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d60dfbe4 AM |
1 | /* |
2 | * Copyright (C) 2015 - EfficiOS Inc., Alexandre Montplaisir <alexmonthy@efficios.com> | |
3 | * Copyright (C) 2013 - David Goulet <dgoulet@efficios.com> | |
4 | * | |
5 | * This library is free software; you can redistribute it and/or modify it | |
6 | * under the terms of the GNU Lesser General Public License, version 2.1 only, | |
7 | * as published by the Free Software Foundation. | |
8 | * | |
9 | * This library is distributed in the hope that it will be useful, but WITHOUT | |
10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License | |
12 | * for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU Lesser General Public License | |
15 | * along with this library; if not, write to the Free Software Foundation, | |
16 | * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
17 | */ | |
18 | ||
19 | package org.lttng.ust.agent; | |
20 | ||
68a1ef73 | 21 | import java.util.Collection; |
d60dfbe4 | 22 | import java.util.HashSet; |
d60dfbe4 AM |
23 | import java.util.Map; |
24 | import java.util.NavigableMap; | |
25 | import java.util.Set; | |
26 | import java.util.concurrent.ConcurrentHashMap; | |
27 | import java.util.concurrent.ConcurrentSkipListMap; | |
28 | import java.util.concurrent.atomic.AtomicInteger; | |
29 | ||
3165c2f5 | 30 | import org.lttng.ust.agent.client.ILttngTcpClientListener; |
d60dfbe4 | 31 | import org.lttng.ust.agent.client.LttngTcpSessiondClient; |
4fb826b1 | 32 | import org.lttng.ust.agent.filter.FilterChangeNotifier; |
3daf5cba | 33 | import org.lttng.ust.agent.session.EventRule; |
d60dfbe4 AM |
34 | |
35 | /** | |
36 | * Base implementation of a {@link ILttngAgent}. | |
37 | * | |
38 | * @author Alexandre Montplaisir | |
39 | * @param <T> | |
40 | * The type of logging handler that should register to this agent | |
41 | */ | |
3165c2f5 AM |
42 | public abstract class AbstractLttngAgent<T extends ILttngHandler> |
43 | implements ILttngAgent<T>, ILttngTcpClientListener { | |
d60dfbe4 AM |
44 | |
45 | private static final String WILDCARD = "*"; | |
46 | private static final int INIT_TIMEOUT = 3; /* Seconds */ | |
47 | ||
48 | /** The handlers registered to this agent */ | |
49 | private final Set<T> registeredHandlers = new HashSet<T>(); | |
50 | ||
51 | /** | |
52 | * The trace events currently enabled in the sessions. | |
53 | * | |
54 | * The key represents the event name, the value is the ref count (how many | |
55 | * different sessions currently have this event enabled). Once the ref count | |
56 | * falls to 0, this means we can avoid sending log events through JNI | |
57 | * because nobody wants them. | |
58 | * | |
3daf5cba | 59 | * It uses a concurrent hash map, so that the {@link #isEventEnabled} and |
d60dfbe4 AM |
60 | * read methods do not need to take a synchronization lock. |
61 | */ | |
62 | private final Map<String, Integer> enabledEvents = new ConcurrentHashMap<String, Integer>(); | |
63 | ||
64 | /** | |
65 | * The trace events prefixes currently enabled in the sessions, which means | |
66 | * the event names finishing in *, like "abcd*". We track them separately | |
67 | * from the standard event names, so that we can use {@link String#equals} | |
68 | * and {@link String#startsWith} appropriately. | |
69 | * | |
70 | * We track the lone wildcard "*" separately, in {@link #enabledWildcards}. | |
71 | */ | |
72 | private final NavigableMap<String, Integer> enabledEventPrefixes = | |
73 | new ConcurrentSkipListMap<String, Integer>(); | |
74 | ||
75 | /** Number of sessions currently enabling the wildcard "*" event */ | |
76 | private final AtomicInteger enabledWildcards = new AtomicInteger(0); | |
77 | ||
8ab5c06b AM |
78 | /** |
79 | * The application contexts currently enabled in the tracing sessions. | |
80 | * | |
81 | * It is first indexed by context retriever, then by context name. This | |
82 | * allows to efficiently query all the contexts for a given retriever. | |
83 | * | |
84 | * Works similarly as {@link #enabledEvents}, but for app contexts (and with | |
85 | * an extra degree of indexing). | |
86 | * | |
87 | * TODO Could be changed to a Guava Table once/if we start using it. | |
88 | */ | |
89 | private final Map<String, Map<String, Integer>> enabledAppContexts = new ConcurrentHashMap<String, Map<String, Integer>>(); | |
90 | ||
d60dfbe4 AM |
91 | /** Tracing domain. Defined by the sub-classes via the constructor. */ |
92 | private final Domain domain; | |
93 | ||
94 | /* Lazy-loaded sessiond clients and their thread objects */ | |
95 | private LttngTcpSessiondClient rootSessiondClient = null; | |
96 | private LttngTcpSessiondClient userSessiondClient = null; | |
97 | private Thread rootSessiondClientThread = null; | |
98 | private Thread userSessiondClientThread = null; | |
99 | ||
100 | /** Indicates if this agent has been initialized. */ | |
101 | private boolean initialized = false; | |
102 | ||
103 | /** | |
104 | * Constructor. Should only be called by sub-classes via super(...); | |
105 | * | |
106 | * @param domain | |
107 | * The tracing domain of this agent. | |
108 | */ | |
109 | protected AbstractLttngAgent(Domain domain) { | |
110 | this.domain = domain; | |
111 | } | |
112 | ||
113 | @Override | |
114 | public Domain getDomain() { | |
115 | return domain; | |
116 | } | |
117 | ||
118 | @Override | |
119 | public void registerHandler(T handler) { | |
120 | synchronized (registeredHandlers) { | |
121 | if (registeredHandlers.isEmpty()) { | |
122 | /* | |
123 | * This is the first handler that registers, we will initialize | |
124 | * the agent. | |
125 | */ | |
126 | init(); | |
127 | } | |
128 | registeredHandlers.add(handler); | |
129 | } | |
130 | } | |
131 | ||
132 | @Override | |
133 | public void unregisterHandler(T handler) { | |
134 | synchronized (registeredHandlers) { | |
135 | registeredHandlers.remove(handler); | |
136 | if (registeredHandlers.isEmpty()) { | |
137 | /* There are no more registered handlers, close the connection. */ | |
138 | dispose(); | |
139 | } | |
140 | } | |
141 | } | |
142 | ||
143 | private void init() { | |
144 | /* | |
145 | * Only called from a synchronized (registeredHandlers) block, should | |
146 | * not need additional synchronization. | |
147 | */ | |
148 | if (initialized) { | |
149 | return; | |
150 | } | |
151 | String rootClientThreadName = "Root sessiond client started by agent: " + this.getClass().getSimpleName(); | |
152 | ||
3165c2f5 | 153 | rootSessiondClient = new LttngTcpSessiondClient(this, getDomain().value(), true); |
d60dfbe4 AM |
154 | rootSessiondClientThread = new Thread(rootSessiondClient, rootClientThreadName); |
155 | rootSessiondClientThread.setDaemon(true); | |
156 | rootSessiondClientThread.start(); | |
157 | ||
158 | String userClientThreadName = "User sessiond client started by agent: " + this.getClass().getSimpleName(); | |
159 | ||
3165c2f5 | 160 | userSessiondClient = new LttngTcpSessiondClient(this, getDomain().value(), false); |
d60dfbe4 AM |
161 | userSessiondClientThread = new Thread(userSessiondClient, userClientThreadName); |
162 | userSessiondClientThread.setDaemon(true); | |
163 | userSessiondClientThread.start(); | |
164 | ||
165 | /* Give the threads' registration a chance to end. */ | |
166 | if (!rootSessiondClient.waitForConnection(INIT_TIMEOUT)) { | |
167 | userSessiondClient.waitForConnection(INIT_TIMEOUT); | |
168 | } | |
169 | ||
170 | initialized = true; | |
171 | } | |
172 | ||
173 | /** | |
174 | * Dispose the agent | |
175 | */ | |
176 | private void dispose() { | |
177 | /* | |
178 | * Only called from a synchronized (registeredHandlers) block, should | |
179 | * not need additional synchronization. | |
180 | */ | |
181 | rootSessiondClient.close(); | |
182 | userSessiondClient.close(); | |
183 | ||
184 | try { | |
185 | rootSessiondClientThread.join(); | |
186 | userSessiondClientThread.join(); | |
187 | ||
188 | } catch (InterruptedException e) { | |
189 | e.printStackTrace(); | |
190 | } | |
191 | rootSessiondClient = null; | |
192 | rootSessiondClientThread = null; | |
193 | userSessiondClient = null; | |
194 | userSessiondClientThread = null; | |
195 | ||
196 | /* Reset all enabled event counts to 0 */ | |
197 | enabledEvents.clear(); | |
198 | enabledEventPrefixes.clear(); | |
199 | enabledWildcards.set(0); | |
200 | ||
201 | initialized = false; | |
d60dfbe4 AM |
202 | } |
203 | ||
3165c2f5 | 204 | @Override |
3daf5cba | 205 | public boolean eventEnabled(EventRule eventRule) { |
4fb826b1 AM |
206 | /* Notify the filter change manager of the command */ |
207 | FilterChangeNotifier.getInstance().addEventRule(eventRule); | |
208 | ||
3daf5cba AM |
209 | String eventName = eventRule.getEventName(); |
210 | ||
d60dfbe4 AM |
211 | if (eventName.equals(WILDCARD)) { |
212 | enabledWildcards.incrementAndGet(); | |
213 | return true; | |
214 | } | |
d60dfbe4 AM |
215 | if (eventName.endsWith(WILDCARD)) { |
216 | /* Strip the "*" from the name. */ | |
217 | String prefix = eventName.substring(0, eventName.length() - 1); | |
8ab5c06b | 218 | return incrementRefCount(prefix, enabledEventPrefixes); |
d60dfbe4 AM |
219 | } |
220 | ||
8ab5c06b | 221 | return incrementRefCount(eventName, enabledEvents); |
d60dfbe4 AM |
222 | } |
223 | ||
3165c2f5 | 224 | @Override |
d60dfbe4 | 225 | public boolean eventDisabled(String eventName) { |
4fb826b1 AM |
226 | /* Notify the filter change manager of the command */ |
227 | FilterChangeNotifier.getInstance().removeEventRules(eventName); | |
228 | ||
d60dfbe4 AM |
229 | if (eventName.equals(WILDCARD)) { |
230 | int newCount = enabledWildcards.decrementAndGet(); | |
231 | if (newCount < 0) { | |
232 | /* Event was not enabled, bring the count back to 0 */ | |
233 | enabledWildcards.incrementAndGet(); | |
234 | return false; | |
235 | } | |
cbaa5167 | 236 | return true; |
d60dfbe4 AM |
237 | } |
238 | ||
239 | if (eventName.endsWith(WILDCARD)) { | |
240 | /* Strip the "*" from the name. */ | |
241 | String prefix = eventName.substring(0, eventName.length() - 1); | |
8ab5c06b AM |
242 | return decrementRefCount(prefix, enabledEventPrefixes); |
243 | } | |
244 | ||
245 | return decrementRefCount(eventName, enabledEvents); | |
246 | } | |
247 | ||
248 | @Override | |
249 | public boolean appContextEnabled(String contextRetrieverName, String contextName) { | |
250 | synchronized (enabledAppContexts) { | |
251 | Map<String, Integer> retrieverMap = enabledAppContexts.get(contextRetrieverName); | |
252 | if (retrieverMap == null) { | |
253 | /* There is no submap for this retriever, let's create one. */ | |
254 | retrieverMap = new ConcurrentHashMap<String, Integer>(); | |
255 | enabledAppContexts.put(contextRetrieverName, retrieverMap); | |
256 | } | |
257 | ||
258 | return incrementRefCount(contextName, retrieverMap); | |
d60dfbe4 | 259 | } |
8ab5c06b AM |
260 | } |
261 | ||
262 | @Override | |
263 | public boolean appContextDisabled(String contextRetrieverName, String contextName) { | |
264 | synchronized (enabledAppContexts) { | |
265 | Map<String, Integer> retrieverMap = enabledAppContexts.get(contextRetrieverName); | |
266 | if (retrieverMap == null) { | |
267 | /* There was no submap for this retriever, invalid command? */ | |
268 | return false; | |
269 | } | |
270 | ||
271 | boolean ret = decrementRefCount(contextName, retrieverMap); | |
d60dfbe4 | 272 | |
8ab5c06b AM |
273 | /* If the submap is now empty we can remove it from the main map. */ |
274 | if (retrieverMap.isEmpty()) { | |
275 | enabledAppContexts.remove(contextRetrieverName); | |
276 | } | |
277 | ||
278 | return ret; | |
279 | } | |
d60dfbe4 AM |
280 | } |
281 | ||
68a1ef73 AM |
282 | /* |
283 | * Implementation of this method is domain-specific. | |
284 | */ | |
3165c2f5 | 285 | @Override |
68a1ef73 | 286 | public abstract Collection<String> listAvailableEvents(); |
3165c2f5 | 287 | |
d60dfbe4 AM |
288 | @Override |
289 | public boolean isEventEnabled(String eventName) { | |
290 | /* If at least one session enabled the "*" wildcard, send the event */ | |
291 | if (enabledWildcards.get() > 0) { | |
292 | return true; | |
293 | } | |
294 | ||
295 | /* Check if at least one session wants this exact event name */ | |
296 | if (enabledEvents.containsKey(eventName)) { | |
297 | return true; | |
298 | } | |
299 | ||
300 | /* Look in the enabled prefixes if one of them matches the event */ | |
301 | String potentialMatch = enabledEventPrefixes.floorKey(eventName); | |
302 | if (potentialMatch != null && eventName.startsWith(potentialMatch)) { | |
303 | return true; | |
304 | } | |
305 | ||
306 | return false; | |
307 | } | |
308 | ||
8ab5c06b AM |
309 | @Override |
310 | public Collection<Map.Entry<String, Map<String, Integer>>> getEnabledAppContexts() { | |
311 | return enabledAppContexts.entrySet(); | |
312 | } | |
313 | ||
314 | private static boolean incrementRefCount(String key, Map<String, Integer> refCountMap) { | |
315 | synchronized (refCountMap) { | |
316 | Integer count = refCountMap.get(key); | |
d60dfbe4 AM |
317 | if (count == null) { |
318 | /* This is the first instance of this event being enabled */ | |
8ab5c06b | 319 | refCountMap.put(key, Integer.valueOf(1)); |
d60dfbe4 AM |
320 | return true; |
321 | } | |
322 | if (count.intValue() <= 0) { | |
323 | /* It should not have been in the map in the first place! */ | |
324 | throw new IllegalStateException(); | |
325 | } | |
326 | /* The event was already enabled, increment its refcount */ | |
8ab5c06b | 327 | refCountMap.put(key, Integer.valueOf(count.intValue() + 1)); |
d60dfbe4 AM |
328 | return true; |
329 | } | |
330 | } | |
331 | ||
8ab5c06b AM |
332 | private static boolean decrementRefCount(String key, Map<String, Integer> refCountMap) { |
333 | synchronized (refCountMap) { | |
334 | Integer count = refCountMap.get(key); | |
d60dfbe4 AM |
335 | if (count == null || count.intValue() <= 0) { |
336 | /* | |
337 | * The sessiond asked us to disable an event that was not | |
338 | * enabled previously. Command error? | |
339 | */ | |
340 | return false; | |
341 | } | |
342 | if (count.intValue() == 1) { | |
343 | /* | |
344 | * This is the last instance of this event being disabled, | |
345 | * remove it from the map so that we stop sending it. | |
346 | */ | |
8ab5c06b | 347 | refCountMap.remove(key); |
d60dfbe4 AM |
348 | return true; |
349 | } | |
350 | /* | |
351 | * Other sessions are still looking for this event, simply decrement | |
352 | * its refcount. | |
353 | */ | |
8ab5c06b | 354 | refCountMap.put(key, Integer.valueOf(count.intValue() - 1)); |
d60dfbe4 AM |
355 | return true; |
356 | } | |
357 | } | |
358 | } | |
359 |