Madan Jampani | 12390c1 | 2014-11-12 00:35:56 -0800 | [diff] [blame] | 1 | package org.onlab.onos.store.service.impl; |
| 2 | |
Madan Jampani | a88d1f5 | 2014-11-14 16:45:24 -0800 | [diff] [blame] | 3 | import static org.slf4j.LoggerFactory.getLogger; |
| 4 | |
Madan Jampani | 12390c1 | 2014-11-12 00:35:56 -0800 | [diff] [blame] | 5 | import java.util.UUID; |
| 6 | import java.util.concurrent.CompletableFuture; |
| 7 | import java.util.concurrent.ExecutionException; |
| 8 | import java.util.concurrent.TimeUnit; |
| 9 | import java.util.concurrent.TimeoutException; |
| 10 | import java.util.concurrent.atomic.AtomicBoolean; |
| 11 | |
| 12 | import org.joda.time.DateTime; |
| 13 | import org.onlab.onos.cluster.ClusterService; |
| 14 | import org.onlab.onos.store.service.DatabaseService; |
| 15 | import org.onlab.onos.store.service.Lock; |
Madan Jampani | a88d1f5 | 2014-11-14 16:45:24 -0800 | [diff] [blame] | 16 | import org.slf4j.Logger; |
Madan Jampani | 12390c1 | 2014-11-12 00:35:56 -0800 | [diff] [blame] | 17 | |
| 18 | /** |
| 19 | * A distributed lock implementation. |
| 20 | */ |
| 21 | public class DistributedLock implements Lock { |
| 22 | |
Madan Jampani | a88d1f5 | 2014-11-14 16:45:24 -0800 | [diff] [blame] | 23 | private final Logger log = getLogger(getClass()); |
| 24 | |
| 25 | private static final long MAX_WAIT_TIME_MS = 100000000L; |
| 26 | |
Madan Jampani | 12390c1 | 2014-11-12 00:35:56 -0800 | [diff] [blame] | 27 | private final DistributedLockManager lockManager; |
| 28 | private final DatabaseService databaseService; |
| 29 | private final String path; |
| 30 | private DateTime lockExpirationTime; |
| 31 | private AtomicBoolean isLocked = new AtomicBoolean(false); |
| 32 | private byte[] lockId; |
| 33 | |
| 34 | public DistributedLock( |
| 35 | String path, |
| 36 | DatabaseService databaseService, |
| 37 | ClusterService clusterService, |
| 38 | DistributedLockManager lockManager) { |
| 39 | |
| 40 | this.path = path; |
| 41 | this.databaseService = databaseService; |
| 42 | this.lockManager = lockManager; |
| 43 | this.lockId = |
| 44 | (UUID.randomUUID().toString() + "::" + clusterService.getLocalNode().id().toString()).getBytes(); |
| 45 | } |
| 46 | |
| 47 | @Override |
| 48 | public String path() { |
| 49 | return path; |
| 50 | } |
| 51 | |
| 52 | @Override |
| 53 | public void lock(int leaseDurationMillis) { |
Madan Jampani | 12390c1 | 2014-11-12 00:35:56 -0800 | [diff] [blame] | 54 | if (isLocked() && lockExpirationTime.isAfter(DateTime.now().plusMillis(leaseDurationMillis))) { |
| 55 | // Nothing to do. |
| 56 | // Current expiration time is beyond what is requested. |
| 57 | return; |
| 58 | } else { |
Madan Jampani | a88d1f5 | 2014-11-14 16:45:24 -0800 | [diff] [blame] | 59 | tryLock(MAX_WAIT_TIME_MS, leaseDurationMillis); |
Madan Jampani | 12390c1 | 2014-11-12 00:35:56 -0800 | [diff] [blame] | 60 | } |
| 61 | } |
| 62 | |
| 63 | @Override |
| 64 | public boolean tryLock(int leaseDurationMillis) { |
Madan Jampani | a88d1f5 | 2014-11-14 16:45:24 -0800 | [diff] [blame] | 65 | if (databaseService.putIfAbsent( |
Madan Jampani | c22123d | 2014-11-12 02:12:19 -0800 | [diff] [blame] | 66 | DistributedLockManager.ONOS_LOCK_TABLE_NAME, |
| 67 | path, |
Madan Jampani | a88d1f5 | 2014-11-14 16:45:24 -0800 | [diff] [blame] | 68 | lockId)) { |
| 69 | isLocked.set(true); |
| 70 | lockExpirationTime = DateTime.now().plusMillis(leaseDurationMillis); |
| 71 | return true; |
| 72 | } |
| 73 | return false; |
Madan Jampani | 12390c1 | 2014-11-12 00:35:56 -0800 | [diff] [blame] | 74 | } |
| 75 | |
| 76 | @Override |
| 77 | public boolean tryLock( |
| 78 | long waitTimeMillis, |
| 79 | int leaseDurationMillis) { |
Madan Jampani | a88d1f5 | 2014-11-14 16:45:24 -0800 | [diff] [blame] | 80 | if (tryLock(leaseDurationMillis)) { |
| 81 | return true; |
Madan Jampani | 12390c1 | 2014-11-12 00:35:56 -0800 | [diff] [blame] | 82 | } |
Madan Jampani | a88d1f5 | 2014-11-14 16:45:24 -0800 | [diff] [blame] | 83 | |
| 84 | CompletableFuture<DateTime> future = |
| 85 | lockManager.lockIfAvailable(this, waitTimeMillis, leaseDurationMillis); |
| 86 | try { |
| 87 | lockExpirationTime = future.get(waitTimeMillis, TimeUnit.MILLISECONDS); |
| 88 | return true; |
| 89 | } catch (ExecutionException | InterruptedException e) { |
| 90 | log.error("Encountered an exception trying to acquire lock for " + path, e); |
| 91 | // TODO: ExecutionException could indicate something |
| 92 | // wrong with the backing database. |
| 93 | // Throw an exception? |
| 94 | return false; |
| 95 | } catch (TimeoutException e) { |
| 96 | log.debug("Timed out waiting to acquire lock for {}", path); |
| 97 | return false; |
| 98 | } |
Madan Jampani | 12390c1 | 2014-11-12 00:35:56 -0800 | [diff] [blame] | 99 | } |
| 100 | |
| 101 | @Override |
| 102 | public boolean isLocked() { |
| 103 | if (isLocked.get()) { |
| 104 | // We rely on local information to check |
Madan Jampani | a88d1f5 | 2014-11-14 16:45:24 -0800 | [diff] [blame] | 105 | // if the lock expired. |
Madan Jampani | 12390c1 | 2014-11-12 00:35:56 -0800 | [diff] [blame] | 106 | // This should should make this call |
Madan Jampani | a88d1f5 | 2014-11-14 16:45:24 -0800 | [diff] [blame] | 107 | // light weight, while still retaining the |
Madan Jampani | 12390c1 | 2014-11-12 00:35:56 -0800 | [diff] [blame] | 108 | // safety guarantees. |
| 109 | if (DateTime.now().isAfter(lockExpirationTime)) { |
| 110 | isLocked.set(false); |
| 111 | return false; |
Madan Jampani | f5d263b | 2014-11-13 10:04:40 -0800 | [diff] [blame] | 112 | } else { |
| 113 | return true; |
Madan Jampani | 12390c1 | 2014-11-12 00:35:56 -0800 | [diff] [blame] | 114 | } |
| 115 | } |
Madan Jampani | f5d263b | 2014-11-13 10:04:40 -0800 | [diff] [blame] | 116 | return false; |
Madan Jampani | 12390c1 | 2014-11-12 00:35:56 -0800 | [diff] [blame] | 117 | } |
| 118 | |
| 119 | @Override |
| 120 | public void unlock() { |
| 121 | if (!isLocked()) { |
| 122 | return; |
| 123 | } else { |
Madan Jampani | a88d1f5 | 2014-11-14 16:45:24 -0800 | [diff] [blame] | 124 | if (databaseService.removeIfValueMatches(DistributedLockManager.ONOS_LOCK_TABLE_NAME, path, lockId)) { |
| 125 | isLocked.set(false); |
| 126 | } |
Madan Jampani | 12390c1 | 2014-11-12 00:35:56 -0800 | [diff] [blame] | 127 | } |
| 128 | } |
| 129 | |
| 130 | @Override |
| 131 | public boolean extendExpiration(int leaseDurationMillis) { |
Madan Jampani | a88d1f5 | 2014-11-14 16:45:24 -0800 | [diff] [blame] | 132 | if (!isLocked()) { |
| 133 | log.warn("Ignoring request to extend expiration for lock {}." |
| 134 | + " ExtendExpiration must be called for locks that are already acquired.", path); |
Pavlin Radoslavov | 20ded69 | 2014-11-17 16:03:15 -0800 | [diff] [blame^] | 135 | return false; |
Madan Jampani | a88d1f5 | 2014-11-14 16:45:24 -0800 | [diff] [blame] | 136 | } |
| 137 | |
| 138 | if (databaseService.putIfValueMatches( |
| 139 | DistributedLockManager.ONOS_LOCK_TABLE_NAME, |
| 140 | path, |
| 141 | lockId, |
| 142 | lockId)) { |
| 143 | lockExpirationTime = DateTime.now().plusMillis(leaseDurationMillis); |
| 144 | log.debug("Succeeded in extending lock {} expiration time to {}", lockExpirationTime); |
Madan Jampani | 12390c1 | 2014-11-12 00:35:56 -0800 | [diff] [blame] | 145 | return true; |
| 146 | } else { |
Madan Jampani | a88d1f5 | 2014-11-14 16:45:24 -0800 | [diff] [blame] | 147 | log.info("Failed to extend expiration for {}", path); |
| 148 | return false; |
Madan Jampani | 12390c1 | 2014-11-12 00:35:56 -0800 | [diff] [blame] | 149 | } |
| 150 | } |
Madan Jampani | a88d1f5 | 2014-11-14 16:45:24 -0800 | [diff] [blame] | 151 | } |