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/*-
* ============LICENSE_START=======================================================
* Copyright (C) 2016-2018 Ericsson. All rights reserved.
* Modifications Copyright (C) 2019 Nordix 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.
*
* SPDX-License-Identifier: Apache-2.0
* ============LICENSE_END=========================================================
*/
package org.onap.policy.apex.plugins.event.protocol.yaml;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import org.onap.policy.apex.context.SchemaHelper;
import org.onap.policy.apex.context.impl.schema.SchemaHelperFactory;
import org.onap.policy.apex.model.basicmodel.service.ModelService;
import org.onap.policy.apex.model.eventmodel.concepts.AxEvent;
import org.onap.policy.apex.model.eventmodel.concepts.AxEvents;
import org.onap.policy.apex.model.eventmodel.concepts.AxField;
import org.onap.policy.apex.service.engine.event.ApexEvent;
import org.onap.policy.apex.service.engine.event.ApexEventException;
import org.onap.policy.apex.service.engine.event.ApexEventProtocolConverter;
import org.onap.policy.apex.service.engine.event.ApexEventRuntimeException;
import org.onap.policy.apex.service.parameters.eventprotocol.EventProtocolParameters;
import org.slf4j.ext.XLogger;
import org.slf4j.ext.XLoggerFactory;
import org.yaml.snakeyaml.DumperOptions.FlowStyle;
import org.yaml.snakeyaml.Yaml;
/**
* The Class Apex2YamlEventConverter converts {@link ApexEvent} instances to and from YAML string representations of
* Apex events.
*
* @author Liam Fallon (liam.fallon@ericsson.com)
*/
public class Apex2YamlEventConverter implements ApexEventProtocolConverter {
private static final XLogger LOGGER = XLoggerFactory.getXLogger(Apex2YamlEventConverter.class);
// The parameters for the YAML event protocol
private YamlEventProtocolParameters yamlPars;
/**
* {@inheritDoc}.
*/
@Override
public void init(final EventProtocolParameters parameters) {
// Check and get the YAML parameters
if (!(parameters instanceof YamlEventProtocolParameters)) {
final String errorMessage = "specified consumer properties are not applicable to the YAML event protocol";
LOGGER.warn(errorMessage);
throw new ApexEventRuntimeException(errorMessage);
}
yamlPars = (YamlEventProtocolParameters) parameters;
}
/**
* {@inheritDoc}.
*/
@Override
public List<ApexEvent> toApexEvent(final String eventName, final Object eventObject) throws ApexEventException {
// Check the event eventObject
if (eventObject == null) {
LOGGER.warn("event processing failed, event is null");
throw new ApexEventException("event processing failed, event is null");
}
// Cast the event to a string, if our conversion is correctly configured, this cast should
// always work
if (!(eventObject instanceof String)) {
final String errorMessage = "error converting event \"" + eventObject + "\" to a string";
LOGGER.debug(errorMessage);
throw new ApexEventException(errorMessage);
}
final String yamlEventString = (String) eventObject;
// The list of events we will return
final List<ApexEvent> eventList = new ArrayList<>();
// Convert the YAML document string into an object
Object yamlObject = new Yaml().load(yamlEventString);
// If the incoming YAML did not create a map it is a primitive type or a collection so we
// convert it into a map for processing
Map<?, ?> yamlMap;
if (yamlObject instanceof Map) {
// We already have a map so just cast the object
yamlMap = (Map<?, ?>) yamlObject;
} else {
// Create a single entry map, new map creation and assignment is to avoid a
// type checking warning
LinkedHashMap<String, Object> newYamlMap = new LinkedHashMap<>();
newYamlMap.put(yamlPars.getYamlFieldName(), yamlObject);
yamlMap = newYamlMap;
}
try {
eventList.add(yamlMap2ApexEvent(eventName, yamlMap));
} catch (final Exception e) {
final String errorString = "Failed to unmarshal YAML event: " + e.getMessage() + ", event="
+ yamlEventString;
LOGGER.warn(errorString, e);
throw new ApexEventException(errorString, e);
}
// Return the list of events we have unmarshalled
return eventList;
}
/**
* {@inheritDoc}.
*/
@Override
public Object fromApexEvent(final ApexEvent apexEvent) throws ApexEventException {
// Check the Apex event
if (apexEvent == null) {
LOGGER.warn("event processing failed, Apex event is null");
throw new ApexEventException("event processing failed, Apex event is null");
}
// Get the event definition for the event from the model service
final AxEvent eventDefinition = ModelService.getModel(AxEvents.class).get(apexEvent.getName(),
apexEvent.getVersion());
// Create a map for output of the APEX event to YAML
LinkedHashMap<String, Object> yamlMap = new LinkedHashMap<>();
yamlMap.put(ApexEvent.NAME_HEADER_FIELD, apexEvent.getName());
yamlMap.put(ApexEvent.VERSION_HEADER_FIELD, apexEvent.getVersion());
yamlMap.put(ApexEvent.NAMESPACE_HEADER_FIELD, apexEvent.getNameSpace());
yamlMap.put(ApexEvent.SOURCE_HEADER_FIELD, apexEvent.getSource());
yamlMap.put(ApexEvent.TARGET_HEADER_FIELD, apexEvent.getTarget());
if (apexEvent.getExceptionMessage() != null) {
yamlMap.put(ApexEvent.EXCEPTION_MESSAGE_HEADER_FIELD, apexEvent.getExceptionMessage());
}
for (final AxField eventField : eventDefinition.getFields()) {
final String fieldName = eventField.getKey().getLocalName();
if (!apexEvent.containsKey(fieldName)) {
if (!eventField.getOptional()) {
final String errorMessage = "error parsing " + eventDefinition.getId() + " event to Json. "
+ "Field \"" + fieldName + "\" is missing, but is mandatory. Fields: " + apexEvent;
LOGGER.debug(errorMessage);
throw new ApexEventRuntimeException(errorMessage);
}
continue;
}
yamlMap.put(fieldName, apexEvent.get(fieldName));
}
// Use Snake YAML to convert the APEX event to YAML
Yaml yaml = new Yaml();
return yaml.dumpAs(yamlMap, null, FlowStyle.BLOCK);
}
/**
* This method converts a YAML map into an Apex event.
*
* @param eventName the name of the event
* @param yamlMap the YAML map that holds the event
* @return the apex event that we have converted the JSON object into
* @throws ApexEventException thrown on unmarshaling exceptions
*/
private ApexEvent yamlMap2ApexEvent(final String eventName, final Map<?, ?> yamlMap) throws ApexEventException {
// Process the mandatory Apex header
final ApexEvent apexEvent = processApexEventHeader(eventName, yamlMap);
// Get the event definition for the event from the model service
final AxEvent eventDefinition = ModelService.getModel(AxEvents.class).get(apexEvent.getName(),
apexEvent.getVersion());
// Iterate over the input fields in the event
for (final AxField eventField : eventDefinition.getFields()) {
final String fieldName = eventField.getKey().getLocalName();
if (!yamlMap.containsKey(fieldName)) {
if (!eventField.getOptional()) {
final String errorMessage = "error parsing " + eventDefinition.getId() + " event from Json. "
+ "Field \"" + fieldName + "\" is missing, but is mandatory.";
LOGGER.debug(errorMessage);
throw new ApexEventException(errorMessage);
}
continue;
}
final Object fieldValue = getYamlField(yamlMap, fieldName, null, !eventField.getOptional());
if (fieldValue != null) {
// Get the schema helper
final SchemaHelper fieldSchemaHelper = new SchemaHelperFactory().createSchemaHelper(eventField.getKey(),
eventField.getSchema());
apexEvent.put(fieldName, fieldSchemaHelper.createNewInstance(fieldValue));
} else {
apexEvent.put(fieldName, null);
}
}
return apexEvent;
}
/**
* This method processes the event header of an Apex event.
*
* @param eventName the name of the event
* @param yamlMap the YAML map that holds the event
* @return an apex event constructed using the header fields of the event
* @throws ApexEventRuntimeException the apex event runtime exception
* @throws ApexEventException on invalid events with missing header fields
*/
private ApexEvent processApexEventHeader(final String eventName, final Map<?, ?> yamlMap)
throws ApexEventException {
String name = getYamlStringField(yamlMap, ApexEvent.NAME_HEADER_FIELD, yamlPars.getNameAlias(),
ApexEvent.NAME_REGEXP, false);
// Check that an event name has been specified
if (name == null && eventName == null) {
throw new ApexEventRuntimeException(
"event received without mandatory parameter \"name\" on configuration or on event");
}
// Check if an event name was specified on the event parameters
if (eventName != null) {
if (name != null && !eventName.equals(name)) {
LOGGER.warn("The incoming event name \"{}\" does not match the configured event name \"{}\", "
+ "using configured event name", name, eventName);
}
name = eventName;
}
// Now, find the event definition in the model service. If version is null, the newest event
// definition in the model service is used
String version = getYamlStringField(yamlMap, ApexEvent.VERSION_HEADER_FIELD, yamlPars.getVersionAlias(),
ApexEvent.VERSION_REGEXP, false);
final AxEvent eventDefinition = ModelService.getModel(AxEvents.class).get(name, version);
if (eventDefinition == null) {
throw new ApexEventRuntimeException("an event definition for an event named \"" + name
+ "\" with version \"" + version + "\" not found in Apex model");
}
// Use the defined event version if no version is specified on the incoming fields
if (version == null) {
version = eventDefinition.getKey().getVersion();
}
String namespace = getEventHeaderNamespace(yamlMap, name, eventDefinition);
String source = getEventHeaderSource(yamlMap, eventDefinition);
String target = getHeaderTarget(yamlMap, eventDefinition);
return new ApexEvent(name, version, namespace, source, target);
}
/**
* Get the event header name space.
*
* @param yamlMap the YAML map to read from
* @param eventDefinition the event definition
* @return the event header name space
*/
private String getEventHeaderNamespace(final Map<?, ?> yamlMap, String name, final AxEvent eventDefinition) {
// Check the name space is OK if it is defined, if not, use the name space from the model
String namespace = getYamlStringField(yamlMap, ApexEvent.NAMESPACE_HEADER_FIELD, yamlPars.getNameSpaceAlias(),
ApexEvent.NAMESPACE_REGEXP, false);
if (namespace != null) {
if (!namespace.equals(eventDefinition.getNameSpace())) {
throw new ApexEventRuntimeException("namespace \"" + namespace + "\" on event \"" + name
+ "\" does not match namespace \"" + eventDefinition.getNameSpace()
+ "\" for that event in the Apex model");
}
} else {
namespace = eventDefinition.getNameSpace();
}
return namespace;
}
/**
* Get the event header source.
*
* @param yamlMap the YAML map to read from
* @param eventDefinition the event definition
* @return the event header source
*/
private String getEventHeaderSource(final Map<?, ?> yamlMap, final AxEvent eventDefinition) {
// For source, use the defined source only if the source is not found on the incoming event
String source = getYamlStringField(yamlMap, ApexEvent.SOURCE_HEADER_FIELD, yamlPars.getSourceAlias(),
ApexEvent.SOURCE_REGEXP, false);
if (source == null) {
source = eventDefinition.getSource();
}
return source;
}
/**
* Get the event header target.
*
* @param yamlMap the YAML map to read from
* @param eventDefinition the event definition
* @return the event header target
*/
private String getHeaderTarget(final Map<?, ?> yamlMap, final AxEvent eventDefinition) {
// For target, use the defined source only if the source is not found on the incoming event
String target = getYamlStringField(yamlMap, ApexEvent.TARGET_HEADER_FIELD, yamlPars.getTargetAlias(),
ApexEvent.TARGET_REGEXP, false);
if (target == null) {
target = eventDefinition.getTarget();
}
return target;
}
/**
* This method gets an event string field from a JSON object.
*
* @param yamlMap the YAML containing the YAML representation of the incoming event
* @param fieldName the field name to find in the event
* @param fieldAlias the alias for the field to find in the event, overrides the field name if it is not null
* @param fieldRegexp the regular expression to check the field against for validity
* @param mandatory true if the field is mandatory
* @return the value of the field in the JSON object or null if the field is optional
* @throws ApexEventRuntimeException the apex event runtime exception
*/
private String getYamlStringField(final Map<?, ?> yamlMap, final String fieldName, final String fieldAlias,
final String fieldRegexp, final boolean mandatory) {
// Get the YAML field for the string field
final Object yamlField = getYamlField(yamlMap, fieldName, fieldAlias, mandatory);
// Null strings are allowed
if (yamlField == null) {
return null;
}
if (!(yamlField instanceof String)) {
// The element is not a string so throw an error
throw new ApexEventRuntimeException("field \"" + fieldName + "\" with type \""
+ yamlField.getClass().getName() + "\" is not a string value");
}
final String fieldValueString = (String) yamlField;
// Is regular expression checking required
if (fieldRegexp == null) {
return fieldValueString;
}
// Check the event field against its regular expression
if (!fieldValueString.matches(fieldRegexp)) {
throw new ApexEventRuntimeException(
"field \"" + fieldName + "\" with value \"" + fieldValueString + "\" is invalid");
}
return fieldValueString;
}
/**
* This method gets an event field from a YAML object.
*
* @param yamlMap the YAML containing the YAML representation of the incoming event
* @param fieldName the field name to find in the event
* @param fieldAlias the alias for the field to find in the event, overrides the field name if it is not null
* @param mandatory true if the field is mandatory
* @return the value of the field in the YAML object or null if the field is optional
* @throws ApexEventRuntimeException the apex event runtime exception
*/
private Object getYamlField(final Map<?, ?> yamlMap, final String fieldName, final String fieldAlias,
final boolean mandatory) {
// Check if we should use the alias for this field
String fieldToFind = fieldName;
if (fieldAlias != null) {
fieldToFind = fieldAlias;
}
// Get the event field
final Object eventElement = yamlMap.get(fieldToFind);
if (eventElement == null) {
if (!mandatory) {
return null;
} else {
throw new ApexEventRuntimeException("mandatory field \"" + fieldToFind + "\" is missing");
}
}
return eventElement;
}
}
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