1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
|
// Copyright (c) 2022 by Apex.AI Inc. All rights reserved.
//
// 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
//! [include custom discovery]
#include "discovery_blocking.hpp"
//! [include custom discovery]
#include "iceoryx_hoofs/posix_wrapper/signal_watcher.hpp"
#include "iceoryx_posh/runtime/posh_runtime.hpp"
#include <iostream>
using namespace discovery;
constexpr char APP_NAME[] = "iox-wait-for-service";
//! [service to wait for]
iox::capro::IdString_t service{"Camera"};
iox::capro::IdString_t instance{"FrontLeft"};
iox::capro::IdString_t event{"Image"};
//! [service to wait for]
void printSearchResult(const discovery::ServiceContainer& result)
{
std::cout << APP_NAME << " search result: " << (result.empty() ? "empty" : "") << std::endl;
for (auto entry : result)
{
std::cout << APP_NAME << " <" << entry.getServiceIDString() << ", " << entry.getInstanceIDString() << ", "
<< entry.getEventIDString() << ">" << std::endl;
}
}
Discovery* discoveryPtr{nullptr};
void sigHandler(int)
{
//! [unblock wait]
if (discoveryPtr)
{
discoveryPtr->unblockWait();
}
//! [unblock wait]
}
int main()
{
iox::runtime::PoshRuntime::initRuntime(APP_NAME);
//! [create custom discovery]
// requires the runtime to be created first
Discovery discovery;
//! [create custom discovery]
discoveryPtr = &discovery;
auto sigTermGuard = iox::posix::registerSignalHandler(iox::posix::Signal::TERM, sigHandler);
auto sigIntGuard = iox::posix::registerSignalHandler(iox::posix::Signal::INT, sigHandler);
//! [define search query]
auto query = [&]() {
auto result = discovery.findService(service, instance, event);
return !result.empty();
};
//! [define search query]
std::cout << APP_NAME << " waiting for service <" << service << ", " << instance << ", " << event << "> ...\n"
<< std::endl;
//! [wait until service was available]
bool serviceWasAvailable = discovery.waitUntil(query);
//! [wait until service was available]
// did we wake up due to an unblock or because the service was available?
if (serviceWasAvailable)
{
std::cout << APP_NAME << " <" << service << ", " << instance << ", " << event << "> was available\n"
<< std::endl;
// service was available, but we can never be sure the service is still available
// if this is important we need to monitor it (see discovery monitor example)
std::cout << APP_NAME << " waiting for any discovery change ...\n" << std::endl;
do
{
//! [wait until discovery changes]
discovery.waitUntilChange();
//! [wait until discovery changes]
std::cout << APP_NAME << " discovery changed. Searching <" << service << ", " << instance << ", " << event
<< "> ..." << std::endl;
//! [check service availability]
if (discovery.findService(service, instance, event).empty())
{
break;
}
//! [check service availability]
std::cout << APP_NAME << " <" << service << ", " << instance << ", " << event << "> was available\n"
<< std::endl;
// loop while the service is available (e.g. perform some computation etc.)
} while (true);
std::cout << APP_NAME << " <" << service << ", " << instance << ", " << event << "> was unavailable"
<< std::endl;
}
return (EXIT_SUCCESS);
}
|
