history_server: Add a tutorial for server side history data

examples/CMakeLists.txt

@@ -3,6 +3,7 @@ include_directories(${PROJECT_SOURCE_DIR}/plugins)
 include_directories(${PROJECT_BINARY_DIR})
 include_directories(${PROJECT_SOURCE_DIR}/examples)
 include_directories(${PROJECT_SOURCE_DIR}/arch)
+include_directories(${PROJECT_SOURCE_DIR}/plugins/historydata)
 
 set(examples_headers
     ${examples_headers}
@@ -114,6 +115,10 @@ add_example(server_repeated_job server_repeated_job.c)
 
 add_example(server_inheritance server_inheritance.c)
 
+if(UA_ENABLE_HISTORIZING)
+    add_example(tutorial_server_historicaldata tutorial_server_historicaldata.c)
+endif()
+
 if(UA_ENABLE_ENCRYPTION)
     add_example(server_basic128rsa15 encryption/server_basic128rsa15.c)
     add_example(server_basic256sha256 encryption/server_basic256sha256.c)

examples/tutorial_server_historicaldata.c

@@ -0,0 +1,141 @@
+/* This work is licensed under a Creative Commons CCZero 1.0 Universal License.
+ * See http://creativecommons.org/publicdomain/zero/1.0/ for more information.
+ *
+ * Copyright 2019 (c) basysKom GmbH <opensource@basyskom.com> (Author: Peter Rustler)
+ */
+
+#include <ua_server.h>
+#include <ua_config_default.h>
+#include <ua_log_stdout.h>
+#include <ua_plugin_historydatabase.h>
+#include <ua_plugin_history_data_gathering.h>
+#include <ua_historydatagathering_default.h>
+#include <ua_historydatabase_default.h>
+#include <ua_historydatabackend_memory.h>
+#include <signal.h>
+
+static UA_Boolean running = true;
+static void stopHandler(int sign) {
+    (void)sign;
+    UA_LOG_INFO(UA_Log_Stdout, UA_LOGCATEGORY_SERVER, "received ctrl-c");
+    running = false;
+}
+
+
+int main(void) {
+    signal(SIGINT, stopHandler);
+    signal(SIGTERM, stopHandler);
+
+    UA_ServerConfig *config = UA_ServerConfig_new_default();
+    /*
+     * We need a gathering for the plugin to constuct.
+     * The UA_HistoryDataGathering is responsible to collect data and store it to the database.
+     * We will use this gathering for one node, only. initialNodeIdStoreSize = 1
+     * The store will grow if you register more than one node, but this is expensive.
+     */
+    UA_HistoryDataGathering gathering = UA_HistoryDataGathering_Default(1);
+    /*
+     * We set the responsible plugin in the configuration.
+     * UA_HistoryDatabase is the main plugin which handles the historical data service.
+     */
+    config->historyDatabase = UA_HistoryDatabase_default(gathering);
+    UA_Server *server = UA_Server_new(config);
+    /* Define the attribute of the uint32 variable node */
+    UA_VariableAttributes attr = UA_VariableAttributes_default;
+    UA_UInt32 myUint32 = 40;
+    UA_Variant_setScalar(&attr.value, &myUint32, &UA_TYPES[UA_TYPES_UINT32]);
+    attr.description = UA_LOCALIZEDTEXT("en-US","myUintValue");
+    attr.displayName = UA_LOCALIZEDTEXT("en-US","myUintValue");
+    attr.dataType = UA_TYPES[UA_TYPES_UINT32].typeId;
+    /*
+     * We set the access level to also support history read
+     * This is what will be reported to clients
+     */
+    attr.accessLevel = UA_ACCESSLEVELMASK_READ | UA_ACCESSLEVELMASK_WRITE | UA_ACCESSLEVELMASK_HISTORYREAD;
+    /*
+     * We also set this node to historizing, so the server internals also know from it.
+     */
+    attr.historizing = true;
+
+    /* Add the variable node to the information model */
+    UA_NodeId uint32NodeId = UA_NODEID_STRING(1, "myUintValue");
+    UA_QualifiedName uint32Name = UA_QUALIFIEDNAME(1, "myUintValue");
+    UA_NodeId parentNodeId = UA_NODEID_NUMERIC(0, UA_NS0ID_OBJECTSFOLDER);
+    UA_NodeId parentReferenceNodeId = UA_NODEID_NUMERIC(0, UA_NS0ID_ORGANIZES);
+    UA_NodeId outNodeId;
+    UA_NodeId_init(&outNodeId);
+    UA_StatusCode retval = UA_Server_addVariableNode(server,
+                                                     uint32NodeId,
+                                                     parentNodeId,
+                                                     parentReferenceNodeId,
+                                                     uint32Name,
+                                                     UA_NODEID_NUMERIC(0, UA_NS0ID_BASEDATAVARIABLETYPE),
+                                                     attr,
+                                                     NULL,
+                                                     &outNodeId);
+    UA_LOG_INFO(UA_Log_Stdout, UA_LOGCATEGORY_SERVER, "UA_Server_addVariableNode %s", UA_StatusCode_name(retval));
+    /*
+     * Now we define the settings for our node
+     */
+    UA_HistorizingNodeIdSettings setting;
+    /*
+     * There is a memory based database plugin. We will use that.
+     * We just reserve space for 3 nodes with 100 values each.
+     * This will also automaticaly grow if needed, but that is expensive,
+     * because all data must be copied.
+     */
+    setting.historizingBackend = UA_HistoryDataBackend_Memory(3, 100);
+    /*
+     * We want the server to serve a maximum of 100 values per request.
+     * This value depend on the plattform you are running the server.
+     * A big server can serve more values, smaller ones less.
+     */
+    setting.maxHistoryDataResponseSize = 100;
+    /*
+     * If we have a sensor which do not report updates
+     * and need to be polled we change the setting like that.
+     * The polling interval in ms.
+     *
+    setting.pollingInterval = 100;
+     *
+     * Set the update strategie to polling.
+     *
+    setting.historizingUpdateStrategy = UA_HISTORIZINGUPDATESTRATEGY_POLL;
+     */
+
+    /*
+     * If you want to insert the values to the database yourself, we can set the user strategy here.
+     * This is useful if you for example want a value stored, if a defined delta is reached.
+     * Then you should use a local monitored item with a fuzziness and store the value in the callback.
+     *
+    setting.historizingUpdateStrategy = UA_HISTORIZINGUPDATESTRATEGY_USER;
+     */
+
+    /*
+     * We want the values stored in the database, when the nodes value is set.
+     */
+    setting.historizingUpdateStrategy = UA_HISTORIZINGUPDATESTRATEGY_VALUESET;
+    /*
+     * At the end we register the node for gathering data in the database.
+     */
+    retval = gathering.registerNodeId(server, gathering.context, &outNodeId, setting);
+    UA_LOG_INFO(UA_Log_Stdout, UA_LOGCATEGORY_SERVER, "registerNodeId %s", UA_StatusCode_name(retval));
+    /*
+     * If you use UA_HISTORIZINGUPDATESTRATEGY_POLL, then start the polling.
+     *
+    retval = gathering.startPoll(server, gathering.context, &outNodeId);
+    UA_LOG_INFO(UA_Log_Stdout, UA_LOGCATEGORY_SERVER, "startPoll %s", UA_StatusCode_name(retval));
+    */
+    retval = UA_Server_run(server, &running);
+    UA_LOG_INFO(UA_Log_Stdout, UA_LOGCATEGORY_SERVER, "UA_Server_run %s", UA_StatusCode_name(retval));
+    /*
+     * If you use UA_HISTORIZINGUPDATESTRATEGY_POLL, then stop the polling.
+     *
+    retval = gathering.stopPoll(server, gathering.context, &outNodeId);
+    UA_LOG_INFO(UA_Log_Stdout, UA_LOGCATEGORY_SERVER, "stopPoll %s", UA_StatusCode_name(retval));
+    */
+    UA_Server_run_shutdown(server);
+    UA_Server_delete(server);
+    UA_ServerConfig_delete(config);
+    return (int)retval;
+}