2 * Copyright (C) 2015 - EfficiOS Inc., Alexandre Montplaisir <alexmonthy@efficios.com>
3 * Copyright (C) 2013 - David Goulet <dgoulet@efficios.com>
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.
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
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
19 package org
.lttng
.ust
.agent
;
21 import java
.util
.Collection
;
22 import java
.util
.HashSet
;
24 import java
.util
.NavigableMap
;
26 import java
.util
.concurrent
.ConcurrentHashMap
;
27 import java
.util
.concurrent
.ConcurrentSkipListMap
;
28 import java
.util
.concurrent
.atomic
.AtomicInteger
;
30 import org
.lttng
.ust
.agent
.client
.ILttngTcpClientListener
;
31 import org
.lttng
.ust
.agent
.client
.LttngTcpSessiondClient
;
32 import org
.lttng
.ust
.agent
.filter
.FilterChangeNotifier
;
33 import org
.lttng
.ust
.agent
.session
.EventRule
;
36 * Base implementation of a {@link ILttngAgent}.
38 * @author Alexandre Montplaisir
40 * The type of logging handler that should register to this agent
42 public abstract class AbstractLttngAgent
<T
extends ILttngHandler
>
43 implements ILttngAgent
<T
>, ILttngTcpClientListener
{
45 private static final String WILDCARD
= "*";
46 private static final int INIT_TIMEOUT
= 3; /* Seconds */
48 /** The handlers registered to this agent */
49 private final Set
<T
> registeredHandlers
= new HashSet
<T
>();
52 * The trace events currently enabled in the sessions.
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.
59 * It uses a concurrent hash map, so that the {@link #isEventEnabled} and
60 * read methods do not need to take a synchronization lock.
62 private final Map
<String
, Integer
> enabledEvents
= new ConcurrentHashMap
<String
, Integer
>();
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.
70 * We track the lone wildcard "*" separately, in {@link #enabledWildcards}.
72 private final NavigableMap
<String
, Integer
> enabledEventPrefixes
=
73 new ConcurrentSkipListMap
<String
, Integer
>();
75 /** Number of sessions currently enabling the wildcard "*" event */
76 private final AtomicInteger enabledWildcards
= new AtomicInteger(0);
79 * The application contexts currently enabled in the tracing sessions.
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.
84 * Works similarly as {@link #enabledEvents}, but for app contexts (and with
85 * an extra degree of indexing).
87 * TODO Could be changed to a Guava Table once/if we start using it.
89 private final Map
<String
, Map
<String
, Integer
>> enabledAppContexts
= new ConcurrentHashMap
<String
, Map
<String
, Integer
>>();
91 /** Tracing domain. Defined by the sub-classes via the constructor. */
92 private final Domain domain
;
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;
100 /** Indicates if this agent has been initialized. */
101 private boolean initialized
= false;
104 * Constructor. Should only be called by sub-classes via super(...);
107 * The tracing domain of this agent.
109 protected AbstractLttngAgent(Domain domain
) {
110 this.domain
= domain
;
114 public Domain
getDomain() {
119 public void registerHandler(T handler
) {
120 synchronized (registeredHandlers
) {
121 if (registeredHandlers
.isEmpty()) {
123 * This is the first handler that registers, we will initialize
128 registeredHandlers
.add(handler
);
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. */
143 private void init() {
145 * Only called from a synchronized (registeredHandlers) block, should
146 * not need additional synchronization.
151 String rootClientThreadName
= "Root sessiond client started by agent: " + this.getClass().getSimpleName();
153 rootSessiondClient
= new LttngTcpSessiondClient(this, getDomain().value(), true);
154 rootSessiondClientThread
= new Thread(rootSessiondClient
, rootClientThreadName
);
155 rootSessiondClientThread
.setDaemon(true);
156 rootSessiondClientThread
.start();
158 String userClientThreadName
= "User sessiond client started by agent: " + this.getClass().getSimpleName();
160 userSessiondClient
= new LttngTcpSessiondClient(this, getDomain().value(), false);
161 userSessiondClientThread
= new Thread(userSessiondClient
, userClientThreadName
);
162 userSessiondClientThread
.setDaemon(true);
163 userSessiondClientThread
.start();
165 /* Give the threads' registration a chance to end. */
166 if (!rootSessiondClient
.waitForConnection(INIT_TIMEOUT
)) {
167 userSessiondClient
.waitForConnection(INIT_TIMEOUT
);
176 private void dispose() {
178 * Only called from a synchronized (registeredHandlers) block, should
179 * not need additional synchronization.
181 rootSessiondClient
.close();
182 userSessiondClient
.close();
185 rootSessiondClientThread
.join();
186 userSessiondClientThread
.join();
188 } catch (InterruptedException e
) {
191 rootSessiondClient
= null;
192 rootSessiondClientThread
= null;
193 userSessiondClient
= null;
194 userSessiondClientThread
= null;
196 /* Reset all enabled event counts to 0 */
197 enabledEvents
.clear();
198 enabledEventPrefixes
.clear();
199 enabledWildcards
.set(0);
201 enabledAppContexts
.clear();
207 public boolean eventEnabled(EventRule eventRule
) {
208 /* Notify the filter change manager of the command */
209 FilterChangeNotifier
.getInstance().addEventRule(eventRule
);
211 String eventName
= eventRule
.getEventName();
213 if (eventName
.equals(WILDCARD
)) {
214 enabledWildcards
.incrementAndGet();
217 if (eventName
.endsWith(WILDCARD
)) {
218 /* Strip the "*" from the name. */
219 String prefix
= eventName
.substring(0, eventName
.length() - 1);
220 return incrementRefCount(prefix
, enabledEventPrefixes
);
223 return incrementRefCount(eventName
, enabledEvents
);
227 public boolean eventDisabled(String eventName
) {
228 /* Notify the filter change manager of the command */
229 FilterChangeNotifier
.getInstance().removeEventRules(eventName
);
231 if (eventName
.equals(WILDCARD
)) {
232 int newCount
= enabledWildcards
.decrementAndGet();
234 /* Event was not enabled, bring the count back to 0 */
235 enabledWildcards
.incrementAndGet();
241 if (eventName
.endsWith(WILDCARD
)) {
242 /* Strip the "*" from the name. */
243 String prefix
= eventName
.substring(0, eventName
.length() - 1);
244 return decrementRefCount(prefix
, enabledEventPrefixes
);
247 return decrementRefCount(eventName
, enabledEvents
);
251 public boolean appContextEnabled(String contextRetrieverName
, String contextName
) {
252 synchronized (enabledAppContexts
) {
253 Map
<String
, Integer
> retrieverMap
= enabledAppContexts
.get(contextRetrieverName
);
254 if (retrieverMap
== null) {
255 /* There is no submap for this retriever, let's create one. */
256 retrieverMap
= new ConcurrentHashMap
<String
, Integer
>();
257 enabledAppContexts
.put(contextRetrieverName
, retrieverMap
);
260 return incrementRefCount(contextName
, retrieverMap
);
265 public boolean appContextDisabled(String contextRetrieverName
, String contextName
) {
266 synchronized (enabledAppContexts
) {
267 Map
<String
, Integer
> retrieverMap
= enabledAppContexts
.get(contextRetrieverName
);
268 if (retrieverMap
== null) {
269 /* There was no submap for this retriever, invalid command? */
273 boolean ret
= decrementRefCount(contextName
, retrieverMap
);
275 /* If the submap is now empty we can remove it from the main map. */
276 if (retrieverMap
.isEmpty()) {
277 enabledAppContexts
.remove(contextRetrieverName
);
285 * Implementation of this method is domain-specific.
288 public abstract Collection
<String
> listAvailableEvents();
291 public boolean isEventEnabled(String eventName
) {
292 /* If at least one session enabled the "*" wildcard, send the event */
293 if (enabledWildcards
.get() > 0) {
297 /* Check if at least one session wants this exact event name */
298 if (enabledEvents
.containsKey(eventName
)) {
302 /* Look in the enabled prefixes if one of them matches the event */
303 String potentialMatch
= enabledEventPrefixes
.floorKey(eventName
);
304 if (potentialMatch
!= null && eventName
.startsWith(potentialMatch
)) {
312 public Collection
<Map
.Entry
<String
, Map
<String
, Integer
>>> getEnabledAppContexts() {
313 return enabledAppContexts
.entrySet();
316 private static boolean incrementRefCount(String key
, Map
<String
, Integer
> refCountMap
) {
317 synchronized (refCountMap
) {
318 Integer count
= refCountMap
.get(key
);
320 /* This is the first instance of this event being enabled */
321 refCountMap
.put(key
, Integer
.valueOf(1));
324 if (count
.intValue() <= 0) {
325 /* It should not have been in the map in the first place! */
326 throw new IllegalStateException();
328 /* The event was already enabled, increment its refcount */
329 refCountMap
.put(key
, Integer
.valueOf(count
.intValue() + 1));
334 private static boolean decrementRefCount(String key
, Map
<String
, Integer
> refCountMap
) {
335 synchronized (refCountMap
) {
336 Integer count
= refCountMap
.get(key
);
337 if (count
== null || count
.intValue() <= 0) {
339 * The sessiond asked us to disable an event that was not
340 * enabled previously. Command error?
344 if (count
.intValue() == 1) {
346 * This is the last instance of this event being disabled,
347 * remove it from the map so that we stop sending it.
349 refCountMap
.remove(key
);
353 * Other sessions are still looking for this event, simply decrement
356 refCountMap
.put(key
, Integer
.valueOf(count
.intValue() - 1));