fix(linq): Flux AST for Tag parameters which are not String (#202)

Author: bednar

CHANGELOG.md

@@ -6,6 +6,7 @@
 
 ### Bug Fixes
 1. [#193](https://github.com/influxdata/influxdb-client-csharp/pull/193): Create services without API implementation
+1. [#202](https://github.com/influxdata/influxdb-client-csharp/pull/202): Flux AST for Tag parameters which are not `String` [LINQ]
 
 ## 1.18.0 [2021-04-30]
 

Client.Linq.Test/DomainObjects.cs

@@ -53,4 +53,20 @@ class SensorAttribute
         public string Name { get; set; }
         public string Value { get; set; }
     }
+    
+    [Measurement(nameof(TagIsNotDefinedAsString))]
+    class TagIsNotDefinedAsString
+    {
+        [Column(IsTag = true)]
+        public int Id { get; set; }
+
+        [Column(IsTag = true)]
+        public string Tag { get; set; }
+
+        [Column(nameof(Energy))]
+        public decimal Energy { get; set; }
+
+        [Column(IsTimestamp = true)]
+        public DateTime Timestamp { get; set; }
+    }
 }

Client.Linq.Test/InfluxDBQueryVisitorTest.cs

@@ -766,6 +766,46 @@ orderby s.Timestamp
             Assert.AreEqual(expected, ((InfluxDBQueryable<Sensor>) query).ToDebugQuery()._Query);
         }
 
+        [Test]
+        public void TagIsNotDefinedAsString()
+        {
+            var fromDateTime = new DateTime(2020, 10, 15, 8, 20, 15, DateTimeKind.Utc);
+            var queries = new[]
+            {
+                (
+                    from s in InfluxDBQueryable<TagIsNotDefinedAsString>.Queryable("my-bucket", "my-org", _queryApi)
+                    where s.Timestamp >= fromDateTime
+                    where s.Id == 123456
+                    select s,
+                    "(r[\"Id\"] == p4)"
+                ),
+                (
+                    from s in InfluxDBQueryable<TagIsNotDefinedAsString>.Queryable("my-bucket", "my-org", _queryApi)
+                    where s.Timestamp >= fromDateTime
+                    where 123456 == s.Id
+                    select s,
+                    "(p4 == r[\"Id\"])"
+                ),
+            };
+
+            foreach (var (queryable, expression) in queries)
+            {
+                var visitor = BuildQueryVisitor(queryable);
+
+                var expected = "start_shifted = int(v: time(v: p3))\n\n" +
+                               "from(bucket: p1) " +
+                               "|> range(start: time(v: start_shifted)) " +
+                               $"|> filter(fn: (r) => {expression}) " +
+                               "|> pivot(rowKey:[\"_time\"], columnKey: [\"_field\"], valueColumn: \"_value\") " +
+                               "|> drop(columns: [\"_start\", \"_stop\", \"_measurement\"])";
+                
+                Assert.AreEqual(expected, visitor.BuildFluxQuery());
+                var ast = visitor.BuildFluxAST();
+                Assert.AreEqual(fromDateTime, GetLiteral<DateTimeLiteral>(ast, 2).Value);
+                Assert.AreEqual("123456", GetLiteral<StringLiteral>(ast, 3).Value);
+            }
+        }
+
         private InfluxDBQueryVisitor BuildQueryVisitor(IQueryable queryable, Expression expression = null)
         {
             var queryExecutor = (InfluxDBQueryExecutor) ((DefaultQueryProvider) queryable.Provider).Executor;

Client.Linq/Internal/Expressions/AssignmentValue.cs

@@ -5,16 +5,16 @@ namespace InfluxDB.Client.Linq.Internal.Expressions
     internal class AssignmentValue: IExpressionPart
     {
         internal readonly object Value;
-        private readonly string _assignment;
+        internal readonly string Assignment;
         internal AssignmentValue(object value, string assignment)
         {
             Value = value;
-            _assignment = assignment;
+            Assignment = assignment;
         }
 
         public void AppendFlux(StringBuilder builder)
         {
-            builder.Append(_assignment);
+            builder.Append(Assignment);
         }
     }
 }

Client.Linq/Internal/QueryExpressionTreeVisitor.cs

@@ -185,7 +185,7 @@ private void NormalizeNamedField()
 
             NormalizeNamedField();
         }
-        
+
         private void NormalizeNamedFieldValue()
         {
             var index = _expressionParts
@@ -241,6 +241,33 @@ private void NormalizeNamedFieldValue()
             NormalizeNamedFieldValue();
         }
 
+        /// <summary>
+        /// Mark variables that are use to filter by tag by tag as tag.
+        /// </summary>
+        internal static void NormalizeTagsAssignments(List<IExpressionPart> parts, QueryGenerationContext context)
+        {
+            var indexes = Enumerable.Range(0, parts.Count)
+                .Where(i => parts[i] is BinaryOperator)
+                .ToList();
+
+            foreach (var index in indexes)
+            {
+                // "sensorId == 123456"
+                if (index >= 1 && parts[index - 1] is TagColumnName && parts[index + 1] is AssignmentValue)
+                {
+                    var assignmentValue = (AssignmentValue) parts[index + 1];
+                    context.Variables.VariableIsTag(assignmentValue.Assignment);
+                }
+
+                // "123456 == sensorId"
+                if (index >= 1 && parts[index - 1] is AssignmentValue && parts[index + 1] is TagColumnName)
+                {
+                    var assignmentValue = (AssignmentValue) parts[index - 1];
+                    context.Variables.VariableIsTag(assignmentValue.Assignment);
+                }
+            }
+        }
+
         /// <summary>
         /// Normalize generated expression.
         /// </summary>

Client.Linq/Internal/QueryVisitor.cs

@@ -109,6 +109,7 @@ public override void VisitWhereClause(WhereClause whereClause, QueryModel queryM
 
             QueryExpressionTreeVisitor.NormalizeExpressions(rangeFilter);
             QueryExpressionTreeVisitor.NormalizeExpressions(tagFilter);
+            QueryExpressionTreeVisitor.NormalizeTagsAssignments(tagFilter, _context);
             QueryExpressionTreeVisitor.NormalizeExpressions(fieldFilter);
 
             Debug.WriteLine("--- normalized LINQ expressions: ---");

Client.Linq/Internal/VariableAggregator.cs

@@ -14,18 +14,35 @@ internal string AddNamedVariable(object value)
             var variable = new NamedVariable
             {
                 Value = value,
-                Name = $"p{_variables.Count + 1}"
+                Name = $"p{_variables.Count + 1}",
+                IsTag = false
             };
             _variables.Add(variable);
             return variable.Name;
         }
 
+        /// <summary>
+        /// Mark variable with specified name as a Tag.
+        /// </summary>
+        /// <param name="variableName">variable name</param>
+        internal void VariableIsTag(string variableName)
+        {
+            foreach (var namedVariable in _variables.Where(it => it.Name.Equals(variableName)))
+            {
+                namedVariable.IsTag = true;
+            }
+        }
+
         internal List<Statement> GetStatements()
         {
             return _variables.Select(variable =>
             {
                 Expression literal;
-                if (variable.Value is int i)
+                if (variable.IsTag)
+                {
+                    literal = CreateStringLiteral(variable);
+                }
+                else if (variable.Value is int i)
                 {
                     literal = new IntegerLiteral("IntegerLiteral", Convert.ToString(i));
                 }
@@ -47,7 +64,7 @@ internal List<Statement> GetStatements()
                 }
                 else
                 {
-                    literal = new StringLiteral("StringLiteral", Convert.ToString(variable.Value));
+                    literal = CreateStringLiteral(variable);
                 }
 
                 var assignment = new VariableAssignment("VariableAssignment",
@@ -56,11 +73,17 @@ internal List<Statement> GetStatements()
                 return new OptionStatement("OptionStatement", assignment) as Statement;
             }).ToList();
         }
+
+        private StringLiteral CreateStringLiteral(NamedVariable variable)
+        {
+            return new StringLiteral("StringLiteral", Convert.ToString(variable.Value));
+        }
     }
 
     internal sealed class NamedVariable
     {
-        public string Name { get; set; }
-        public object Value { get; set; }
+        internal string Name { get; set; }
+        internal object Value { get; set; }
+        internal bool IsTag { get; set; }
     }
 }

Client.Linq/README.md

@@ -32,6 +32,8 @@ The library supports to use a LINQ expression to query the InfluxDB.
 - [How to debug output Flux Query](#how-to-debug-output-flux-query)
 
 ## Changelog
+### 1.19.0-dev.??? [???]
+  - Fix Flux AST for Tag parameters which are not `String`. See details - [#202](https://github.com/influxdata/influxdb-client-csharp/pull/202)
 ### 1.19.0-dev.3084 [2021-05-07]
   - optimize Flux Query for querying one time-series. See details - [#197](https://github.com/influxdata/influxdb-client-csharp/pull/197)
 ### 1.18.0-dev.2973 [2021-04-27]