feat: Add IsMeasurement option to Column attribute for dynamic measur…

…ement names in POCO classes (#240)

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ### Features
 1. [#239](https://github.com/influxdata/influxdb-client-csharp/pull/239): Add support for Asynchronous queries [LINQ]
+1. [#240](https://github.com/influxdata/influxdb-client-csharp/pull/240): Add IsMeasurement option to Column attribute for dynamic measurement names in POCO classes
 
 ## 3.0.0 [2021-09-17]
 
@@ -11,7 +12,6 @@ Adds a `Type` overload for POCOs to `QueryAsync`. This will add `object ConvertT
 ### Features
 1. [#232](https://github.com/influxdata/influxdb-client-csharp/pull/232): Add a `Type` overload for POCOs to `QueryAsync`.
 1. [#233](https://github.com/influxdata/influxdb-client-csharp/pull/233): Add possibility to follow HTTP redirects
-1. [#239](https://github.com/influxdata/influxdb-client-csharp/pull/239): Add support for Asynchronous queries [LINQ]
 
 ### Bug Fixes
 1. [#236](https://github.com/influxdata/influxdb-client-csharp/pull/236): Mapping `long` type into Flux AST [LINQ]

Client.Core.Test/AbstractTest.cs

@@ -114,13 +114,13 @@ private async Task InfluxDbRequest(HttpRequestMessage request)
  try
  {
  var response = await httpClient.SendAsync(request);
- Assert.IsTrue(response.IsSuccessStatusCode);
+ Assert.IsTrue(response.IsSuccessStatusCode, $"Failed to make HTTP request: {response.ReasonPhrase}");
 
  Thread.Sleep(DefaultInfluxDBSleep);
  }
- catch (Exception)
+ catch (Exception e)
  {
- Assert.Fail("Unexpected exception");
+ Assert.Fail("Unexpected exception: " + e);
  }
  }
  }

Client.Core/Attributes.cs

@@ -5,6 +5,7 @@ namespace InfluxDB.Client.Core
  /// <summary>
  /// The annotation is used for mapping POCO class into line protocol.
  /// </summary>
+ [AttributeUsage(AttributeTargets.Class)]
  public sealed class Measurement : Attribute
  {
  public string Name { get; }
@@ -18,10 +19,13 @@ public Measurement(string name)
  /// <summary>
  /// The annotation is used to customize bidirectional mapping between POCO and Flux query result or Line Protocol.
  /// </summary>
+ [AttributeUsage(AttributeTargets.Property)]
  public sealed class Column : Attribute
  {
  public string Name { get; }
 
+ public bool IsMeasurement { get; set; }
+
  public bool IsTag { get; set; }
 
  public bool IsTimestamp { get; set; }

Client.Core/Flux/Internal/AttributesCache.cs

@@ -30,7 +30,7 @@ public PropertyInfo[] GetProperties(Type type)
  }
 
  /// <summary>
- /// Get Mapping attribute for specified propery.
+ /// Get Mapping attribute for specified property.
  /// </summary>
  /// <param name="property">property of DomainObject</param>
  /// <returns>Property Attribute</returns>

Client.Core/Flux/Internal/FluxResultMapper.cs

@@ -69,6 +69,10 @@ internal object ToPoco(FluxRecord record, Type type)
  {
  var attribute = _attributesCache.GetAttribute(property);
 
+ if (attribute != null && attribute.IsMeasurement)
+ {
+ SetFieldValue(poco, property, record.GetMeasurement());
+ }
  if (attribute != null && attribute.IsTimestamp)
  {
  SetFieldValue(poco, property, record.GetTime());

Client.Linq.Test/DomainObjects.cs

@@ -37,6 +37,18 @@ class SensorDateTimeOffset
  [Column(IsTimestamp = true)] public DateTimeOffset Timestamp { get; set; }
  }
 
+ class SensorWithCustomMeasurement
+ {
+ [Column(IsMeasurement = true)]
+ public string Measurement { get; set; }
+
+ [Column("sensor_id", IsTag = true)]
+ public string SensorId { get; set; }
+
+ [Column("data")]
+ public int Value { get; set; }
+ }
+
  class SensorCustom
  {
  public Guid Id { get; set; }

Client.Linq.Test/InfluxDBQueryVisitorTest.cs

@@ -428,6 +428,36 @@ where month11 > s.Timestamp
  }
  }
 
+ [Test]
+ public void ResultOperatorByMeasurement()
+ {
+ var settings = new QueryableOptimizerSettings
+ {
+ DropMeasurementColumn = false
+ };
+
+ var query = from s in InfluxDBQueryable<SensorWithCustomMeasurement>.Queryable("my-bucket", "my-org", _queryApi, settings)
+ where s.Value > 10
+ where s.Measurement == "my-measurement"
+ select s;
+ var visitor = BuildQueryVisitor(query);
+
+ const string expected = "start_shifted = int(v: time(v: p2))\n\nfrom(bucket: p1) " +
+ "|> range(start: time(v: start_shifted)) " +
+ "|> filter(fn: (r) => (r[\"_measurement\"] == p4)) " +
+ "|> pivot(rowKey:[\"_time\"], columnKey: [\"_field\"], valueColumn: \"_value\") " +
+ "|> drop(columns: [\"_start\", \"_stop\"]) " +
+ "|> filter(fn: (r) => (r[\"data\"] > p3))";
+
+ Assert.AreEqual(expected, visitor.BuildFluxQuery());
+
+ var ast = visitor.BuildFluxAST();
+
+ var measurementAssignment = ((OptionStatement)ast.Body[3]).Assignment as VariableAssignment;
+ Assert.AreEqual("p4", measurementAssignment?.Id.Name);
+ Assert.AreEqual("my-measurement", (measurementAssignment?.Init as StringLiteral)?.Value);
+ }
+
  [Test]
  public void TimestampAsDateTimeOffset()
  {

Client.Linq/IMemberNameResolver.cs

@@ -33,6 +33,7 @@ public interface IMemberNameResolver
 
  public enum MemberType
  {
+ Measurement,
  Tag,
  Field,
  Timestamp,
@@ -52,6 +53,11 @@ public MemberType ResolveMemberType(MemberInfo memberInfo)
 
  if (attribute != null)
  {
+ if (attribute.IsMeasurement)
+ {
+ return MemberType.Measurement;
+ }
+
  if (attribute.IsTag)
  {
  return MemberType.Tag;

Client.Linq/InfluxDBQueryable.cs

@@ -18,17 +18,50 @@ public class QueryableOptimizerSettings
  public QueryableOptimizerSettings()
  {
  QueryMultipleTimeSeries = false;
+ DropMeasurementColumn = true;
+ DropStartColumn = true;
+ DropStopColumn = true;
  }
 
  /// <summary>
  /// Gets or sets whether the drive is used to query multiple time series.
  /// Setting this variable to true will change how the produced Flux Query looks like:
  /// <list type="bullet">
- /// <item>appends <a href="https://docs.influxdata.com/influxdb/v2.0/reference/flux/stdlib/built-in/transformations/group/">group operator</a></item>
- /// <item>enable use default sorting: <i>sort(columns: ["_time"], desc: false)</i></item>
+ /// <item>Appends <a href="https://docs.influxdata.com/flux/v0.x/stdlib/universe/group/">group operator</a></item>
+ /// <item>Enable use default sorting: <i>sort(columns: ["_time"], desc: false)</i></item>
  /// </list>
  /// </summary>
  public bool QueryMultipleTimeSeries { get; set; }
+
+ /// <summary>
+ /// Gets or sets whether the _measurement column will be dropped from query results.
+ /// Setting this variable to true will change how the produced Flux Query looks like:
+ /// <list type="bullet">
+ /// <item>Appends <a href="https://docs.influxdata.com/flux/v0.x/stdlib/universe/drop/">drop operator</a></item>
+ /// <item>Drops the _measurement column: <i>drop(columns: ["_measurement"])</i></item>
+ /// </list>
+ /// </summary>
+ public bool DropMeasurementColumn { get; set; }
+
+ /// <summary>
+ /// Gets or sets whether the _start column will be dropped from query results.
+ /// Setting this variable to true will change how the produced Flux Query looks like:
+ /// <list type="bullet">
+ /// <item>Appends <a href="https://docs.influxdata.com/flux/v0.x/stdlib/universe/drop/">drop operator</a></item>
+ /// <item>Drops the _start column: <i>drop(columns: ["_start"])</i></item>
+ /// </list>
+ /// </summary>
+ public bool DropStartColumn { get; set; }
+
+ /// <summary>
+ /// Gets or sets whether the _stop column will be dropped from query results.
+ /// Setting this variable to true will change how the produced Flux Query looks like:
+ /// <list type="bullet">
+ /// <item>Appends <a href="https://docs.influxdata.com/flux/v0.x/stdlib/universe/drop/">drop operator</a></item>
+ /// <item>Drops the _stop column: <i>drop(columns: ["_stop"])</i></item>
+ /// </list>
+ /// </summary>
+ public bool DropStopColumn { get; set; }
  }
 
  /// <summary>

Client.Linq/Internal/Expressions/ColumnName.cs

@@ -18,6 +18,9 @@ public void AppendFlux(StringBuilder builder)
  {
  switch (_memberResolver.ResolveMemberType(_member))
  {
+ case MemberType.Measurement:
+ builder.Append("_measurement");
+ break;
  case MemberType.Timestamp:
  builder.Append("_time");
  break;

Client.Linq/Internal/Expressions/MeasurementColumnName.cs

@@ -0,0 +1,22 @@
+using System.Reflection;
+using System.Text;
+
+namespace InfluxDB.Client.Linq.Internal.Expressions
+{
+ internal class MeasurementColumnName : IExpressionPart
+ {
+ private readonly ColumnName _delegate;
+
+ internal MeasurementColumnName(MemberInfo member, IMemberNameResolver memberNameResolver)
+ {
+ _delegate = new ColumnName(member, memberNameResolver);
+ }
+
+ public void AppendFlux(StringBuilder builder)
+ {
+ builder.Append("r[\"");
+ _delegate.AppendFlux(builder);
+ builder.Append("\"]");
+ }
+ }
+}

Client.Linq/Internal/QueryAggregator.cs

@@ -155,12 +155,18 @@ internal string BuildFluxQuery(QueryableOptimizerSettings settings)
  BuildOperator("from", "bucket", _bucketAssignment),
  BuildRange(transforms),
  BuildFilter(_filterByTags),
- "pivot(rowKey:[\"_time\"], columnKey: [\"_field\"], valueColumn: \"_value\")",
- "drop(columns: [\"_start\", \"_stop\", \"_measurement\"])",
- settings.QueryMultipleTimeSeries ? "group()" : "",
- BuildFilter(_filterByFields)
+ "pivot(rowKey:[\"_time\"], columnKey: [\"_field\"], valueColumn: \"_value\")"
  };
 
+ var drop = BuildDrop(settings);
+ if (!string.IsNullOrEmpty(drop))
+ {
+ parts.Add(drop);
+ }
+
+ parts.Add(settings.QueryMultipleTimeSeries ? "group()" : "");
+ parts.Add(BuildFilter(_filterByFields));
+
  // https://docs.influxdata.com/influxdb/cloud/reference/flux/stdlib/built-in/transformations/sort/
  foreach (var ((column, columnVariable, descending, descendingVariable), index) in _orders.Select((value, i) => (value, i)))
  {
@@ -203,6 +209,33 @@ internal string BuildFluxQuery(QueryableOptimizerSettings settings)
  return query.ToString();
  }
 
+ private string BuildDrop(QueryableOptimizerSettings settings)
+ {
+ var columns = new List<string>();
+
+ if (settings.DropStartColumn)
+ {
+ columns.Add("\"_start\"");
+ }
+
+ if (settings.DropStopColumn)
+ {
+ columns.Add("\"_stop\"");
+ }
+
+ if (settings.DropMeasurementColumn)
+ {
+ columns.Add("\"_measurement\"");
+ }
+
+ if (columns.Count == 0)
+ {
+ return null;
+ }
+
+ return $"drop(columns: [{string.Join(", ", columns)}])";
+ }
+
  private string BuildRange(List<string> transforms)
  {
  string rangeStartShift = null;

Client.Linq/Internal/QueryExpressionTreeVisitor.cs

@@ -102,6 +102,9 @@ protected override Expression VisitMember(MemberExpression expression)
  {
  switch (_context.MemberResolver.ResolveMemberType(expression.Member))
  {
+ case MemberType.Measurement:
+ _expressionParts.Add(new MeasurementColumnName(expression.Member, _context.MemberResolver));
+ break;
  case MemberType.Timestamp:
  _expressionParts.Add(new TimeColumnName(expression.Member, _context.MemberResolver));
  break;

Client.Linq/Internal/QueryVisitor.cs

@@ -75,7 +75,7 @@ public override void VisitWhereClause(WhereClause whereClause, QueryModel queryM
  var tagFilter = new List<IExpressionPart>();
  var fieldFilter = new List<IExpressionPart>();
 
- // Map LINQ filter expresion to right place: range, tag filtering, field filtering
+ // Map LINQ filter expression to right place: range, tag filtering, field filtering
  foreach (var expression in expressions)
  {
  switch (expression)
@@ -86,6 +86,7 @@ public override void VisitWhereClause(WhereClause whereClause, QueryModel queryM
  break;
  // Tag
  case TagColumnName _:
+ case MeasurementColumnName _:
  tagFilter.Add(expression);
  break;
  // Field
@@ -187,7 +188,7 @@ private string ConcatExpression(IEnumerable<IExpressionPart> expressions)
  }).ToString();
  }
 
-  private void AddFilterByRange(List<IExpressionPart> rangeFilter)
+ private void AddFilterByRange(List<IExpressionPart> rangeFilter)
  {
  var rangeBinaryIndexes = Enumerable.Range(0, rangeFilter.Count)
  .Where(i => rangeFilter[i] is BinaryOperator)