
+     * Returns the subject key of the config.
+     *
+     * @return subject key
+     */
+    public String subjectKey() {
+        return subjectKey;
+    }
+
+    /**
+     * Returns the string representation of the subject of the config.
+     *
+     * @return subject
+     */
+    public String subject() {
+        return subject;
+    }
+
+    /**
+     * Returns the config key of the config.
+     *
+     * @return config key
+     */
+    public String configKey() {
+        return configKey;
+    }
+
+    private static String message(String subjectKey, String subject, String configKey, Throwable cause) {
+        String error = "Error parsing config " + subjectKey + "/" + subject + "/" + configKey;
+        if (cause != null) {
+            error = error + ": " + cause.getMessage();
+        }
+        return error;
+    }
+}

+/*
+ * Copyright 2016-present Open Networking Laboratory
+ *
+ * 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.onosproject.net.config;
+
+/**
+ * Indicates a field of a configuration was invalid.
+ */
+public class InvalidFieldException extends RuntimeException {
+
+    private final String field;
+    private final String reason;
+
+    /**
+     * Creates a new invalid field exception about a given field.
+     *
+     * @param field field name
+     * @param reason reason the field is invalid
+     */
+    public InvalidFieldException(String field, String reason) {
+        super(message(field, reason));
+        this.field = field;
+        this.reason = reason;
+    }
+
+    /**
+     * Creates a new invalid field exception about a given field.
+     *
+     * @param field field name
+     * @param cause throwable that occurred while trying to validate field
+     */
+    public InvalidFieldException(String field, Throwable cause) {
+        super(message(field, cause.getMessage()));
+        this.field = field;
+        this.reason = cause.getMessage();
+    }
+
+    /**
+     * Returns the field name.
+     *
+     * @return field name
+     */
+    public String field() {
+        return field;
+    }
+
+    /**
+     * Returns the reason the field failed to validate.
+     *
+     * @return reason
+     */
+    public String reason() {
+        return reason;
+    }
+
+    private static String message(String field, String reason) {
+        return "Field \"" + field + "\" is invalid: " + reason;
+    }
+
+}

@@ -39,6 +39,7 @@ import org.onlab.util.KryoNamespace;
 import org.onosproject.net.config.Config;
 import org.onosproject.net.config.ConfigApplyDelegate;
 import org.onosproject.net.config.ConfigFactory;
+import org.onosproject.net.config.InvalidConfigException;
 import org.onosproject.net.config.NetworkConfigEvent;
 import org.onosproject.net.config.NetworkConfigStore;
 import org.onosproject.net.config.NetworkConfigStoreDelegate;
@@ -248,7 +249,17 @@ public class DistributedNetworkConfigStore
     public <S, C extends Config<S>> C applyConfig(S subject, Class<C> configClass, JsonNode json) {
         // Create the configuration and validate it.
         C config = createConfig(subject, configClass, json);
-        checkArgument(config.isValid(), INVALID_CONFIG_JSON);
+
+        try {
+            checkArgument(config.isValid(), INVALID_CONFIG_JSON);
+        } catch (RuntimeException e) {
+            ConfigFactory<S, C> configFactory = getConfigFactory(configClass);
+            String subjectKey = configFactory.subjectFactory().subjectClassKey();
+            String subjectString = configFactory.subjectFactory().subjectKey(config.subject());
+            String configKey = config.key();
+
+            throw new InvalidConfigException(subjectKey, subjectString, configKey, e);
+        }
 
         // Insert the validated configuration and get it back.
         Versioned<JsonNode> versioned = configs.putAndGet(key(subject, configClass), json);

+/*
+ * Copyright 2016-present Open Networking Laboratory
+ *
+ * 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.onosproject.rest.exceptions;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import org.onlab.rest.exceptions.AbstractMapper;
+import org.onosproject.net.config.InvalidConfigException;
+import org.onosproject.net.config.InvalidFieldException;
+
+import javax.ws.rs.core.Response;
+
+/**
+ * Maps InvalidConfigException to JSON output.
+ */
+public class InvalidConfigExceptionMapper extends AbstractMapper<InvalidConfigException> {
+
+    @Override
+    protected Response.Status responseStatus() {
+        return Response.Status.BAD_REQUEST;
+    }
+
+    @Override
+    protected Response.ResponseBuilder response(Response.Status status, Throwable exception) {
+        error = exception;
+
+        InvalidConfigException ex = (InvalidConfigException) exception;
+
+        ObjectMapper mapper = new ObjectMapper();
+        String message = messageFrom(exception);
+        ObjectNode result = mapper.createObjectNode()
+                .put("code", status.getStatusCode())
+                .put("message", message)
+                .put("subjectKey", ex.subjectKey())
+                .put("subject", ex.subject())
+                .put("configKey", ex.configKey());
+
+        if (ex.getCause() instanceof InvalidFieldException) {
+            InvalidFieldException fieldException = (InvalidFieldException) ex.getCause();
+            result.put("field", fieldException.field())
+                    .put("reason", fieldException.reason());
+        }
+
+        return Response.status(status).entity(result.toString());
+    }
+}

+/*
+ * Copyright 2016-present Open Networking Laboratory
+ *
+ * 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.
+ */
+
+/**
+ * REST exceptions.
+ */
+package org.onosproject.rest.exceptions;

@@ -17,6 +17,7 @@
 package org.onosproject.rest.resources;
 
 import org.onlab.rest.AbstractWebApplication;
+import org.onosproject.rest.exceptions.InvalidConfigExceptionMapper;
 
 import java.util.Set;
 
@@ -49,7 +50,8 @@ public class CoreWebApplication extends AbstractWebApplication {
                 RegionsWebResource.class,
                 TenantWebResource.class,
                 VirtualNetworkWebResource.class,
-                MastershipWebResource.class
+                MastershipWebResource.class,
+                InvalidConfigExceptionMapper.class
         );
     }
 }