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* Under feature flag `sqlExpressions` and is experimental * Excluded from arm32 * Will not work with the Query Service yet * Does not have limits in place yet * Does not working with alerting yet * Currently requires "prepare time series" Transform for time series viz --------- Co-authored-by: Sam Jewell <sam.jewell@grafana.com>
127 lines
2.8 KiB
Go
127 lines
2.8 KiB
Go
//go:build !arm
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package sql
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import (
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"io"
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"strings"
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mysql "github.com/dolthub/go-mysql-server/sql"
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"github.com/grafana/grafana-plugin-sdk-go/data"
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)
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// FrameTable fulfills the mysql.Table interface for a data.Frame.
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type FrameTable struct {
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Frame *data.Frame
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schema mysql.Schema
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}
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// Name implements the sql.Nameable interface
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func (ft *FrameTable) Name() string {
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return ft.Frame.RefID
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}
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// String implements the fmt.Stringer interface
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func (ft *FrameTable) String() string {
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return ft.Name()
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}
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func schemaFromFrame(frame *data.Frame) mysql.Schema {
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schema := make(mysql.Schema, len(frame.Fields))
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for i, field := range frame.Fields {
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schema[i] = &mysql.Column{
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Name: field.Name,
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Type: convertDataType(field.Type()),
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Nullable: field.Type().Nullable(),
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Source: strings.ToLower(frame.RefID),
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}
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}
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return schema
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}
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// Schema implements the mysql.Table interface
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func (ft *FrameTable) Schema() mysql.Schema {
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if ft.schema == nil {
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ft.schema = schemaFromFrame(ft.Frame)
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}
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return ft.schema
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}
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// Collation implements the mysql.Table interface
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func (ft *FrameTable) Collation() mysql.CollationID {
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return mysql.Collation_Unspecified
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}
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// Partitions implements the mysql.Table interface
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func (ft *FrameTable) Partitions(ctx *mysql.Context) (mysql.PartitionIter, error) {
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return &noopPartitionIter{}, nil
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}
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// PartitionRows implements the mysql.Table interface
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func (ft *FrameTable) PartitionRows(ctx *mysql.Context, _ mysql.Partition) (mysql.RowIter, error) {
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return &rowIter{ft: ft, row: 0}, nil
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}
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type rowIter struct {
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ft *FrameTable
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row int
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}
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func (ri *rowIter) Next(_ *mysql.Context) (mysql.Row, error) {
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// We assume each field in the Frame has the same number of rows.
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numRows := 0
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if len(ri.ft.Frame.Fields) > 0 {
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numRows = ri.ft.Frame.Fields[0].Len()
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}
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// If we've already exhausted all rows, return EOF
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if ri.row >= numRows {
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return nil, io.EOF
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}
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// Construct a Row (which is []interface{} under the hood) by pulling
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// the value from each column at the current row index.
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row := make(mysql.Row, len(ri.ft.Frame.Fields))
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for colIndex, field := range ri.ft.Frame.Fields {
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if nilAt(*field, ri.row) {
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continue
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}
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row[colIndex], _ = field.ConcreteAt(ri.row)
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}
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ri.row++
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return row, nil
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}
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// Close implements the mysql.RowIter interface.
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// In this no-op example, there isn't anything to do here.
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func (ri *rowIter) Close(*mysql.Context) error {
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return nil
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}
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type noopPartitionIter struct {
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done bool
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}
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func (i *noopPartitionIter) Next(*mysql.Context) (mysql.Partition, error) {
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if !i.done {
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i.done = true
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return noopParition, nil
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}
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return nil, io.EOF
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}
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func (i *noopPartitionIter) Close(*mysql.Context) error {
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return nil
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}
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var noopParition = partition(nil)
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type partition []byte
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func (p partition) Key() []byte {
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return p
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}
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