/// <summary>
/// Gets an open READ UNCOMMITTED connection using the specified connection string, optionally timing out on the initial connect.
/// </summary>
/// <param name="connectionString">The connection string to use for the connection.</param>
/// <param name="connectionTimeoutMs">(Optional) Milliseconds to wait to connect.</param>
/// <returns>A READ UNCOMMITTED connection to the specified connection string.</returns>
/// <exception cref="Exception">Throws if a connection isn't able to be made.</exception>
/// <exception cref="TimeoutException">Throws if a connection can't be made in <paramref name="connectionTimeoutMs"/>.</exception>
public static async Task <DbConnection> GetOpenAsync(string connectionString, int?connectionTimeoutMs = null)
{
var conn = new ProfiledDbConnection(new SqlConnection(connectionString), MiniProfiler.Current);
var tmpTimeout = connectionTimeoutMs.GetValueOrDefault(0);
if (connectionTimeoutMs.GetValueOrDefault(0) == 0)
{
await conn.OpenAsync().ConfigureAwait(false);
await conn.SetReadUncommittedAsync().ConfigureAwait(false);
}
else
{
// In the case of remote monitoring, the timeout will be at the NIC level, not responding to traffic,
// in that scenario, connection timeouts don't really do much, because they're never reached, the timeout happens
// before their timer starts. Because of that, we need to spin up our own overall timeout
using (MiniProfiler.Current.Step($"Opening Connection, Timeout: {conn.ConnectionTimeout}"))
using (var tokenSource = new CancellationTokenSource())
{
tokenSource.CancelAfter(connectionTimeoutMs.Value);
try
{
await conn.OpenAsync(tokenSource.Token).ConfigureAwait(false); // Throwing Null Refs
await conn.SetReadUncommittedAsync().ConfigureAwait(false);
}
catch (TaskCanceledException e)
{
conn.Close();
var csb = new SqlConnectionStringBuilder(connectionString);
var sqlException = $"Error opening connection to {csb.InitialCatalog} at {csb.DataSource}, timeout out at {connectionTimeoutMs.ToComma()} ms";
throw new Exception(sqlException, e);
}
catch (SqlException e)
{
conn.Close();
var csb = new SqlConnectionStringBuilder(connectionString);
var sqlException = $"Error opening connection to {csb.InitialCatalog} at {csb.DataSource}: {e.Message}";
throw new Exception(sqlException, e);
}
if (conn.State == ConnectionState.Connecting)
{
tokenSource.Cancel();
var b = new SqlConnectionStringBuilder {
ConnectionString = connectionString
};
throw new TimeoutException($"Timeout expired connecting to {b.InitialCatalog} on {b.DataSource} on in the alloted {connectionTimeoutMs.Value.ToComma()} ms");
}
}
}
return(conn);
}
