PubSub¶
In PubSub the participating OPC UA Applications take their roles as Publishers and Subscribers. Publishers are the sources of data, while Subscribers consume that data. Communication in PubSub is message-based. Publishers send messages to a Message Oriented Middleware, without knowledge of what, if any, Subscribers there may be. Similarly, Subscribers express interest in specific types of data, and process messages that contain this data, without knowledge of what Publishers there are.
Message Oriented Middleware is software or hardware infrastructure that supports sending and receiving messages between distributed systems. OPC UA PubSub supports two different Message Oriented Middleware variants, namely the broker-less form and broker-based form. A broker-less form is where the Message Oriented Middleware is the network infrastructure that is able to route datagram-based messages. Subscribers and Publishers use datagram protocols like UDP. In a broker-based form, the core component of the Message Oriented Middleware is a message Broker. Subscribers and Publishers use standard messaging protocols like AMQP or MQTT to communicate with the Broker.
This makes PubSub suitable for applications where location independence and/or scalability are required.
The Publish/Subscribe (PubSub) extension for OPC UA enables fast and efficient 1:m communication. The PubSub extension is protocol agnostic and can be used with broker based protocols like MQTT and AMQP or brokerless implementations like UDP-Multicasting.
The configuration model for PubSub uses the following components:
typedef enum {
UA_PUBSUB_COMPONENT_CONNECTION,
UA_PUBSUB_COMPONENT_WRITERGROUP,
UA_PUBSUB_COMPONENT_DATASETWRITER,
UA_PUBSUB_COMPONENT_READERGROUP,
UA_PUBSUB_COMPONENT_DATASETREADER
} UA_PubSubComponentEnumType;
The open62541 PubSub API uses the following scheme:
Create a configuration for the needed PubSub element.
Call the add[element] function and pass in the configuration.
The add[element] function returns the unique nodeId of the internally created element.
Take a look on the PubSub Tutorials for more details about the API usage:
+-----------+
| UA_Server |
+-----------+
| |
| |
| |
| | +----------------------+
| +--> UA_PubSubConnection | UA_Server_addPubSubConnection
| +----------------------+
| | |
| | | +----------------+
| | +----> UA_WriterGroup | UA_PubSubConnection_addWriterGroup
| | +----------------+
| | |
| | | +------------------+
| | +----> UA_DataSetWriter | UA_WriterGroup_addDataSetWriter +-+
| | +------------------+ |
| | |
| | +----------------+ | r
| +---------> UA_ReaderGroup | UA_PubSubConnection_addReaderGroup | e
| +----------------+ | f
| | |
| | +------------------+ |
| +----> UA_DataSetReader | UA_ReaderGroup_addDataSetReader |
| +------------------+ |
| | |
| | +----------------------+ |
| +----> UA_SubscribedDataSet | |
| +----------------------+ |
| | |
| | +----------------------------+ |
| +----> UA_TargetVariablesDataType | |
| | +----------------------------+ |
| | |
| | +------------------------------------+ |
| +----> UA_SubscribedDataSetMirrorDataType | |
| +------------------------------------+ |
| |
| +---------------------------+ |
+-------> UA_PubSubPublishedDataSet | UA_Server_addPublishedDataSet <-+
+---------------------------+
|
| +-----------------+
+----> UA_DataSetField | UA_PublishedDataSet_addDataSetField
+-----------------+
PubSub Information Model Representation¶
The complete PubSub configuration is available inside the information model. The entry point is the node ‘PublishSubscribe’, located under the Server node. The standard defines for PubSub no new Service set. The configuration can optionally be done over methods inside the information model. The information model representation of the current PubSub configuration is generated automatically. This feature can be enabled/disabled by changing the UA_ENABLE_PUBSUB_INFORMATIONMODEL option.
Connections¶
The PubSub connections are the abstraction between the concrete transport protocol and the PubSub functionality. It is possible to create multiple connections with different transport protocols at runtime.
/* Valid PublisherId types from Part 14 */
typedef enum {
UA_PUBLISHERIDTYPE_BYTE = 0,
UA_PUBLISHERIDTYPE_UINT16 = 1,
UA_PUBLISHERIDTYPE_UINT32 = 2,
UA_PUBLISHERIDTYPE_UINT64 = 3,
UA_PUBLISHERIDTYPE_STRING = 4
} UA_PublisherIdType;
/* Publisher Id
Valid types are defined in Part 14, 7.2.2.2.2 NetworkMessage Layout:
Bit range 0-2: PublisherId Type
000 The PublisherId is of DataType Byte This is the default value if ExtendedFlags1 is omitted
001 The PublisherId is of DataType UInt16
010 The PublisherId is of DataType UInt32
011 The PublisherId is of DataType UInt64
100 The PublisherId is of DataType String
*/
typedef union {
UA_Byte byte;
UA_UInt16 uint16;
UA_UInt32 uint32;
UA_UInt64 uint64;
UA_String string;
} UA_PublisherId;
typedef struct {
UA_String name;
UA_Boolean enabled;
UA_PublisherIdType publisherIdType;
UA_PublisherId publisherId;
UA_String transportProfileUri;
UA_Variant address;
UA_KeyValueMap connectionProperties;
UA_Variant connectionTransportSettings;
UA_EventLoop *eventLoop; /* Use an external EventLoop (use the EventLoop of
* the server if this is NULL). Propagates to the
* ReaderGroup/WriterGroup attached to the
* Connection. */
} UA_PubSubConnectionConfig;
#ifdef UA_ENABLE_PUBSUB_MONITORING
typedef enum {
UA_PUBSUB_MONITORING_MESSAGE_RECEIVE_TIMEOUT
// extend as needed
} UA_PubSubMonitoringType;
/* PubSub monitoring interface */
typedef struct {
UA_StatusCode (*createMonitoring)(UA_Server *server, UA_NodeId Id,
UA_PubSubComponentEnumType eComponentType,
UA_PubSubMonitoringType eMonitoringType,
void *data, UA_ServerCallback callback);
UA_StatusCode (*startMonitoring)(UA_Server *server, UA_NodeId Id,
UA_PubSubComponentEnumType eComponentType,
UA_PubSubMonitoringType eMonitoringType, void *data);
UA_StatusCode (*stopMonitoring)(UA_Server *server, UA_NodeId Id,
UA_PubSubComponentEnumType eComponentType,
UA_PubSubMonitoringType eMonitoringType, void *data);
UA_StatusCode (*updateMonitoringInterval)(UA_Server *server, UA_NodeId Id,
UA_PubSubComponentEnumType eComponentType,
UA_PubSubMonitoringType eMonitoringType,
void *data);
UA_StatusCode (*deleteMonitoring)(UA_Server *server, UA_NodeId Id,
UA_PubSubComponentEnumType eComponentType,
UA_PubSubMonitoringType eMonitoringType, void *data);
} UA_PubSubMonitoringInterface;
#endif /* UA_ENABLE_PUBSUB_MONITORING */
/* General PubSub configuration */
struct UA_PubSubConfiguration {
/* Callback for PubSub component state changes: If provided this callback
* informs the application about PubSub component state changes. E.g. state
* change from operational to error in case of a DataSetReader
* MessageReceiveTimeout. The status code provides additional
* information. */
void (*stateChangeCallback)(UA_Server *server, UA_NodeId *id,
UA_PubSubState state, UA_StatusCode status);
UA_Boolean enableDeltaFrames;
#ifdef UA_ENABLE_PUBSUB_INFORMATIONMODEL
UA_Boolean enableInformationModelMethods;
#endif
#ifdef UA_ENABLE_PUBSUB_ENCRYPTION
/* PubSub security policies */
size_t securityPoliciesSize;
UA_PubSubSecurityPolicy *securityPolicies;
#endif
#ifdef UA_ENABLE_PUBSUB_MONITORING
UA_PubSubMonitoringInterface monitoringInterface;
#endif
};
/* Add a new PubSub connection to the given server and open it.
* @param server The server to add the connection to.
* @param connectionConfig The configuration for the newly added connection.
* @param connectionIdentifier If not NULL will be set to the identifier of the
* newly added connection.
* @return UA_STATUSCODE_GOOD if connection was successfully added, otherwise an
* error code. */
UA_StatusCode UA_THREADSAFE
UA_Server_addPubSubConnection(UA_Server *server,
const UA_PubSubConnectionConfig *connectionConfig,
UA_NodeId *connectionIdentifier);
/* Returns a deep copy of the config */
UA_StatusCode UA_THREADSAFE
UA_Server_getPubSubConnectionConfig(UA_Server *server,
const UA_NodeId connection,
UA_PubSubConnectionConfig *config);
/* Remove Connection, identified by the NodeId. Deletion of Connection
* removes all contained WriterGroups and Writers. */
UA_StatusCode UA_THREADSAFE
UA_Server_removePubSubConnection(UA_Server *server, const UA_NodeId connection);
PublishedDataSets¶
The PublishedDataSets (PDS) are containers for the published information. The PDS contain the published variables and meta information. The metadata is commonly autogenerated or given as constant argument as part of the template functions. The template functions are standard defined and intended for configuration tools. You should normally create an empty PDS and call the functions to add new fields.
/* The UA_PUBSUB_DATASET_PUBLISHEDITEMS has currently no additional members and
* thus no dedicated config structure. */
typedef enum {
UA_PUBSUB_DATASET_PUBLISHEDITEMS,
UA_PUBSUB_DATASET_PUBLISHEDEVENTS,
UA_PUBSUB_DATASET_PUBLISHEDITEMS_TEMPLATE,
UA_PUBSUB_DATASET_PUBLISHEDEVENTS_TEMPLATE,
} UA_PublishedDataSetType;
typedef struct {
UA_DataSetMetaDataType metaData;
size_t variablesToAddSize;
UA_PublishedVariableDataType *variablesToAdd;
} UA_PublishedDataItemsTemplateConfig;
typedef struct {
UA_NodeId eventNotfier;
UA_ContentFilter filter;
} UA_PublishedEventConfig;
typedef struct {
UA_DataSetMetaDataType metaData;
UA_NodeId eventNotfier;
size_t selectedFieldsSize;
UA_SimpleAttributeOperand *selectedFields;
UA_ContentFilter filter;
} UA_PublishedEventTemplateConfig;
/* Configuration structure for PublishedDataSet */
typedef struct {
UA_String name;
UA_PublishedDataSetType publishedDataSetType;
union {
/* The UA_PUBSUB_DATASET_PUBLISHEDITEMS has currently no additional members
* and thus no dedicated config structure.*/
UA_PublishedDataItemsTemplateConfig itemsTemplate;
UA_PublishedEventConfig event;
UA_PublishedEventTemplateConfig eventTemplate;
} config;
} UA_PublishedDataSetConfig;
void
UA_PublishedDataSetConfig_clear(UA_PublishedDataSetConfig *pdsConfig);
typedef struct {
UA_StatusCode addResult;
size_t fieldAddResultsSize;
UA_StatusCode *fieldAddResults;
UA_ConfigurationVersionDataType configurationVersion;
} UA_AddPublishedDataSetResult;
UA_AddPublishedDataSetResult UA_THREADSAFE
UA_Server_addPublishedDataSet(UA_Server *server,
const UA_PublishedDataSetConfig *publishedDataSetConfig,
UA_NodeId *pdsIdentifier);
/* Returns a deep copy of the config */
UA_StatusCode UA_THREADSAFE
UA_Server_getPublishedDataSetConfig(UA_Server *server, const UA_NodeId pds,
UA_PublishedDataSetConfig *config);
/* Returns a deep copy of the DataSetMetaData for an specific PDS */
UA_StatusCode UA_THREADSAFE
UA_Server_getPublishedDataSetMetaData(UA_Server *server, const UA_NodeId pds,
UA_DataSetMetaDataType *metaData);
/* Remove PublishedDataSet, identified by the NodeId. Deletion of PDS removes
* all contained and linked PDS Fields. Connected WriterGroups will be also
* removed. */
UA_StatusCode UA_THREADSAFE
UA_Server_removePublishedDataSet(UA_Server *server, const UA_NodeId pds);
DataSetFields¶
The description of published variables is named DataSetField. Each DataSetField contains the selection of one information model node. The DataSetField has additional parameters for the publishing, sampling and error handling process.
typedef struct{
UA_ConfigurationVersionDataType configurationVersion;
UA_String fieldNameAlias;
UA_Boolean promotedField;
UA_PublishedVariableDataType publishParameters;
/* non std. field */
struct {
UA_Boolean rtFieldSourceEnabled;
/* If the rtInformationModelNode is set, the nodeid in publishParameter must point
* to a node with external data source backend defined
* */
UA_Boolean rtInformationModelNode;
//TODO -> decide if suppress C++ warnings and use 'UA_DataValue * * const staticValueSource;'
UA_DataValue ** staticValueSource;
} rtValueSource;
UA_UInt32 maxStringLength;
} UA_DataSetVariableConfig;
typedef enum {
UA_PUBSUB_DATASETFIELD_VARIABLE,
UA_PUBSUB_DATASETFIELD_EVENT
} UA_DataSetFieldType;
typedef struct {
UA_DataSetFieldType dataSetFieldType;
union {
/* events need other config later */
UA_DataSetVariableConfig variable;
} field;
} UA_DataSetFieldConfig;
void
UA_DataSetFieldConfig_clear(UA_DataSetFieldConfig *dataSetFieldConfig);
typedef struct {
UA_StatusCode result;
UA_ConfigurationVersionDataType configurationVersion;
} UA_DataSetFieldResult;
UA_DataSetFieldResult UA_THREADSAFE
UA_Server_addDataSetField(UA_Server *server,
const UA_NodeId publishedDataSet,
const UA_DataSetFieldConfig *fieldConfig,
UA_NodeId *fieldIdentifier);
/* Returns a deep copy of the config */
UA_StatusCode UA_THREADSAFE
UA_Server_getDataSetFieldConfig(UA_Server *server, const UA_NodeId dsf,
UA_DataSetFieldConfig *config);
UA_DataSetFieldResult UA_THREADSAFE
UA_Server_removeDataSetField(UA_Server *server, const UA_NodeId dsf);
Custom Callback Implementation¶
The user can use his own callback implementation for publishing and subscribing. The user must take care of the callback to call for every publishing or subscibing interval
typedef struct {
/* User's callback implementation. The user configured base time and timer policy
* will be provided as an argument to this callback so that the user can
* implement his callback (thread) considering base time and timer policies */
UA_StatusCode (*addCustomCallback)(UA_Server *server, UA_NodeId identifier,
UA_ServerCallback callback,
void *data, UA_Double interval_ms,
UA_DateTime *baseTime, UA_TimerPolicy timerPolicy,
UA_UInt64 *callbackId);
UA_StatusCode (*changeCustomCallback)(UA_Server *server, UA_NodeId identifier,
UA_UInt64 callbackId, UA_Double interval_ms,
UA_DateTime *baseTime, UA_TimerPolicy timerPolicy);
void (*removeCustomCallback)(UA_Server *server, UA_NodeId identifier, UA_UInt64 callbackId);
} UA_PubSub_CallbackLifecycle;
WriterGroup¶
All WriterGroups are created within a PubSubConnection and automatically deleted if the connection is removed. The WriterGroup is primary used as container for DataSetWriter and network message settings. The WriterGroup can be imagined as producer of the network messages. The creation of network messages is controlled by parameters like the publish interval, which is e.g. contained in the WriterGroup.
typedef enum {
UA_PUBSUB_ENCODING_UADP = 0,
UA_PUBSUB_ENCODING_JSON = 1,
UA_PUBSUB_ENCODING_BINARY = 2
} UA_PubSubEncodingType;
WriterGroup¶
The message publishing can be configured for realtime requirements. The RT-levels go along with different requirements. The below listed levels can be configured:
UA_PUBSUB_RT_NONE - —> Description: Default “none-RT” Mode —> Requirements: - —> Restrictions: - UA_PUBSUB_RT_DIRECT_VALUE_ACCESS (Preview - not implemented) —> Description: Normally, the latest value for each DataSetField is read out of the information model. Within this RT-mode, the value source of each field configured as static pointer to an DataValue. The publish cycle won’t use call the server read function. —> Requirements: All fields must be configured with a ‘staticValueSource’. —> Restrictions: - UA_PUBSUB_RT_FIXED_LENGTH (Preview - not implemented) —> Description: All DataSetFields have a known, non-changing length. The server will pre-generate some buffers and use only memcopy operations to generate requested PubSub packages. —> Requirements: DataSetFields with variable size cannot be used within this mode. —> Restrictions: The configuration must be frozen and changes are not allowed while the WriterGroup is ‘Operational’. UA_PUBSUB_RT_DETERMINISTIC (Preview - not implemented) —> Description: - —> Requirements: - —> Restrictions: -
WARNING! For hard real time requirements the underlying system must be rt-capable.
typedef enum {
UA_PUBSUB_RT_NONE = 0,
UA_PUBSUB_RT_DIRECT_VALUE_ACCESS = 1,
UA_PUBSUB_RT_FIXED_SIZE = 2,
UA_PUBSUB_RT_DETERMINISTIC = 4,
} UA_PubSubRTLevel;
typedef struct {
UA_String name;
UA_Boolean enabled;
UA_UInt16 writerGroupId;
UA_Duration publishingInterval;
UA_Double keepAliveTime;
UA_Byte priority;
UA_ExtensionObject transportSettings;
UA_ExtensionObject messageSettings;
UA_KeyValueMap groupProperties;
UA_PubSubEncodingType encodingMimeType;
/* PubSub Manager Callback */
UA_PubSub_CallbackLifecycle pubsubManagerCallback;
/* non std. config parameter. maximum count of embedded DataSetMessage in
* one NetworkMessage */
UA_UInt16 maxEncapsulatedDataSetMessageCount;
/* non std. field */
UA_PubSubRTLevel rtLevel;
/* Message are encrypted if a SecurityPolicy is configured and the
* securityMode set accordingly. The symmetric key is a runtime information
* and has to be set via UA_Server_setWriterGroupEncryptionKey. */
UA_MessageSecurityMode securityMode; /* via the UA_WriterGroupDataType */
#ifdef UA_ENABLE_PUBSUB_ENCRYPTION
UA_PubSubSecurityPolicy *securityPolicy;
UA_String securityGroupId;
#endif
} UA_WriterGroupConfig;
void
UA_WriterGroupConfig_clear(UA_WriterGroupConfig *writerGroupConfig);
/* Add a new WriterGroup to an existing Connection */
UA_StatusCode UA_THREADSAFE
UA_Server_addWriterGroup(UA_Server *server, const UA_NodeId connection,
const UA_WriterGroupConfig *writerGroupConfig,
UA_NodeId *writerGroupIdentifier);
/* Returns a deep copy of the config */
UA_StatusCode UA_THREADSAFE
UA_Server_getWriterGroupConfig(UA_Server *server, const UA_NodeId writerGroup,
UA_WriterGroupConfig *config);
UA_StatusCode UA_THREADSAFE
UA_Server_updateWriterGroupConfig(UA_Server *server, UA_NodeId writerGroupIdentifier,
const UA_WriterGroupConfig *config);
/* Get state of WriterGroup */
UA_StatusCode UA_THREADSAFE
UA_Server_WriterGroup_getState(UA_Server *server, UA_NodeId writerGroupIdentifier,
UA_PubSubState *state);
UA_StatusCode UA_THREADSAFE
UA_Server_WriterGroup_publish(UA_Server *server, const UA_NodeId writerGroupIdentifier);
UA_StatusCode UA_THREADSAFE
UA_WriterGroup_lastPublishTimestamp(UA_Server *server, const UA_NodeId writerGroupId,
UA_DateTime *timestamp);
UA_StatusCode UA_THREADSAFE
UA_Server_removeWriterGroup(UA_Server *server, const UA_NodeId writerGroup);
UA_StatusCode UA_THREADSAFE
UA_Server_freezeWriterGroupConfiguration(UA_Server *server, const UA_NodeId writerGroup);
UA_StatusCode UA_THREADSAFE
UA_Server_unfreezeWriterGroupConfiguration(UA_Server *server, const UA_NodeId writerGroup);
UA_StatusCode UA_THREADSAFE
UA_Server_setWriterGroupOperational(UA_Server *server, const UA_NodeId writerGroup);
UA_StatusCode UA_THREADSAFE
UA_Server_setWriterGroupDisabled(UA_Server *server, const UA_NodeId writerGroup);
#ifdef UA_ENABLE_PUBSUB_ENCRYPTION
/* Set the group key for the message encryption */
UA_StatusCode UA_THREADSAFE
UA_Server_setWriterGroupEncryptionKeys(UA_Server *server, const UA_NodeId writerGroup,
UA_UInt32 securityTokenId,
const UA_ByteString signingKey,
const UA_ByteString encryptingKey,
const UA_ByteString keyNonce);
#endif
DataSetWriter¶
The DataSetWriters are the glue between the WriterGroups and the PublishedDataSets. The DataSetWriter contain configuration parameters and flags which influence the creation of DataSet messages. These messages are encapsulated inside the network message. The DataSetWriter must be linked with an existing PublishedDataSet and be contained within a WriterGroup.
typedef struct {
UA_String name;
UA_UInt16 dataSetWriterId;
UA_DataSetFieldContentMask dataSetFieldContentMask;
UA_UInt32 keyFrameCount;
UA_ExtensionObject messageSettings;
UA_ExtensionObject transportSettings;
UA_String dataSetName;
UA_KeyValueMap dataSetWriterProperties;
} UA_DataSetWriterConfig;
void
UA_DataSetWriterConfig_clear(UA_DataSetWriterConfig *pdsConfig);
/* Add a new DataSetWriter to an existing WriterGroup. The DataSetWriter must be
* coupled with a PublishedDataSet on creation.
*
* Part 14, 7.1.5.2.1 defines: The link between the PublishedDataSet and
* DataSetWriter shall be created when an instance of the DataSetWriterType is
* created. */
UA_StatusCode UA_THREADSAFE
UA_Server_addDataSetWriter(UA_Server *server,
const UA_NodeId writerGroup, const UA_NodeId dataSet,
const UA_DataSetWriterConfig *dataSetWriterConfig,
UA_NodeId *writerIdentifier);
/* Returns a deep copy of the config */
UA_StatusCode UA_THREADSAFE
UA_Server_getDataSetWriterConfig(UA_Server *server, const UA_NodeId dsw,
UA_DataSetWriterConfig *config);
/* Get state of DataSetWriter */
UA_StatusCode UA_THREADSAFE
UA_Server_DataSetWriter_getState(UA_Server *server, UA_NodeId dataSetWriterIdentifier,
UA_PubSubState *state);
UA_StatusCode UA_THREADSAFE
UA_Server_removeDataSetWriter(UA_Server *server, const UA_NodeId dsw);
SubscribedDataSet¶
SubscribedDataSet describes the processing of the received DataSet. SubscribedDataSet defines which field in the DataSet is mapped to which Variable in the OPC UA Application. SubscribedDataSet has two sub-types called the TargetVariablesType and SubscribedDataSetMirrorType. SubscribedDataSetMirrorType is currently not supported. SubscribedDataSet is set to TargetVariablesType and then the list of target Variables are created in the Subscriber AddressSpace. TargetVariables are a list of variables that are to be added in the Subscriber AddressSpace. It defines a list of Variable mappings between received DataSet fields and added Variables in the Subscriber AddressSpace.
/* SubscribedDataSetDataType Definition */
typedef enum {
UA_PUBSUB_SDS_TARGET,
UA_PUBSUB_SDS_MIRROR
} UA_SubscribedDataSetEnumType;
typedef struct {
/* Standard-defined FieldTargetDataType */
UA_FieldTargetDataType targetVariable;
/* If realtime-handling is required, set this pointer non-NULL and it will be used
* to memcpy the value instead of using the Write service.
* If the beforeWrite method pointer is set, it will be called before a memcpy update
* to the value. But param externalDataValue already contains the new value.
* If the afterWrite method pointer is set, it will be called after a memcpy update
* to the value. */
UA_DataValue **externalDataValue;
void *targetVariableContext; /* user-defined pointer */
void (*beforeWrite)(UA_Server *server,
const UA_NodeId *readerIdentifier,
const UA_NodeId *readerGroupIdentifier,
const UA_NodeId *targetVariableIdentifier,
void *targetVariableContext,
UA_DataValue **externalDataValue);
void (*afterWrite)(UA_Server *server,
const UA_NodeId *readerIdentifier,
const UA_NodeId *readerGroupIdentifier,
const UA_NodeId *targetVariableIdentifier,
void *targetVariableContext,
UA_DataValue **externalDataValue);
} UA_FieldTargetVariable;
typedef struct {
size_t targetVariablesSize;
UA_FieldTargetVariable *targetVariables;
} UA_TargetVariables;
/* Return Status Code after creating TargetVariables in Subscriber AddressSpace */
UA_StatusCode UA_THREADSAFE
UA_Server_DataSetReader_createTargetVariables(UA_Server *server,
UA_NodeId dataSetReaderIdentifier,
size_t targetVariablesSize,
const UA_FieldTargetVariable *targetVariables);
/* To Do:Implementation of SubscribedDataSetMirrorType
* UA_StatusCode
* A_PubSubDataSetReader_createDataSetMirror(UA_Server *server, UA_NodeId dataSetReaderIdentifier,
* UA_SubscribedDataSetMirrorDataType* mirror) */
DataSetReader¶
DataSetReader can receive NetworkMessages with the DataSetMessage of interest sent by the Publisher. DataSetReaders represent the configuration necessary to receive and process DataSetMessages on the Subscriber side. DataSetReader must be linked with a SubscribedDataSet and be contained within a ReaderGroup.
typedef enum {
UA_PUBSUB_RT_UNKNOWN = 0,
UA_PUBSUB_RT_VARIANT = 1,
UA_PUBSUB_RT_DATA_VALUE = 2,
UA_PUBSUB_RT_RAW = 4,
} UA_PubSubRtEncoding;
/* Parameters for PubSub DataSetReader Configuration */
typedef struct {
UA_String name;
UA_Variant publisherId;
UA_UInt16 writerGroupId;
UA_UInt16 dataSetWriterId;
UA_DataSetMetaDataType dataSetMetaData;
UA_DataSetFieldContentMask dataSetFieldContentMask;
UA_Double messageReceiveTimeout;
UA_ExtensionObject messageSettings;
UA_ExtensionObject transportSettings;
UA_SubscribedDataSetEnumType subscribedDataSetType;
/* TODO UA_SubscribedDataSetMirrorDataType subscribedDataSetMirror */
union {
UA_TargetVariables subscribedDataSetTarget;
// UA_SubscribedDataSetMirrorDataType subscribedDataSetMirror;
} subscribedDataSet;
/* non std. fields */
UA_String linkedStandaloneSubscribedDataSetName;
UA_PubSubRtEncoding expectedEncoding;
} UA_DataSetReaderConfig;
/* Copy the configuration of DataSetReader */
UA_StatusCode
UA_DataSetReaderConfig_copy(const UA_DataSetReaderConfig *src,
UA_DataSetReaderConfig *dst);
/* Clear the configuration of a DataSetReader */
void
UA_DataSetReaderConfig_clear(UA_DataSetReaderConfig *cfg);
/* Update configuration to the DataSetReader */
UA_StatusCode UA_THREADSAFE
UA_Server_DataSetReader_updateConfig(UA_Server *server, UA_NodeId dataSetReaderIdentifier,
UA_NodeId readerGroupIdentifier,
const UA_DataSetReaderConfig *config);
/* Get the configuration (copy) of the DataSetReader */
UA_StatusCode UA_THREADSAFE
UA_Server_DataSetReader_getConfig(UA_Server *server, UA_NodeId dataSetReaderIdentifier,
UA_DataSetReaderConfig *config);
/* Get state of DataSetReader */
UA_StatusCode UA_THREADSAFE
UA_Server_DataSetReader_getState(UA_Server *server, UA_NodeId dataSetReaderIdentifier,
UA_PubSubState *state);
typedef struct {
UA_String name;
UA_SubscribedDataSetEnumType subscribedDataSetType;
union {
/* datasetmirror is currently not implemented */
UA_TargetVariablesDataType target;
} subscribedDataSet;
UA_DataSetMetaDataType dataSetMetaData;
UA_Boolean isConnected;
} UA_StandaloneSubscribedDataSetConfig;
void
UA_StandaloneSubscribedDataSetConfig_clear(UA_StandaloneSubscribedDataSetConfig *sdsConfig);
UA_StatusCode UA_THREADSAFE
UA_Server_addStandaloneSubscribedDataSet(UA_Server *server,
const UA_StandaloneSubscribedDataSetConfig *subscribedDataSetConfig,
UA_NodeId *sdsIdentifier);
/* Remove StandaloneSubscribedDataSet, identified by the NodeId. */
UA_StatusCode UA_THREADSAFE
UA_Server_removeStandaloneSubscribedDataSet(UA_Server *server, const UA_NodeId sds);
ReaderGroup¶
ReaderGroup is used to group a list of DataSetReaders. All ReaderGroups are created within a PubSubConnection and automatically deleted if the connection is removed. All network message related filters are only available in the DataSetReader.
The RT-levels go along with different requirements. The below listed levels can be configured for a ReaderGroup.
UA_PUBSUB_RT_NONE: RT applied to this level
PUBSUB_CONFIG_FASTPATH_FIXED_OFFSETS: Extends PubSub RT functionality and implements fast path message decoding in the Subscriber. Uses a buffered network message and only decodes the necessary offsets stored in an offset buffer.
/* ReaderGroup configuration */
typedef struct {
UA_String name;
/* non std. field */
UA_PubSubRTLevel rtLevel;
UA_KeyValueMap groupProperties;
UA_PubSubEncodingType encodingMimeType;
UA_ExtensionObject transportSettings;
/* Messages are decrypted if a SecurityPolicy is configured and the
* securityMode set accordingly. The symmetric key is a runtime information
* and has to be set via UA_Server_setReaderGroupEncryptionKey. */
UA_MessageSecurityMode securityMode;
#ifdef UA_ENABLE_PUBSUB_ENCRYPTION
UA_PubSubSecurityPolicy *securityPolicy;
UA_String securityGroupId;
#endif
} UA_ReaderGroupConfig;
void
UA_ReaderGroupConfig_clear(UA_ReaderGroupConfig *readerGroupConfig);
/* Add DataSetReader to the ReaderGroup */
UA_StatusCode UA_THREADSAFE
UA_Server_addDataSetReader(UA_Server *server, UA_NodeId readerGroupIdentifier,
const UA_DataSetReaderConfig *dataSetReaderConfig,
UA_NodeId *readerIdentifier);
/* Remove DataSetReader from ReaderGroup */
UA_StatusCode UA_THREADSAFE
UA_Server_removeDataSetReader(UA_Server *server, UA_NodeId readerIdentifier);
/* To Do: Update Configuration of ReaderGroup
* UA_StatusCode
* UA_Server_ReaderGroup_updateConfig(UA_Server *server, UA_NodeId readerGroupIdentifier,
* const UA_ReaderGroupConfig *config);
*/
/* Get configuraiton of ReaderGroup */
UA_StatusCode UA_THREADSAFE
UA_Server_ReaderGroup_getConfig(UA_Server *server, UA_NodeId readerGroupIdentifier,
UA_ReaderGroupConfig *config);
/* Get state of ReaderGroup */
UA_StatusCode UA_THREADSAFE
UA_Server_ReaderGroup_getState(UA_Server *server, UA_NodeId readerGroupIdentifier,
UA_PubSubState *state);
/* Add ReaderGroup to the created connection */
UA_StatusCode UA_THREADSAFE
UA_Server_addReaderGroup(UA_Server *server, UA_NodeId connectionIdentifier,
const UA_ReaderGroupConfig *readerGroupConfig,
UA_NodeId *readerGroupIdentifier);
/* Remove ReaderGroup from connection */
UA_StatusCode UA_THREADSAFE
UA_Server_removeReaderGroup(UA_Server *server, UA_NodeId groupIdentifier);
UA_StatusCode UA_THREADSAFE
UA_Server_freezeReaderGroupConfiguration(UA_Server *server, const UA_NodeId readerGroupId);
UA_StatusCode UA_THREADSAFE
UA_Server_unfreezeReaderGroupConfiguration(UA_Server *server, const UA_NodeId readerGroupId);
UA_StatusCode UA_THREADSAFE
UA_Server_setReaderGroupOperational(UA_Server *server, const UA_NodeId readerGroupId);
UA_StatusCode UA_THREADSAFE
UA_Server_setReaderGroupDisabled(UA_Server *server, const UA_NodeId readerGroupId);
#ifdef UA_ENABLE_PUBSUB_ENCRYPTION
/* Set the group key for the message encryption */
UA_StatusCode UA_THREADSAFE
UA_Server_setReaderGroupEncryptionKeys(UA_Server *server, UA_NodeId readerGroup,
UA_UInt32 securityTokenId,
UA_ByteString signingKey,
UA_ByteString encryptingKey,
UA_ByteString keyNonce);
#endif
#ifdef UA_ENABLE_PUBSUB_SKS
SecurityGroup¶
A SecurityGroup is an abstraction that represents the message security settings and security keys for a subset of NetworkMessages exchanged between Publishers and Subscribers. The SecurityGroup objects are created on a Security Key Service (SKS). The SKS manages the access to the keys based on the role permission for a user assigned to a SecurityGroup Object. A SecurityGroup is identified with a unique identifier called the SecurityGroupId. It is unique within the SKS.
Note
The access to the SecurityGroup and therefore the securitykeys managed by SKS requires management of Roles and Permissions in the SKS. The Role Permission model is not supported at the time of writing. However, the access control plugin can be used to create and manage role permission on SecurityGroup object.
typedef struct {
UA_String securityGroupName;
UA_Duration keyLifeTime;
UA_String securityPolicyUri;
UA_UInt32 maxFutureKeyCount;
UA_UInt32 maxPastKeyCount;
} UA_SecurityGroupConfig;
@brief Creates a SecurityGroup object and add it to the list in PubSub Manager. If the information model is enabled then the SecurityGroup object Node is also created in the server. A keyStorage with initial list of keys is created with a SecurityGroup. A callback is added to new SecurityGroup which updates the keys periodically at each KeyLifeTime expire.
@param server The server instance @param securityGroupFolderNodeId The parent node of the SecurityGroup. It must be of SecurityGroupFolderType @param securityGroupConfig The security settings of a SecurityGroup @param securityGroupNodeId The output nodeId of the new SecurityGroup @return UA_StatusCode The return status code
UA_StatusCode UA_THREADSAFE
UA_Server_addSecurityGroup(UA_Server *server, UA_NodeId securityGroupFolderNodeId,
const UA_SecurityGroupConfig *securityGroupConfig,
UA_NodeId *securityGroupNodeId);
@brief Removes the SecurityGroup from PubSub Manager. It removes the KeyStorage associated with the SecurityGroup from the server.
@param server The server instance @param securityGroup The nodeId of the securityGroup to be removed @return UA_StatusCode The returned status code.
UA_StatusCode UA_THREADSAFE
UA_Server_removeSecurityGroup(UA_Server *server, const UA_NodeId securityGroup);
@brief This is a repeated callback which is triggered on each iteration of SKS Pull request. The server uses this callback to notify user about the status of current Pull request iteration. The period is calculated based on the KeylifeTime of specified in the SecurityGroup object node on the SKS server.
@param server The server instance managing the publisher/subscriber. @param sksPullRequestStatus The current status of sks pull request. @param context The pointer to user defined data passed to this callback.
typedef void
(*UA_Server_sksPullRequestCallback)(UA_Server *server, UA_StatusCode sksPullRequestStatus, void* context);
@brief Sets the SKS client config used to call the GetSecurityKeys Method on SKS and get the initial set of keys for a SecurityGroupId and adds timedCallback for the next GetSecurityKeys method Call. This uses async Client API for SKS Pull request. The SKS Client instance is created and destroyed at runtime on each iteration of SKS Pull request by the server. The key Rollover mechanism will check if the new keys are needed then it will call the getSecurityKeys Method on SKS Server. At the end of SKS Pull request iteration, the sks client will be deleted by a delayed callback (in next server iteration).
@note It is be called before setting Reader/Writer Group into Operational because this also allocates a channel context for the pubsub security policy.
@note the stateCallback of sksClientConfig will be overwritten by an internal callback.
@param server the server instance @param clientConfig holds the required configuration to make encrypted connection with SKS Server. The input client config takes the lifecycle as long as SKS request are made. It is deleted with its plugins when the server is deleted or the last Reader/Writer Group of the securityGroupId is deleted. The input config is copied to an internal config object and the content of input config object will be reset to zero. @param endpointUrl holds the endpointUrl of the SKS server @param securityGroupId the SecurityGroupId of the securityGroup on SKS and reader/writergroups @param callback the user defined callback to notify the user about the status of SKS Pull request. @param context passed to the callback function @return UA_StatusCode the retuned status
UA_StatusCode
UA_Server_setSksClient(UA_Server *server, UA_String securityGroupId,
UA_ClientConfig *clientConfig, const char *endpointUrl,
UA_Server_sksPullRequestCallback callback, void *context);
#endif /* UA_ENABLE_PUBSUB_SKS */
#endif /* UA_ENABLE_PUBSUB */