Github user ivakegg commented on a diff in the pull request: https://github.com/apache/accumulo/pull/253#discussion_r129962182 --- Diff: server/base/src/main/java/org/apache/accumulo/server/fs/PerTableVolumeChooser.java --- @@ -18,61 +18,146 @@ import java.util.concurrent.ConcurrentHashMap; -import org.apache.accumulo.core.client.impl.Table; +import org.apache.accumulo.core.client.AccumuloException; +import org.apache.accumulo.core.conf.AccumuloConfiguration; import org.apache.accumulo.core.conf.Property; import org.apache.accumulo.server.client.HdfsZooInstance; import org.apache.accumulo.server.conf.ServerConfigurationFactory; import org.apache.accumulo.server.conf.TableConfiguration; +import org.apache.accumulo.start.classloader.vfs.AccumuloVFSClassLoader; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; /** - * A {@link VolumeChooser} that delegates to another volume chooser based on the presence of an experimental table property, - * {@link Property#TABLE_VOLUME_CHOOSER}. If it isn't found, defaults back to {@link RandomVolumeChooser}. + * A {@link VolumeChooser} that delegates to another volume chooser based on other properties: table.custom.volume.chooser for tables, and + * general.custom.scoped.volume.chooser for scopes. general.custor.{scope}.volume.chooser can override the system wide setting for + * general.custom.scoped.volume.chooser. At the this this was written, the only known scope was "logger". */ public class PerTableVolumeChooser implements VolumeChooser { - - private final VolumeChooser fallbackVolumeChooser = new RandomVolumeChooser(); + private static final Logger log = LoggerFactory.getLogger(PerTableVolumeChooser.class); // TODO Add hint of expected size to construction, see ACCUMULO-3410 /* Track VolumeChooser instances so they can keep state. */ - private final ConcurrentHashMap<Table.ID,VolumeChooser> tableSpecificChooser = new ConcurrentHashMap<>(); + private final ConcurrentHashMap<String,VolumeChooser> tableSpecificChooser = new ConcurrentHashMap<>(); + private final ConcurrentHashMap<String,VolumeChooser> scopeSpecificChooser = new ConcurrentHashMap<>(); + private final RandomVolumeChooser randomChooser = new RandomVolumeChooser(); + // TODO has to be lazily initialized currently because of the reliance on HdfsZooInstance. see ACCUMULO-3411 private volatile ServerConfigurationFactory serverConfs; + public static final String TABLE_VOLUME_CHOOSER = Property.TABLE_ARBITRARY_PROP_PREFIX.getKey() + "volume.chooser"; + + public static final String SCOPED_VOLUME_CHOOSER(String scope) { + return Property.GENERAL_ARBITRARY_PROP_PREFIX.getKey() + scope + ".volume.chooser"; + } + + public static final String DEFAULT_SCOPED_VOLUME_CHOOSER = SCOPED_VOLUME_CHOOSER("scoped"); + @Override - public String choose(VolumeChooserEnvironment env, String[] options) { - VolumeChooser chooser = null; - if (env.hasTableId()) { - // This local variable is an intentional component of the single-check idiom. - ServerConfigurationFactory localConf = serverConfs; - if (localConf == null) { - // If we're under contention when first getting here we'll throw away some initializations. - localConf = new ServerConfigurationFactory(HdfsZooInstance.getInstance()); - serverConfs = localConf; + public String choose(VolumeChooserEnvironment env, String[] options) throws AccumuloException { + if (log.isTraceEnabled()) { + log.trace("PerTableVolumeChooser.choose"); + } + VolumeChooser chooser; + if (!env.hasTableId() && !env.hasScope()) { + // Should only get here during Initialize. Configurations are not yet available. + return randomChooser.choose(env, options); + } + + ServerConfigurationFactory localConf = loadConf(); + if (env.hasScope()) { + // use the system configuration + chooser = getVolumeChooserForNonTable(env, localConf); + } else { // if (env.hasTableId()) { + // use the table configuration + chooser = getVolumeChooserForTable(env, localConf); + } + + return chooser.choose(env, options); + } + + private VolumeChooser getVolumeChooserForTable(VolumeChooserEnvironment env, ServerConfigurationFactory localConf) throws AccumuloException { + if (log.isTraceEnabled()) { + log.trace("Looking up property " + TABLE_VOLUME_CHOOSER + " for Table id: " + env.getTableId()); + } + final TableConfiguration tableConf = localConf.getTableConfiguration(env.getTableId()); + String clazz = tableConf.get(TABLE_VOLUME_CHOOSER); + + return createVolumeChooser(clazz, TABLE_VOLUME_CHOOSER, env.getTableId().canonicalID(), tableSpecificChooser); + } + + private VolumeChooser getVolumeChooserForNonTable(VolumeChooserEnvironment env, ServerConfigurationFactory localConf) throws AccumuloException { + String property = SCOPED_VOLUME_CHOOSER(env.getScope()); + + if (log.isTraceEnabled()) { + log.trace("Looking up property: " + property); + } + + AccumuloConfiguration systemConfiguration = localConf.getSystemConfiguration(); + String clazz = systemConfiguration.get(property); + // only if the custom property is not set to we fallback to the table volume chooser setting --- End diff -- oops, missed that comment. re: scopes. If the scopes were in an enum then this might be cleaner. I will look into that but perhaps that should be a separate ticket.
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