/src/brpc/src/bvar/mvariable.cpp

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// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you 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.

// Date: 2021/11/17 14:37:53

#include <gflags/gflags.h>
#include <gflags/gflags_declare.h>
#include "butil/logging.h"                       // LOG
#include "butil/errno.h"                         // berror
#include "butil/containers/flat_map.h"           // butil::FlatMap
#include "butil/scoped_lock.h"                   // BAIDU_SCOPE_LOCK
#include "butil/file_util.h"                     // butil::FilePath
#include "butil/reloadable_flags.h"
#include "bvar/variable.h"
#include "bvar/mvariable.h"

namespace bvar {

constexpr uint64_t MAX_LABELS_COUNT = 10;

DECLARE_bool(bvar_abort_on_same_name);

extern bool s_bvar_may_abort;

static bool validator_bvar_max_multi_dimension_metric_number(const char*, int32_t v) {
    if (v < 1) {
        LOG(ERROR) << "Invalid bvar_max_multi_dimension_metric_number=" << v;
        return false;
    }
    return true;
}

DEFINE_int32(bvar_max_multi_dimension_metric_number, 1024, "Max number of multi dimension");
BUTIL_VALIDATE_GFLAG(bvar_max_multi_dimension_metric_number,
                     validator_bvar_max_multi_dimension_metric_number);

static bool validator_bvar_max_dump_multi_dimension_metric_number(const char*, int32_t v) {
    if (v < 0) {
        LOG(ERROR) << "Invalid bvar_max_dump_multi_dimension_metric_number=" << v;
        return false;
    }
    return true;
}
DEFINE_int32(bvar_max_dump_multi_dimension_metric_number, 1024,
             "Max number of multi dimension metric number to dump by prometheus rpc service");
BUTIL_VALIDATE_GFLAG(bvar_max_dump_multi_dimension_metric_number,
                     validator_bvar_max_dump_multi_dimension_metric_number);

static bool validator_max_multi_dimension_stats_count(const char*, uint32_t v) {
    if (v < 1) {
        LOG(ERROR) << "Invalid max_multi_dimension_stats_count=" << v;
        return false;
    }
    return true;
}
DEFINE_uint32(max_multi_dimension_stats_count, 20000, "Max stats count of a multi dimension metric.");
BUTIL_VALIDATE_GFLAG(max_multi_dimension_stats_count,
                     validator_max_multi_dimension_stats_count);

class MVarEntry {
public:
    MVarEntry() : var(NULL) {}

    MVariable* var;
};

typedef butil::FlatMap<std::string, MVarEntry> MVarMap;

struct MVarMapWithLock : public MVarMap {
    pthread_mutex_t mutex;

    MVarMapWithLock() {
        if (init(256) != 0) {
            LOG(WARNING) << "Fail to init";
        }
        pthread_mutex_init(&mutex, NULL);
    }
};

// We have to initialize global map on need because bvar is possibly used
// before main().
static pthread_once_t s_mvar_map_once = PTHREAD_ONCE_INIT;
static MVarMapWithLock* s_mvar_map = NULL;

static void init_mvar_map() {
    // It's probably slow to initialize all sub maps, but rpc often expose 
    // variables before user. So this should not be an issue to users.
    s_mvar_map = new MVarMapWithLock();
}

inline MVarMapWithLock& get_mvar_map() {
    pthread_once(&s_mvar_map_once, init_mvar_map);
    return *s_mvar_map;
}

MVariable::MVariable(const std::list<std::string>& labels) {
    _labels.assign(labels.begin(), labels.end());
    size_t n = labels.size();
    if (n > MAX_LABELS_COUNT) {
        LOG(ERROR) << "Too many labels: " << n << " seen, overflow detected, max labels count: " << MAX_LABELS_COUNT;
        _labels.resize(MAX_LABELS_COUNT);
    }
}

MVariable::~MVariable() {
    CHECK(!hide()) << "Subclass of MVariable MUST call hide() manually in their"
    " dtors to avoid displaying a variable that is just destructing";
}

std::string MVariable::get_description() {
    std::ostringstream os;
    describe(os);
    return os.str();
}

int MVariable::describe_exposed(const std::string& name,
                                std::ostream& os) {
    MVarMapWithLock& m = get_mvar_map();
    BAIDU_SCOPED_LOCK(m.mutex);
    MVarEntry* entry = m.seek(name);
    if (entry == NULL) {
        return -1;
    }
    entry->var->describe(os);
    return 0;
}

std::string MVariable::describe_exposed(const std::string& name) {
    std::ostringstream oss;
    if (describe_exposed(name, oss) == 0) {
        return oss.str();
    }
    return std::string();
}

int MVariable::expose_impl(const butil::StringPiece& prefix,
                           const butil::StringPiece& name) {
    if (name.empty()) {
        LOG(ERROR) << "Parameter[name] is empty";
        return -1;
    }
    // NOTE: It's impossible to atomically erase from a submap and insert into
    // another submap without a global lock. When the to-be-exposed name
    // already exists, there's a chance that we can't insert back previous
    // name. But it should be fine generally because users are unlikely to
    // expose a variable more than once and calls to expose() are unlikely
    // to contend heavily.

    // remove previous pointer from the map if needed.
    hide();
    
    // Build the name.
    _name.clear();
    _name.reserve((prefix.size() + name.size()) * 5 / 4);
    if (!prefix.empty()) {
        to_underscored_name(&_name, prefix);
        if (!_name.empty() && butil::back_char(_name) != '_') {
            _name.push_back('_');
        }     
    }
    to_underscored_name(&_name, name);
   
    if (count_exposed() > (size_t)FLAGS_bvar_max_multi_dimension_metric_number) {
        LOG(ERROR) << "Too many metric seen, overflow detected, max metric count:" << FLAGS_bvar_max_multi_dimension_metric_number;
        return -1;
    }

    MVarMapWithLock& m = get_mvar_map();
    {
        BAIDU_SCOPED_LOCK(m.mutex);
        MVarEntry* entry = m.seek(_name);
        if (entry == NULL) {
            entry = &m[_name];
            entry->var = this;
            return 0;
        }
    }

    RELEASE_ASSERT_VERBOSE(!FLAGS_bvar_abort_on_same_name,
                           "Abort due to name conflict");
    if (!s_bvar_may_abort) {
        // Mark name conflict occurs, If this conflict happens before
        // initialization of bvar_abort_on_same_name, the validator will
        // abort the program if needed.
        s_bvar_may_abort = true;
    }

    LOG(WARNING) << "Already exposed `" << _name << "' whose describe is`"
               << get_description() << "'";
    _name.clear();
    return 0;
}

bool MVariable::hide() {
    if (_name.empty()) {
        return false;
    }

    MVarMapWithLock& m = get_mvar_map();
    BAIDU_SCOPED_LOCK(m.mutex);
    MVarEntry* entry = m.seek(_name);
    if (entry) {
        CHECK_EQ(1UL, m.erase(_name));
    } else {
        CHECK(false) << "`" << _name << "' must exist";
    }
    _name.clear();
    return true;
}

#ifdef UNIT_TEST
void MVariable::hide_all() {
    MVarMapWithLock& m = get_mvar_map();
    BAIDU_SCOPED_LOCK(m.mutex);
    m.clear();
}
#endif // end UNIT_TEST

size_t MVariable::count_exposed() {
    MVarMapWithLock& m = get_mvar_map();
    BAIDU_SCOPED_LOCK(m.mutex);
    return m.size();
}

void MVariable::list_exposed(std::vector<std::string>* names) {
    if (names == NULL) {
        return;
    }

    names->clear();

    MVarMapWithLock& mvar_map = get_mvar_map();
    BAIDU_SCOPED_LOCK(mvar_map.mutex);
    names->reserve(mvar_map.size());
    for (MVarMap::const_iterator it = mvar_map.begin(); it != mvar_map.end(); ++it) {
        names->push_back(it->first);
    }
}

size_t MVariable::dump_exposed(Dumper* dumper, const DumpOptions* options) {
    if (NULL == dumper) {
        LOG(ERROR) << "Parameter[dumper] is NULL";
        return -1;
    }
    DumpOptions opt;
    if (options) {
        opt = *options;
    }
    std::vector<std::string> mvars;
    list_exposed(&mvars);
    size_t n = 0;
    for (auto& mvar : mvars) {
        MVarMapWithLock& m = get_mvar_map();
        BAIDU_SCOPED_LOCK(m.mutex);
        MVarEntry* entry = m.seek(mvar);
        if (entry) {
            n += entry->var->dump(dumper, &opt);
        }
        if (n > static_cast<size_t>(FLAGS_bvar_max_dump_multi_dimension_metric_number)) {
            LOG(WARNING) << "truncated because of \
                            exceed max dump multi dimension label number["
                         << FLAGS_bvar_max_dump_multi_dimension_metric_number
                         << "]";
            break;
        }
    }
    return n;
}

} // namespace bvar

Coverage Report

Created: 2025-03-17 06:44

Line	Count	Source (jump to first uncovered line)
1		// Licensed to the Apache Software Foundation (ASF) under one
2		// or more contributor license agreements. See the NOTICE file
3		// distributed with this work for additional information
4		// regarding copyright ownership. The ASF licenses this file
5		// to you under the Apache License, Version 2.0 (the
6		// "License"); you may not use this file except in compliance
7		// with the License. You may obtain a copy of the License at
8		//
9		// http://www.apache.org/licenses/LICENSE-2.0
10		//
11		// Unless required by applicable law or agreed to in writing,
12		// software distributed under the License is distributed on an
13		// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
14		// KIND, either express or implied. See the License for the
15		// specific language governing permissions and limitations
16		// under the License.
17
18		// Date: 2021/11/17 14:37:53
19
20		#include <gflags/gflags.h>
21		#include <gflags/gflags_declare.h>
22		#include "butil/logging.h" // LOG
23		#include "butil/errno.h" // berror
24		#include "butil/containers/flat_map.h" // butil::FlatMap
25		#include "butil/scoped_lock.h" // BAIDU_SCOPE_LOCK
26		#include "butil/file_util.h" // butil::FilePath
27		#include "butil/reloadable_flags.h"
28		#include "bvar/variable.h"
29		#include "bvar/mvariable.h"
30
31		namespace bvar {
32
33		constexpr uint64_t MAX_LABELS_COUNT = 10;
34
35		DECLARE_bool(bvar_abort_on_same_name);
36
37		extern bool s_bvar_may_abort;
38
39	0	static bool validator_bvar_max_multi_dimension_metric_number(const char*, int32_t v) {
40	0	if (v < 1) {
41	0	LOG(ERROR) << "Invalid bvar_max_multi_dimension_metric_number=" << v;
42	0	return false;
43	0	}
44	0	return true;
45	0	}
46
47		DEFINE_int32(bvar_max_multi_dimension_metric_number, 1024, "Max number of multi dimension");
48		BUTIL_VALIDATE_GFLAG(bvar_max_multi_dimension_metric_number,
49		validator_bvar_max_multi_dimension_metric_number);
50
51	0	static bool validator_bvar_max_dump_multi_dimension_metric_number(const char*, int32_t v) {
52	0	if (v < 0) {
53	0	LOG(ERROR) << "Invalid bvar_max_dump_multi_dimension_metric_number=" << v;
54	0	return false;
55	0	}
56	0	return true;
57	0	}
58		DEFINE_int32(bvar_max_dump_multi_dimension_metric_number, 1024,
59		"Max number of multi dimension metric number to dump by prometheus rpc service");
60		BUTIL_VALIDATE_GFLAG(bvar_max_dump_multi_dimension_metric_number,
61		validator_bvar_max_dump_multi_dimension_metric_number);
62
63	0	static bool validator_max_multi_dimension_stats_count(const char*, uint32_t v) {
64	0	if (v < 1) {
65	0	LOG(ERROR) << "Invalid max_multi_dimension_stats_count=" << v;
66	0	return false;
67	0	}
68	0	return true;
69	0	}
70		DEFINE_uint32(max_multi_dimension_stats_count, 20000, "Max stats count of a multi dimension metric.");
71		BUTIL_VALIDATE_GFLAG(max_multi_dimension_stats_count,
72		validator_max_multi_dimension_stats_count);
73
74		class MVarEntry {
75		public:
76	0	MVarEntry() : var(NULL) {}
77
78		MVariable* var;
79		};
80
81		typedef butil::FlatMap<std::string, MVarEntry> MVarMap;
82
83		struct MVarMapWithLock : public MVarMap {
84		pthread_mutex_t mutex;
85
86	0	MVarMapWithLock() {
87	0	if (init(256) != 0) {
88	0	LOG(WARNING) << "Fail to init";
89	0	}
90	0	pthread_mutex_init(&mutex, NULL);
91	0	}
92		};
93
94		// We have to initialize global map on need because bvar is possibly used
95		// before main().
96		static pthread_once_t s_mvar_map_once = PTHREAD_ONCE_INIT;
97		static MVarMapWithLock* s_mvar_map = NULL;
98
99	0	static void init_mvar_map() {
100		// It's probably slow to initialize all sub maps, but rpc often expose
101		// variables before user. So this should not be an issue to users.
102	0	s_mvar_map = new MVarMapWithLock();
103	0	}
104
105	0	inline MVarMapWithLock& get_mvar_map() {
106	0	pthread_once(&s_mvar_map_once, init_mvar_map);
107	0	return *s_mvar_map;
108	0	}
109
110	0	MVariable::MVariable(const std::list<std::string>& labels) {
111	0	_labels.assign(labels.begin(), labels.end());
112	0	size_t n = labels.size();
113	0	if (n > MAX_LABELS_COUNT) {
114	0	LOG(ERROR) << "Too many labels: " << n << " seen, overflow detected, max labels count: " << MAX_LABELS_COUNT;
115	0	_labels.resize(MAX_LABELS_COUNT);
116	0	}
117	0	}
118
119	0	MVariable::~MVariable() {
120	0	CHECK(!hide()) << "Subclass of MVariable MUST call hide() manually in their"
121	0	" dtors to avoid displaying a variable that is just destructing";
122	0	}
123
124	0	std::string MVariable::get_description() {
125	0	std::ostringstream os;
126	0	describe(os);
127	0	return os.str();
128	0	}
129
130		int MVariable::describe_exposed(const std::string& name,
131	0	std::ostream& os) {
132	0	MVarMapWithLock& m = get_mvar_map();
133	0	BAIDU_SCOPED_LOCK(m.mutex);
134	0	MVarEntry* entry = m.seek(name);
135	0	if (entry == NULL) {
136	0	return -1;
137	0	}
138	0	entry->var->describe(os);
139	0	return 0;
140	0	}
141
142	0	std::string MVariable::describe_exposed(const std::string& name) {
143	0	std::ostringstream oss;
144	0	if (describe_exposed(name, oss) == 0) {
145	0	return oss.str();
146	0	}
147	0	return std::string();
148	0	}
149
150		int MVariable::expose_impl(const butil::StringPiece& prefix,
151	0	const butil::StringPiece& name) {
152	0	if (name.empty()) {
153	0	LOG(ERROR) << "Parameter[name] is empty";
154	0	return -1;
155	0	}
156		// NOTE: It's impossible to atomically erase from a submap and insert into
157		// another submap without a global lock. When the to-be-exposed name
158		// already exists, there's a chance that we can't insert back previous
159		// name. But it should be fine generally because users are unlikely to
160		// expose a variable more than once and calls to expose() are unlikely
161		// to contend heavily.
162
163		// remove previous pointer from the map if needed.
164	0	hide();
165
166		// Build the name.
167	0	_name.clear();
168	0	_name.reserve((prefix.size() + name.size()) * 5 / 4);
169	0	if (!prefix.empty()) {
170	0	to_underscored_name(&_name, prefix);
171	0	if (!_name.empty() && butil::back_char(_name) != '_') {
172	0	_name.push_back('_');
173	0	}
174	0	}
175	0	to_underscored_name(&_name, name);
176
177	0	if (count_exposed() > (size_t)FLAGS_bvar_max_multi_dimension_metric_number) {
178	0	LOG(ERROR) << "Too many metric seen, overflow detected, max metric count:" << FLAGS_bvar_max_multi_dimension_metric_number;
179	0	return -1;
180	0	}
181
182	0	MVarMapWithLock& m = get_mvar_map();
183	0	{
184	0	BAIDU_SCOPED_LOCK(m.mutex);
185	0	MVarEntry* entry = m.seek(_name);
186	0	if (entry == NULL) {
187	0	entry = &m[_name];
188	0	entry->var = this;
189	0	return 0;
190	0	}
191	0	}
192
193	0	RELEASE_ASSERT_VERBOSE(!FLAGS_bvar_abort_on_same_name,
194	0	"Abort due to name conflict");
195	0	if (!s_bvar_may_abort) {
196		// Mark name conflict occurs, If this conflict happens before
197		// initialization of bvar_abort_on_same_name, the validator will
198		// abort the program if needed.
199	0	s_bvar_may_abort = true;
200	0	}
201
202	0	LOG(WARNING) << "Already exposed `" << _name << "' whose describe is`"
203	0	<< get_description() << "'";
204	0	_name.clear();
205	0	return 0;
206	0	}
207
208	0	bool MVariable::hide() {
209	0	if (_name.empty()) {
210	0	return false;
211	0	}
212
213	0	MVarMapWithLock& m = get_mvar_map();
214	0	BAIDU_SCOPED_LOCK(m.mutex);
215	0	MVarEntry* entry = m.seek(_name);
216	0	if (entry) {
217	0	CHECK_EQ(1UL, m.erase(_name));
218	0	} else {
219	0	CHECK(false) << "`" << _name << "' must exist";
220	0	}
221	0	_name.clear();
222	0	return true;
223	0	}
224
225		#ifdef UNIT_TEST
226	0	void MVariable::hide_all() {
227	0	MVarMapWithLock& m = get_mvar_map();
228	0	BAIDU_SCOPED_LOCK(m.mutex);
229	0	m.clear();
230	0	}
231		#endif // end UNIT_TEST
232
233	0	size_t MVariable::count_exposed() {
234	0	MVarMapWithLock& m = get_mvar_map();
235	0	BAIDU_SCOPED_LOCK(m.mutex);
236	0	return m.size();
237	0	}
238
239	0	void MVariable::list_exposed(std::vector<std::string>* names) {
240	0	if (names == NULL) {
241	0	return;
242	0	}
243
244	0	names->clear();
245
246	0	MVarMapWithLock& mvar_map = get_mvar_map();
247	0	BAIDU_SCOPED_LOCK(mvar_map.mutex);
248	0	names->reserve(mvar_map.size());
249	0	for (MVarMap::const_iterator it = mvar_map.begin(); it != mvar_map.end(); ++it) {
250	0	names->push_back(it->first);
251	0	}
252	0	}
253
254	0	size_t MVariable::dump_exposed(Dumper* dumper, const DumpOptions* options) {
255	0	if (NULL == dumper) {
256	0	LOG(ERROR) << "Parameter[dumper] is NULL";
257	0	return -1;
258	0	}
259	0	DumpOptions opt;
260	0	if (options) {
261	0	opt = *options;
262	0	}
263	0	std::vector<std::string> mvars;
264	0	list_exposed(&mvars);
265	0	size_t n = 0;
266	0	for (auto& mvar : mvars) {
267	0	MVarMapWithLock& m = get_mvar_map();
268	0	BAIDU_SCOPED_LOCK(m.mutex);
269	0	MVarEntry* entry = m.seek(mvar);
270	0	if (entry) {
271	0	n += entry->var->dump(dumper, &opt);
272	0	}
273	0	if (n > static_cast<size_t>(FLAGS_bvar_max_dump_multi_dimension_metric_number)) {
274	0	LOG(WARNING) << "truncated because of \
275	0	exceed max dump multi dimension label number["
276	0	<< FLAGS_bvar_max_dump_multi_dimension_metric_number
277	0	<< "]";
278	0	break;
279	0	}
280	0	}
281	0	return n;
282	0	}
283
284		} // namespace bvar