Add Duplicate function (#575)

* Add duplicate schema mutation

query/docs/SPEC.md

@@ -1145,6 +1145,26 @@ Additionally exactly two columns must be provided to the `columns` property.
 Count is an aggregate operation.
 For each aggregated column, it outputs the number of non null records as an integer.
 
+#### Duplicate 
+Duplicate will duplicate a specified column in a table
+
+Duplicate has the following properties:
+
+* `column` string
+	The column to duplicate
+* `as` string
+	The name that should be assigned to the duplicate column
+
+Example usage:
+
+Duplicate column `server` under the name `host`:
+```
+from(db: "telegraf")
+	|> range(start:-5m)
+	|> filter(fn: (r) => r._measurement == "cpu")
+	|> duplicate(column: "host", as: "server")
+```
+
 ##### Integral
 
 Integral is an aggregate operation.

query/functions/schema_functions.go

@@ -15,6 +15,7 @@ import (
 const RenameKind = "rename"
 const DropKind = "drop"
 const KeepKind = "keep"
+const DuplicateKind = "duplicate"
 
 type RenameOpSpec struct {
 	Cols map[string]string            `json:"columns"`
@@ -31,6 +32,11 @@ type KeepOpSpec struct {
 	Predicate *semantic.FunctionExpression `json:"fn"`
 }
 
+type DuplicateOpSpec struct {
+	Col string `json:"columns"`
+	As  string `json:"as"`
+}
+
 // The base kind for SchemaMutations
 const SchemaMutationKind = "SchemaMutation"
 
@@ -95,6 +101,15 @@ var Registrars = []MutationRegistrar{
 		Create: createKeepOpSpec,
 		New:    newKeepOp,
 	},
+	{
+		Kind: DuplicateKind,
+		Args: map[string]semantic.Type{
+			"column": semantic.String,
+			"as":     semantic.String,
+		},
+		Create: createDuplicateOpSpec,
+		New:    newDuplicateOp,
+	},
 }
 
 func init() {
@@ -257,6 +272,27 @@ func createKeepOpSpec(args query.Arguments, a *query.Administration) (query.Oper
 	}, nil
 }
 
+func createDuplicateOpSpec(args query.Arguments, a *query.Administration) (query.OperationSpec, error) {
+	if err := a.AddParentFromArgs(args); err != nil {
+		return nil, err
+	}
+
+	col, err := args.GetRequiredString("column")
+	if err != nil {
+		return nil, err
+	}
+
+	newName, err := args.GetRequiredString("as")
+	if err != nil {
+		return nil, err
+	}
+
+	return &DuplicateOpSpec{
+		Col: col,
+		As:  newName,
+	}, nil
+}
+
 func newRenameOp() query.OperationSpec {
 	return new(RenameOpSpec)
 }
@@ -281,6 +317,14 @@ func (s *KeepOpSpec) Kind() query.OperationKind {
 	return KeepKind
 }
 
+func newDuplicateOp() query.OperationSpec {
+	return new(DuplicateOpSpec)
+}
+
+func (s *DuplicateOpSpec) Kind() query.OperationKind {
+	return DuplicateKind
+}
+
 func (s *RenameOpSpec) Copy() SchemaMutation {
 	newCols := make(map[string]string, len(s.Cols))
 	for k, v := range s.Cols {
@@ -317,6 +361,13 @@ func (s *KeepOpSpec) Copy() SchemaMutation {
 	}
 }
 
+func (s *DuplicateOpSpec) Copy() SchemaMutation {
+	return &DuplicateOpSpec{
+		Col: s.Col,
+		As:  s.As,
+	}
+}
+
 func (s *RenameOpSpec) Mutator() (SchemaMutator, error) {
 	m, err := NewRenameMutator(s)
 	if err != nil {
@@ -341,6 +392,14 @@ func (s *KeepOpSpec) Mutator() (SchemaMutator, error) {
 	return m, nil
 }
 
+func (s *DuplicateOpSpec) Mutator() (SchemaMutator, error) {
+	m, err := NewDuplicateMutator(s)
+	if err != nil {
+		return nil, err
+	}
+	return m, nil
+}
+
 type SchemaMutationProcedureSpec struct {
 	Mutations []SchemaMutation
 }

query/functions/schema_functions_test.go

@@ -17,7 +17,7 @@ import (
 	"github.com/influxdata/platform/query/querytest"
 )
 
-func TestDropRenameKeep_NewQueries(t *testing.T) {
+func TestSchemaMutions_NewQueries(t *testing.T) {
 	tests := []querytest.NewQueryTestCase{
 		{
 			Name: "test rename query",
@@ -111,6 +111,37 @@ func TestDropRenameKeep_NewQueries(t *testing.T) {
 				},
 			},
 		},
+		{
+			Name: "test duplicate query",
+			Raw:  `from(db:"mydb") |> duplicate(column: "col1", as: "col1_new") |> sum()`,
+			Want: &query.Spec{
+				Operations: []*query.Operation{
+					{
+						ID: "from0",
+						Spec: &functions.FromOpSpec{
+							Database: "mydb",
+						},
+					},
+					{
+						ID: "duplicate1",
+						Spec: &functions.DuplicateOpSpec{
+							Col: "col1",
+							As:  "col1_new",
+						},
+					},
+					{
+						ID: "sum2",
+						Spec: &functions.SumOpSpec{
+							AggregateConfig: execute.DefaultAggregateConfig,
+						},
+					},
+				},
+				Edges: []query.Edge{
+					{Parent: "from0", Child: "duplicate1"},
+					{Parent: "duplicate1", Child: "sum2"},
+				},
+			},
+		},
 		{
 			Name: "test drop query fn param",
 			Raw:  `from(db:"mydb") |> drop(fn: (col) => col =~ /reg*/) |> sum()`,
@@ -246,7 +277,14 @@ func TestDropRenameKeep_NewQueries(t *testing.T) {
 			Want:    nil,
 			WantErr: true,
 		},
+		{
+			Name:    "test duplicate query invalid",
+			Raw:     `from(db:"mydb") |> duplicate(columns: ["a", "b"], n: -1) |> sum()`,
+			Want:    nil,
+			WantErr: true,
+		},
 	}
+
 	for _, tc := range tests {
 		tc := tc
 		t.Run(tc.Name, func(t *testing.T) {
@@ -367,6 +405,42 @@ func TestDropRenameKeep_Process(t *testing.T) {
 				},
 			}},
 		},
+		{
+			name: "duplicate single col",
+			spec: &functions.SchemaMutationProcedureSpec{
+				Mutations: []functions.SchemaMutation{
+					&functions.DuplicateOpSpec{
+						Col: "a",
+						As:  "a_1",
+					},
+				},
+			},
+			data: []query.Table{&executetest.Table{
+				ColMeta: []query.ColMeta{
+					{Label: "a", Type: query.TFloat},
+					{Label: "b", Type: query.TFloat},
+					{Label: "c", Type: query.TFloat},
+				},
+				Data: [][]interface{}{
+					{1.0, 2.0, 3.0},
+					{11.0, 12.0, 13.0},
+					{21.0, 22.0, 23.0},
+				},
+			}},
+			want: []*executetest.Table{{
+				ColMeta: []query.ColMeta{
+					{Label: "a", Type: query.TFloat},
+					{Label: "a_1", Type: query.TFloat},
+					{Label: "b", Type: query.TFloat},
+					{Label: "c", Type: query.TFloat},
+				},
+				Data: [][]interface{}{
+					{1.0, 1.0, 2.0, 3.0},
+					{11.0, 11.0, 12.0, 13.0},
+					{21.0, 21.0, 22.0, 23.0},
+				},
+			}},
+		},
 		{
 			name: "rename map fn (col) => name",
 			spec: &functions.SchemaMutationProcedureSpec{
@@ -604,6 +678,31 @@ func TestDropRenameKeep_Process(t *testing.T) {
 			want:    []*executetest.Table(nil),
 			wantErr: errors.New(`keep error: column "no_exist" doesn't exist`),
 		},
+		{
+			name: "duplicate no exist",
+			spec: &functions.SchemaMutationProcedureSpec{
+				Mutations: []functions.SchemaMutation{
+					&functions.DuplicateOpSpec{
+						Col: "no_exist",
+						As:  "no_exist_2",
+					},
+				},
+			},
+			data: []query.Table{&executetest.Table{
+				ColMeta: []query.ColMeta{
+					{Label: "server1", Type: query.TFloat},
+					{Label: "local", Type: query.TFloat},
+					{Label: "server2", Type: query.TFloat},
+				},
+				Data: [][]interface{}{
+					{1.0, 2.0, 3.0},
+					{11.0, 12.0, 13.0},
+					{21.0, 22.0, 23.0},
+				},
+			}},
+			want:    []*executetest.Table(nil),
+			wantErr: errors.New(`duplicate error: column "no_exist" doesn't exist`),
+		},
 		{
 			name: "rename group key",
 			spec: &functions.SchemaMutationProcedureSpec{

query/functions/schema_mutators.go

@@ -88,6 +88,13 @@ func toStringSet(arr []string) map[string]bool {
 	return set
 }
 
+func checkCol(label string, cols []query.ColMeta) error {
+	if execute.ColIdx(label, cols) < 0 {
+		return fmt.Errorf(`column "%s" doesn't exist`, label)
+	}
+	return nil
+}
+
 type RenameMutator struct {
 	Cols      map[string]string
 	Fn        compiler.Func
@@ -120,17 +127,6 @@ func NewRenameMutator(qs query.OperationSpec) (*RenameMutator, error) {
 	return m, nil
 }
 
-func (m *RenameMutator) checkColumnReferences(cols []query.ColMeta) error {
-	if m.Cols != nil {
-		for c := range m.Cols {
-			if execute.ColIdx(c, cols) < 0 {
-				return fmt.Errorf(`rename error: column "%s" doesn't exist`, c)
-			}
-		}
-	}
-	return nil
-}
-
 func (m *RenameMutator) renameCol(col *query.ColMeta) error {
 	if col == nil {
 		return errors.New("rename error: cannot rename nil column")
@@ -150,8 +146,17 @@ func (m *RenameMutator) renameCol(col *query.ColMeta) error {
 	return nil
 }
 
+func (m *RenameMutator) checkColumns(tableCols []query.ColMeta) error {
+	for c := range m.Cols {
+		if err := checkCol(c, tableCols); err != nil {
+			return errors.Wrap(err, "rename error")
+		}
+	}
+	return nil
+}
+
 func (m *RenameMutator) Mutate(ctx *BuilderContext) error {
-	if err := m.checkColumnReferences(ctx.Cols()); err != nil {
+	if err := m.checkColumns(ctx.Cols()); err != nil {
 		return err
 	}
 
@@ -225,21 +230,23 @@ func NewDropKeepMutator(qs query.OperationSpec) (*DropKeepMutator, error) {
 	return m, nil
 }
 
-func (m *DropKeepMutator) checkColumnReferences(cols []query.ColMeta) error {
+func (m *DropKeepMutator) checkColumns(tableCols []query.ColMeta) error {
 	if m.DropCols != nil {
 		for c := range m.DropCols {
-			if execute.ColIdx(c, cols) < 0 {
-				return fmt.Errorf(`drop error: column "%s" doesn't exist`, c)
+			if err := checkCol(c, tableCols); err != nil {
+				return errors.Wrap(err, "drop error")
 			}
 		}
 	}
+
 	if m.KeepCols != nil {
 		for c := range m.KeepCols {
-			if execute.ColIdx(c, cols) < 0 {
-				return fmt.Errorf(`keep error: column "%s" doesn't exist`, c)
+			if err := checkCol(c, tableCols); err != nil {
+				return errors.Wrap(err, "keep error")
 			}
 		}
 	}
+
 	return nil
 }
 
@@ -282,7 +289,7 @@ func (m *DropKeepMutator) keepToDropCols(cols []query.ColMeta) {
 }
 
 func (m *DropKeepMutator) Mutate(ctx *BuilderContext) error {
-	if err := m.checkColumnReferences(ctx.Cols()); err != nil {
+	if err := m.checkColumns(ctx.Cols()); err != nil {
 		return err
 	}
 
@@ -318,6 +325,55 @@ func (m *DropKeepMutator) Mutate(ctx *BuilderContext) error {
 	return nil
 }
 
+type DuplicateMutator struct {
+	Col string
+	As  string
+}
+
+func NewDuplicateMutator(qs query.OperationSpec) (*DuplicateMutator, error) {
+	s, ok := qs.(*DuplicateOpSpec)
+	if !ok {
+		return nil, fmt.Errorf("invalid spec type %T", qs)
+	}
+
+	return &DuplicateMutator{
+		Col: s.Col,
+		As:  s.As,
+	}, nil
+}
+
+func (m *DuplicateMutator) Mutate(ctx *BuilderContext) error {
+	if err := checkCol(m.Col, ctx.Cols()); err != nil {
+		return errors.Wrap(err, "duplicate error")
+	}
+
+	newCols := make([]query.ColMeta, 0, len(ctx.Cols())+1)
+	newColMap := make([]int, 0, len(ctx.Cols())+1)
+	oldColMap := ctx.ColMap()
+
+	for i, c := range ctx.Cols() {
+		newCols = append(newCols, c)
+		newColMap = append(newColMap, oldColMap[i])
+
+		if c.Label == m.Col {
+			newCols = append(newCols, duplicate(c, m.As))
+			newColMap = append(newColMap, oldColMap[i])
+		}
+	}
+
+	ctx.TableColumns = newCols
+	ctx.ColIdxMap = newColMap
+
+	return nil
+}
+
+func duplicate(col query.ColMeta, dupName string) query.ColMeta {
+	return query.ColMeta{
+		Type:  col.Type,
+		Label: dupName,
+	}
+}
+
 // TODO: determine pushdown rules
 /*
 func (s *SchemaMutationProcedureSpec) PushDownRules() []plan.PushDownRule {

query/functions/testdata/duplicate.flux

@@ -0,0 +1,3 @@
+from(db: "test")
+	|> range(start:2018-05-22T19:53:26Z)
+	|> duplicate(column: "host", as: "host_new")

query/functions/testdata/duplicate.in.csv

@@ -0,0 +1,16 @@
+#datatype,string,long,dateTime:RFC3339,dateTime:RFC3339,dateTime:RFC3339,double,string,string,string,string
+#group,false,false,false,false,false,false,true,true,true,true
+#default,_result,,,,,,,,,
+,result,table,_start,_stop,_time,_value,_field,_measurement,cpu,host
+,,0,2018-05-22T19:53:24.421470485Z,2018-05-22T19:54:24.421470485Z,2018-05-22T19:53:26Z,0,usage_guest,cpu,cpu-total,host.local
+,,0,2018-05-22T19:53:24.421470485Z,2018-05-22T19:54:24.421470485Z,2018-05-22T19:53:36Z,0,usage_guest,cpu,cpu-total,host.local
+,,0,2018-05-22T19:53:24.421470485Z,2018-05-22T19:54:24.421470485Z,2018-05-22T19:53:46Z,0,usage_guest,cpu,cpu-total,host.local
+,,0,2018-05-22T19:53:24.421470485Z,2018-05-22T19:54:24.421470485Z,2018-05-22T19:53:56Z,0,usage_guest,cpu,cpu-total,host.local
+,,0,2018-05-22T19:53:24.421470485Z,2018-05-22T19:54:24.421470485Z,2018-05-22T19:54:06Z,0,usage_guest,cpu,cpu-total,host.local
+,,0,2018-05-22T19:53:24.421470485Z,2018-05-22T19:54:24.421470485Z,2018-05-22T19:54:16Z,0,usage_guest,cpu,cpu-total,host.local
+,,1,2018-05-22T19:53:24.421470485Z,2018-05-22T19:54:24.421470485Z,2018-05-22T19:53:26Z,0,usage_guest_nice,cpu,cpu-total,host.local
+,,1,2018-05-22T19:53:24.421470485Z,2018-05-22T19:54:24.421470485Z,2018-05-22T19:53:36Z,0,usage_guest_nice,cpu,cpu-total,host.local
+,,1,2018-05-22T19:53:24.421470485Z,2018-05-22T19:54:24.421470485Z,2018-05-22T19:53:46Z,0,usage_guest_nice,cpu,cpu-total,host.local
+,,1,2018-05-22T19:53:24.421470485Z,2018-05-22T19:54:24.421470485Z,2018-05-22T19:53:56Z,0,usage_guest_nice,cpu,cpu-total,host.local
+,,1,2018-05-22T19:53:24.421470485Z,2018-05-22T19:54:24.421470485Z,2018-05-22T19:54:06Z,0,usage_guest_nice,cpu,cpu-total,host.local
+,,1,2018-05-22T19:53:24.421470485Z,2018-05-22T19:54:24.421470485Z,2018-05-22T19:54:16Z,0,usage_guest_nice,cpu,cpu-total,host.local

query/functions/testdata/duplicate.out.csv

@@ -0,0 +1,17 @@
+#datatype,string,long,dateTime:RFC3339,dateTime:RFC3339,dateTime:RFC3339,double,string,string,string,string,string
+#group,false,false,false,false,false,false,true,true,true,true,false
+#default,_result,,,,,,,,,,
+,result,table,_start,_stop,_time,_value,_field,_measurement,cpu,host,host_new
+,,0,2018-05-22T19:53:26Z,2018-05-22T19:54:24.421470485Z,2018-05-22T19:53:26Z,0,usage_guest,cpu,cpu-total,host.local,host.local
+,,0,2018-05-22T19:53:26Z,2018-05-22T19:54:24.421470485Z,2018-05-22T19:53:36Z,0,usage_guest,cpu,cpu-total,host.local,host.local
+,,0,2018-05-22T19:53:26Z,2018-05-22T19:54:24.421470485Z,2018-05-22T19:53:46Z,0,usage_guest,cpu,cpu-total,host.local,host.local
+,,0,2018-05-22T19:53:26Z,2018-05-22T19:54:24.421470485Z,2018-05-22T19:53:56Z,0,usage_guest,cpu,cpu-total,host.local,host.local
+,,0,2018-05-22T19:53:26Z,2018-05-22T19:54:24.421470485Z,2018-05-22T19:54:06Z,0,usage_guest,cpu,cpu-total,host.local,host.local
+,,0,2018-05-22T19:53:26Z,2018-05-22T19:54:24.421470485Z,2018-05-22T19:54:16Z,0,usage_guest,cpu,cpu-total,host.local,host.local
+,,1,2018-05-22T19:53:26Z,2018-05-22T19:54:24.421470485Z,2018-05-22T19:53:26Z,0,usage_guest_nice,cpu,cpu-total,host.local,host.local
+,,1,2018-05-22T19:53:26Z,2018-05-22T19:54:24.421470485Z,2018-05-22T19:53:36Z,0,usage_guest_nice,cpu,cpu-total,host.local,host.local
+,,1,2018-05-22T19:53:26Z,2018-05-22T19:54:24.421470485Z,2018-05-22T19:53:46Z,0,usage_guest_nice,cpu,cpu-total,host.local,host.local
+,,1,2018-05-22T19:53:26Z,2018-05-22T19:54:24.421470485Z,2018-05-22T19:53:56Z,0,usage_guest_nice,cpu,cpu-total,host.local,host.local
+,,1,2018-05-22T19:53:26Z,2018-05-22T19:54:24.421470485Z,2018-05-22T19:54:06Z,0,usage_guest_nice,cpu,cpu-total,host.local,host.local
+,,1,2018-05-22T19:53:26Z,2018-05-22T19:54:24.421470485Z,2018-05-22T19:54:16Z,0,usage_guest_nice,cpu,cpu-total,host.local,host.local
+