Documentation
¶
Index ¶
- Constants
- func DataSourceModel() *models.DataSource
- func IsDataSource(uid string) bool
- func WideToMany(frame *data.Frame) ([]mathexp.Series, error)
- type CMDNode
- type Command
- type CommandType
- type DSNode
- type DataPipeline
- type MathCommand
- type Node
- type NodeType
- type Query
- type QueryError
- type ReduceCommand
- type Request
- type ResampleCommand
- type Service
- type TimeRange
Constants ¶
const DatasourceID = -100
DatasourceID is the fake datasource id used in requests to identify it as an expression command.
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.
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.
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() *models.DataSource
func IsDataSource ¶
IsDataSource checks if the uid points to an expression query
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, s *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.
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, s *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 (*DSNode) ID ¶
func (b *DSNode) ID() int64
ID returns the id of the node so it can fulfill the gonum's graph Node interface.
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 ¶
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, 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.
type Query ¶
type Query struct {
RefID string
TimeRange TimeRange
DataSource *models.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 ¶
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 ¶
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 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 ¶
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 (*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, 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 *Request) (r *backend.QueryDataResponse, err error)
TransformData takes Queries which are either expressions nodes or are datasource requests.
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