influxdb/query/influxql/function.go

416 lines
10 KiB
Go

package influxql
import (
"errors"
"fmt"
"time"
"github.com/influxdata/flux/ast"
"github.com/influxdata/flux/execute"
"github.com/influxdata/influxql"
)
func isTransformation(expr influxql.Expr) bool {
if call, ok := expr.(*influxql.Call); ok {
switch call.Name {
// TODO(ethan): more to be added here.
case "difference", "derivative", "cumulative_sum", "elapsed":
return true
}
}
return false
}
// function contains the prototype for invoking a function.
// TODO(jsternberg): This should do a lot more heavy lifting, but it mostly just
// pre-validates that we know the function exists. The cursor creation should be
// done by this struct, but it isn't at the moment.
type function struct {
Ref *influxql.VarRef
call *influxql.Call
}
// parseFunction parses a call AST and creates the function for it.
func parseFunction(expr *influxql.Call) (*function, error) {
switch expr.Name {
case "count":
if exp, got := 1, len(expr.Args); exp != got {
return nil, fmt.Errorf("invalid number of arguments for %s, expected %d, got %d", expr.Name, exp, got)
}
switch ref := expr.Args[0].(type) {
case *influxql.VarRef:
return &function{
Ref: ref,
call: expr,
}, nil
case *influxql.Call:
if ref.Name == "distinct" {
return nil, errors.New("unimplemented: count(distinct)")
}
return nil, fmt.Errorf("expected field argument in %s()", expr.Name)
case *influxql.Distinct:
return nil, errors.New("unimplemented: count(distinct)")
case *influxql.Wildcard:
return nil, errors.New("unimplemented: wildcard function")
case *influxql.RegexLiteral:
return nil, errors.New("unimplemented: wildcard regex function")
default:
return nil, fmt.Errorf("expected field argument in %s()", expr.Name)
}
case "min", "max", "sum", "first", "last", "mean", "median", "difference", "stddev", "spread":
if exp, got := 1, len(expr.Args); exp != got {
return nil, fmt.Errorf("invalid number of arguments for %s, expected %d, got %d", expr.Name, exp, got)
}
switch ref := expr.Args[0].(type) {
case *influxql.VarRef:
return &function{
Ref: ref,
call: expr,
}, nil
case *influxql.Wildcard:
return nil, errors.New("unimplemented: wildcard function")
case *influxql.RegexLiteral:
return nil, errors.New("unimplemented: wildcard regex function")
default:
return nil, fmt.Errorf("expected field argument in %s()", expr.Name)
}
case "percentile":
if exp, got := 2, len(expr.Args); exp != got {
return nil, fmt.Errorf("invalid number of arguments for %s, expected %d, got %d", expr.Name, exp, got)
}
var functionRef *influxql.VarRef
switch ref := expr.Args[0].(type) {
case *influxql.VarRef:
functionRef = ref
case *influxql.Wildcard:
return nil, errors.New("unimplemented: wildcard function")
case *influxql.RegexLiteral:
return nil, errors.New("unimplemented: wildcard regex function")
default:
return nil, fmt.Errorf("expected field argument in %s()", expr.Name)
}
switch expr.Args[1].(type) {
case *influxql.IntegerLiteral:
case *influxql.NumberLiteral:
default:
return nil, fmt.Errorf("expected float argument in %s()", expr.Name)
}
return &function{
Ref: functionRef,
call: expr,
}, nil
default:
return nil, fmt.Errorf("unimplemented function: %q", expr.Name)
}
}
// createFunctionCursor creates a new cursor that calls a function on one of the columns
// and returns the result.
func createFunctionCursor(t *transpilerState, call *influxql.Call, in cursor, normalize bool) (cursor, error) {
cur := &functionCursor{
call: call,
parent: in,
}
switch call.Name {
case "count", "min", "max", "sum", "first", "last", "mean", "difference", "stddev", "spread":
value, ok := in.Value(call.Args[0])
if !ok {
return nil, fmt.Errorf("undefined variable: %s", call.Args[0])
}
cur.expr = &ast.PipeExpression{
Argument: in.Expr(),
Call: &ast.CallExpression{
Callee: &ast.Identifier{
Name: call.Name,
},
},
}
cur.value = value
cur.exclude = map[influxql.Expr]struct{}{call.Args[0]: {}}
case "elapsed":
// TODO(ethan): https://github.com/influxdata/influxdb/issues/10733 to enable this.
value, ok := in.Value(call.Args[0])
if !ok {
return nil, fmt.Errorf("undefined variable: %s", call.Args[0])
}
unit := []ast.Duration{{
Magnitude: 1,
Unit: "ns",
}}
// elapsed has an optional unit parameter, default to 1ns
// https://docs.influxdata.com/influxdb/v1.7/query_language/functions/#elapsed
if len(call.Args) == 2 {
switch arg := call.Args[1].(type) {
case *influxql.DurationLiteral:
unit = durationLiteral(arg.Val)
default:
return nil, errors.New("argument unit must be a duration type")
}
}
cur.expr = &ast.PipeExpression{
Argument: in.Expr(),
Call: &ast.CallExpression{
Callee: &ast.Identifier{
Name: call.Name,
},
Arguments: []ast.Expression{
&ast.ObjectExpression{
Properties: []*ast.Property{
{
Key: &ast.Identifier{
Name: "unit",
},
Value: &ast.DurationLiteral{
Values: unit,
},
},
},
},
},
},
}
cur.value = value
case "median":
value, ok := in.Value(call.Args[0])
if !ok {
return nil, fmt.Errorf("undefined variable: %s", call.Args[0])
}
cur.expr = &ast.PipeExpression{
Argument: in.Expr(),
Call: &ast.CallExpression{
Callee: &ast.Identifier{
Name: "median",
},
Arguments: []ast.Expression{
&ast.ObjectExpression{
Properties: []*ast.Property{
{
Key: &ast.Identifier{
Name: "method",
},
Value: &ast.StringLiteral{
Value: "exact_mean",
},
},
},
},
},
},
}
cur.value = value
cur.exclude = map[influxql.Expr]struct{}{call.Args[0]: {}}
case "percentile":
if len(call.Args) != 2 {
return nil, errors.New("percentile function requires two arguments field_key and N")
}
fieldName, ok := in.Value(call.Args[0])
if !ok {
return nil, fmt.Errorf("undefined variable: %s", call.Args[0])
}
var percentile float64
switch arg := call.Args[1].(type) {
case *influxql.NumberLiteral:
percentile = arg.Val / 100.0
case *influxql.IntegerLiteral:
percentile = float64(arg.Val) / 100.0
default:
return nil, errors.New("argument N must be a float type")
}
if percentile < 0 || percentile > 1 {
return nil, errors.New("argument N must be between 0 and 100")
}
args := []*ast.Property{
{
Key: &ast.Identifier{
Name: "q",
},
Value: &ast.FloatLiteral{
Value: percentile,
},
},
{
Key: &ast.Identifier{
Name: "method",
},
Value: &ast.StringLiteral{
Value: "exact_selector",
},
},
}
if fieldName != execute.DefaultValueColLabel {
args = append(args, &ast.Property{
Key: &ast.Identifier{
Name: "columns",
},
Value: &ast.ArrayExpression{
Elements: []ast.Expression{
&ast.StringLiteral{Value: fieldName},
},
},
})
}
cur.expr = &ast.PipeExpression{
Argument: in.Expr(),
Call: &ast.CallExpression{
Callee: &ast.Identifier{
Name: "quantile",
},
Arguments: []ast.Expression{
&ast.ObjectExpression{
Properties: args,
},
},
},
}
cur.value = fieldName
cur.exclude = map[influxql.Expr]struct{}{call.Args[0]: {}}
default:
return nil, fmt.Errorf("unimplemented function: %q", call.Name)
}
// If we have been told to normalize the time, we do it here.
if normalize {
if influxql.IsSelector(call) {
cur.expr = &ast.PipeExpression{
Argument: cur.expr,
Call: &ast.CallExpression{
Callee: &ast.Identifier{
Name: "drop",
},
Arguments: []ast.Expression{
&ast.ObjectExpression{
Properties: []*ast.Property{{
Key: &ast.Identifier{
Name: "columns",
},
Value: &ast.ArrayExpression{
Elements: []ast.Expression{
&ast.StringLiteral{Value: execute.DefaultTimeColLabel},
},
},
}},
},
},
},
}
}
// err checked in caller
interval, _ := t.stmt.GroupByInterval()
var timeValue ast.Expression
if interval > 0 {
timeValue = &ast.MemberExpression{
Object: &ast.Identifier{
Name: "r",
},
Property: &ast.Identifier{
Name: execute.DefaultStartColLabel,
},
}
} else if isTransformation(call) || influxql.IsSelector(call) {
timeValue = &ast.MemberExpression{
Object: &ast.Identifier{
Name: "r",
},
Property: &ast.Identifier{
Name: execute.DefaultTimeColLabel,
},
}
} else {
valuer := influxql.NowValuer{Now: t.config.Now}
_, tr, err := influxql.ConditionExpr(t.stmt.Condition, &valuer)
if err != nil {
return nil, err
}
if tr.MinTime().UnixNano() == influxql.MinTime {
timeValue = &ast.DateTimeLiteral{Value: time.Unix(0, 0).UTC()}
} else {
timeValue = &ast.MemberExpression{
Object: &ast.Identifier{
Name: "r",
},
Property: &ast.Identifier{
Name: execute.DefaultStartColLabel,
},
}
}
}
cur.expr = &ast.PipeExpression{
Argument: cur.expr,
Call: &ast.CallExpression{
Callee: &ast.Identifier{
Name: "map",
},
Arguments: []ast.Expression{
&ast.ObjectExpression{
Properties: []*ast.Property{
{
Key: &ast.Identifier{
Name: "fn",
},
Value: &ast.FunctionExpression{
Params: []*ast.Property{{
Key: &ast.Identifier{Name: "r"},
}},
Body: &ast.ObjectExpression{
With: &ast.Identifier{Name: "r"},
Properties: []*ast.Property{{
Key: &ast.Identifier{Name: execute.DefaultTimeColLabel},
Value: timeValue,
}},
},
},
},
},
},
},
},
}
}
return cur, nil
}
type functionCursor struct {
expr ast.Expression
call *influxql.Call
value string
exclude map[influxql.Expr]struct{}
parent cursor
}
func (c *functionCursor) Expr() ast.Expression {
return c.expr
}
func (c *functionCursor) Keys() []influxql.Expr {
keys := []influxql.Expr{c.call}
if a := c.parent.Keys(); len(a) > 0 {
for _, e := range a {
if _, ok := c.exclude[e]; ok {
continue
}
keys = append(keys, e)
}
}
return keys
}
func (c *functionCursor) Value(expr influxql.Expr) (string, bool) {
if expr == c.call {
return c.value, true
} else if _, ok := c.exclude[expr]; ok {
return "", false
}
return c.parent.Value(expr)
}