expr

package
v0.0.0-...-34898ab Latest Latest
Warning

This package is not in the latest version of its module.

 Go to latest Published: Jan 30, 2024 License: Apache-2.0 Imports: 23 Imported by: 0

Documentation

Index

Constants

View Source 
const DatasourceID = -100

DatasourceID is the fake datasource id used in requests to identify it as an expression command.

View Source 
const DatasourceName = "__expr__"

DatasourceName is the string constant used as the datasource name in requests to identify it as an expression command.

View Source 
const DatasourceUID = "-100"

DatasourceUID is the fake datasource uid used in requests to identify it as an expression command.

Variables

This section is empty.

Functions

func QueryData 

func QueryData(ctx context.Context, req *backend.QueryDataRequest) (*backend.QueryDataResponse, error)

QueryData is called used to query datasources that are not expression commands, but are used alongside expressions and/or are the input of an expression command.

func WideToMany 

func WideToMany(frame *data.Frame) ([]mathexp.Series, error)

WideToMany converts a data package wide type Frame to one or multiple Series. A series is created for each value type column of wide frame.

This might not be a good idea long term, but works now as an adapter/shim.

Types

type CMDNode 

type CMDNode struct {
	CMDType CommandType
	Command Command
	// contains filtered or unexported fields
}

CMDNode is a DPNode that holds an expression command.

func (*CMDNode) Execute 

func (gn *CMDNode) Execute(ctx context.Context, vars mathexp.Vars) (mathexp.Results, error)

Execute runs the node and adds the results to vars. If the node requires other nodes they must have already been executed and their results must already by in vars.

func (*CMDNode) ID 

func (b *CMDNode) ID() int64

ID returns the id of the node so it can fulfill the gonum's graph Node interface.

func (*CMDNode) NodeType 

func (gn *CMDNode) NodeType() NodeType

NodeType returns the data pipeline node type.

func (*CMDNode) RefID 

func (b *CMDNode) RefID() string

RefID returns the refId of the node.

func (*CMDNode) String 

func (b *CMDNode) String() string

String returns a string representation of the node. In particular for %v formating in error messages.

type Command 

type Command interface {
	NeedsVars() []string
	Execute(c context.Context, vars mathexp.Vars) (mathexp.Results, error)
}

Command is an interface for all expression commands.

type CommandType 

type CommandType int

CommandType is the type of the expression command. 

const (
	// TypeUnknown is the CMDType for an unrecognized expression type.
	TypeUnknown CommandType = iota
	// TypeMath is the CMDType for a math expression.
	TypeMath
	// TypeReduce is the CMDType for a reduction expression.
	TypeReduce
	// TypeResample is the CMDType for a resampling expression.
	TypeResample
	// TypeClassicConditions is the CMDType for the classic condition operation.
	TypeClassicConditions
)

func ParseCommandType 

func ParseCommandType(s string) (CommandType, error)

ParseCommandType returns a CommandType from its string representation.

func (CommandType) String 

func (gt CommandType) String() string

type DSNode 

type DSNode struct {
	// contains filtered or unexported fields
}

DSNode is a DPNode that holds a datasource request.

func (*DSNode) Execute 

func (dn *DSNode) Execute(ctx context.Context, vars mathexp.Vars) (mathexp.Results, error)

Execute runs the node and adds the results to vars. If the node requires other nodes they must have already been executed and their results must already by in vars.

func (*DSNode) ID 

func (b *DSNode) ID() int64

ID returns the id of the node so it can fulfill the gonum's graph Node interface.

func (*DSNode) NodeType 

func (dn *DSNode) NodeType() NodeType

NodeType returns the data pipeline node type.

func (*DSNode) RefID 

func (b *DSNode) RefID() string

RefID returns the refId of the node.

func (*DSNode) String 

func (b *DSNode) String() string

String returns a string representation of the node. In particular for %v formating in error messages.

type DataPipeline 

type DataPipeline []Node

DataPipeline is an ordered set of nodes returned from DPGraph processing.

type MathCommand 

type MathCommand struct {
	RawExpression string
	Expression    *mathexp.Expr
	// contains filtered or unexported fields
}

MathCommand is a command for a math expression such as "1 + $GA / 2"

func NewMathCommand 

func NewMathCommand(refID, expr string) (*MathCommand, error)

NewMathCommand creates a new MathCommand. It will return an error if there is an error parsing expr.

func UnmarshalMathCommand 

func UnmarshalMathCommand(rn *rawNode) (*MathCommand, error)

UnmarshalMathCommand creates a MathCommand from Grafarg's frontend query.

func (*MathCommand) Execute 

func (gm *MathCommand) Execute(ctx context.Context, vars mathexp.Vars) (mathexp.Results, error)

Execute runs the command and returns the results or an error if the command failed to execute.

func (*MathCommand) NeedsVars 

func (gm *MathCommand) NeedsVars() []string

NeedsVars returns the variable names (refIds) that are dependencies to execute the command and allows the command to fulfill the Command interface.

type Node 

type Node interface {
	ID() int64 // ID() allows the gonum graph node interface to be fulfilled
	NodeType() NodeType
	RefID() string
	Execute(c context.Context, vars mathexp.Vars) (mathexp.Results, error)
	String() string
}

Node is a node in a Data Pipeline. Node is either a expression command or a datasource query.

type NodeType 

type NodeType int

NodeType is the type of a DPNode. Currently either a expression command or datasource query. 

const (
	// TypeCMDNode is a NodeType for expression commands.
	TypeCMDNode NodeType = iota
	// TypeDatasourceNode is a NodeType for datasource queries.
	TypeDatasourceNode
)

type ReduceCommand 

type ReduceCommand struct {
	Reducer     string
	VarToReduce string
	// contains filtered or unexported fields
}

ReduceCommand is an expression command for reduction of a timeseries such as a min, mean, or max.

func NewReduceCommand 

func NewReduceCommand(refID, reducer, varToReduce string) *ReduceCommand

NewReduceCommand creates a new ReduceCMD.

func UnmarshalReduceCommand 

func UnmarshalReduceCommand(rn *rawNode) (*ReduceCommand, error)

UnmarshalReduceCommand creates a MathCMD from Grafarg's frontend query.

func (*ReduceCommand) Execute 

func (gr *ReduceCommand) Execute(ctx context.Context, vars mathexp.Vars) (mathexp.Results, error)

Execute runs the command and returns the results or an error if the command failed to execute.

func (*ReduceCommand) NeedsVars 

func (gr *ReduceCommand) NeedsVars() []string

NeedsVars returns the variable names (refIds) that are dependencies to execute the command and allows the command to fulfill the Command interface.

type ResampleCommand 

type ResampleCommand struct {
	Window        time.Duration
	VarToResample string
	Downsampler   string
	Upsampler     string
	TimeRange     backend.TimeRange
	// contains filtered or unexported fields
}

ResampleCommand is an expression command for resampling of a timeseries.

func NewResampleCommand 

func NewResampleCommand(refID, rawWindow, varToResample string, downsampler string, upsampler string, tr backend.TimeRange) (*ResampleCommand, error)

NewResampleCommand creates a new ResampleCMD.

func UnmarshalResampleCommand 

func UnmarshalResampleCommand(rn *rawNode) (*ResampleCommand, error)

UnmarshalResampleCommand creates a ResampleCMD from Grafarg's frontend query.

func (*ResampleCommand) Execute 

func (gr *ResampleCommand) Execute(ctx context.Context, vars mathexp.Vars) (mathexp.Results, error)

Execute runs the command and returns the results or an error if the command failed to execute.

func (*ResampleCommand) NeedsVars 

func (gr *ResampleCommand) NeedsVars() []string

NeedsVars returns the variable names (refIds) that are dependencies to execute the command and allows the command to fulfill the Command interface.

type Service 

type Service struct {
	Cfg *setting.Cfg
}

Service is service representation for expression handling.

func (*Service) BuildPipeline 

func (s *Service) BuildPipeline(req *backend.QueryDataRequest) (DataPipeline, error)

BuildPipeline builds a pipeline from a request.

func (*Service) ExecutePipeline 

func (s *Service) ExecutePipeline(ctx context.Context, pipeline DataPipeline) (*backend.QueryDataResponse, error)

ExecutePipeline executes an expression pipeline and returns all the results.

func (*Service) TransformData 

func (s *Service) TransformData(ctx context.Context, req *backend.QueryDataRequest) (r *backend.QueryDataResponse, err error)

TransformData takes Queries which are either expressions nodes or are datasource requests.

func (*Service) WrapTransformData 

func (s *Service) WrapTransformData(ctx context.Context, query *tsdb.TsdbQuery) (*tsdb.Response, error)

WrapTransformData creates and executes transform requests

Source Files

View all Source files

Directories

Path Synopsis
parse
Package parse builds parse trees for expressions as defined by expr.
 Package parse builds parse trees for expressions as defined by expr.

Jump to

Keyboard shortcuts

? : This menu
/ : Search site
f or F : Jump to
y or Y : Canonical URL
go.dev uses cookies from Google to deliver and enhance the quality of its services and to analyze traffic. Learn more.