/// <summary>
/// Will check for a predefined keyspace and table to see if there is a lock.
/// Otherwise, always returns true, because the lock is granted at table level.
/// </summary>
public override bool TryAcquireApplicationLock()
{
string clusterLockKeyspaceName = "cluster_lock";
string clusterLockTableName = "lock";
if (Configuration.ConfigurationFileExists())
{
var clusterLock = JSON.Parse(Configuration.GetConfiguration()).Linq
.SingleOrDefault(x => x.Key.Equals("clusterLock", StringComparison.OrdinalIgnoreCase)).Value?.Linq
.ToDictionary(x => x.Key, x => x.Value.Value, StringComparer.OrdinalIgnoreCase);
clusterLockKeyspaceName = clusterLock !.GetValue("defaultClusterLockKeyspace", clusterLockKeyspaceName) !;
clusterLockTableName = clusterLock !.GetValue("defaultClusterLockTable", clusterLockTableName) !;
}
try
{
return(WrappedConnection.QueryForLong($"select count(locked) from {clusterLockKeyspaceName}.{clusterLockTableName}") == 0);
}
catch (EvolveException ex)
when(ex?.InnerException?.GetType().ToString() == "Cassandra.InvalidQueryException")
{
//These error messages are very specific to Cassandra's drivers and could change
return(ex.Message.StartsWith($"keyspace {clusterLockKeyspaceName} does not exist", StringComparison.OrdinalIgnoreCase) ||
ex.Message.StartsWith($"unconfigured table {clusterLockTableName}", StringComparison.OrdinalIgnoreCase) ||
ex.Message.StartsWith($"table {clusterLockTableName} does not exist", StringComparison.OrdinalIgnoreCase));
}
}
/// <summary>
/// Will chekc for a predefined keyspace and table to see if there is a lock.
/// Otherwise, always returns true, because the lock is granted at table level.
/// <see cref="CassandraMetadataTable.TryLock"/>
/// </summary>
public override bool TryAcquireApplicationLock()
{
const string DefaultClusterLockKeyspaceName = "cluster_lock";
const string DefaultClusterLockTableName = "lock";
var clusterLockKeyspaceName = DefaultClusterLockKeyspaceName;
var clusterLockTableName = DefaultClusterLockTableName;
if (Configuration.ConfigurationFileExists())
{
var configuration = Configuration.GetConfiguration()
.FromJson <Dictionary <string, Dictionary <string, object> > >()
.GetValue("clusterLock", new Dictionary <string, object>());
clusterLockKeyspaceName = configuration.GetValue("defaultClusterLockKeyspace", DefaultClusterLockKeyspaceName) as string;
clusterLockTableName = configuration.GetValue("defaultClusterLockTable", DefaultClusterLockTableName) as string;
}
try
{
return(WrappedConnection.QueryForLong($"select count(locked) from {clusterLockKeyspaceName}.{clusterLockTableName}") == 0);
}
catch (EvolveException ex)
when(ex?.InnerException.GetType().ToString() == "Cassandra.InvalidQueryException")
{
//These error messages are very specific to Cassandra's drivers and could change
if (ex.Message.StartsWith($"Keyspace {clusterLockKeyspaceName} does not exist") ||
ex.Message.StartsWith($"unconfigured table {clusterLockTableName}"))
{
return(true);
}
else
{
return(true);
}
}
}
public override bool ReleaseApplicationLock() => WrappedConnection.QueryForLong($"SELECT RELEASE_LOCK('{LOCK_ID}');") == 1;
public override bool TryAcquireApplicationLock() => WrappedConnection.QueryForLong($"SELECT GET_LOCK('{LOCK_ID}', 0);") == 1;
