graph

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 Go to latest Published: Aug 24, 2020 License: Apache-2.0 Imports: 10 Imported by: 0

Documentation

Overview

Package graph is the internal representation of the Beam execution plan. This package is used by the public-facing Beam package to organize the user's pipeline into a connected graph structure. This graph is a precise, strongly-typed representation of the user's intent, and allows the runtime to verify typing of collections, and tracks the data dependency relationships to allow an optimizer to schedule the work.

Index

Constants

View Source 
const (
	MainUnknown mainInputs = -1 // Number of inputs is unknown for DoFn validation.
	MainSingle  mainInputs = 1  // Number of inputs for single value elements.
	MainKv      mainInputs = 2  // Number of inputs for KV elements.
)

The following constants prefixed with "Main" represent valid numbers of DoFn main inputs for DoFn construction and validation.

View Source 
const CombinePerKeyScope = "CombinePerKey"

CombinePerKeyScope is the Go SDK canonical name for the combine composite scope. With Beam Portability, "primitive" composite transforms like combine have their URNs & payloads attached to a high level scope, with a default representation beneath. The use of this const permits the translation layer to confirm the SDK expects this combine to be liftable by a runner and should set this scope's URN and Payload accordingly.

Variables

This section is empty.

Functions

func Bounded 

func Bounded(ns []*Node) bool

Bounded returns true iff all nodes are bounded.

func CoGBKMainInput 

func CoGBKMainInput(components int) func(*config)

CoGBKMainInput is an optional config to NewDoFn which specifies the number of components of a CoGBK input to the DoFn being created, allowing for more complete validation.

Example usage: 

var col beam.PCollection
graph.NewDoFn(fn, graph.CoGBKMainInput(len(col.Type().Components())))

func NodeTypes 

func NodeTypes(list []*Node) []typex.FullType

NodeTypes returns the fulltypes of the supplied slice of nodes.

func NumMainInputs 

func NumMainInputs(num mainInputs) func(*config)

NumMainInputs is an optional config to NewDoFn which specifies the number of main inputs to the DoFn being created, allowing for more complete validation. Valid inputs are the package constants of type mainInputs.

Example usage: 

graph.NewDoFn(fn, graph.NumMainInputs(graph.MainKv))

Types

type CombineFn 

type CombineFn Fn

CombineFn represents a CombineFn.

func AsCombineFn 

func AsCombineFn(fn *Fn) (*CombineFn, error)

AsCombineFn converts a Fn to a CombineFn, if possible.

func NewCombineFn 

func NewCombineFn(fn interface{}) (*CombineFn, error)

NewCombineFn constructs a CombineFn from the given value, if possible.

func (*CombineFn) AddInputFn 

func (f *CombineFn) AddInputFn() *funcx.Fn

AddInputFn returns the "AddInput" function, if present.

func (*CombineFn) CompactFn 

func (f *CombineFn) CompactFn() *funcx.Fn

CompactFn returns the "Compact" function, if present.

func (*CombineFn) CreateAccumulatorFn 

func (f *CombineFn) CreateAccumulatorFn() *funcx.Fn

CreateAccumulatorFn returns the "CreateAccumulator" function, if present.

func (*CombineFn) ExtractOutputFn 

func (f *CombineFn) ExtractOutputFn() *funcx.Fn

ExtractOutputFn returns the "ExtractOutput" function, if present.

func (*CombineFn) MergeAccumulatorsFn 

func (f *CombineFn) MergeAccumulatorsFn() *funcx.Fn

MergeAccumulatorsFn returns the "MergeAccumulators" function. If it is the only method present, then InputType == AccumulatorType == OutputType.

func (*CombineFn) Name 

func (f *CombineFn) Name() string

Name returns the name of the function or struct.

func (*CombineFn) SetupFn 

func (f *CombineFn) SetupFn() *funcx.Fn

SetupFn returns the "Setup" function, if present.

func (*CombineFn) TeardownFn 

func (f *CombineFn) TeardownFn() *funcx.Fn

TeardownFn returns the "Teardown" function, if present.

type DoFn 

type DoFn Fn

DoFn represents a DoFn.

func AsDoFn 

func AsDoFn(fn *Fn, numMainIn mainInputs) (*DoFn, error)

AsDoFn converts a Fn to a DoFn, if possible. numMainIn specifies how many main inputs are expected in the DoFn's method signatures. Valid inputs are the package constants of type mainInputs. If that number is MainUnknown then validation is done by best effort and may miss some edge cases.

func NewDoFn 

func NewDoFn(fn interface{}, options ...func(*config)) (*DoFn, error)

NewDoFn constructs a DoFn from the given value, if possible.

func (*DoFn) FinishBundleFn 

func (f *DoFn) FinishBundleFn() *funcx.Fn

FinishBundleFn returns the "FinishBundle" function, if present.

func (*DoFn) IsSplittable 

func (f *DoFn) IsSplittable() bool

IsSplittable returns whether the DoFn is a valid Splittable DoFn.

func (*DoFn) Name 

func (f *DoFn) Name() string

Name returns the name of the function or struct.

func (*DoFn) ProcessElementFn 

func (f *DoFn) ProcessElementFn() *funcx.Fn

ProcessElementFn returns the "ProcessElement" function.

func (*DoFn) SetupFn 

func (f *DoFn) SetupFn() *funcx.Fn

SetupFn returns the "Setup" function, if present.

func (*DoFn) StartBundleFn 

func (f *DoFn) StartBundleFn() *funcx.Fn

StartBundleFn returns the "StartBundle" function, if present.

func (*DoFn) TeardownFn 

func (f *DoFn) TeardownFn() *funcx.Fn

TeardownFn returns the "Teardown" function, if present.

type DynFn 

type DynFn struct {
	// Name is the name of the function. It does not have to be a valid symbol.
	Name string
	// T is the type of the generated function
	T reflect.Type
	// Data holds the data, if any, for the generator. Each function
	// generator typically needs some configuration data, which is
	// required by the DynFn to be encoded.
	Data []byte
	// Gen is the function generator. The function generator itself must be a
	// function with a unique symbol.
	Gen func(string, reflect.Type, []byte) reflectx.Func
}

DynFn is a generator for dynamically-created functions: 

gen: (name string, t reflect.Type, []byte) -> func : T

where the generated function, fn : T, is re-created at runtime. This concept allows serialization of dynamically-generated functions, which do not have a valid (unique) symbol such as one created via reflect.MakeFunc.

type Fn 

type Fn struct {
	// Fn holds the function, if present. If Fn is nil, Recv must be
	// non-nil.
	Fn *funcx.Fn
	// Recv hold the struct receiver, if present. If Recv is nil, Fn
	// must be non-nil.
	Recv interface{}
	// DynFn holds the function-generator, if dynamic. If not nil, Fn
	// holds the generated function.
	DynFn *DynFn
	// contains filtered or unexported fields
}

Fn holds either a function or struct receiver.

func NewFn 

func NewFn(fn interface{}) (*Fn, error)

NewFn pre-processes a function, dynamic function or struct for graph construction.

func (*Fn) Name 

func (f *Fn) Name() string

Name returns the name of the function or struct.

type Graph 

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

Graph represents an in-progress deferred execution graph and is easily translatable to the model graph. This graph representation allows precise control over scope and connectivity.

func New 

func New() *Graph

New returns an empty graph with the scope set to the root.

func (*Graph) Build 

func (g *Graph) Build() ([]*MultiEdge, []*Node, error)

Build performs finalization on the graph. It verifies the correctness of the graph structure, typechecks the plan and returns a slice of the edges in the graph.

func (*Graph) NewEdge 

func (g *Graph) NewEdge(parent *Scope) *MultiEdge

NewEdge creates a new edge of the graph in the supplied scope.

func (*Graph) NewNode 

func (g *Graph) NewNode(t typex.FullType, w *window.WindowingStrategy, bounded bool) *Node

NewNode creates a new node in the graph of the supplied fulltype.

func (*Graph) NewScope 

func (g *Graph) NewScope(parent *Scope, name string) *Scope

NewScope creates and returns a new scope that is a child of the supplied scope.

func (*Graph) Root 

func (g *Graph) Root() *Scope

Root returns the root scope of the graph.

func (*Graph) String 

func (g *Graph) String() string

type Inbound 

type Inbound struct {
	// Kind presents the form of the data that the edge expects. Main input
	// must be processed element-wise, but side input may take several
	// convenient forms. For example, a DoFn that processes ints may choose
	// among the following parameter types:
	//
	//   * Main:      int
	//   * Singleton: int
	//   * Slice:     []int
	//   * Iter:      func(*int) bool
	//   * ReIter:    func() func(*int) bool
	//
	// If the DoFn is generic then int may be replaced by any of the type
	// variables. For example,
	//
	//   * Slice:     []typex.T
	//   * Iter:      func(*typex.X) bool
	//
	// If the input type is KV<int,string>, say, then the options are:
	//
	//   * Main:      int, string  (as two separate parameters)
	//   * Map:       map[int]string
	//   * MultiMap:  map[int][]string
	//   * Iter:      func(*int, *string) bool
	//   * ReIter:    func() func(*int, *string) bool
	//
	// As above, either int, string, or both can be replaced with type
	// variables. For example,
	//
	//   * Map:       map[typex.X]typex.Y
	//   * MultiMap:  map[typex.T][]string
	//   * Iter:      func(*typex.Z, *typex.Z) bool
	//
	// Note that in the last case the parameter type requires that both
	// the key and value types are identical. Bind enforces such constraints.
	Kind InputKind

	// From is the incoming node in the graph.
	From *Node

	// Type is the fulltype matching the actual type used by the transform.
	// Due to the loose signatures of DoFns, we can only determine the
	// inbound structure when the fulltypes of the incoming links are present.
	// For example,
	//
	//     func (ctx context.Context, key int, value typex.X) error
	//
	// is a generic DoFn that if bound to KV<int,string> would have one
	// Inbound link with type KV<int, X>.
	Type typex.FullType
}

Inbound represents an inbound data link from a Node.

func (*Inbound) String 

func (i *Inbound) String() string

type InputKind 

type InputKind string

InputKind represents the role of the input and its shape. 

const (
	Main      InputKind = "Main"
	Singleton InputKind = "Singleton"
	Slice     InputKind = "Slice"
	Map       InputKind = "Map"      // TODO: allow?
	MultiMap  InputKind = "MultiMap" // TODO: allow?
	Iter      InputKind = "Iter"
	ReIter    InputKind = "ReIter"
)

Valid input kinds.

func Bind 

func Bind(fn *funcx.Fn, typedefs map[string]reflect.Type, in ...typex.FullType) ([]typex.FullType, []InputKind, []typex.FullType, []typex.FullType, error)

Bind returns the inbound, outbound and underlying output types for a Fn, when bound to the underlying input types. The complication of bind is primarily that UserFns have loose signatures and bind must produce valid type information for the execution plan.

For example, 

func (t EventTime, k typex.X, v int, emit func(string, typex.X))

or 

func (context.Context, k typex.X, v int) (string, typex.X, error)

are UserFns that may take one or two incoming fulltypes: either KV<X,int> or X with a singleton side input of type int. For the purpose of the shape of data processing, the two forms are equivalent. The non-data types, context.Context and error, are not part of the data signature, but in play only at runtime.

If either was bound to the input type [KV<string,int>], bind would return: 

inbound:  [Main: KV<X,int>]
outbound: [KV<string,X>]
output:   [KV<string,string>]

Note that it propagates the assignment of X to string in the output type.

If either was instead bound to the input fulltypes [float, int], the result would be: 

inbound:  [Main: X, Singleton: int]
outbound: [KV<string,X>]
output:   [KV<string, float>]

Here, the inbound shape and output types are different from before.

type MultiEdge 

type MultiEdge struct {
	Op               Opcode
	DoFn             *DoFn        // ParDo
	RestrictionCoder *coder.Coder // SplittableParDo
	CombineFn        *CombineFn   // Combine
	AccumCoder       *coder.Coder // Combine
	Value            []byte       // Impulse
	Payload          *Payload     // External
	WindowFn         *window.Fn   // WindowInto

	Input  []*Inbound
	Output []*Outbound
	// contains filtered or unexported fields
}

MultiEdge represents a primitive data processing operation. Each non-user code operation may be implemented by either the harness or the runner.

func NewCoGBK 

func NewCoGBK(g *Graph, s *Scope, ns []*Node) (*MultiEdge, error)

NewCoGBK inserts a new CoGBK edge into the graph.

func NewCombine 

func NewCombine(g *Graph, s *Scope, u *CombineFn, in *Node, ac *coder.Coder, typedefs map[string]reflect.Type) (*MultiEdge, error)

NewCombine inserts a new Combine edge into the graph. Combines cannot have side input.

func NewExternal 

func NewExternal(g *Graph, s *Scope, payload *Payload, in []*Node, out []typex.FullType, bounded bool) *MultiEdge

NewExternal inserts an External transform. The system makes no assumptions about what this transform might do.

func NewFlatten 

func NewFlatten(g *Graph, s *Scope, in []*Node) (*MultiEdge, error)

NewFlatten inserts a new Flatten edge in the graph. Flatten output type is the shared input type.

func NewImpulse 

func NewImpulse(g *Graph, s *Scope, value []byte) *MultiEdge

NewImpulse inserts a new Impulse edge into the graph. It must use the built-in bytes coder.

func NewParDo 

func NewParDo(g *Graph, s *Scope, u *DoFn, in []*Node, rc *coder.Coder, typedefs map[string]reflect.Type) (*MultiEdge, error)

NewParDo inserts a new ParDo edge into the graph.

func NewReshuffle 

func NewReshuffle(g *Graph, s *Scope, in *Node) (*MultiEdge, error)

NewReshuffle inserts a new Reshuffle edge into the graph.

func NewWindowInto 

func NewWindowInto(g *Graph, s *Scope, wfn *window.Fn, in *Node) *MultiEdge

NewWindowInto inserts a new WindowInto edge into the graph.

func (*MultiEdge) ID 

func (e *MultiEdge) ID() int

ID returns the graph-local identifier for the edge.

func (*MultiEdge) Name 

func (e *MultiEdge) Name() string

Name returns a not-necessarily-unique name for the edge.

func (*MultiEdge) Scope 

func (e *MultiEdge) Scope() *Scope

Scope return the scope.

func (*MultiEdge) String 

func (e *MultiEdge) String() string

type Node 

type Node struct {

	// Coder defines the data encoding. It can be changed, but must be of
	// the underlying type, t.
	Coder *coder.Coder
	// contains filtered or unexported fields
}

Node is a typed connector describing the data type and encoding. A node may have multiple inbound and outbound connections. The underlying type must be a complete type, i.e., not include any type variables.

func (*Node) Bounded 

func (n *Node) Bounded() bool

Bounded returns true iff the collection is bounded.

func (*Node) ID 

func (n *Node) ID() int

ID returns the graph-local identifier for the node.

func (*Node) String 

func (n *Node) String() string

func (*Node) Type 

func (n *Node) Type() typex.FullType

Type returns the underlying full type of the data, such as KV<int,string>.

func (*Node) WindowingStrategy 

func (n *Node) WindowingStrategy() *window.WindowingStrategy

WindowingStrategy returns the window applied to the data.

type Opcode 

type Opcode string

Opcode represents a primitive Beam instruction kind. 

const (
	Impulse    Opcode = "Impulse"
	ParDo      Opcode = "ParDo"
	CoGBK      Opcode = "CoGBK"
	Reshuffle  Opcode = "Reshuffle"
	External   Opcode = "External"
	Flatten    Opcode = "Flatten"
	Combine    Opcode = "Combine"
	WindowInto Opcode = "WindowInto"
)

Valid opcodes.

type Outbound 

type Outbound struct {
	// To is the outgoing node in the graph.
	To *Node

	// Type is the fulltype matching the actual type used by the transform.
	// For DoFns, unlike inbound, the outbound types closely mimic the type
	// signature. For example,
	//
	//     func (ctx context.Context, emit func (key int, value typex.X)) error
	//
	// is a generic DoFn that produces one Outbound link of type KV<int,X>.
	Type typex.FullType // representation type of data
}

Outbound represents an outbound data link to a Node.

func (*Outbound) String 

func (o *Outbound) String() string

type Payload 

type Payload struct {
	URN  string
	Data []byte
}

Payload represents an external payload.

type Scope 

type Scope struct {

	// Label is the human-visible label for this scope.
	Label string
	// Parent is the parent scope, if nested.
	Parent *Scope
	// contains filtered or unexported fields
}

Scope is a syntactic Scope, such as arising from a composite Transform. It has no semantic meaning at execution time. Used by monitoring.

func (*Scope) ID 

func (s *Scope) ID() int

ID returns the graph-local identifier for the scope.

func (*Scope) String 

func (s *Scope) String() string

type SplittableDoFn 

type SplittableDoFn DoFn

SplittableDoFn represents a DoFn implementing SDF methods.

func (*SplittableDoFn) CreateInitialRestrictionFn 

func (f *SplittableDoFn) CreateInitialRestrictionFn() *funcx.Fn

CreateInitialRestrictionFn returns the "CreateInitialRestriction" function, if present.

func (*SplittableDoFn) CreateTrackerFn 

func (f *SplittableDoFn) CreateTrackerFn() *funcx.Fn

CreateTrackerFn returns the "CreateTracker" function, if present.

func (*SplittableDoFn) Name 

func (f *SplittableDoFn) Name() string

Name returns the name of the function or struct.

func (*SplittableDoFn) RestrictionSizeFn 

func (f *SplittableDoFn) RestrictionSizeFn() *funcx.Fn

RestrictionSizeFn returns the "RestrictionSize" function, if present.

func (*SplittableDoFn) RestrictionT 

func (f *SplittableDoFn) RestrictionT() reflect.Type

RestrictionT returns the restriction type from the SDF.

func (*SplittableDoFn) SplitRestrictionFn 

func (f *SplittableDoFn) SplitRestrictionFn() *funcx.Fn

SplitRestrictionFn returns the "SplitRestriction" function, if present.

Source Files

View all Source files

Directories

Path Synopsis
Package coder contains coder representation and utilities.
 Package coder contains coder representation and utilities.
Package mtime contains a millisecond representation of time.
 Package mtime contains a millisecond representation of time.
Package window contains window representation, windowing strategies and utilities.
 Package window contains window representation, windowing strategies and utilities.

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