Madan Jampani | 08822c4 | 2014-11-04 17:17:46 -0800 | [diff] [blame] | 1 | package org.onlab.onos.store.service.impl; |
| 2 | |
| 3 | import java.util.ArrayList; |
| 4 | import java.util.List; |
| 5 | import java.util.Map; |
| 6 | import java.util.Set; |
| 7 | |
| 8 | import net.kuujo.copycat.Command; |
| 9 | import net.kuujo.copycat.Query; |
| 10 | import net.kuujo.copycat.StateMachine; |
| 11 | |
| 12 | import org.onlab.onos.store.serializers.KryoSerializer; |
| 13 | import org.onlab.onos.store.service.ReadRequest; |
| 14 | import org.onlab.onos.store.service.ReadResult; |
Madan Jampani | 37c2e70 | 2014-11-04 18:11:10 -0800 | [diff] [blame] | 15 | import org.onlab.onos.store.service.VersionedValue; |
Madan Jampani | 08822c4 | 2014-11-04 17:17:46 -0800 | [diff] [blame] | 16 | import org.onlab.onos.store.service.WriteRequest; |
| 17 | import org.onlab.onos.store.service.WriteResult; |
| 18 | import org.onlab.util.KryoNamespace; |
| 19 | |
| 20 | import com.google.common.collect.Maps; |
| 21 | |
Madan Jampani | 686fa18 | 2014-11-04 23:16:27 -0800 | [diff] [blame] | 22 | /** |
| 23 | * StateMachine whose transitions are coordinated/replicated |
| 24 | * by Raft consensus. |
| 25 | * Each Raft cluster member has a instance of this state machine that is |
| 26 | * independently updated in lock step once there is consensus |
| 27 | * on the next transition. |
| 28 | */ |
Madan Jampani | 08822c4 | 2014-11-04 17:17:46 -0800 | [diff] [blame] | 29 | public class DatabaseStateMachine implements StateMachine { |
| 30 | |
| 31 | public static final KryoSerializer SERIALIZER = new KryoSerializer() { |
| 32 | @Override |
| 33 | protected void setupKryoPool() { |
| 34 | serializerPool = KryoNamespace.newBuilder() |
| 35 | .register(VersionedValue.class) |
| 36 | .register(State.class) |
Madan Jampani | 9b19a82 | 2014-11-04 21:37:13 -0800 | [diff] [blame] | 37 | .register(ClusterMessagingProtocol.COMMON) |
Madan Jampani | 08822c4 | 2014-11-04 17:17:46 -0800 | [diff] [blame] | 38 | .build() |
| 39 | .populate(1); |
| 40 | } |
| 41 | }; |
| 42 | |
| 43 | private State state = new State(); |
| 44 | |
| 45 | @Command |
| 46 | public boolean createTable(String tableName) { |
| 47 | return state.getTables().putIfAbsent(tableName, Maps.newHashMap()) == null; |
| 48 | } |
| 49 | |
| 50 | @Command |
| 51 | public boolean dropTable(String tableName) { |
| 52 | return state.getTables().remove(tableName) != null; |
| 53 | } |
| 54 | |
| 55 | @Command |
| 56 | public boolean dropAllTables() { |
| 57 | state.getTables().clear(); |
| 58 | return true; |
| 59 | } |
| 60 | |
| 61 | @Query |
| 62 | public Set<String> listTables() { |
| 63 | return state.getTables().keySet(); |
| 64 | } |
| 65 | |
| 66 | @Query |
| 67 | public List<InternalReadResult> read(List<ReadRequest> requests) { |
| 68 | List<InternalReadResult> results = new ArrayList<>(requests.size()); |
| 69 | for (ReadRequest request : requests) { |
| 70 | Map<String, VersionedValue> table = state.getTables().get(request.tableName()); |
| 71 | if (table == null) { |
| 72 | results.add(new InternalReadResult(InternalReadResult.Status.NO_SUCH_TABLE, null)); |
| 73 | continue; |
| 74 | } |
| 75 | VersionedValue value = table.get(request.key()); |
| 76 | results.add(new InternalReadResult( |
| 77 | InternalReadResult.Status.OK, |
| 78 | new ReadResult( |
| 79 | request.tableName(), |
| 80 | request.key(), |
| 81 | value))); |
| 82 | } |
| 83 | return results; |
| 84 | } |
| 85 | |
| 86 | @Command |
| 87 | public List<InternalWriteResult> write(List<WriteRequest> requests) { |
| 88 | boolean abort = false; |
| 89 | List<InternalWriteResult.Status> validationResults = new ArrayList<>(requests.size()); |
| 90 | for (WriteRequest request : requests) { |
| 91 | Map<String, VersionedValue> table = state.getTables().get(request.tableName()); |
| 92 | if (table == null) { |
| 93 | validationResults.add(InternalWriteResult.Status.NO_SUCH_TABLE); |
| 94 | abort = true; |
| 95 | continue; |
| 96 | } |
| 97 | VersionedValue value = table.get(request.key()); |
| 98 | if (value == null) { |
| 99 | if (request.oldValue() != null) { |
| 100 | validationResults.add(InternalWriteResult.Status.PREVIOUS_VALUE_MISMATCH); |
| 101 | abort = true; |
| 102 | continue; |
| 103 | } else if (request.previousVersion() >= 0) { |
| 104 | validationResults.add(InternalWriteResult.Status.OPTIMISTIC_LOCK_FAILURE); |
| 105 | abort = true; |
| 106 | continue; |
| 107 | } |
| 108 | } |
| 109 | if (request.previousVersion() >= 0 && value.version() != request.previousVersion()) { |
| 110 | validationResults.add(InternalWriteResult.Status.OPTIMISTIC_LOCK_FAILURE); |
| 111 | abort = true; |
| 112 | continue; |
| 113 | } |
| 114 | |
| 115 | validationResults.add(InternalWriteResult.Status.OK); |
| 116 | } |
| 117 | |
| 118 | List<InternalWriteResult> results = new ArrayList<>(requests.size()); |
| 119 | |
| 120 | if (abort) { |
| 121 | for (InternalWriteResult.Status validationResult : validationResults) { |
| 122 | if (validationResult == InternalWriteResult.Status.OK) { |
| 123 | results.add(new InternalWriteResult(InternalWriteResult.Status.ABORTED, null)); |
| 124 | } else { |
| 125 | results.add(new InternalWriteResult(validationResult, null)); |
| 126 | } |
| 127 | } |
| 128 | return results; |
| 129 | } |
| 130 | |
| 131 | for (WriteRequest request : requests) { |
| 132 | Map<String, VersionedValue> table = state.getTables().get(request.tableName()); |
| 133 | synchronized (table) { |
| 134 | VersionedValue previousValue = |
| 135 | table.put(request.key(), new VersionedValue(request.newValue(), state.nextVersion())); |
| 136 | results.add(new InternalWriteResult( |
| 137 | InternalWriteResult.Status.OK, |
| 138 | new WriteResult(request.tableName(), request.key(), previousValue))); |
| 139 | } |
| 140 | } |
| 141 | return results; |
| 142 | } |
| 143 | |
| 144 | public class State { |
| 145 | |
| 146 | private final Map<String, Map<String, VersionedValue>> tables = |
| 147 | Maps.newHashMap(); |
| 148 | private long versionCounter = 1; |
| 149 | |
| 150 | Map<String, Map<String, VersionedValue>> getTables() { |
| 151 | return tables; |
| 152 | } |
| 153 | |
| 154 | long nextVersion() { |
| 155 | return versionCounter++; |
| 156 | } |
| 157 | } |
| 158 | |
| 159 | @Override |
| 160 | public byte[] takeSnapshot() { |
| 161 | try { |
| 162 | return SERIALIZER.encode(state); |
| 163 | } catch (Exception e) { |
| 164 | e.printStackTrace(); |
| 165 | return null; |
| 166 | } |
| 167 | } |
| 168 | |
| 169 | @Override |
| 170 | public void installSnapshot(byte[] data) { |
| 171 | try { |
| 172 | this.state = SERIALIZER.decode(data); |
| 173 | } catch (Exception e) { |
| 174 | e.printStackTrace(); |
| 175 | } |
| 176 | } |
| 177 | } |