// constructors
/// <summary>
/// Initializes a new instance of the <see cref="ReadPreference" /> class.
/// </summary>
/// <param name="mode">The read preference mode.</param>
/// <param name="tagSets">The tag sets.</param>
/// <param name="maxStaleness">The maximum staleness.</param>
/// <param name="hedge">The hedge.</param>
public ReadPreference(
ReadPreferenceMode mode,
IEnumerable <TagSet> tagSets = null,
TimeSpan?maxStaleness = null,
ReadPreferenceHedge hedge = null)
{
var tagSetsArray = tagSets == null ? __emptyTagSetsArray : tagSets.ToArray();
if (tagSetsArray.Length > 0)
{
Ensure.That(mode != ReadPreferenceMode.Primary, "TagSets cannot be used with ReadPreferenceMode Primary.", nameof(tagSets));
}
if (maxStaleness.HasValue)
{
Ensure.IsInfiniteOrGreaterThanZero(maxStaleness.Value, nameof(maxStaleness));
if (maxStaleness.Value > TimeSpan.Zero)
{
Ensure.That(maxStaleness.Value.Ticks % TimeSpan.TicksPerMillisecond == 0, "MaxStaleness must not have fractional seconds.", nameof(maxStaleness));
}
Ensure.That(mode != ReadPreferenceMode.Primary, "MaxStaleness cannot be used with ReadPreferenceMode Primary.", nameof(maxStaleness));
}
if (hedge != null)
{
Ensure.That(mode != ReadPreferenceMode.Primary, "Hedged reads cannot be used with ReadPreferenceMode Primary.", nameof(hedge));
}
_mode = mode;
_tagSets = tagSetsArray;
_maxStaleness = maxStaleness;
_hedge = hedge;
}
public void constructor_should_throw_when_hedge_is_not_null_and_mode_is_primary()
{
var hedge = new ReadPreferenceHedge(true);
var exception = Record.Exception(() => new ReadPreference(ReadPreferenceMode.Primary, hedge: hedge));
var argumentException = exception.Should().BeOfType <ArgumentException>().Subject;
argumentException.ParamName.Should().Be("hedge");
}
// public static methods
/// <summary>
/// Creates a new ReadPreference instance from a BsonDocument.
/// </summary>
/// <param name="document">The document.</param>
/// <returns>A ReadPreference.</returns>
public static ReadPreference FromBsonDocument(BsonDocument document)
{
ReadPreferenceMode mode = ReadPreferenceMode.Primary;
TimeSpan? maxStaleness = null;
List <TagSet> tagSets = null;
ReadPreferenceHedge hedge = null;
foreach (var element in document)
{
switch (element.Name)
{
case "mode":
mode = (ReadPreferenceMode)Enum.Parse(typeof(ReadPreferenceMode), element.Value.AsString, ignoreCase: true);
break;
case "tags":
tagSets = new List <TagSet>();
foreach (var tagsDocument in element.Value.AsBsonArray.Cast <BsonDocument>())
{
var tags = new List <Tag>();
foreach (var tagElement in tagsDocument)
{
var tag = new Tag(tagElement.Name, tagElement.Value.AsString);
tags.Add(tag);
}
var tagSet = new TagSet(tags);
tagSets.Add(tagSet);
}
break;
case "maxStaleness":
maxStaleness = element.Value.BsonType switch
{
BsonType.String => TimeSpanParser.Parse(element.Value.AsString),
_ => TimeSpan.FromSeconds(element.Value.ToDouble())
};
break;
case "maxStalenessSeconds":
maxStaleness = TimeSpan.FromSeconds(element.Value.ToDouble());
break;
case "hedge":
var hedgeEnabled = element.Value.AsBsonDocument["enabled"].AsBoolean;
hedge = new ReadPreferenceHedge(hedgeEnabled);
break;
default:
throw new ArgumentException($"Invalid element in ReadPreference document: {element.Name}.");
}
}
return(new ReadPreference(mode, tagSets, maxStaleness, hedge));
}
public void With_hedge_should_return_expected_result(
[Values(false, true)]
bool originalIsEnabled,
[Values(false, true)]
bool isEnabled)
{
var originalHedge = new ReadPreferenceHedge(isEnabled: originalIsEnabled);
var hedge = new ReadPreferenceHedge(isEnabled: isEnabled);
var subject = new ReadPreference(ReadPreferenceMode.Secondary, hedge: originalHedge);
var result = subject.With(hedge);
result.Hedge.Should().Be(hedge);
result.With(originalHedge).Should().Be(subject);
}
/// <summary>
/// Returns a new instance of ReadPreference with some values changed.
/// </summary>
/// <param name="hedge">The hedge.</param>
/// <returns>A new instance of ReadPreference.</returns>
public ReadPreference With(ReadPreferenceHedge hedge)
{
return(new ReadPreference(_mode, _tagSets, _maxStaleness, hedge));
}
