Fix: pipelines: string ops on missing attribs in pipeline filters should not spam warnings (#4049)

* chore: add test validating collector doesn't spam logs for string ops on missing attributes

* fix: pipelines filter: check if attrib is not nil before running string operator

* chore: do a nil check for all but == and != ops

pkg/query-service/app/logparsingpipeline/pipelineBuilder_test.go

@@ -420,3 +420,65 @@ func TestResourceFiltersWork(t *testing.T) {
 
 	require.Equal(result[0].Attributes_string["test"], "test-value")
 }
+
+func TestPipelineFilterWithStringOpsShouldNotSpamWarningsIfAttributeIsMissing(t *testing.T) {
+	require := require.New(t)
+
+	for _, operator := range []v3.FilterOperator{
+		v3.FilterOperatorContains,
+		v3.FilterOperatorNotContains,
+		v3.FilterOperatorRegex,
+		v3.FilterOperatorNotRegex,
+	} {
+		testPipeline := Pipeline{
+			OrderId: 1,
+			Name:    "pipeline1",
+			Alias:   "pipeline1",
+			Enabled: true,
+			Filter: &v3.FilterSet{
+				Operator: "AND",
+				Items: []v3.FilterItem{
+					{
+						Key: v3.AttributeKey{
+							Key:      "service",
+							DataType: v3.AttributeKeyDataTypeString,
+							Type:     v3.AttributeKeyTypeResource,
+						},
+						Operator: operator,
+						Value:    "nginx",
+					},
+				},
+			},
+			Config: []PipelineOperator{
+				{
+					ID:      "add",
+					Type:    "add",
+					Enabled: true,
+					Name:    "add",
+					Field:   "attributes.test",
+					Value:   "test-value",
+				},
+			},
+		}
+
+		testLog := model.SignozLog{
+			Timestamp:         uint64(time.Now().UnixNano()),
+			Body:              "test log",
+			Attributes_string: map[string]string{},
+			Resources_string:  map[string]string{},
+			SeverityText:      entry.Info.String(),
+			SeverityNumber:    uint8(entry.Info),
+			SpanID:            "",
+			TraceID:           "",
+		}
+
+		result, collectorWarnAndErrorLogs, err := SimulatePipelinesProcessing(
+			context.Background(),
+			[]Pipeline{testPipeline},
+			[]model.SignozLog{testLog},
+		)
+		require.Nil(err)
+		require.Equal(0, len(collectorWarnAndErrorLogs), strings.Join(collectorWarnAndErrorLogs, "\n"))
+		require.Equal(1, len(result))
+	}
+}

pkg/query-service/queryBuilderToExpr/queryBuilderToExpr.go

@@ -64,6 +64,11 @@ func Parse(filters *v3.FilterSet) (string, error) {
 			filter = fmt.Sprintf("%s %s %s", exprFormattedValue(v.Key.Key), logOperatorsToExpr[v.Operator], getTypeName(v.Key.Type))
 		default:
 			filter = fmt.Sprintf("%s %s %s", name, logOperatorsToExpr[v.Operator], exprFormattedValue(v.Value))
+
+			// Avoid running operators on nil values
+			if v.Operator != v3.FilterOperatorEqual && v.Operator != v3.FilterOperatorNotEqual {
+				filter = fmt.Sprintf("%s != nil && %s", name, filter)
+			}
 		}
 
 		// check if the filter is a correct expression language