expr

package
v0.0.0-cloud Latest Latest
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 Go to latest Published: Mar 30, 2023 License: AGPL-3.0 Imports: 20 Imported by: 0

Documentation

Index

Constants

View Source 
const (
	ThresholdIsAbove        = "gt"
	ThresholdIsBelow        = "lt"
	ThresholdIsWithinRange  = "within_range"
	ThresholdIsOutsideRange = "outside_range"
)
View Source 
const DatasourceID = -100

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

View Source 
const DatasourceType = "__expr__"

DatasourceType is the string constant used as the datasource when the property is in Datasource.Type. Type in requests is used to identify what type of data source plugin the request belongs to.

View Source 
const DatasourceUID = DatasourceType

DatasourceUID is the string constant used as the datasource name in requests to identify it as an expression command when use in Datasource.UID.

View Source 
const OldDatasourceUID = "-100"

OldDatasourceUID is the datasource uid used in requests to identify it as an expression command. It goes with the query root level datasourceUID property. It was accidentally set to the Id and is now kept for backwards compatibility. The newer Datasource.UID property should be used instead and should be set to "__expr__".

Variables

This section is empty.

Functions

func DataSourceModel 

func DataSourceModel() *datasources.DataSource

func IsDataSource 

func IsDataSource(uid string) bool

IsDataSource checks if the uid points to an expression query

func IsSupportedThresholdFunc 

func IsSupportedThresholdFunc(name string) bool

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 AbsoluteTimeRange 

type AbsoluteTimeRange struct {
	From time.Time
	To   time.Time
}

func (AbsoluteTimeRange) AbsoluteTime 

func (r AbsoluteTimeRange) AbsoluteTime(_ time.Time) backend.TimeRange

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, now time.Time, vars mathexp.Vars, _ *Service) (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 formatting in error messages.

type Command 

type Command interface {
	NeedsVars() []string
	Execute(ctx context.Context, now time.Time, 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
	// TypeThreshold is the CMDType for checking if a threshold has been crossed
	TypeThreshold
)

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 ConditionEvalJSON 

type ConditionEvalJSON struct {
	Params []float64 `json:"params"`
	Type   string    `json:"type"` // e.g. "gt"
}

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, now time.Time, _ mathexp.Vars, s *Service) (r mathexp.Results, e 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 formatting 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 Grafana's frontend query.

func (*MathCommand) Execute 

func (gm *MathCommand) Execute(_ context.Context, _ time.Time, 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(ctx context.Context, now time.Time, vars mathexp.Vars, s *Service) (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
)

func (NodeType) String 

func (nt NodeType) String() string

type Query 

type Query struct {
	RefID         string
	TimeRange     TimeRange
	DataSource    *datasources.DataSource `json:"datasource"`
	JSON          json.RawMessage
	Interval      time.Duration
	QueryType     string
	MaxDataPoints int64
}

Query is like plugins.DataSubQuery, but with a a time range, and only the UID for the data source. Also interval is a time.Duration.

type QueryError 

type QueryError struct {
	RefID string
	Err   error
}

func (QueryError) Error 

func (e QueryError) Error() string

func (QueryError) Unwrap 

func (e QueryError) Unwrap() error

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, mapper mathexp.ReduceMapper) (*ReduceCommand, error)

NewReduceCommand creates a new ReduceCMD.

func UnmarshalReduceCommand 

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

UnmarshalReduceCommand creates a MathCMD from Grafana's frontend query.

func (*ReduceCommand) Execute 

func (gr *ReduceCommand) Execute(_ context.Context, _ time.Time, 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 RelativeTimeRange 

type RelativeTimeRange struct {
	From time.Duration
	To   time.Duration
}

RelativeTimeRange is a time range relative to some absolute time.

func (RelativeTimeRange) AbsoluteTime 

func (r RelativeTimeRange) AbsoluteTime(t time.Time) backend.TimeRange

type Request 

type Request struct {
	Headers map[string]string
	Debug   bool
	OrgId   int64
	Queries []Query
	User    *backend.User
}

Request is similar to plugins.DataQuery but with the Time Ranges is per Query.

type ResampleCommand 

type ResampleCommand struct {
	Window        time.Duration
	VarToResample string
	Downsampler   string
	Upsampler     string
	TimeRange     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 TimeRange) (*ResampleCommand, error)

NewResampleCommand creates a new ResampleCMD.

func UnmarshalResampleCommand 

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

UnmarshalResampleCommand creates a ResampleCMD from Grafana's frontend query.

func (*ResampleCommand) Execute 

func (gr *ResampleCommand) Execute(_ context.Context, now time.Time, 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 {
	// contains filtered or unexported fields
}

Service is service representation for expression handling.

func ProvideService 

func ProvideService(cfg *setting.Cfg, pluginClient plugins.Client, dataSourceService datasources.DataSourceService) *Service

func (*Service) BuildPipeline 

func (s *Service) BuildPipeline(req *Request) (DataPipeline, error)

BuildPipeline builds a pipeline from a request.

func (*Service) ExecutePipeline 

func (s *Service) ExecutePipeline(ctx context.Context, now time.Time, 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, now time.Time, req *Request) (r *backend.QueryDataResponse, err error)

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

type ThresholdCommand 

type ThresholdCommand struct {
	ReferenceVar  string
	RefID         string
	ThresholdFunc string
	Conditions    []float64
}

func NewThresholdCommand 

func NewThresholdCommand(refID, referenceVar, thresholdFunc string, conditions []float64) (*ThresholdCommand, error)

func UnmarshalThresholdCommand 

func UnmarshalThresholdCommand(rn *rawNode) (*ThresholdCommand, error)

UnmarshalResampleCommand creates a ResampleCMD from Grafana's frontend query.

func (*ThresholdCommand) Execute 

func (tc *ThresholdCommand) Execute(ctx context.Context, now time.Time, vars mathexp.Vars) (mathexp.Results, error)

func (*ThresholdCommand) NeedsVars 

func (tc *ThresholdCommand) 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 ThresholdConditionJSON 

type ThresholdConditionJSON struct {
	Evaluator ConditionEvalJSON `json:"evaluator"`
}

type TimeRange 

type TimeRange interface {
	AbsoluteTime(now time.Time) backend.TimeRange
}

TimeRange is a time.Time based TimeRange.

Source Files

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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.

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