Files
pvxs/example/mailbox.cpp
T

114 lines
3.3 KiB
C++

/**
* Copyright - See the COPYRIGHT that is included with this distribution.
* pvxs is distributed subject to a Software License Agreement found
* in file LICENSE that is included with this distribution.
*/
/**
* Serves a single PV name.
* Any updates written (PUT) to this PV will be stored verbatim
* and sent to any subscribers.
*/
#include <iostream>
#include <epicsTime.h>
#include <pvxs/sharedpv.h>
#include <pvxs/server.h>
#include <pvxs/nt.h>
#include <pvxs/log.h>
using namespace pvxs;
int main(int argc, char* argv[])
{
if(argc<=1) {
std::cerr<<"Usage: "<<argv[0]<<" <pvname> [pvname1 [...]]\n";
return 1;
}
// Read $PVXS_LOG from process environment and update
// logging configuration. eg.
// export PVXS_LOG=*=DEBUG
// makes a lot of noise.
logger_config_env();
// Must provide a data type for the mailbox.
// Use pre-canned definition of scalar with meta-data
Value initial = nt::NTScalar{TypeCode::Float64}.create();
// (optional) Provide an initial value
initial["value"] = 42.0;
initial["alarm.severity"] = 0;
initial["alarm.status"] = 0;
initial["alarm.message"] = "";
std::vector<server::SharedPV> pvs(argc-1u);
for(size_t i=0ul; i<pvs.size(); i++) {
// Actually creating a mailbox PV.
// buildMailbox() installs a default onPut() handler which
// stores whatever a client sends (subject to our data type).
server::SharedPV pv(server::SharedPV::buildMailbox());
// (optional) Replace the default PUT handler to do a range check
pv.onPut([](server::SharedPV& pv,
std::unique_ptr<server::ExecOp>&& op,
Value&& top)
{
// (optional) arbitrarily clip value to [-100.0, 100.0]
double val(top["value"].as<double>());
if(val<-100.0)
top["value"] = -100.0;
else if(val>100.0)
top["value"] = 100.0;
// (optional) Provide a timestamp if the client has not (common)
Value ts(top["timeStamp"]);
if(!ts.isMarked(true, true)) {
// use current time
epicsTimeStamp now;
if(!epicsTimeGetCurrent(&now)) {
ts["secondsPastEpoch"] = now.secPastEpoch + POSIX_TIME_AT_EPICS_EPOCH;
ts["nanoseconds"] = now.nsec;
}
}
// (optional) update the SharedPV cache and send
// a update to any subscribers
pv.post(top);
// Required. Inform client that PUT operation is complete.
op->reply();
});
// Associate a data type (and maybe initial value) with this PV
pv.open(initial);
pvs[i] = std::move(pv);
}
// Build server which will serve this PV
// Configure using process environment.
auto serv(server::Server::fromEnv());
for(size_t i=0ul; i<pvs.size(); i++) {
serv.addPV(argv[i+1], pvs[i]);
}
// (optional) Print the configuration this server is using
// with any auto-address list expanded.
std::cout<<"Effective config\n"<<serv.config();
std::cout<<"Running\n";
// Start server and run forever, or until Ctrl+c is pressed.
// Returns on SIGINT or SIGTERM
serv.run();
std::cout<<"Done\n";
return 0;
}